环境工程、给排水专业外文参考文献译文

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给排水专业外文翻译

History of Water SupplyMan’s search for pure water began in prehistoric times. Much of his earliest activity is subject to speculation. Some individuals might have led water where they wanted it through trenches dug in the earth, a hollow log was perhaps used as the first water pipe.Thousands of years must have passed before our more recent ancestors learned to build cities and enjoy the convenience of water pipes to the home and drains for water-carried wastes. Our earliest archeological records of central water supply and wastewater disposal date back about 5000 years, to Nippur of Sumeria. In the ruins of Nippur there is an arched drain with the stones set in full "voussoir" position, each stone being a wedge tapering downward into place. Water was drawn from wells and cisterns.An extensive system of drainage conveyed the wastes from the palaces and residential districts of the city.The earliest recorded knowledge of water treatment is in the Sanskrit medical lore and Egyptian Wall inscri ptions. Sanskrit writings dating about 2000 B.C. tell how to purify foul water by boiling in copper vessels,exposing to sunlight, filtering through charcoal, and cooling in an earthen vessel.The earliest known apparatus for clarifying liquids was pictureed on Egyptian walls in the fifteenth and thirteenth centuries B.C. The first picture represents the siphoning of either water of settled wine. A second picture shows the use of wick siphons in an Egyptian kitchen.The first engineering report on water supply and treatment was made in A.D. 98 by Sextus Julius Frontinus, water-commissioner of Rome. He produced two books on the water supply of Rome. In these he described a settling reservoir at the head of one of the aqueducts. His writings were first translated into English by the noted hydraulic engineer Clemens Herschel in 1899.In the eight century A.D. an Arabian alchemist,Geber,wrote a rather specialized treatise on distillation that included various stills for water and other liquids.The English philosopher Sir Francis Bacon wrote of his experiments on the purification of water by filtration, boiling, distillation and clarification by coagulation. This was published in 1627, one year after his death. Bacon also noted that clarifying water trends to improve health and increase the "pleasure of the eye".The first known illutrated descri ption of sand filters was published in 1685 by LucAntonio Porzio, an Italian physician. He wrote a book on conserving the health of soldier in camps, based on his experience in the Austro-Turkish War. This was probably the earliest published work on mass sanitation.He described and illustrated the use of sand filters and sedimentation. Porzio also stated that his filtration was the same as "by those who built the wells in the Palace of the Doges in Venice and in the palace of Cardinal Sachett,at Rome."The oldest known archeological examples of water filtration are in Venice and the colonies she occupied. The ornate heads on the cisterns bear dates,but it is not known when the filters were placed.Venice,Built on a Series of islands, depended on catching and storing rainwater for its principal freshwater supply for over 1300 years. Cisterns were built and many were connected in stone-grated catch basins and then filtered through sand into cisterns.A comprehensive article on the water supply of Venice appeared in the Practical Mechanics Journal in 1863.The land area of Venice was 12.85 acres and the average yearly rainfall was 32 inches(in). Nearly all of this rainfall was collected in 177 public and 1900 private cisterns. Thesecisterns provided a daily average supply of about 4.2 gallons per capita per day(gpcd).This low consumption was due in part to the absence of sewers, the practice of washing clothes in the lagoon,and the universal drinking of wine. These cisterns continued to be the principal water supply of Venice until about the sixteenth century.Many experiments were conducted in the eighteenth and nineteenth centuries in England,France Germany,and Russia.Henry Darcy patented filters in france and England in 1865 and anticipated all aspects of the American rapid sand filter except coagulatin.He appears to be the first to apply the law of hydraulics to filter design.The first filter to supply water to a whole town was completed at Paisley,Scotland,in 1804,but this water was carted to consumers. In Glasgow, Scotland,in 1807 filtered water was piped to consumers.In the United States little attention was given to water treatment until after the Civil War. Turbidity was not as urgent a problem as in Europe. The first filters were of the slow sandtype,similar to British design. About 1890 rapid sand filters were developed in the United States and coagulants were introduced to increase their efficency. These filters soon evolved to our present rapid sand filters with slight modification.历史上的水供应人类对纯净水的搜寻开始于史前时代。

给水排水中英文对照外文翻译文献

中英文对照外文翻译文献(文档含英文原文和中文翻译)原文：Optimum combination of water drainage,water supply and eco-environment protection in coal-accumulated basin of North ChinaAbstract The conflict among water drainage,water supply and eco-environment protection is getting more and more serious due to the irrational drainage and exploitation of ground water resources in coal-accumulated basins of North China.Efficient solutions to the conflict are tomaintain long-term dynamic balance between input and output of theground water basins,and to try to improve resourcification of the mine water.All solutions must guarantee the eco-environment quality.This paper presents a new idea of optimum combination of water drainage，water supply and eco-environment protection so as to solve theproblem of unstable mine water supply,which is caused by the changeable water drainage for the whole combination system.Both the management of hydraulic techniques and constraints in economy,society,ecology,environment,insustuial structural adjustments and sustainable developments have been taken into account.Since the traditional and separate management of different departments of water drainage,water supply and eco-environment protection is broken up these departments work together to avoid repeated geological survey and specific evaluation calculations so that large amount of national investment can be saved and precise calculation for the whole system can be obtained.In the light of the conflict of water drainage,water supply and eco-environment protection in a typical sector in Jiaozuo coal mine,a case study puts forward an optimum combination scheme,in which a maximum economic benefit objective is constrained by multiple factors.The scheme provides a very important scientific base for finding a sustainable development strategy.Keywords combination system of water drainage,water supply and eco-environment protection,optimal combination,resourcification of mine water.1Analyses of necessity for the combinationThere are three related problems in the basin.It is well known that the major mine-hydrogeological characteristics of the coal accumulated basin in North China display a stereo water-filling structure,which is formed by multi-layer aquifers connected hydraulically together with various kinds of inner or outer boundaries.Mine water hazards have seriously restricted the healthy development of coal industry in China because of more water-filling sources and stronger water-filling capacity in coal mines of the basin.Coal reserves in the basin are threatened by the water hazards.In Fengfeng,Xingtai,Jiaozuo,Zibao,Huaibei and Huainan coal mine districts,for example,it is estimatedthat coal reserves are threatened by the water hazards up to 52％,71.％40,％,60％,48％and 90％of total prospecting reserves respectively.It is obvious that un-mining phenomenon caused by the water hazards is serious.Water-bursting accidents under coal layers have seriously influenced safe production.Some statistical data show that there were 17 water-bursting accidents with over 1 m3/s inflow from 1985.Water drainage is an increasing burden on coal mines threatened by water hazards:high cost of water drainage raises coal prices and reduces profits of the enterprise.On the other hand,it is more and more difficult to meet the demand of water supply in coal mine districts in the basin.The reasons are not only arid and semi-arid weather conditions,but also a large amount of water drainage with deep drawdown in coal mines and irrational water exploitation.The deterioration of eco-environment is another problem.Phenomena of land surface karst collapse can be found.Many famous karst springs,which are discharge points for the whole karst groundwater syatem,stop flowing or their discharge rates decrease on a large scale.Desert cremophytes in large areas in west China die because of falling groundwater level.These three problems are related and contradictory.In order to solve the problems while ensuring safe mining,meeting water resource demands and slowing down the pace of eco-environment deterioration,it is necessary to study the optimum combination of water drainage,water supply and eco-environment protection in the basin.2The state of the art of research and the problemsAlthough research into the combination of water drainage and water supply started much earlier in some countries,their conception is simple and some shortcomings remain in their study on the theory and pattern of combination.China’s research history on the combination can be divided into three stages.The first stage is the utilization of mine water.A century ago mine water started to be used as water supply for mines.But the utilization scale and efficiency were quite limited at that time.The second stage is a comprehensive one:mine water was used while water hazards were harnessed.Great progress was made both in theory and practice of the combination.For example,the combination of water drainage and water supply not only means the utilization of mine water,but also means that it is a technique of preventing water hazards.It is unfortunate,however,that the combination research in this stage offered less sense ofeco-environment protection.Optimum combination management of water drainage,water supply and eco-environment protection is the third stage.Main features in this stage are to widen traditional research,and to establish an economic-hydraulic management model,in which safe mining,eco-environment protection and sustainable development demands,etc.are simultaneously considered as constraint conditions.3Trinity systemThe trinity system combines water drainage,water supply and eco-environment quality protection.The water-collecting structures of the system consist of land surface pumping wells in the mines,shallow land surface well in groundwater recharge areas and artificial relief wells under the mines.Both integration and coordination for the trinity system are distinguished according to the combination.The integration for the system means to utilize drainage water under the mines and pump water onto the land surface as water supply for different purposes without harming the eco-environmental quality.The coal mines are not only drainage sites,but also water supply sources.The purpose of drilling pumping wells on the land surface is to eliminate special influences on different consumers,which are caused by terminating drainage processes under the mines due to unexpected accidents in mining.The coordination for the system means to bulid some water supply sources for different consumers while ensuring eco-environmental quality in groundwater recharge positions,where pumping groundwater is quite effective on lowering groundwater heads in the mine areas.Itintercepts in advance the recharging groundwater flow towards the mines,which may not only provide consumers with good quality groundwater,achieve the goal of dropping down groundwater heads in the mines,but also effectively reduce the high costs of drainage and water treatment,which are needed by traditional dewatering measures with large drainage flow rates under the mines.The coordination changes the traditional passive pattern of preventing and controlling groundwater hazards under the mines into that of active surface interception.Both very developed karst flow belts and accumulated groundwater recharge ones under the ground are relatively ideal interceptive coordination positions in the system.For the integration of the trinity system,artificial relief wells under the mines and the land surface pumping wells mainly penetrate into direct thin bedded karst aquifers interbedded with the mining coal layers,while for the coordination of the system,the shallow land surface wells mainly penetrate into very thick karst aquifer.Therefore,hydrogeological conceptual model for the system involves the multi-layer aquifers connected hydraulically by different inner boundaries.Setting up stereo hydrogeological conceptual models and corresponding mathematical models is a prerequisite for solving the managemental problems for the system.Management of the trinity system not only considers the effects of lowering groundwater heads and safe operation for water drainage subsystem,but also pays attention to the water demands for water supply subsystem and quality changes for eco-environment protection subsystem.They play the same important role in the whole combination system.It controls the groundwater heads in each aquifer to satisfy the conditions of safe mining with certain water head pressures in the mines,and to guarantee a certain amount of water supply for the mines and near areas,but the maximum drawdown of groundwater must not be ex ceded,which may result in lowering eco-environmental quality.4Economic-hydraulic management modelIn the trinity system management,groundwater resources in the mines and nearby areas,which are assessed on the premise of eco-environment qualities and safe operation in the mines,may be provided as water supply prices,drainage costs,transportation costs(including pipeline and purchasing the land costs)and groundwater quality treatment costs for the three different waterconsumers,the optimum management models may automatically allocate to each consumer a certain amount of groundwater resources and a concrete water supply scenario based on comparisons of each consumer’s economic contribution to the whole system in objective function.Therefore the management studies on the optimal combination among water drainage,water supply and eco-environment protection involve both the management of groundwater hydraulic techniques and the economic evaluations,eco-environment quality protection and industrial structure programs.In addition to realizing an economic operation,they also guarantee a safe operation which is a key point for the combination of the whole system.5The management model for the trinity system can reach water supply goals with drainage water under the mines and the land surface pumping water on the premise of ensuring eco-environmental quality.And it can make use of one model to lay down comprehensively optimum management scenarios for each subsystem by means of selecting proper constraints and maximum economic benefit objective produced by multiple water consumers.The model can raise the security and reliability of operation for the whole trinity system,and the drainage water can be forecast for the mines and the management of water supply resource and the evaluation of eco-environment quality can be performed at the same time so as to respectively stop the separate or closed management,of departments of drainage water,water supply and eco-environment protection from geological survey stage to management evaluation.This,in economic aspect,can not only avoid much geological survery and special assessment work which are often repeated by the three departments,and save a lot of funds,but also ,in technical aspect,make use of one model to simultaneously consider interference and influence on each other for different groundwater seepage fields so as to guarantee calculating precision of the forecast,the management and the evaluation work.The economic-hydraulic management model can be expressed as follows.6 A case studyA typical sector is chosen.It is located in the east of Jiaozuo coal mine,Henan Province,China.Itconsists of three mines:Hanwang Mine,Yanmazhuang Mine and Jiulishan Mine.The land surface is flat,and the whole area is about 30 km2.An intermittent river Shanmen flows through the sector from the north to the south.Average annual precipitation in the sector is about 662.3mm.Theprecipitation mainly concentrates inJune,July,August and September each year.Strata in the sector consist of very thick limestone in Middle Ordovician,coal-bearing rock series in Permo Carboniferous and loose deposits in Quaternary.There are four groups of faulted structures.The first is in northeast-southwest direction such as F3 and F1..The second is in the northwest-southeast direction such as Fangzhuang fault.The third is in the east-west direction such as Fenghuangling fault.The last is almost in north-south.These faults are all found to be normal faults with a high degree of dip angle.Four major aquifers have been found in the sector.The top one is a semi-confined porous aquifer.The next one is a very thin bedded limeston aquifer.The third is a thin bedded limestone aquifer.The last one at the bottom is a very thick limestone aquifer.Objective function of the management model is designed to be maximum economic benefit produced by domestic,industrial and agricultural water supply.Policy making variables of the model are considered as the domestic,industrial and agricultural groundwater supply rates in every management time step,and they are supplied by artificial relief flow wells under the mines,the land surface pumping wells in the mines and the shallow land surface wells in the groundwater recharge areas.All the 135 policy making variables are chosen in the model,27 for drainage wells under the mines in aquifer,27 for the land surface pumping wells in the mine districts in aquifer 27 in aquifer 27 in aquifer O2 27 for the shallow land surface wells in aquifer O2Based on the problems,the following constraint conditions should be considered:(1)Safe mining constraint with groundwater pressure in aquifer L8.There are altogether three coalmines in the typical sector,i.e.Hanwang Mine,Yanmazhuang Mine and Jiulishan Mine.Elevations of mining level for these mines are different because it is about 88-150 m in the second mining level for Hanwang Mine,and -200m in the second mining level for Yanmazhuang Mine,and-225 m in the first mining level for Jiulishan Mine.According to mining experiences,pressure-loaded heights for groundwater heads in safe mining state are considered as about 100-130m.Therefore,the groundwater level drawdowns in the three management time steps for aquifer L8 at three mines have to be equivalent to safe drawdown values at least in order to pervert groundwater hazards under the mines and to guarantee their safe operation.(2)Geological eco-environment quality constraint.In order to prevernt groundwater leakage fromupper contaminater porous aquifer into bottom one and then to seepage further down to contaminate the thin bedded limestone aquifer in the position of buried outcrop,the groundwater heads in the bottom porous aquifer must keep a certain height,i.e.the groundwater drawdowns in it are not allowed to exceed maximum values.(3)Groundwater head constraint at the shallow land surface wells in aquifer O2,The shallow landsurface wells should penetrate in aquifer O2 in order to avoid geological environment hazards,such as karst collapse and deep karst groundwater contamination.Groundwater head drawdowns in aquifer O2 for the shallow land surface wells are not allowed to exceed criticalvalues.(4)Industrial water supply constraint for the groundwater source in aquifer O2 .The rate ofindustrial water supply needed by the planned thermal power plant in the north of the sectoris designed to be 1.5 m3/s according to the comprehensive design of the system in thesector.In order to meet the demands of water,the rate industrial water supply for thegroundwater source in aquifer O2 in every management time step must be equivalent at leastto 1.5 m3/s.(5)Maximum amount constraint of groundwater resource available for abstraction.In order tomaintain the balance of the groundwater system in the sector for a long time and to avoid anyharmful results caused by continuous falling of groundwater head,the sum of groundwaterabstraction in each management time step is not allowed to exceed the maximum amount ofgroundwater resource available for abstraction.Since there is not only water drainage in the mines,but also water supply in the whole combination system,management period for the model is selected from June 1,1978 to May 31,1979,in which annual average rate of precipitation is about 50％.Management time steps for the period are divided into three.The first one is from June to September,the second from October to next January,and the last one from next February to May.According to comprehensive information about actual economic ability,economic development program and industrial structure adjustment in the sector at present and in the near future,and different association forms of water collecting structures among the land surface pumping wells,the shallow land surface wells and artificial relief flow wells under the mines,this paper designs 12 management scenarious,all of which take the safe operation in the trinity system as the most important condition.After making comparisons of optimum calculation results for the 12 scenarious,this paper comes to a conclusion that scenarios is the most ideal and applicable one for the typical sector.This scenario not only considers the effective dewatering advantage of the artificial relief flow wells under the mines and safe stable water supply advantage of the land surface pumping wells,but also pays attention to the disadvantage of low safe guaranty rate for the relief flow wells under the mines for water supply and of large drilling investment in the land surface pumping wells.Meanwhile,eh shallow land surface wells inaquifer O2in this scenario would not only provide water supply for the thermal power plant as planned,but also play an important role in dewatering the bottom aquifer,which is major recharge source of groundwater for the mines.If the drainage subsystem under the mines runs normally,this scenario could fully offer the effective dewatering functions of the artificial relief flow wells under the mines,and makes the trinity system operate normally.But if the drainage subsystem has to stop suddenly because of unexpected accidents,the scenario could still fully utilize the land surface pumping wells and the shallow land surface wells,and increae their pumping rates in order to make up for temporary shortage of water supply for the trinity system and to make its economic losses reduced to a minimum extent.Increasing groundwater abstraction rate for the land surface pumping wells and the shallow land surface wells,in fact,is very favorable for harnessing the water-accidents under the mines and for recovery production of the mines.To sum up,this scenario sets up a new pattern for the combination of water drainage,water supply and eco-environment protection.It solves quite well the conflicts between the low safe guaranty rate and the effective dewatering result for the artificial relief flow wells under the mines.It makes full use of beneficial aspect of the conflicts,and meanwhile compensates for the unbeneficial one by arranging the land surface pumping wells in the coal mine districts.Therefore,this scenario should be comprehensive and feasible.In this scenario,Hanwan Mine,Yanmazhuang Mine and Jiulishan Mine are distributed optimally for certain amount of domestic and industrial water supply,but not for much agricultural water supply.The land surface pumping wells are also distributed for different purposes of water supply.The water supply for the thermal power plant (1.5 m3/s) is provided by the shallow land surface prehensive effects,produced by the above three kinds of water collecting structures,completely satisfy all of the constraint conditions in the management model,and achieve an extremely good economic objective of 16.520551million RMB yuan per year.In order to examine the uncertainty of the management model,12management scenarios are all tested with sensitive analysis.7Conclusion(1)The optimum combination research among water drainage,water supply and eco-environmentprotection is of great theoretical significance and application value in the basin of North China for solving unbalanced relation between water supply and demands,developing new potential water supply sources and protecting weak eco-environment.(2)The combination research is concerned not only with hydraulic technique management but alsowith constraints of economic benefits,society,ecology,environment quality,safe mining and sustainable development in the coal mines.(3)The combination model,for the first time,breaks up the closed situation existing for a longtime,under which the government departments of drainage water,water supply and eco-environment protection from geological survey stage to management evaluation work respectively.Economically,it can spare the repeated geological survey and special assessment work done by the three departments and save a lot of funds;technically,one model is made use of to cover the interference and influence each other for different groundwater seepage fields soas to guarantee a high calculating precision of the forecast,the management and the evaluation work.(4)The management scenario presented in the case study is the most ideal and applicable for thetypical sector.This scenario not only makes full use of the effective dewatering advantages of the artificial relief flow wells under the mines and safe stable water supply advantages of the land surface pumping wells,but also pays attention to the disadvantages of low safe guaranty rate for the relief flow wells under the mines for water supply and of large drilling investment for the land surface pumping wells.References1.Investigation team on mine-hydrogeology and engineering geology in the Ministry ofGeology and Mineral Resources.Investigation Report on Karst-water-filling Mines(inChinese).Beijing:Geological Publishing House,19962.Liu Qiren,Lin Pengqi,Y u Pei,Investigation comments on mine-hydrogeological conditionsfor national karst-water-filling mines,Journal of Hydrogeology and Engineering Geology(in Chinese),19793.Wang Mengyu,Technology development on preventing and curing mine water in coalmines in foreign countries,Science and Technology in Coal(in Chinese),19834.Coldewey,W.G.Semrau.L.Mine water in the Ruhr Area(Federal Republic of Germany),inProceedings of 5th International Mine Water Congress,Leicestershire:Quorn SelectiveRepro Limited,19945.Sivakumar,M.Morten,S,Singh,RN,Case history analysis of mine water pollution,inProceedings of 5th International Mine Water Congress,Leicestershire;Quorn SelectiveRepro Limited,19946.Ye Guijun.Zhang Dao,Features of Karst-water-filling mines and combination betweenwater drainage and water supply in China,Journal of Hydrogeology and EngineeringGeology(in China),19887.Tan Jiwen,Shao Aijun,Prospect analyses on Combination between water drainage andwater supply in karst water basin in northern China,Jounnal of Hebei College ofGeology(in Chinese),19858.Xin Kuide,Yu Pei,Combination between water drainage and water for seriouskarst-water-filling mines in northern China,Journal of Hydrogeology and Engineering Geology(in Chinese),19869.Wu Qiang,Luo Yuanhua,Sun Weijiang et al.Resourcification of mine water andenvironment protection,Geological Comments(in Chinese),199710.Gao Honglian,Lin Zhengping,Regional characteristics of mine-hydrogeological conditionsof coal deposits in China,Journal of Hydrogeology and Engineering Geology(in Chinese),198511.Jiang Ben,A tentative plan for preventing and curing measures on mine water in coal minesin northern China,Geology and Prospecting for Coaofield(in Chinese),1993中国北方煤炭积聚区的最佳组合排水，供水和生态环境保护摘要为了开采中国北方煤炭资源丰富的区域，不合理的排水使排水、供水和保护生态环境之间的冲突日趋严重。

建筑工程及给排水专业中英文对照翻译

建筑工程及给排水专业中英文对照翻译Laminar and Turbulent FlowObservation shows that two entirely different types of fluid flow exist. This was demon- strated by Osborne Reynolds in 1883 through an experiment in which water was discharged from a tank through a glass tube. The rate of flow could be controlled by a valve at the outlet, and a fine filament of dye injected at the entrance to the tube. At low velocities, it was found that the dye filament remained intact throughout the length of the tube, showing that the particles of water moved in parallel lines. This type of flow is known as laminar, viscous or streamline, the particles of fluid moving in an orderly manner and retaining the same relative positions in successive cross- sections.As the velocity in the tube was increased by opening the outlet valve, a point was eventually reached at which the dye filament at first began to oscillate and then broke up so that the colour was diffused over the whole cross-section, showing that the particles of fluid no longer moved in an orderly manner but occupied different relative position in successive cross-sections. This type of flow is known as turbulent and is characterized by continuous small fluctuations in the magnitude and direction of the velocity of the fluid particles, which are accompanied by corresponding small fluctuations of pressure.When the motion of a fluid particle in a stream is disturbed, its inertiawill tend to carry it on in the new direction, but the viscous forces due to the surrounding fluid will tend to make it conform to the motion of the rest of the stream. In viscous flow, the viscous shear stresses are sufficient to eliminate the effects of anydeviation, but in turbulent flow they are inadequate. The criterion which determines whether flow will be viscous of turbulent is therefore the ratio of the inertial force to the viscous force acting on the particle. The ratioμρvl const force Viscous force Inertial ?= Thus, the criter ion which determines whether flow is viscous or turbulent is the quantity ρvl /μ, known as the Reynolds number. It is a ratio of forces and, therefore, a pure number and may also be written as ul /v where is the kinematic viscosity (v=μ/ρ).Experiments carried out with a number of different fluids in straight pipes of different diameters have established that if the Reynolds number is calculated by making 1 equal to the pipe diameter and using the mean velocity v , then, below a critical value of ρvd /μ = 2000, flow will normally be laminar (viscous), any tendency to turbulence being damped out by viscous friction. This value of the Reynolds number applies only to flow in pipes, but critical values of the Reynolds number can be established for other types of flow, choosing a suitable characteristic length such as the chord of an aerofoil in place of the pipe diameter. For a given fluid flowing in a pipe of a given diameter, there will be a critical velocity of flow corresponding to the critical value of the Reynolds number, below which flow will be viscous.In pipes, at values of the Reynolds number > 2000, flow will not necessarily be turbulent. Laminar flow has been maintained up to Re = 50,000, but conditions are unstable and any disturbance will cause reversion to normal turbulent flow. In straight pipes of constant diameter, flow can be assumed to be turbulent if the Reynolds number exceeds 4000.Pipe NetworksAn extension of compound pipes in parallel is a case frequently encountered in municipal distribution system, in which the pipes are interconnected so that the flow to a given outlet may come by several different paths. Indeed, it is frequently impossible to tell by inspection which way the flow travels. Nevertheless, the flow in any networks, however complicated, must satisfy the basic relations of continuity and energy as follows:1. The flow into any junction must equal the flow out of it.2. The flow in each pipe must satisfy the pipe-friction laws for flow in a single pipe.3. The algebraic sum of the head losses around any closed circuit must be zero.Pipe networks are generally too complicated to solve analytically, as was possible in the simpler cases of parallel pipes.A practical procedure is the method of successive approximations, introduced by Cross. It consists of the following elements, in order:1. By careful inspection assume the most reasonable distribution of flows that satisfies condition 1.2. Write condition 2 for each pipe in the formh L = KQ n(7.5) where K is a constant for each pipe. For example, the standard pipe-friction equation would yield K= 1/C2and n= 2 for constant f. Minor losses within any circuit may be included, but minor losses at the junction points are neglected.3. To investigate condition 3, compute the algebraic sum of the head losses around each elementary circuit. ∑h L= ∑KQ n. Consider losses from clockwise flows as positive, counterclockwise negative. Only by good luck will these add tozero on the first trial.4. Adjust the flow in each circuit by a correction, ΔQ , to balance the head in that circuit and give ∑KQ n = 0. The heart of this method lies in the determination of ΔQ . For any pipe we may writeQ = Q 0 ＋ΔQwhere Q is the correct discharge and Q 0 is the assumed discharge. Then, for a circuit100/Q h n h Q Kn Q K Q L L n n ∑∑∑∑?-=-=- (7.6) It must be emphasized again that the numerator of Eq. (7.6) is to be summed algebraically, with due account of sign, while the denominator is summed arithmetically. The negative sign in Eq.(7.6) indicates that when there is an excess of head loss around a loop in the clockwise direction, the ΔQ must be subtracted from clockwise Q 0’s and added to counterclockwise ones. The reverse is true if there is a deficiency of head loss around a loop in the clockwise direction.5. After each circuit is given a first correction, the losses will still not balance because of the interaction of one circuit upon another (pipes which are common to two circuits receive two independent corrections, one for each circuit). The procedure is repeated, arriving at a second correction, and so on, until the corrections become negligible.Either form of Eq. (7.6) may be used to find ΔQ . As values of K appear in both numerator and denominator of the first form, values proportional to the actual K may be used to find the distribution. Thesecond form will be found most convenient for use with pipe-friction diagrams for water pipes.An attractive feature of the approximation method is thaterrors in computation have the same effect as errors in judgment and will eventually be corrected by the process.The pipe-networks problem lends itself well to solution by use of a digital computer. Programming takes time and care, but once set up, there is great flexibility and many man-hours of labor can be saved.The Future of Plastic Pipe at Higher PressuresParticipants in an AGA meeting panel on plastic pipe discussed the possibility of using polyethylene gas pipe at higher pressures. Topics included the design equation, including work being done by ISO on an updated version, and the evaluation of rapid crack propagation in a PE pipe resin. This is of critical importance because as pipe is used at higher pressure and in larger diameters, the possibility of RCP increases.Se veral years ago, AGA’s Plastic Pipe Design Equation Task Group reviewed the design equation to determine if higher operating pressurescould be used in plastic piping systems. Members felt the performance of our pipe resins was not truly reflected by the design equation. It was generally accepted that the long-term properties of modern resins far surpassed those of older resins. Major considerations were new equations being developed and selection of an appropriate design factor.Improved pipe performanceMany utilities monitored the performance of plastic pipe resins. Here are some of the long-term tests used and the kinds of performance change they have shown for typical gas pipe resins.Elevated temperature burst testThey used tests like the Elevated Temperature Burst T est, inwhich the long-term performance of the pipe is checked by measuring the time required for formation of brittle cracks in the pipe wall under high temperatures and pressures (often 80 degrees C and around 4 to 5-MPa hoop stress). At Consumers Gas we expected early resins to last at least 170 hrs. at 80 degrees C and a hoop stress of 3 MPa. Extrapolation showed that resins passing these limits should have a life expectancy of more than 50 yrs. Quality control testing on shipments of pipe made fromthese resins sometimes resulted in product rejection for failure to meet this criterion.At the same temperature, today’s resins last thousands of hours at hoop stresses of 4.6 MPa. Tests performed on pipe made from new resins have been terminated with no failure at times exceeding 5,700 hrs. These results were performed on samples that were squeezed off before testing. Such stresses were never applied in early testing. When extrapolated to operating conditions, this difference in test performance is equivalent to an increase in lifetime of hundreds (and in some cases even thousands) of years.Environmental stress crack resistance testSome companies also used the Environmental Stress Crack Resistance test which measured brittle crack formation in pipes but which used stress cracking agents to shorten test times.This test has also shown dramatic improvement in resistance brittle failure. For example, at my company a test time of more than 20 hrs. at 50 degrees C was required on our early resins. Today’s resins last well above 1,000 hrs. with no failure.Notch testsNotch tests, which are quickly run, measure brittle crack formation in notched pipe or molded coupon samples. This isimportant for the newer resins since some other tests to failure can take very long times. Notch test results show that while early resins lasted for test times ranging between 1,000 to 10,000 min., current resins usually last for longer than 200,000 min.All of our tests demonstrated the same thing. Newer resins are much more resistant to the growth of brittle crack than their predecessors. Since brittle failure is considered to be the ultimate failure mechanism in polyethylene pipes, we know that new materials will last much longer than the old. This is especially reassuring to the gas industry since many of these older resins have performed very well in the field for the past 25 yrs. with minimal detectable change in properties.While the tests showed greatly improved performance, the equation used to establish the pressure rating of the pipe is still identical to the original except for a change in 1978 to a single design factor for all class locations.To many it seemed that the methods used to pressure rate our pipe were now unduly conservative and that a new design equation was needed. At this time we became aware of a new equation being balloted atISO. The methodology being used seemed to be a more technically correct method of analyzing the data and offered a number of advantages.Thermal Expansion of Piping and Its CompensationA very relevant consideration requiring careful attention is the fact that with temperature of a length of pipe raised or lowered, there is a corresponding increase or decrease in its length and cross-sectional area because of the inherent coefficient of thermal expansion for the particular pipe material. The coefficient of expansion for carbon steel is 0.012 mm/m?Cand for copper 0.0168mm/m?C. Respective module of elasticity a re for steel E = 207×1.06kN/m2 and for copper E = 103×106 kN/m2. As an example, assuming a base temperature for water conducting piping at 0?C, a steel pipe of any diameter if heated to 120?C would experience a linear extension of 1.4 mm and a similarly if heated to copper pipe would extend by 2.016 mm for each meter of their respective lengths. The unit axial force in the steel pipe however would be 39% greater than for copper. The change in pipe diameter is of no practical consequence to linear extension but the axial forces created by expansion or contractionare con- siderable and capable of fracturing any fitments which may tend to impose a restraint;the magnitude of such forces is related to pipe size. As an example,in straight pipes of same length but different diameters, rigidly held at both ends and with temperature raised by say 100?C, total magnitude of linear forces against fixed points would be near enough proportionate to the respective diameters.It is therefore essential that design of any piping layout makes adequate com- pensatory provision for such thermal influence by relieving the system of linear stresses which would be directly related to length of pipework between fixed points and the range of operational temperatures.Compensation for forces due to thermal expansion. The ideal pipework as far as expansion is concerned, is one where maximum free movement with the minimum of restraint is possible. Hence the simplest and most economical way to ensure com- pensation and relief of forces is to take advantage of changes in direction, or where this is not part of the layout and long straight runs are involved it may be feasible to introducedeliberate dog-leg offset changes in direction at suitable intervals.As an alternative,at calculated intervals in a straight pipe run specially designed expansion loops or “U” bends should be inserted. Depending upon design and space availability, expansion bends within a straight pipe run can feature the so called double offset “U” band or thehorseshoe typ e or “lyre” loop.The last named are seldom used for large heating networks; they can be supplied in manufacturers’ standard units but require elaborate constructional works for underground installation.Anchored thermal movement in underground piping would normally be absorbed by three basic types of expansion bends and these include the “U”bend, the “L”bend and the “Z”bend.In cases of 90 changes indirection the “L” and “Z”bends are used.Principles involved in the design of provision for expansion between anchor points are virtually the same for all three types of compensator. The offset “U” bend is usually made up from four 90° elbows and straight pipes; it permits good thermal displacement and imposes smaller anchor loads than the other type of loop. This shape of expansion bend is the standardised pattern for prefabricated pipe-in-pipe systems.All thermal compensators are installed to accommodate an equal amount of expansion or contraction; therefore to obtain full advantage of the length of thermal movement it is necessary to extend the unit during installation thus opening up the loop by an extent roughly equal the half the overall calculated thermal movement.This is done by “cold-pull” or other mechanical means. The total amount of extension between two fixed pointshas to be calculated on basis of ambient temperature prevailing and operational design temperatures so that distribution of stresses and reactions at lower and higher temperatures are controlledwithin permissible limits. Pre-stressing does not affect the fatigue life of piping therefore it does not feature in calculation of pipework stresses .There are numerous specialist publication dealing with design and stressing calculations for piping and especially for proprietary piping and expansion units; comprehensive experience back design data as well as charts and graphs may be obtained in manufacturers’publications, offering solutions for every kind of pipe stressing problem.As an alternative to above mentioned methods of compensation for thermal expansion and useable in places where space is restricted, is the more expensive bellows or telescopic type mechanical compensator. There are many proprietary types and models on the market and the following types of compensators are generally used.The bellows type expansion unit in form of an axial compensator provides for expansion movement in a pipe along its axis; motion in this bellows is due to tension or compression only.There are also articulated bellows units restrained which combine angular and lateral movement; they consist of double compensator units restrained by straps pinned over the center of each bellowsor double tied thus being restrained over its length.Such compensators are suitable for accommodating very pipeline expansion and also for combinations of angular and lateral movements.层流与紊流有两种完全不同的流体流动形式存在，这一点在1883年就由Osborne Reynolds 用试验演示证明。

给排水工程外文翻译

给排水工程外文翻译 Final approval draft on November 22, 2020Short and Long Term Advantage roof drainage design performanceDecade has witnessed great changes in the design of the roof drainage system recently, particularly, siphon rainwater drainage system has been gradually improved, and there is likely to be the key application. At the same time these changes, urban drainage system design has undergone tremendous changes, because the scope of a wider urban drainage system design for sustainable development, as well as people for climate change flooding more attention. The main contents of this article is how to design roof drainage systems and make a good performance. Special attention is how to get rid of bad habits already formed the design, but also need to consider innovative roof drainage system, such as green roofs and rainwater harvesting systems.Practical application: In the past few years, the design of the roof rainwater drainage system has undergone tremendous changes. On large buildings, siphon rainwater drainage technology has been very common, as well as green roofs because it is conducive to green development, being more and more applications. Taking into account the ongoing research, this article focuses on how to effectively design a variety of roof rainwater drainage system, and make it achieve the desired design effect.1. IntroductionIn the past decade, the city and the water drainage system design has been widely accepted thinking about sustainable urban drainage system, or the optimal management direction. The main principles of the design of these systems is both a local level in line with the quality of development, but also to create some economic benefits for the investors. This principle has led to the development of new changes in the sump. Although the application of such a device is gradually reduced, but the urban environment relatively high demand areas still require 100% waterproof and rapid drainage, such as the roof. Typically roof drainage system in the design, construction and maintenance has not been given due attention. Although the drainage system investment costs account for only a small portion of the total construction investment, but not able to judge the loss caused by poor design.There are two different forms of roof drainage system design methods, namely the traditional and siphon method. Traditional systems rely on atmospheric pressure work, the drive ram affectedsink flow depth. Therefore, the conventional roof drainage systems require a relatively large diameter vertical drop tube, prior to discharge, all devices must be connected to the groundwatercollection pipe network. In contrast, siphonic roof drainage pipe systems are generally designed to full flow (turbulent flow meansthat require less exhaust pipe), which will form a negative pressure, the larger the higher flow rate and pressure head. Typically siphon system requires less down pipe work under negative pressure to the water distribution network can mean higher altitude work, thereby reducing the amount of underground pipe network.Both systems consists of three parts: the roof, rainwater collection pipes, pipe network.All of these elements are able to change the water pressure distribution system. This section focuses on the role and performance of each part. Due to the principle of siphon system has not been well understood, resulting argument is relatively small, this article will highlight siphon system.2. RoofThe roof is usually designed by the architect, designer and not by the drainage design. There are three main roof.2.1 Flat roofFlat roofs are used in industrial buildings less rainfall regions and countries. This roof is not completely flat, but lower than the minimum roof slope may require. For example, the United Kingdom require maximum slope of 10 °. Setting minimum slope in order to avoid any unnecessary water.Despite the flat roof if it is not properly maintained will have more problems, but it will reduce the dead zone within the building, and the ratio of sloping roofs in favor of indoor air.2.2 sloping roofsMost residential and commercial buildings are pitched roof, inclined roof is the biggest advantage can quickly drain, thereby reducing leakage. In temperate regions, we need to consider carrying roof snow load. Once it rains, rainfall through the sloping roofs can be determined by calculation. When rainfall data can be used, you can use the kinematic theory to solve such problems.2.3 green roof (flat or inclined)It can prove roof is the oldest green roofs, including rainfall can reduce or disperse roof planted with plants. It can be planted with trees and shrubs roof garden, it can also be a vegetated roof light carpet. Wherein the latter technique has been widely used. Some of these applications tend to focus on aesthetic requirements and are often used in green development. Since the aesthetic requirements and pressure requirements, as well as green roofs thermal insulation function, reduce the heat island effect, silencer effect, extend the life of the roof.Green roofs in Germany, the most widely used, followed in North America, but to consider the impact on the aesthetics. Germany is by far the most experienced countries in the 19th century have practical application, then as an alternative to reduce the risk of fire tarroof an option in urban areas. Germany is currently the main research question on the cultivation of other issues to consider smaller cities. A study from 1987 to 1989, was found packed with 70 mm thick green roof can be reduced by 60% -80% of heat loss. In a Canadianwork computer model based on the roof indicates that as long as the sump, the area can reach 70% of the roof area can be reduced by 60 percent in one year, the same model was also used for artificial rainfall, which the results indicate that rainfall in the catchment season helps to drain away rainwater.However, none of these studies show that green roofs can play a useful role in the rainfall season, or how high collection efficiency of water supply. The United States did some tests, as long as the green roofs regular watering, can reduce 65 percent of the runoff ina rainfall. America's most authoritative green roof guidelines by the New Jersey state environmental agencies promulgated. The mainprinciple is to solve the structural problems of light, and how can the normal drainage after two years.Rainfall period is based on the probability of failure is determined. The system is typically based on rainfall during rainstorms two minutes, two minutes, have a choice. Although this model will get more traffic, but there is no other better alternative. Studies have shown that the traditional model is applied to study green roofs are premature.Loss factor than traditional roof records should be small, about 98.7%.Peak flow will be reduced, although not penetrate, the surface roughness but also have a significant impact.Concentrated rainfall than two minutes for a long time,especially for large roof areas, such as public buildings, commercial buildings, industrial buildings.Urban drainage design should also consider other factors, for a complex system, a green roof in a rain is not enough. Water flow duration curve shows a longer than traditional systems. And two independent and will affect between is possible, which requires a more precise time period.3. Rainwater CollectorBasic requirements rainwater collector is designed to be able to accommodate rainfall rainstorms. Although it is possible to make a slightly inclined roof drainage purposes, but the nature of the construction industry and building settlement will become flat roofTypically, the tank is placed in a horizontal, sectional view of the water is outwardly inclined, which the role of hydrostatic.3.1 drain outletAnalyzing rainwater collector has sufficient volume is the key to the sump outlet external setting conditions. Also affect the flow rate into the storm water drainage system piping, but also affect the depth of the water catchment. Although the depth of the sump will not bring any particular problems, but too deep can cause excessive sump.Numerous studies in the 1980s showed that the flow of conventional roof drainage system outlet can be divided into two cases. It depends on the size of the depth and size of the outlet. When the water depth is less than half the diameter of the outlet, the flow of the first type, and the outlet of the flow can be calculated by an appropriate equation; water depth increases, exports are slowly clogging the flow will become another form forms, at the same time, the flow of exports can be obtained through other equations. While conventional roof drainage systems are designed to be free-draining, but may cause limitations encountered in the design of the flow is not free. In this case, it will require additional depth.Siphon roof drainage systems, the outlet is designed to be submerged stream. In this case, the depth of the outlet of the decision is more complicated, because the design of the sump depends on the flow. Recent studies have shown that conventional roof drainage systems use a variety of non-standard catchment, their depth and height, bigger than the diameter of the outlet. This will eventually result in a siphon effect. For a given catchment, the flow depends on the starting end of the drop tube diameter. A similar phenomenon has also been used to study the standard catchment, in these circumstances, only limited siphon action occurs within relatively close distance from the exit.3.2 tank flow classificationIn the complex flow sump outlet flow classification, can be seen from Table 2a, the flow will be uniform layering, regardless of whether the same inlet flow. Table 2b and 2c show, exportdistribution will greatly influence the flow.When the outlet is not a free jet, sump outlet complex flow classification is difficult to describe. Because each catchment tank pressures are likely to be merged. For example, the siphon tube system design point is at near full jet outlet flow classification depends on the energy loss of each branch.3.3 hydrostatic sectionalSump shape of the water surface in the canal can be classified according to the flow equation. In most cases, a low flow rate meansthat there is less friction loss, if exports are free jet, thefriction loss is negligible cross-section through the hydrostatic equation 1 to determine the horizontal distance.Where Q-- flow (m3 / s)T- surface width (m)g- acceleration of gravity (m / s2)F- flow area (m2)Equation 1 can not be ignored when the friction required to correct (or very long pipe velocity is large), or not a free jet.3.4 The current design methodsThe previous discussion has highlighted the main factors that should be considered with sink design. However, without the help of a certain number of models, computing hydrostatic sectional roof drainage system, the volume of the sump is possible. This large commercial and manufacturing industry, is a development opportunity, you can merge several kilometers of water routes. Thus, the conventional drainage system sump design methods are mainly based on experience, and assume that exports are free jet.Sump location in the building, it may cause the example to fail. Different interface sumpExcept in the case cited above, but also allows designers to use empirical data.3.5 Digital ModelLarge number of digital models can be used to accurately describe the flow of any form of catchment tank, regardless of whether the roof flows stable. An example of this model is a combination of roof space model. This model enables users to classify different aspects of the data indicated, includes: details of the rains, the roof surface drainage and other details. Kinematics have also been used to study rainwater tank to flow from the research collection. A typical method is based on open system to solve a basic problem of spatial mobility. This model automatically resolve the sump outlet flow situation, but also to deal with the case of free jet can also be simulated space limited mobility and submerged discharge. Output values include depth and flow rate.Currently, the model is essentially just a variety of research tools, but also through practical engineering test. However, we should face up to the various role models.4 pipe systems groupComposition in the form and scope of the tube group determinesthe roof drainage system relies mainly on the traditional system or siphon action.4.1 Traditional stormwater systemsConventional roof drainage systems, the ground plane is generally vertical pipe-line network, connected to the sump outlet and underground drainage systems, critical systems as well as compensating tube. It should be emphasized that the angle between the ground and the compensating tube is less than 10 °. Capacity of the entire system relies mainly on the outlet tube instead of down.Flow vertical tube is usually free-flowing, full of only 33%, the efficiency depends on the excess length of the tube. If the drop tube long enough (typically greater than 5m), there may be an annular flow. Similarly, under normal circumstances flow compensation pipe is free-flowing, full of up to 70%. Such designed process both for the design, various equations can also be used.4.2 Siphon roof drainage systemIn contrast with the traditional drainage systems, Siphon roof drainage system relies on air flow outside the system, and the tubeis full pipe flow stream.The designs are usually made on the assumption that the design of heavy rain, the system can quickly siphon discharge rainwater. This assumption allows the application of hydrostatic siphon system theory. Often used steady flow energy equation. While this approach ignores the small amount of energy loss at the entrance, but after the experiment showed that there are still conducive to practical use.However, steady-state design methods in the siphon system is exposed to rain when the system does not meet the standard requirements or changes in rainfall intensity is large is not applied. In the first case, there will be some mixing of air quality, annular flow occurs. These problems are not integrated in the system when more serious. Because usually designed rains are common, it is clear now design methodology over time may not apply to siphon system. This is a major disadvantage, because the design of the main problem isthe noise and vibration problems.Despite the disadvantages of the prior design approach, but a lot of the world's very few engineering failure reports. When a failure occurs, most likely for the following reasons:An incorrect understanding of the operation pointsSubstandard materials listInstallation defectsMaintenance mismanagementTo overcome these disadvantages, we have recently launched aseries of research projects, to discuss the siphon system, and the development of digital models. From this work we learn a lot.In contrast with conventional design methods of some assumptions, siphon system mainly has the following aspects:1) non-flow system of full flow2) levels of certain pipe-flowing full pipe flow3) full pipe flow downstream propagation through a vertical pipe, riser, etc.4) the inner tube flow occurs over the vertical section, the system to reduce the pressure5) downward tube is full pipe flow, there will be air lock6) appears completely siphon action until well into the air system is lower than a certain levelTable 4a column data indicate that below the design point, the system will siphon unstable flow, depth of the water collecting tank is insufficient to maintain the siphon action. Table 4b show that the unsteady flow in siphon system when it will appear.Table 5 lists the data output of a digital model. It can be seen that the model can accurately describe the siphon action, siphon and steady state, the data also show that the model can accurately describe the complex siphon action.5 ConclusionThis article has illustrated the critical roof drainage systems, but these are often overlooked in the urban drainage system design. This article also shows that the design process is a complex process, rely mainly on the performance of exports. The following conclusions are based on the design summed up:1) Run depend on three interacting parts: the roof, sump, water pipes2) Green roofs can reduce traffic and beautify the city3) the export performance of the system is essential4) siphon drainage system have a greater advantage in large-scale projects, but must be considered high maintenance costs5) Design siphon drainage system should consider additional capacity and operational issuesAlthough the green roof is a more attractive option, but the traditional roof of a building in the country will continue to dominate. Green roofs will be gradually developed, and gradually been widely accepted. Similarly, the roof drainage system shown effective that it will continue to play a huge role in the commercial building drainage systems.Roof drainage system of the greatest threats from climate change, existing systems tend to be not simply aging; rainfall patterns of change will result in inefficient operation, self-cleaning rate will be reduced. Changes in wind speed and the roof will also accelerate the aging of the roof, it is necessary to carry out maintenance. Taking into account the climate change, the increase in materials, roof collected rainwater will be more extensive. Currently, the amount of rain around the globe per person per day 7-300 liters in the UK, with an average consumption of 145L / h / d, of which onlyabout one liter is used by people, about 30 per cent of the toilet, study shows If water shortage, rainwater collected on the roof of developed and developing countries are recommended approach.屋顶排水设计性能的近期与远期优势最近十年见证了屋顶排水系统设计方面的巨大变化，特别的是，虹吸雨水排水系统已经得到逐步改善，并且有可能得到重点应用。

给水排水工程专业英语文献翻译原文第一篇

聚丙烯
Abbreviations: ADF, Aerobic Dynamic Feeding, also designated as “feast and famine”; CSTR, Continuous Stirred Tank Reactor; C/N, Carbon to nitrogen ratio; HAc, Acetic acid; HB, Hydroxybutyrate; HBut, Butyric acid; HLac, Lactic acid; HProp, Propionic acid; HV, Hydroxyvalerate; HVal, Valeric acid; HRT, Hydraulic Retention Time; OUR, Oxygen Uptake Rate; PHA, Polyhydroxyalkanoate; qP, Maximum speciﬁc polymer storage rate; -qS, Maximum speciﬁc substrate uptake rate; SBR, Sequencing Batch Reactor; SRT, Sludge Retention Time; TOC, Total Organic Carbon; VFA, Volatile Fatty Acid; VSS, Volatile Suspended Solid; VSSmax, Volatile Suspended Solids at the time of maximum polymer accumulation; X, Active Biomass; Xi, Initial active biomass concentration; YO2/X, Respiration yield, in Cmmol/Cmmol VFA; YP/S, Polymer storage yield, in Cmmol HA/Cmmol VFA; YX/S, Growth yield in Cmmol X/Cmmol VFA

环境工程外文文献及翻译-水处理

环境工程外文文献及翻译-水处理摘要水是人类生存不可或缺的资源，但当前全球范围内的水资源短缺和水污染问题越来越严重，给人类带来了严重的环境和健康问题。

环境工程领域的研究者们在水处理方面做出了重要的贡献，下面是关于水处理的外文文献及翻译，希望对读者们有所启发。

文献1：Removal of pharmaceuticals from municipal wastewater using membrane bioreactor technology这篇论文来源于《Water Research》期刊，讨论了利用膜生物反应器技术处理城市污水中的药物问题。

文章指出，生物膜反应器技术可以有效地去除医药废水中的药物，其净化效率高于传统的生物处理方法。

并且，就经济效益而言，膜生物反应器技术比传统的处理方法更为可行。

翻译1：膜生物反应器技术处理城市污水中的医药废水根据《Water Research》期刊报道，膜生物反应器技术是一种有效去除医药废水中药物的方法。

研究表明，这种技术比传统的生物处理方法更为高效，而且在经济上也更加可行。

文献2：Application of a Modified Ultrafiltration Process for Water Reuse in a Municipal Wastewater Treatment Plant这篇论文来源于《Environmental Engineering Science》期刊，介绍了一种改进的超滤技术，在城市污水处理厂中进行水资源回收利用。

论文指出，这种技术能够去除水中的有机物和微生物等污染物，同时还能够保持水质的稳定性。

该技术对于水资源短缺的地区来说十分有用。

翻译2：改进的超滤技术在城市污水处理厂的水资源回收中的应用据《Environmental Engineering Science》期刊报道，一种改进的超滤技术已成功应用于城市污水处理厂中，用于水资源回收利用。

给水排水工程专业英语文献翻译译文第一篇

一种利用蜜糖废水产生PHA的侧流工艺的建立方法摘要试验建立了一种利用蜜糖废水生产聚羟基烷酸脂（PHA）的三阶段过程。

该过程包括（1）糖蜜废水酸酵解，（2）PHA富集菌的筛选，（3）利用富集完毕的污泥和酵解之后的糖蜜废水批次累积PHA。

在发酵阶段，试验评估了PH（5~7）对有机酸型体分布以及产率的影响。

PH较高时乙酸和丙酸为主要产物，然而较低的PH值有利于丙酸和戊酸的产生。

试验评估了利用乙酸盐和发酵糖蜜废水为基质筛选的两类菌群的PHA积累能力。

考察了有机酸型体分布对利用醋酸盐筛选菌群产生的多聚体的组成以及产率的影响。

PHA富集产率在0.37到0.50CmmolHA/Cmmol VFA之间变化。

试验观察到了被利用有机酸的类型和多聚物成分的一种直接关系。

在糖蜜废水中，低氨氮浓度（0.1Nmmol/l）促进了PHA 的储存（0.59 Cmmol HA/Cmmol VFA）。

此外，试验建立了一种控制反应器运行利用发酵糖蜜废水筛选PHA富集菌群的方法。

利用高有机负荷以及低氨氮浓度选择了一种具有稳定储存PHA能力的菌群，富集产率达到0.59Cmmol HA/Cmmol VFA)，这一能力与醋酸盐筛选菌相似。

前言聚羟基烷酸脂被认为是优良的可生物降解塑料的候选者。

这类含有多种单体组分具有热塑性的多聚物是被细菌作为能量和碳储存物质的。

它们的结构特性与聚丙烯的结构性质一致，同时又具有诸多优势：可生物降解、可生物相容、能进一步由可再生碳源产生从而使可持续生产过程成为可能。

然而，PHAs与石化工业衍生的塑料制品在成本上相当大的差异成了这类高聚物部分替代后者的阻碍。

目前，商业可行的PHAs是由纯菌（野生的和基因重组的菌种）和纯底物（通常很昂贵）工业化生产而来。

PHAs的价格主要取决于底物成本，约占总成本的40%（Choi和Lee，1997）。

最近十年来，一系列低成本的碳源基质（例如淀粉、木薯粉水解物、乳清和蜜糖）在纯菌生产PHA过程中得到检验。

环境工程英文文献附带带翻译

Environmental problems caused by Istanbul subwayexcavation and suggestions for remediationIbrahim OcakAbstract:Many environmental problems caused by subway excavations have inevitably become an important point in city life. These problems can be categorized as transporting and stocking of excavated material, trafﬁc jams, noise, vibrations, piles of dust mud and lack of supplies. Although these problems cause many difﬁculties, the most pressing for a big city like Istanbul is excavation, since other li sted difﬁculties result from it. Moreover, these problems are environmentally and regionally restricted to the period over which construction projects are underway and disappear when construction is ﬁnished. Currently, in Istanbul, there are nine subway construction projects in operation, covering approximately 73 km in length; over 200 km to be constructed in the near future. The amount of material excavated from ongoing construction projects covers approximately 12 million m3. In this study, problems—primarily, the problem with excavation waste (EW)—caused by subway excavation are analyzed and suggestions for remediation are offered.Keywords: Environmental problems Subway excavation Waste managementIntroductionNowadays, cities are spreading over larger areas with increasing demand on extending transport facilities. Thus, all over the world, especially in cities where the population exceeds 300,000–400,000 people, railway-based means of transportation is being accepted as the ultimate solution. Therefore, large investments in subway and light rail construction are required. The construction of stated systems requires surface excavations, cut and cover tunnel excavations, bored tunnel excavations, redirection of infrastructures and tunnel construction projects. These elements disturb the environment and affect everyday life of citizens in terms of running water, natural gas, sewer systems and telephone lines.One reason why metro excavations affect the environment is the huge amount of excavated material produced. Moreover, a large amount of this excavated material is composed of muddy and bentonite material. Storing excavated material then becomes crucial. A considerable amount of pressure has been placed on ofﬁcials to store and recycle any kind of excavated material. Waste management has become a branch of study by itself. Many studies have been carried out on the destruction, recycling and storing of solid, (Vlachos 1975; Huang et al. 2001; Winkler 2005; Huang et al. 2006; Khan et al. 1987; Boadi and Kuitunen 2003; Staudt and Schroll 1999; Wang 2001; Okuda and Thomson 2007; Yang and Innes 2007), organic (Edwards et al. 1998, Jackson 2006; Debra et al. 1991; Akhtar and Mahmood 1996; Bruun et al. 2006; Minh et al. 2006), plastic (Idris et al. 2004; Karani and Stan Jewasikiewitz 2007; Ali et al. 2004; Nishino et al. 2003; Vasile et al.2006; Kato et al. 2003; Kasakura et al. 1999; Hayashi et al. 2000), toxic (Rodgers et al. 1996; Bell and Wilson 1988; Chen et al. 1997; Sullivan and Yelton 1988), oily(Ahumada et al. 2004; Al-Masri and Suman 2003), farming(Garnier et al. 1998; Mohanty 2001) and radioactive materials(Rocco and Zucchetti 1997; Walker et al. 2001; Adamov et al. 1992; Krinitsyn et al. 2003).Today, traditional materials, including sand, stone, gravel, cement, brick and tiles are being used as major building components in the construction sector. All of these materials have been produced from existing natural resources and may have intrinsic distinctions that damage the environment due to their continuous exploitation. In addition, the cost of construction materials is incrementally increasing. In Turkey, the prices of construction materials have increased over the last few years. Therefore, it is very important to use excavation and demolition wastes (DW) in construction operations to limit the environmental impact and excessive increase of raw material prices. Recycling ratios for excavation waste (EW) and DW of some countries are in shown Table 1 (Hendriks and Pietersen 2000). The recycling ratio for Turkey is 10%. Every year, 14 million tons of waste materials are generated in Istanbul. These waste materials consist of 7.6 million tons EW, 1.6 million tons organic materials and 2.7 million tons DW (IMM 2007). Approximately, 3.7 million tons of municipal wastes are produced in Istanbul every year. However, the recycling rate is approximately equal to only 7%. This rate will increase to 27%, when the construction of the plant is completed. Medical wastes are another problem, with over 9,000 tons dumped every year. Medical wastes are disposed by burning. Distributions of municipal wastes are given in Fig. 1Country Concentration of CWin total waste (in%)CW and DW recycled (in%)Japan36 65Australia44 51Germany19 50Finland14 40United Kingdom over 50 40USA29 25France25 25Spain70 17Italy30 10Brazil15 8Table 1 C omparison of a few countries’ construction waste concentrationFig. 1 Current status of municipal waste distribution in IstanbulIn this study, environmental problems in Istanbul, such as EW resulting from tunnelling operations, DW resulting from building demolition and home wastes, are evaluated. Resources of EW, material properties and alternatives of possible usage are also evaluated.Railway system studiesThree preliminary studies concerning transportation in Istanbul were conducted in 1985, 1987 and 1997. A fourth study is currently being conducted. The Istanbul Transportation Main Plan states that railway systems must constitute the main facet of Istanbul’s transportation net-work (IMM 2005). In addition to existing lines, within the scope of the Marmaray Project, 36 km of metro, 96 km of light rail, and 7 km of tram, with a total of 205 km of new railway lines, must be constructed. Consequently, the total length of railway line will exceed 250 km.Environmental problems caused by subway excavationsTransporting and storing excavated materialAlmost all land in Istanbul is inhabited. Therefore, it is of utmost importance to store and recycle excavated material obtained either from metro excavations or other construction activities, causing minimal damage and disturbance to the city. The collection, temporary storage, recycling, reuse, transportation and destruction of excavated material and construction waste are controlled by environmental law number 2872. According to this law, it is essential that:1. Waste must be reduced at its source.2. Management must take necessary precautions to reduce the harmful effects of waste.3. Excavated material must be recycled and reused, especially within the construction infrastructure.4. Excavated material and construction waste must not be mixed.5. Waste must be separated from its source and subjected to “selective destruction” in order to form a sound system for recycling and destruction.6. Producers of excavated material or construction waste must provide required funds to destroy waste.According to environmental laws, municipalities are responsible for ﬁnding areas within their province limits to excavate and operate these systems. Both the Istanbul Metropolitan Municipality Environmental Protection and Waste Recycling Company are the foundations that actively carryout all operations regarding excavated material.Since dumping areas have limited space, they are quickly ﬁlled, without a ny available plausible solution for remediation. In addition, existing dumping areas are far away from metro excavation areas. This means that loaded trucks are competing with city trafﬁc, causing trafﬁc congestion with their low speed and pollutants dropping off their wheels or bodies. Furthermore, this results in a loss of money and labour.The approximate amount of excavated material from ongoing railway excavation will be equal to 12 million m3. All tunnels have been excavated with new Austrian tunnelling method (NATM), earth pressure balance method (EPBM), tunnel boring machine (TBM), and cut and cover method.Existing dumping areas in Istanbul are listed in Table 2. It can be seen that existing dumping areas can only accommodate material excavated from the metro construction. Another important matter according to Table 2 is that 93% of existing dumping areas are on the European side of Istanbul, with 88% of them in Kemerburgaz. Thus, all excavated material on the Anatolian side must cross over European site every day for a distance of approximately 150 km. Every day, on average, 3,000 trucks carry various types of excavated material to Kemerburgaz from other parts of Istanbul. This leads to a waste of time and increased environmental pollution.Name of firm Dumping Capacity (m3)%Total of European side13,984,158 93.3 Total of Anatolian side (six companies)Various 1,011,486 6.7Table 2 Existing dumping areas in IstanbulAnother problem related to excavation is that the materials, obtained from EPBM machines and muddy areas, cannot be directly sent to dumping facilities. They have to be kept in suitable places, so that water can be drained off from the materialand then sent to proper facilities. However, this causes muddy material to drop from trucks, causing increased litter in cities.Trafﬁc jamSince most of the railway constructions are carried out in the most densely populated areas, city trafﬁc must be cl osed and redirected during the construction. In most cases, an entire area must be closed for trafﬁc. For example, Uskudar square is now closed due to the Marmaray project and most bus stops and piers have been moved to other locations.With cut and cover constructions, the case becomes even more complicated. In this case, an entire route is closed to trafﬁc because cut and cover tunnels are constructed across streets. In order to ensure that machine operation and construction can continue uninterrupted and to minimize the risk of accidents to the people living around the construction zone, streets are either totally closed to trafﬁc or trafﬁc is redirected. This causes long-term difficulties. For example, shop owners on closed streets have difﬁculties re aching their shops, stocking and transporting their goods and retaining customers.Noise and vibrationFor metro excavations, a lot of different machines are used. These machines seriously disturb the environment with their noise and vibrations. In some regions, excavation may be as close as 5–6 m away from inhabited apartment blocks. In such cases, people are disturbed as excavation may take a signiﬁcant p eriod of time to be completed.Drilling–blasting may be needed in conventional methods for drilling through hard rock. In this case, no matter how controlled the blasting is, people who are living in the area experience both noise and vibrations. Some become scared, thinking that an earthquake is happening. In blasting areas, the intensity of vibrations is measured. In order to keep them within accepted limits, delayed capsules are used.In order to minimize vibration and noise caused by machines and to reduce the effects of blasting, working areas are surrounded by fences. Super ﬁcial blasting shaft rims are covered with a large canvas and fences are covered with wet broadcloths. However, these precautions can only reduce negative effects; they cannot totally eliminate them.The formation of dust and mudDepending on the season, both dust and mud disturb the environment. During removal of excavated material, especially muddy material, trucks may pollute the environment despite all precautions taken. Mud that forms around the excavation area may slide down the slope and cover the ground. In this case although roads are frequently cleaned, the environment is still disturbed. Trucks, which travel from dumping areas to areas that are mud dy cannot enter trafﬁc until their wheels and bodies are washed. However, this cannot prevent the truck wheel from dropping mud on the roads while on move.Interrupted utilitiesInterrupted utilities are also one of the most crucial problems facing citizens during excavation projects due to the fact that telephone, natural gas, electricity, water, and infrastructure lines must be cut off and moved to other areas. During the transfer of these lines, services may remain unavailable for some time. Some institutions will not allow others to do this and carry out operations themselves. With so many providers conducting individual moves, services may be interrupted for an extended term of time.Damage to neighbouring buildingsMetro excavations cause deformations around the excavation area. These deformations are continuously checked and efforts are made to keep them under control. However, some deformations may become extensive; including cracks or even collapses of neighbouring buildings. Every metro tunnel excavation in Istanbul causes problems as mentioned earlier. These kinds of problems are more frequent in shallow tunnels. In such cases, although people’s financial losses are compen sated, their overall livelihood and way of life is compromised. For example, in a landslip during the ﬁrst stage of the Istanbul Metro excavation, ﬁve people died. Obviously, no amount of money can compensate the death of a person.Suggestions for remedying environmental problemsEnvironmental problems that arise during tunnel excavations include trafﬁc jams, noise, vibrations, dust, mud and deformation of surrounding buildings. Some possible solutions are recommended as listed below:• In big cities, railway systems are crucial to city transportation. However, a tram should not be considered as a viable railway system due to its low transportation capacity (approximately 1/3 of the metro). At the same time, a tram uses the same route as wheeled transportation devices. Therefore, trams occupy the same space as regular trafﬁc a nd do not offer substantial advantages.• The most crucial problem facing metro excavations is not providing railway lines in a timely manner. Proof of this exists in big cities, including London, Paris, Moscow or Berlin, where metro lines of over 500 km exist. However, in Istanbul, there are only 8 km of metro line. Had the metro been built earlier when the city was not overcrowded, many problems facing the city would not currently exist. Now, ofﬁcials must do their best to reduce troubles that future generations are likely to face.• Any kind of railway construction carried out above the ground causes serious problems to people living in the area. In addition, these kinds of construction cause both noise and litter. All railway lines are constructed completely underground in many parts of the world. This has two advantages; ﬁrst, since excavation is carried out underground, it causes minimal interruption in utilities and provides a more comfortable area to work. Thus, the environment is exposed to very little damage because all operations are carried out underground.• Before beginning metro excavations, the route must be carefully examined for weaknesses in infrastructures and existing historical buildings. Otherwise, these elements cause problems, including interruptions in excavation when work must stop until the environment is stabilized. An example of this is that during the second stage of the Taksim–Yenikapi route of the Istanbul Metro, the construction of the Halic Bridge could not be started due to historical ramparts.• A lack of coordination among related institutions providing utility services is a major problem. Therefore, founding of an institution that strictly deals with relocating natural gas lines, telephone lines, sewer systems, and electricity will deﬁnitely accelerate the transfer of energy lines and avert accidents and inconveniences caused by this lack of coordination.•In order to increase beneﬁts of railway systems both in constr uction and operational stages, projects must be continuously revised from time to time. This is the main problem facing Istanbul metro excavations. It has taken 110 years to restart metro projects in Istanbul, with the last project, the opening of the Karakoy tunnel, established in 1876 (Ocak 2004).From this time onward, initiated projects must have been stable and continuous. In 1935, 314,000 passengers were travelling daily. In the 1950s, the total length of tram lines reached 130 km (Kayserilioglu 2001). However, as the trolleybus was introduced in 1961, all tram lines on the European side, and in 1966, all lines on the Anatolian side were removed in order to make way for private vehicles (Kayserilioglu 2001).Results and discussionTBM and classic tunnel construction methods are widely used in Istanbul for different purposes, like metro, sewerage and water tunnels. Waste from rock is rarely used as construct ion material as the suitability of the material for this purpose is not well examined. However, it is believed that the muck may be used for some applications. If this suitability is realized, cost savings may be signiﬁcant for tunnel construction, where the use of aggregate is a common requirement. A review of standard construction aggregate speciﬁcations indicates th at hard rock TBM waste would be suitable for several construction applications, including pavement and structural concrete (Gertsch et al. 2000). Size distributions of waste materials produced by tunnel boring machines are less (up to 125mm) than the waste materials produced by using classical construction methods. Muck size distribution is uniform, generally larger (up to 30–40 cm) and can be changed to meet a wide range of classical construction methods, making the reuse of waste more common. The waste product is used as construction materials. Fifty -seven percent of EW generated during tunnel excavations result from classical tunnel construction, 33.5% from TBM, while the remaining percentage stems from EPBM and slurry TBM. Different from TBM waste materials generated by EPB and slurry, TBM include mud and chemical materials.The annual quantity of EW generated in Istanbul is approximately 7.6 million tons. 13.8% of this total is clay and ﬁll. The rest is composed of rock. Rock material can be properly used in roadway structures, ﬁllings, road slopes, for erosion controland as a sub-base material, as long as it conforms to local standards (TS706, TS1114). Sand and clay have properties appropriate for use as raw materials for industrial use, depending on local standards. More studies should be completed to determine other potential uses for this material. Only 10% of rock material generated during tunnel excavation can be evaluated. A large percentage of soil material, nearly 70,000 m3, can be recycled.Generally, for any subway construction project, plans for recycling waste materials should be implemented prior to work commencement. These plans should identify which types of waste will be generated and the methods that will be used to handle, recycle and dispose these materials. Additionally, areas for temporary accumulation or storage should be clearly designated. A waste management plan directs construction activities towards an environmentally friendly process by reducing the amount of used and unused waste materials. Environmental andecon omic advantages occurring when waste materials are diverted from landﬁlls include the following (Batayneh et al. 2007):1. The conservation of raw materials2. A reduction in the cost of waste disposal3. An efﬁcient use of materials.EW materials mu st be kept clean and separate in order for them to be efﬁciently used or recycled. Storage methods should be investigated to prevent material from being lost due to mishandling. In addition, orders for materials should be placed just before work commences. To complete a waste management plan, an estimation of the amount and type of usable and unusable EW materials expected to be generated should be developed. Listing all expected quantities of each type of waste will give an indication of what type of man agement activities are appropriate for each speciﬁc waste material. At each stage of excavation, speciﬁc ways to reduce, reuse or recycle produced EW should be implement ed. The ﬂow chart in Fig. 2 includes suggestions for an EW management plan.This paper focuses on EW produced by metro tunnel excavation through hard rock and soil. TBM and classical tunnelling wastes can be successfully used in many construction and speciality applications, including aggregates, erosion control, roadway structures, ﬁll, sub-base material and road slopes. In order to minimize negative effects caused by excavated material both on the environment and on people, it must be reduced at its source. Including forcible decrees through the acceptance of environmental laws would also be useful. Soil and clay material, excavated through the use of EPBM machines, must be reused. It is possible to separate clay and sand, making its reuse possible and minimizing harmful environmental effect.Waste and recycling management plans should be developed for any construction project prior to commencement in order to sustain environmental, economic, and social development principles. Waste management is a critical issue facing the construction industry in Istanbul as the industry is one of the biggest generators of pollution. During different excavation projects, construction, demolitions and domestic activities, Istanbul produces about 14 million tons of solid waste each year, posing major environmental and ecological problems, including the need for a large area of land to be used as storage and disposal facilities. This wasteconsists of EW (7.6 million tons), DW (2.7 million tons) and municipal waste (3.7 million tons). The recycling rate of municipal waste is only 7%. The recycling rate of EW and DW is below 10% (IMM 2007).Fig. 2 Flow chart for EW management伊斯坦布尔地铁开挖引起的环境问题及补救建议摘要：许多地铁开挖引起的环境问题不可避免地成为城市生活的重要部分。

给排水专业毕业设计翻译中英文对照(20页)

Oxidize ditch craft in dirty water handle of application and development Summary: This text expatiated primarily the Carrousel oxidizes the construction, craft mechanism of the ditch and circulate the problem exsited in the process with the homologous the method of solution.Finally, introduce the Carrousel oxidize the latest research progress of the ditch and pointed out the future and main research direction.Key phrase: The Carrousel oxidizes ditch divideds by the phosphor takes off the nitrogen construction mechanism Application and Development of Carrousel Oxidation Ditch Process on Wastewater TreatmentAbstract: The structure and the techniques of carrousel oxidation ditch process on nitrogen and phosphor removal are introduced in this paper. The problems inrunning and their corresponding resolvent are also pointed. At last, The authorshowed the up to date research improvement and the mainly future research dire-ction.Key words: Carrousel; oxidation ditch; nitrogen and phosphor removal; structure;techniques1. ForewordOxidize the ditch( oxidation ditch) again a continuous circulation spirit pond( Continuous loop reactor), is a live and dirty mire method a kind of to transform.Oxidizing the dirty water in ditch handles the craft be researched to manufacture by the hygiene engineering graduate school of Holland in the 50's of 20 centuries success.Since in 1954 at Dutch throw in the usage for the very first time.Because its a water fluid matter good, circulate the stability and manage convenience etc. technique characteristics, already at domestic andinternational and extensive application in live the dirty water to is dirty to manage aqueously with the industry[1].Current application than oxidize extensively the ditch type include:The ( Pasveer) oxidizes the ditch, the ( Carrousel) oxidizes the ditch, ( Orbal) oxidizes the ditch, the type of T oxidizes the ditch( three ditch types oxidize the ditch), the type of DE oxidizes the ditch to turn to oxidize the ditch with the integral whole.These oxidize the ditch because of the difference of esse in construction with circulating, therefore each characteristics[2].This text will introduce construction, mechanism, existent problem and its latest developments that Carrousel oxidize ditches primarily.2. The Carrousel oxidizes the construction of the ditchThe Carrousel oxidize the ditch to be researched to manufacture by Dutch DHV company development in 1967.Oxidize the last the company of DHV in foundation of the ditch in the original Carrousel to permited specially the company EIMCO to invent again with its patent in the United States Carrousel 2000 system( see the figure ), realizes the living creature of the higher request takes off the nitrogen with divided by the function of .There has been in the world up to now more than 850 Carrousels oxidize the ditch with the Carrousel 2000 system are circulating[3].From diagram therefore, the Carrousel oxidizes the ditch the usage the spirit of that definite direction control with shake up the device, face to mix with the liquid deliver the level speed, from but make drive the liquid of admixture that shake up is in oxidize ditch shut match outlet circulate flow.Therefore oxidize the ditch have the special hydraulics flows the , current complete mix with the characteristics of the type reactor, have the characteristics that push the flow type reactor again, the ditch inside exsits obviously of deliquescence oxygen density steps degree.Oxidizing the ditch crosssection is rectangle or trapezoids, the flat surface shape is many for oval, the ditch internal water is deep general for 2.5 ～4.5 ｍ, the breadth is deep compare for 2:1, also have the deep water amount to 7 ms of, ditch inside average speed in water current is 0.3 ms/ s.Oxidize ditch spirit admixture equipments contain surface spirit machine, the spirit of turn to brush or turn the dish and shoot to flow the spirit machine, pipe type spirit machine with promote take care of type spirit machine etc., match with in recent years usage still contain underwater push machine[4~6].3. The Carrousel oxidizes the mechanism of the ditch3.1 The Carrousel oxidizes the ditch handles dirty and aqueous principleThe at the beginning common Carrousel oxidizes the dirty water in inside in craft of the ditch direct with dirty mire in reflux together enter oxidize the ditch system.The surface spirit machine makes fuse in the liquid of admixture the density of the oxygen DO increases about 2 the 3 mgs/ L.Under this kind of well the term of the oxygen , the microorganism gets the enough deliquescence oxygen comes and go to divided by the BOD;At the same time, the ammonia were too oxidized nitrate with second nitrate, this time, mix with the liquid be placed in the oxygen appearance.In the spirit machine downstream, after water current be become by the swift flow appearance of the spirit District of even flow the appearance, the water current maintains in the minimum current velocity, guaranteeing the live and dirty mire be placed in the floats the appearance.( average current velocity>0.3 ms/ s)Oxidize microbially the process consumed to fuse the oxygen in the water, until the value of DO declines for zero, mixing with the liquid report the anoxia appearance.Versa nitric that turn the function through anoxia area, mix with the liquid enter to have the oxygen area, completing once circulating.That system inside, theBOD declines the solution is a continuous process, the nitric turns the function to turn with the versa nitric the function take place in same pond.Because of structural restrict, this kind of oxidize the ditch although can then valid whereabouts BOD, divided by the phosphorus take off the nitrogenous ability limited[7].For the sake of the acquisition better divided by the phosphorus take off the nitrogenous result, Carrousel 2000 systems increased a oxygen District before common Carrousel oxidize ditch with the unique oxygen area.( call again that the versa nitric in front turns the area)The dirty mire in all refluxes enters the anaerobic District with 10-30% dirty water, can under the anoxia with 10-30% carbon source term complete remaining of dirty mire in reflux inside nitric acid nitrogen to versa nitric to turn, creates for the unique oxygen pond of hereafter unique oxygen term.At the same time, anaerobic District inside of concurrently the sex germs convert the dissolubility BOD VFA, the germ acquire the VFA its assimilation PHB, the energy source needed solves in the phosphoric water and cause phosphatic releasing.The anaerobic District a water enters the inner part installs the unique oxygen area that have the mixer, the so-called unique oxygen is a pond inside to mix with liquid since have no the numerator oxygen, also have no the compound oxygen( nitric acid root), the here unique oxygen environment is next,70-90% dirty water can provide the enough carbon source, can make the germ of released the phosphorus well.The unique oxygen area connects behind the common Carrousel oxidizes the ditch system, further completing to do away with the BOD and take off the nitrogen with divided by the phosphorus .Finally, mix with the liquid transfer the dirty mire inside in oxidize ditch enrich oxygen area eject, while enriching the oxygen environment germ surfeit, phosphorus from the water, ejecting the system with the dirty mire in surplus.Like this, in Carrousel 2000systems, than completed to do away with the BOD, COD with take off at the same time goodly the nitrogen divided by the phosphorus .Synthesizing and dirty water in the river City , long sand City decontamination center[s of the dirty the factory of water in the first in Kunming of adoption that crafts handles the movement result of the factory therefore:Through Carrousel 2000 system after handling, the BOD, COD, SS does away with the rate to all come to a 90% above, the TN does away with the rate comes to a 80%, the TP does away with the rate to also come to a 90%.3.2 The Carrousel oxidizes the ditch divideds by the phosphorus takes off the nitrogenous influence factor.Affecting the Carrousel oxidizes the ditch divideds by the phosphoric factor is dirty mire , nitrate density and quality densities primarily.The research expresses, being total and dirty mire as 11% that a hour biggest phosphorus 4% with deal is its fuck dirty mire deal within live and dirty mire, keep for the the germ physical endowment measures, but when dirty mire over 15 d hour dirty mire the inside is biggest to contain the obvious descent in deal in phosphorus , canning not reach the biggest divideding by the result of phosphorus on the contrary.Therefore, prolong persistently the dirty mire ( for example 20ds,25ds,30ds) is to have no necessary, proper choose to use within the scope of 8~15 d.At the same time, high nitrate density with low quality density disadvantage in divided by the process of phosphorus .Affecting the Carrousel oxidizes the ditch takes off the nitrogenous and main factor is DO, nitrate density and carbon source densities.The research expresses, oxidizing the ditch inside exsits deliquescence oxygen density steps degree namely the good oxygen area DO attains 3~3.5 mgs/ L, the anoxia area DO attains 0~0.5 mgs/ L is a prior condition to take place nitric turn reaction and versa nitricsturn the reaction.At the same time, ample carbon source and higher C/ the N ratio benefits to take off to complete nitrogenously[7].4. The Carrousel oxidizes problem and solution methods of the ditch esse.Though the Carrousel oxidizes the ditch has a water fluid matter good, the anti- pounds at the burthen ability strong, divided by the phosphorus take off the nitrogen efficiency. But, in physically of movement process, still exsits a series of problem.4.1 Dirty mire inflation problemWhen discard the aquatic carbohydrate more, the N, P contains the unbalance of deal, the pH value is low, oxidizing the dirty mire in inside in ditch carries high, fuse the oxygen density the shortage, line up the mire not etc. causes easily dirty mire in germ in form in silk inflation;Not the dirty mire in germ in form in silk inflation takes place primarily at the waste water water temperature is lower but the dirty mire carries higher hour.The microbial burthen is high, the germs absorbed the large quantity nourishment material, is low because of the temperature, metabolism the speed is slower, accumulating the rises large quantity is high to glue sexual and many sugar materials, making the surface of the live and dirty mire adhere to the water to increase consumedly, SVI the value is very high, becoming the dirty mire inflation.Cause that aim at the dirty mire inflation, can adopt the different counterplan:From the anoxia, water temperature high result in of, can enlargement tolerance or lower into the water measures to alleviate burthen, or the adequacy lowers the MLSS( control dirty mire reflux measure), making need the oxygen measures decrease;If the dirty mire carries high, can increase MLSS, to adjust the burthen, necessity the hour can stop into the water, stuffy a period of time;Can pass the hurl add the nitrogen fertilizer, phosphorus fatty, adjust the admixturenourishment in the liquid material equilibrium( BOD5:N:P=100:5:1);The value of pH over low, can throw to add the lime regulate;Bleach the powder with the liquid chlorin( press to fuck 0.3% of the dirty mire~0.6% the hurl adds), can repress the silk form germ breed, controling the dirty mire in combinative water inflation[11].4.2 Foam problemBecause entering to take the grease of large quantity in the water, handling system can't completely and availably its obviation, parts of greases enriches to gather in in the dirty mire, through turn to brush the oxygen agitation, creation large quantity foam;The mire is partial to long, the dirty mire is aging, and also easy creation foam.Spray to pour the water or divided by with the surface the of do away with the foam, in common use divided by the an organism oil, kerosene, the oil of silicon, throw deal as 0.5~1.5 mgs/ L.Pass to increase dirty mire in pond in spirit in density or adequacies let up the tolerance of , also can control the foam creation effectively.When contain the live material in surface in the waste water more, separate with the foam easily and in advance method or other methods do away with.Also can consider to increase to establish a set of divideding by the oil device moreover.But enhance most importantly the headwaters manage, reducing to contain the oil over the high waste water and other poisonous waste water of into[12].4.3 Float the problem on the dirty mireWhen contain in the waste water the oil measures big, whole system mire quality become light, can't like to control very much in operate process its at two sink the pond stop over time, resulting in the anoxia easily, producing the corrupt and dirty mire ascend to float;When spirit time over long, take place in pond the high degree nitric turn the function, making nitrate density high, at two sink theversa nitric in easy occurrence in pond turn the function, creation nitrogen spirit, make dirty mire ascend float;Moreover, contain the oil in the waste water?Take place the dirty mire ascend after floating should pause enter water, broke off or dirty mire in clearance, judge the clear reason, adjust the operation.The dirty mire sinks to decline the sex bad, can throw to add of oagulate or sloth materials, the improvement precipitates the sex;Such as enter the water carries big let up into the water measures or the enlargement reflux measures;Such as the dirty mire grain small lower the spirit machine turn soon;If discovers versa nitric turning, should let up the toerance , enlarge the reflux or row the mire measures;If discover the dirty mire is corrupt, should enlargement tolerance, the clearance accumulates the mire, and try the ameliorative pond internal water dint term[12].4.4 Current velocity is not all and the dirty mire sinks to accumulate the problemIn Carrousel oxidize ditch, for acquiring its special admixture with handles result, mix with liquid must with certain current velocity is in ditch circulate flow.Think generally, the lowest current velocity should should attain for an average current velocity for, doing not take place sinking accumulating 0.3~0.5 ms/ s.The spirit equipments that oxidize the ditch is general to turn to brush for the spirit of to turn the dish with the spirit of , turning to brush of immerse to have no depth for 250~300 mms, turn the dish immerse to have no depth for 480~530 mms.With oxidize the ditch water the deep(3.0~3.6 ms) comparing, turn to brush occupied the deep 1/10~ in water 1/12, turned the dish to also occupy the 1/6~ only 1/7, therefore result in to oxidize the ditch upper part current velocity bigger( roughly 0.8~1.2 ms, even larger), but the bottom current velocity is very small( especially at the water is deep 2/3 or 3/4 below, mix with theliquid has no current velocity almost), causing ditch bottom large quantity accumulate the mire( sometimes accumulate the mire thickness amount to a 1.0 ms), the valid capacity that reduced to oxidize the ditch consumedly, lowered to handle result, affected a water fluid matter.Adding the top, downstream leads to flow the plank is a valid method that ameliorative current velocity distribute, increases the oxygen ability with the most convenient measure.The upper stream leads to flow the plank installs at be apart from to turn the 4.0 places( upper stream) ：dish( turn to brush) axis, lead to flow plank high degree as the deep 1/5~ in water 1/6, combine the perpendicularity install in the surface;The downstream leads to flow the plank installs at be apart from to turn dish( turn to brush) axis 3.0 ms.Leading to flow knothole material can use metals or glass steels, but regard glass steel as good.Lead to flow the plank compares with other ameliorative measure, can't not only increase the motive consumes with revolves cost, but also can still than significantly exaltation 充oxygen ability with theories motive efficiency[13].Moreover, pass in the spirit on board swim to establish the underwater push machine can also turn to the spirit of the liquid of admixture that brush the bottom low speed area circulates to flow to rise positive push function, from but the solution oxidizes the problem that low and dirty mire in current velocity in bottom in ditch sink accumulates.Establish the underwater push machine useds for exclusively the push mixs with the liquid can make movement method that oxidize the ditch much more vivid, this for economy energy, lift the high-efficiency having the very important meaning[14].5. The Carrousel oxidizes the development of the ditchBecause the dirty water handles standard inside to divided by the phosphorus take off the nitrogenous request more and more strict,the development that Carrousel further oxidized the ditch to also get.Current, the research and application includes morely below two category type:Tiny bore spirit type Carrousel 2000 systems, Carrousel 3000 system.5.1 Tiny bore spirit type Carrousel 2000 systemTiny bore spirit type Carrousel 2000 tiny bore in adoption in system spirit( provide oxygen equipments as the drum breeze machine), the tiny bore spirit machine can produce the diameter of large quantity as a surface for or so and small spirit steeping, this consumedly increases spirit bubble accumulates, undering the certain circumstance in capacity in pond make the oxygen transfer the gross measures aggrandizement.( if deep increment in pond, its spread the quality efficiency will be higher)Produce the technique ability of the factory house according to the current drum breeze machine, the valid water of the pond is deep biggest amounting to a 8 ms, therefore can select by examinations according to the different craft request the fit water is deep.The tradition oxidizes the ditch pushes to flow is to make use of to turn to brush, turn a disc or pour the umbrella type form machine realizes of, its equipments utilization is low, the motive consumes big.Tiny bore spirit type Carrousel 2000 systems then adopted the underwater pushes the way that flow, rises to dive the propeller the leaf the motivation that round creation the direct function namely in the of water, at push to flow the function to can keep dirty mire from sinking to decline effectively again at the same time.As a result, the adoption dives the propeller since lower the motive consume, making mire water got again to mixs with adequately.Seeing from water power characteristic, tiny bore spirit type Carrousel 2000 systems are wreaths form the fold flows the pond type, concurrently pushing the flow type with complete mix with the typeflows .In regard to whole oxidize ditch, can think that oxidize the ditch is a complete mix with spirit pond, its density variety coefficient smallest even can neglect to do not account, enter the water will get the dilution quickly, therefore it have the very strong anti- pounds at the burthen ability.But have oxidize ditch inside of a certain very much the some pushing the characteristic of the flow type, in the nearby district in downstream in machine in spirit inDO density higher, but along with increase with spirit machine distance continuously then the density of DO lowers continuously.( appear the anoxia area)This kind of structure method makes friendly oxygen in area in anoxia area exsited to build the thing inside , making use of its water power characteristic well, coming to an efficiently the living creature takes off the nitrogenous purpose.Tiny bore spirit type Carrousel 2000 system though have the oxygen ability strong, divided by the phosphorus take off the nitrogen effective, cover the area little with can consume low etc. advantage, it also exsits at the same time the problem that tiny bore spirit equipments maintain.Current, the service life of the local and tiny bore spirit machine is 5 years in 4~, can amount to 10 years in 8~ goodly, but with import the tiny bore spirit machine compare to still have the certain margin.The spirit machine maintains unlike the form equipments is so convenient, it need to fuck the pond talent fixs, and also is to say once the tiny bore spirit machine appears the problem to need the adoption parallel two inconvenience for or third sets to solving problem, or adopting promoting device waiting to resolving, this too will giving production with managing bringing biggest[15 16].5.2 Carrousel 3000 systemCarrousel 3000 systems are in the Carrousel 2000 systems are ex- to plus a living creature the choice the area.That living creaturechoice area is a craft to make use of high organism carries to sieve germ grow, repress silk form germ increase, increase each pollutant do away with the rate, afterward principle together Carrousel 2000 system.Carrousel 3000 system of bigger increases to express at:An is to increased the pond deep, can amount to 7.5~8 ms, united at heart circle type, the pond wall uses totally, reducing to cover the area, lowering to build the price to increases to bear the low temperature ability at the same time;( can amount to 7 ℃ )Two is the liquid of admixture that spirit equipments that skillful design, the form machine descends to install to lead to flow , the anoxia of take out , adopt the underwater propeller solution current velocity problem;Three is to used the advanced spirit controller QUTE.( it adopt the much aer kind of changing the deal control mode)Four is to adopt the integral whole turn the design, starting from the center, including below wreath form consecution craft unit:Enter the well of water with the cent water machine that used for the live and dirty mire in reflux;Difference from four-part the choice pond that cent constitute with 厌oxygen pond.This outside is a Carrousel to have three spirit machine with a prepare versa nitric turn the pond 2000 system.( such as figure 2 show)Five is tube line that the design that the circular integral whole turn to make oxidize the ditch do not need additionally, can immediately realize dirty mire in reflux allotment in different craft unit[17].6. ConclusionThe Carrousel oxidizes the ditch because of having the good a phosphorus takes off the nitrogen ability, anti- pounds at the burthen ability with circulate to manage the convenience etc. the advantage, having got the extensive application.But because of technological development with social advance, that craft is necessarily willexaltation getting further.The author thinks:The Carrousel oxidizes the future research direction of the ditch will now of main below several aspects.1 Combination living creature method, research with develop the living creature model Carrousel oxidize the ditch.Like this can not only increases the microorganism gross of the unit reactor measures, from but increases the organism carries, but also living creature oneself the inside that have places the A/ the system of O enhances to take off the nitrogen result[18].2 Increases continuously the Carrousel oxidize the microbial activity in inside in ditch.For example throw to add the EM in oxidize ditch with single mind the germ grow, throws in that the salt of iron make the microorganism tame the live char in iron, devotion in living creature to become the formation to strengthen the germ gum regiment and increases to bear the toxicity pound at etc..3 Increasing the Carrousel oxidizes the ditch equipments function with supervise and control the technique.Function that increases form machine, underwater propeller, reduce to maintain the workload;Making use of DO, etc. of ORP many targets supervises and control the technique and changes the technique of is from now on the Carrousel oxidizes ditch science circulate necessarily from it road.4 Increasing the Carrousel oxidizes the ditch resistant to cold and bear toxicity can, reduce to cover the area to build the price with the engineering.Theoretical application, deep pond in water power term with the research of the craft function is to lowers the engineering builds the price and increases resistant to cold bear the toxicity can wait to provide the possible direction.氧化沟工艺在污水处理中的应用与发展摘要：本文主要阐述了Carrousel氧化沟的结构、工艺机理、运行过程中存在的问题和相应的解决方法。

环境工程外文文献及翻译水处理

氧化沟工艺在污水处理中的应用和发展摘要：本文主要阐叙了Carrousel氧化沟的结构、工艺机理、运行过程中存在的问题和相应的解决办法。

最后，介绍了Carrousel氧化沟的最新的研究进展并指出了未来的主要研究方向。

关键词：Carrousel氧化沟除磷脱氮结构机理1、前言氧化沟又名连续环曝气池，是活性污泥法的一种变形。

氧化沟处理工艺在20世纪50年代由荷兰卫生工程研究所研制成功的。

自从1954年在荷兰的首次投入使用以来。

由于其出水水质好、运行稳定、管理方便等技术特点，已经在国内外广泛的应用于生活污水和工业污水的治理。

目前应用较为广泛的氧化沟类型包括：帕斯维尔氧化沟、卡鲁塞尔氧化沟，奥尔博氧化沟、T型氧化沟、DE型氧化沟和一体化氧化沟。

这些氧化沟由于在结构和运行上存在差异，因此各具特点。

本文将主要介绍Carrousel氧化沟的的结构、机理、存在的问题及其最新发展。

2、Carrousel氧化沟的结构Carrousel氧化沟是1967年由荷兰的DHV公司开发研制。

在原Carrouse氧化沟的基础上DHV公司和其在美国的专利特许公司EIMCO又发明了Carrousel 2000系统，实现了更高要求的生物脱氮和除磷功能。

至今世界上已有850多座Carrousel氧化沟和Carrousel 2000系统正在运行。

Carrousel氧化沟使用定向控制的曝气和搅动装置，向混合液传递水平速度，从而使被搅动的混合液在氧化沟闭合渠道内循环流动。

因此氧化沟具有特殊的水力学流态，既有完全混合式反应器的特点，又有推流式反应器的特点，沟内存在明显的溶解氧浓度梯度。

氧化沟断面为矩形或梯形，平面形状多为椭圆形，沟内水深一般为2.5~4.5m，宽深比为2:1，亦有水深达7m的，沟内水流平均流速为0.3m/s。

氧化沟的曝气混合设备有表面、曝气转刷或转盘，射流曝气池、导管式曝气器和提升管曝气机等，近年来配合使用的还有水下推动器。

3、Carrousel氧化沟的机理3.1 Carrousel氧化沟处理污水的机理最初的普通Carrousel氧化沟的工艺中污水直接与回流污泥一起进入氧化沟系统。

给水排水工程专业英语文献翻译原文第三篇

Journal of Membrane Science 376 (2011) 196–206Contents lists available at ScienceDirectJournal of MembraneSciencej o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /m e m s ciFouling and cleaning of RO membranes fouled by mixtures of organic foulants simulating wastewater efﬂuentWui Seng Ang 1,Alberto Tiraferri,Kai Loon Chen 2,Menachem Elimelech ∗Department of Chemical and Environmental Engineering,P.O.Box 208286,Yale University,New Haven,CT 06520-8286,USAa r t i c l e i n f o Article history:Received 6December 2010Received in revised form 7April 2011Accepted 9April 2011Available online 20 April 2011Keywords:Reverse osmosis FoulingWastewater efﬂuent CleaningOrganic foulantsWastewater treatment Efﬂuent organic matter Wastewater reclamation Membranesa b s t r a c tThe fouling and subsequent cleaning of RO membranes fouled by a mixture of organic foulants sim-ulating wastewater efﬂuent has been systematically investigated.The organic foulants investigated included alginate,bovine serum albumin (BSA),Suwannee River natural organic matter,and octanoic acid,representing,respectively,polysaccharides,proteins,humic substances,and fatty acids,which are ubiquitous in efﬂuent organic matter.After establishing the fouling behavior and mechanisms with a mixture of organic foulants in the presence and absence of calcium ions,our study focused on the clean-ing mechanisms of RO membranes fouled by the mixture of organic foulants.The chemical cleaning agents used included an alkaline solution (NaOH),a metal chelating agent (EDTA),an anionic surfactant (SDS),and a concentrated salt solution (NaCl).Speciﬁcally,we examined the impact of cleaning agent type,cleaning solution pH,cleaning time,and fouling layer composition on membrane cleaning efﬁ-ciency.Foulant–foulant adhesion forces measured under conditions simulating chemical cleaning of a membrane fouled by a mixture of the investigated organic foulants provided insights into the chemical cleaning mechanisms.It was shown that while alkaline solution (NaOH)alone is not effective in dis-rupting the complexes formed by the organic foulants with calcium,a higher solution pH can lead to effective cleaning if sufﬁcient hydrodynamic shear (provided by crossﬂow)prevails.Surfactant (SDS),a strong chelating agent (EDTA),and salt solution (NaCl)were effective in cleaning RO membranes fouled by a mixture of foulants,especially if applied at high pH and for longer cleaning times.The observed cleaning efﬁciencies with the various cleaning agents were consistent with the related measurements of foulant–foulant intermolecular forces.Furthermore,we have shown that an optimal cleaning agent con-centration can be derived from a plot presenting the percent reduction in the foulant–foulant adhesion force versus cleaning agent concentration.© 2011 Elsevier B.V. All rights reserved.1.IntroductionAs demand for potable water increases worldwide,the paradigm for selecting water sources to meet this demand is transitioning from conventional sources,such as reservoirs and lakes,to less con-ventional sources,such as treated secondary wastewater efﬂuent.In order to produce water of superior quality,the use of mem-branes in desalination and wastewater reclamation has become more widespread.Membrane fouling is a major impediment to the use of membrane technology for such applications,because fouling is inevitable.Despite research efforts to develop better anti-fouling membranes [1]and improved fouling-control strategies [2,3],membrane fouling still occurs over time.Thus,a long-term∗Corresponding author.Tel.:+12034322789;fax:+12034324387.E-mail address:menachem.elimelech@ (M.Elimelech).1Current address:Public Utility Board of Singapore,Singapore.2Current address:Department of Geography and Environmental Engineering,Johns Hopkins University,Baltimore,MD 21218,United States.solution would be to remove the foulant deposited on the mem-brane via chemical cleaning.To select the appropriate cleaning agents and adopt an effective chemical cleaning protocol for fouled membranes in wastewater reclamation,the implications of wastewater efﬂuent characteris-tics on membrane fouling have to be well-understood.Wastewater efﬂuent contains dissolved organic matter,commonly known as efﬂuent organic matter (EfOM),which comprises polysaccha-rides,proteins,aminosugars,nucleic acids,humic and fulvic acids,organic acids,and cell components [2–4].Organic fouling of the RO membranes by the EfOM can be extensive since EfOM is gener-ally small enough to pass through the pores of pretreatment (MF or UF)membranes [4].In particular,recent ﬁndings suggest that while biofouling can prevail on the tail-element of the membrane module,fouling of the lead-element exposed to reclaimed water is dominated by EfOM adsorption [5].In addition,higher potential of fouling was observed for the higher molecular weight hydropho-bic/aromatic fraction of the EfOM [6,7].The presence of Ca 2+in the feed source for the RO membranes has been reported to form complexes with the constituents of EfOM,such as polysaccharidesW.S.Ang et al./Journal of Membrane Science376 (2011) 196–206197[8]and natural organic matter[9],and to signiﬁcantly enhance membrane fouling.While our previous studies have addressed the fouling of RO membranes by individual organic foulant types,such as polysaccharides[10],proteins[11],and fatty acids[12],only recently have investigations reported on the effects of a combina-tion or mixture of foulants on the fouling of RO membranes[13,14].A variety of chemical cleaning agents are commonly used to clean RO membranes fouled by organic matter[15].Alkaline solutions remove organic foulants on membranes by hydroly-sis and solubilization of the fouling layer.Alkaline solutions also increase the solution pH,and,therefore,increase the negative charges and solubility of the organic foulant.Metal chelating agents remove divalent cations from the complexed organic molecules and weaken the structural integrity of the fouling layer matrix[16]. Surfactants solubilize macromolecules by forming micelles around them[17],thereby facilitating removal of the foulants from the membrane surface.In our earlier study on salt cleaning of organic matter-fouled RO membranes[18],we demonstrated that NaCl and other common inert salts can be used as an effective alternative for the cleaning of RO membranes fouled by gel-forming hydrophilic organic foulants.In the presence of a salt solution,the fouling layer swells and becomes more porous.As a result,this would facil-itate the diffusion of Na+into the fouling layer and breakup of Ca2+–alginate bonds by ion exchange.Understanding the fouling layer characteristics and the interaction of chemical agents with foulants is therefore critical for the effective cleaning of organic matter-fouled RO membranes.Atomic force microscopy(AFM)has been applied in mem-brane fouling/cleaning research to quantify intermolecular forces [10,19–21].Our research has shown that foulant–foulant inter-actions could be determined by performing force measurements using a carboxylate-modiﬁed latex colloid probe in an AFMﬂuid cell[10,20].The technique has been used to quantify the foul-ing behavior of a nanoﬁltration membrane fouled by humic acid and the cleaning efﬁciencies of EDTA and SDS[20],and has been extended to quantify RO membrane fouling by organic foulant in the form of alginate[10],BSA[11],and octanoic acid[12].In this study,the AFM has also been employed as an alternative tool to indicate the optimal concentration of cleaning agent for cleaning fouled membranes.The original protocol[11,12]for using the AFM has been modiﬁed to investigate the intermolecular adhesion force between different foulants.The objective of this study is to explore the mechanisms govern-ing the fouling of RO membranes by mixtures of organic foulants simulating wastewater efﬂuent,and the ensuing chemical cleaning of the fouled membranes by cleaning agents.To make this study rel-evant to wastewater reclamation,we systematically investigate the fouling of RO membranes by each individual organic foulant type (polysaccharides,proteins,humic acids,or fatty acids)and mix-tures containing several types of organic foulants in the absence and presence of calcium ions.Cleaning experiments are performed with the fouled membranes using NaOH,EDTA,SDS,and NaCl as model alkaline solution,metal chelating agent,surfactant,and salt cleaning solution,respectively.The intermolecular adhesion forces between the different foulants and estimated aggregate sizes in foulant mixtures were used to explain the fouling mechanism of RO membranes and the cleaning behavior of a cleaning agent on the fouled membranes.2.Materials and methodsanic foulants Louis,MO),Suwannee River natural organic matter(SRNOM) (International Humic Substances Society,St.Paul,MN),bovine serum albumin(BSA)(Sigma–Aldrich,St.Louis,MO),and octanoic acid(OA)(Sigma–Aldrich,St.Louis,MO),respectively.According to the manufacturer,the molecular weight of the sodium alginate ranges from12to80kDa.Other characteristics of SRNOM,includ-ing molecular weight and mass fraction of hydrophobic NOM,can be found elsewhere[22,23].According to the manufacturer,the molecular weight of the BSA is about66kDa.BSA is reported to have an isoelectric point at pH4.7[24].Octanoic acid(Sigma–Aldrich,St. Louis,MO)was selected to model fatty acids in EfOM because of its presence in food and solubility in water(saturation concentration of4.7mM at20◦C)[12].Sodium alginate,BSA,and SRNOM were received in powder form,and stock solutions(2g/L)were prepared by dissolving each of the foulants in deionized(DI)water.DI water was supplied from a Milli-Q ultrapure water puriﬁcation system(Millipore,Billerica, MA).Mixing of the stock solutions was performed for over24h to ensure complete dissolution of the foulants,followed byﬁl-tration with a0.45-␮mﬁlter(Durapore,Millipore,Billerica,MA). Theﬁltered stock solutions were stored in sterilized glass bottles at4◦C.Octanoic acid was received in solution(≥98%concentra-tion)and was stored at room temperature.To achieve the intended octanoic acid concentration during fouling,octanoic acid was dis-solved separately for at least8h prior to fouling so that,at the initiation of fouling,octanoic acid could be introduced as a solu-tion.A few hours before the initiation of fouling,the ionic strength of the stock solution was adjusted to the same concentration as that of the feed solution(10mM)and the stock solution pH was elevated,as needed,from ambient pH of3.9–9.0by adding small amounts of1M NaOH.2.2.Chemical cleaning agentsThe chemical cleaning agents used were:NaOH(pH11.0)as an alkaline solution,certiﬁed grade disodium ethylenediaminete-traacetate(Na2–EDTA)as a metal chelating agent,certiﬁed grade sodium dodecyl sulfate(SDS)as an anionic surfactant,and NaCl as a salt cleaning solution.The agents were purchased from Fisher Sci-entiﬁc(Pittsburgh,PA)and used with no further puriﬁcation.The stock chemical solutions were prepared fresh by dissolving each chemical in deionized(DI)water.The pH of the EDTA,SDS,and NaCl cleaning solutions was adjusted with1.0M NaOH as necessary.2.3.RO membraneThe relatively well-characterized thin-ﬁlm composite LFC-1 membrane(Hydranautics,Oceanside,CA)was used as a model RO membrane.The average hydraulic resistance was determined to be 9.16(±0.11)×1013m−1corresponding to a hydraulic permeabil-ity of10.9(±0.13)×10−11m s−1Pa−1.The observed salt rejection was98.7–99.3%,determined with a10mM(584mg/L)NaCl feed solution at an applied pressure of300psi(2068.5kPa)and a cross-ﬂow velocity of8.6cm/s.Membrane samples were received as dry large sheets,and were cut and stored in DI water at4◦C.The membrane has been reported to be negatively charged at solu-tion chemistries typical to wastewater efﬂuents,with an isoelectric point at about pH4.6[25].The membrane has been reported to be coated with a neutral polyalcohol layer rich in–COH functional groups,which renders the surface less charged than the surfaces of other polyamide RO membranes without a coating layer[25,26].2.4.Crossﬂow test unit198W.S.Ang et al./Journal of Membrane Science376 (2011) 196–206unit consists of a membrane cell,pump,feed reservoir,temper-ature control system,and data acquisition system.The membrane cell consisted of a rectangular plate-and-frame unit,which con-tained aﬂat membrane sheet placed in a rectangular channel with dimensions measuring7.7cm long,2.6cm wide,and0.3cm high. Both permeate and retentate were recirculated back to the feed reservoir.Permeateﬂux was registered continuously by a digital ﬂow meter(Optiﬂow1000,Humonics,CA),interfaced with a com-puter.Aﬂoating disc rotameter(King Instrument,Fresno,CA)was used to monitor the retentateﬂow rate.The crossﬂow velocity and operating pressure were adjusted using a bypass valve(Swagelok, Solon,OH)in conjunction with a back-pressure regulator(U.S.Para Plate,Auburn,CA).Temperature was controlled by a recirculating chiller/heater(Model633,Polysciences)with a stainless steel coil submerged in the feed water reservoir.2.5.Fouling and cleaning experimentsThe membrane wasﬁrst compacted with DI water until the permeateﬂux became constant,followed by the initial baseline performance for1h.The membrane was then stabilized and equi-librated with a foulant-free electrolyte solution for2h.Theﬂux at which the baseline run was performed was predetermined so that the initialﬂux would drop to a speciﬁedﬂux of2.3×10−5m s−1(or 83L m−2h−1)after adding the electrolyte solution.The chemistry of the foulant-free electrolyte solution and operating conditions adjusted in this stage were similar to those used for the ensuing fouling runs.As octanoic acid takes time to dissolve completely,the mixture of organic foulant solution has to be prepared8h before the fouling run.The feed foulant solution was prepared separately in another container.The chemistry of the feed foulant solution was adjusted to be identical to that of the foulant-free electrolyte solution so that the overall ionic strength and solution chemistry would not change when the feed foulant solution was added to initiate fouling. Fouling runs were carried out for17h.At the end of the fouling run, the solution in the feed reservoir was disposed off and chemical cleaning solution was added to the feed reservoir to clean the fouled membrane.At the end of the cleaning stage,the chemical cleaning solution in the reservoir was discarded,and both the reservoir and membrane cell were rinsed with DI water toﬂush out the residual chemical cleaning solution.Finally,the cleaned RO membrane was subjected to the second baseline performance with DI water to re-determine the pure waterﬂux.The crossﬂow velocity throughout the experiment,except dur-ing cleaning,was maintained at8.6cm/s.The operating conditions (i.e.,initialﬂux,crossﬂow velocity,and temperature)at this stage were identical to those applied during the initial baseline perfor-mance,so as to determine the cleaning efﬁciency by comparing the pure waterﬂuxes determined before fouling and after clean-ing.Throughout all the fouling/cleaning stages,the feed water in the reservoir,which was located on top of a magnetic stirrer,was mixed rigorously to ensure complete mixing of the feed water and cleaning solution.To conﬁrm the reproducibility of determined cleaning efﬁ-ciency,selected fouling/cleaning runs were duplicated.Results showed that fouling rate and cleaning efﬁciency obtained from the duplicate runs were within less than a5%difference.To investigate the change in the permeate quality during the fouling stage,permeate samples taken before and at the start and end of fouling were analyzed for salt(NaCl)rejection using an ICP-AES(ICP Optima3000,Perkin Elmer,Waltham,MA).Permeate and feed samplings obtained before the fouling run were collected at the end were collected during theﬁnal40min of the fouling run.2.6.AFM adhesion force measurementsAtomic force microscopy(AFM)was used to measure the inter-facial force between the foulant in the bulk solution and the foulant in the fouling layer on the membrane.The force measurements were performed with a colloid probe,modiﬁed from a commercial-ized SiN AFM probe(Veeco Metrology Group,Santa Barbara,CA).A carboxylate modiﬁed latex(CML)particle(Interfacial Dynam-ics Corp.,Portland,OR)was used as a surrogate for the organic foulants,because organic foulants(alginate and SRNOM)carry pre-dominantly carboxylic functional groups.To make a colloid probe, a CML particle with a diameter of4.0␮m was attached using Nor-land Optical adhesive(Norland Products,Inc.,Cranbury,NJ)to a tipless SiN cantilever.The colloid probe was cured under UV light for20min.The AFM adhesion force measurements were performed in a ﬂuid cell using a closed inlet/outlet loop.The solution chemistries of the test solutions injected into theﬂuid cell were identical to those used in the bench-scale fouling/cleaning experiments.Once all the air bubbles had beenﬂushed out of theﬂuid cell,the injection would stop and the outlet was closed.The membrane was equilibrated with the test solution for30–45min before force measurements were performed.The force measurements were conducted at three toﬁve different locations,and at least10measurements were taken at each location.Because the focus of this study was on the foulant–foulant interaction(adhesion),only the raw data obtained from the retracting force curves were processed and converted to obtain the force versus surface-to-surface separation curves.The force curves presented were the averages of all the representative force curves obtained at the different locations.The protocol for AFM analysis has been modiﬁed slightly to investigate the interaction between different foulant types. The AFM colloidal probe is soaked in organic foulant solution (2000mg/L alginate,BSA,or SRNOM,or>98%octanoic acid)for at least24h(at4◦C for alginate,BSA,and SRNOM solutions to prevent organic degradation,and at room temperature for octanoic acid). The membrane is fouled with200mg/L organic foulant(alginate, BSA,SRNOM,or octanoic acid)using the crossﬂow unit for about 17h.After transferring the colloidal probe to the AFMﬂuid cell and the membrane to the AFM disc puck,an electrolyte solution con-taining0.5mM CaCl2and8.5mM NaCl(adjusted to pH6.5±0.2) (identical solution chemistry as during fouling)is injected into the ﬂuid cell.The volume of electrolyte solution added is just enough toﬁll up theﬂuid cell so as to minimize the possibility ofﬂush-ing away the foulants on the membrane and probe surfaces.AFM force measurements are taken after20min of equilibration time.To investigate the effect of cleaning agent on the intermolecular adhe-sion force,the cleaning agent was added to the electrolyte solution at the same concentration as that used in the cleaning experiments.2.7.Light scatteringDynamic light scattering experiments were performed on foulant solution to determine the effective hydrodynamic diam-eters of the foulant aggregates in foulant mixtures using a multi-detector light scattering unit(ALV-5000,Langen,Germany). New glass vials(Supelco,Bellefonte,PA)for containing foulant solu-tions under various solution chemistries were cleaned prior to use by soaking overnight in a cleaning solution(Extran MA01,Merck KGaA,Darmstadt,Germany),rinsing with DI water,and drying inW.S.Ang et al./Journal of Membrane Science376 (2011) 196–206199Fig.1.Inﬂuence of individual foulant type on fouling of LFC-1membranes:(a)in the absence of Ca2+and(b)in the presence of0.5mM Ca2+.The total ionic strength of the feed solution wasﬁxed at10mM by adjusting with NaCl and the feed solution pH was adjusted to6.0±0.2,as necessary,by adding NaOH.Fouling conditions: foulant concentration of25mg/L,initial permeateﬂux of23␮m/s(or83L m−2h−1), crossﬂow velocity of8.6cm/s,and temperature of21.0±0.5◦C.of1M NaOH.The vial containing the foulant solution was vortexed (Mini Vortexer,Fisher Scientiﬁc)to homogenize the solution.The vial was then allowed to sit for30min before starting the light scattering experiment.All light scattering measurements were conducted by employ-ing the detector positioned at a scattering angle of90◦from the incident laser beam.The detector signal was fed into the correla-tor,which accumulated each autocorrelation function for15s.The intensity-weighted hydrodynamic radius of the colloidal aggre-gates was determined with second-order cumulant analysis(ALV software)[27].The reported size is the average of theﬁrst20mea-surements.3.Results and discussion3.1.Membrane fouling3.1.1.Fouling with individual foulantsFig.1presents the normalizedﬂux proﬁles for LFC-1mem-branes fouled by each individual foulant(alginate,BSA,SRNOM, or octanoic acid)in the absence(Fig.1a)and presence(Fig.1b)of Ca2+,respectively.In the absence of Ca2+,theﬂux decline proﬁles of membranes fouled by the various foulants are insigniﬁcant.The 2+Fig.2.Inﬂuence of a mixture of(a)2foulants or(b)more than2foulants on fouling of LFC-1membranes in the presence of0.5mM Ca2+.The total ionic strength of the feed solution wasﬁxed at10mM by adjusting with NaCl and the feed solution pH was adjusted to6.0±0.2,as necessary,by adding NaOH.Fouling conditions were identical to those in Fig.1.RO membranes by BSA,SRNOM,or octanoic acid is minimal.How-ever,we have observed that the presence of Ca2+can affect fouling behavior when the foulant concentrations are higher(300mg/L BSA;2mM or288mg/L octanoic acid)[11,12].3.1.2.Fouling with mixture of foulantsTo investigate the implications for wastewater reclamation, the effect of Ca2+on fouling of RO membranes by all possible combinations of two or more foulant types is investigated.The con-centration of each foulant type was maintained at25mg/L.Fig.2a shows the normalizedﬂux proﬁles of membranes fouled by a mix-ture of two foulants in the presence of Ca2+.The effect of Ca2+is most signiﬁcant for feed solutions containing alginate as one of the two foulant types.This mechanism will be further investigated with the aid of DLS and AFM paring theﬂux proﬁles of mem-branes fouled by alginate as a co-foulant,theﬂux-decline proﬁle of membrane fouled by alginate and octanoic acid is the least sig-niﬁcant due to the formation of octanoic acid–calcium complexes, which increase the hydrophilicity of the fouling layer[12].Fig.2b shows the normalizedﬂux proﬁles of membranes fouled by a mixture of three foulant types and all foulant types in the presence of Ca2+.In the presence of Ca2+,for membranes fouled by mixtures containing alginate,the effect of Ca2+onﬂux proﬁles is most signiﬁcant,especially for the membrane fouled by a mixture of alginate,BSA,and SRNOM(without octanoic acid).In compar-ing the latter with theﬂux proﬁle of the membrane fouled by all200W.S.Ang et al./Journal of Membrane Science376 (2011) 196–206Fig.3.Sodium ion(Na+)rejection of RO membranes measured before,and at the start and end of the fouling runs,at an adjusted feed solution pH of6.0.The membranes were fouled by combined foulant types,composed of25mg/L each of alginate,BSA,SRNOM,and octanoic acid.Permeate and feed samples obtained before the fouling run were collected30min before the onset of fouling.Samples taken at the start of the fouling run were initiated afterﬁrst discarding20mL of permeate(duration of8min).Permeate and feed samples taken at the end were collected during theﬁnal40min of the fouling run.Error bars indicate one standard deviation.Fouling conditions were identical to those in Fig.1.contained alginate and octanoic acid in the presence of Ca2+.The inhibitory effect of octanoic acid onﬂux-decline proﬁles can also be observed by comparing theﬂux proﬁle of combined foulant types of alginate,SRNOM,and octanoic acid in Fig.2b with the proﬁle of alginate and SRNOM in Fig.2a.3.1.3.Impact of fouling on salt rejectionFig.3presents Na+rejection of the RO membranes fouled by combined foulant types of alginate,BSA,SRNOM,and octanoic acid in the presence of Ca2+,at the start and end of the fouling runs.The trend of observed Na+rejection is similar both in the absence and presence of Ca2+.At the onset of fouling,the Na+rejection instan-taneously increases.This phenomenon is consistent with previous observations,which attributed the decrease in Na+permeability to the fouling layer acting as an additional selective barrier[12]. Toward the end of the fouling runs,the fouling layer becomes thicker and denser,resulting in even higher Na+rejection.It can be inferred that the presence of Ca2+resulted in a more compact fouling layer,which improves the ability of the fouling layer to fur-ther act as a selective barrier against the transport of Na+across the membrane.3.2.Fouling mechanisms3.2.1.Role of foulant–foulant interaction and foulant sizeRecent studies have demonstrated that the long-term organic fouling of RO membranes and the consequent behavior of water ﬂux are dominated by the feed water chemistry and strong foulant–foulant interactions[4,20,21,28].Quantifying these inter-actions provides a basis for the understanding of the fouling mechanisms and for the rational selection of a suitable cleaning strategy.As discussed in Section3.1.2,fouling behavior becomes signiﬁcant when alginate is one of the co-foulants.When alginate is absent from the feed solution,regardless of the other foulant types present,fouling is relatively insigniﬁcant.This behavior can be explained by evaluating the interaction forces among the differ-ent foulants.To investigate the effect of interactions of alginate with other foulant types,DLS analysis is performed on a solution contain-ing2foulant types(200mg/L alginate plus200mg/L of another foulant type)in the presence of Ca2+.Fig.4a shows that the alginate molecules in the solution have an effective hydrodynamic diame-ter of84nm,which is larger than the effective diameter of51nm of alginate molecules in a solution in which the foulant concentration is halved.The results imply that aggregation of alginate molecules is concentration dependent.The larger effective diameter of aggre-gates formed in400mg/L alginate solution as opposed to those formed in200mg/L alginate solution also implies a more exten-sive gel network at a higher concentration.The effective diameters of the foulant molecules in mixtures of alginate and BSA,alginate and SRNOM,and alginate and octanoic acid are,respectively,48, 63,and73nm.The effective diameter is an indirect indication of the foulant size due to aggregation between the foulants.Because of the varying interactions between alginate and another foulant type in the presence of Ca2+,the aggregate size differs for foulant aggregates of different foulant combinations.Fig.4b shows the intermolecular forces between foulant adsorbed on a colloidal probe and a membrane fouled by algi-nate as determined by AFM.For a membrane fouled by alginate and octanoic acid,the dominant foulant interactions are between alginate and alginate molecules(1.03mN/m)and between octanoic acid and octanoic acid molecules(0.90mN/m).For a membrane fouled by alginate and SRNOM,the dominant foulant interaction is between alginate and alginate molecules(1.03mN/m).For a membrane fouled by alginate and BSA,the dominant foulantinter-Fig.4.(a)Effective diameter of foulant aggregates in solutions of various foulant combinations that contain alginate as co-foulant.The foulant solution consists of200mg/L alginate plus200mg/L of another foulant type in an electrolyte solution of0.5mM CaCl2and8.5mM NaCl(same solution chemistry as that used in fouling experiments).TheW.S.Ang et al./Journal of Membrane Science376 (2011) 196–206201Fig.5.Proposed structure of fouling layer on membrane surface under different combinations of foulants.actions are between alginate and alginate molecules(1.03mN/m) and between alginate and BSA molecules(0.73–0.79mN/m).We observe that when alginate is present in the feed,regardless of the co-foulant,the interaction of alginate molecules among them-selves is most dominant,with the possibility of alginate molecules interacting with other molecules,especially BSA molecules.Comparing the effective diameters of the foulant aggregates in various2-foulant mixtures(Fig.4a)with the intermolecular adhe-sion force between different foulants(Fig.4b)reveals that there is an inverse correlation between the foulant aggregate size and the intermolecular adhesion force(foulant aggregate size generally decreases as intermolecular adhesion force increases).It is hypoth-esized that the interaction among the foulant types within the aggregates would affect the conformation,and hence,the size of the aggregates in the foulant solution.For example,the relatively stronger intermolecular adhesion force between alginate and BSA molecules in the feed solution in the presence of Ca2+results in a more‘compact’or‘tighter’conformation of the foulant aggregates as compared to the foulant aggregates formed from a solution of alginate and SRNOM.The deposition of the smaller and more‘com-pact’alginate–BSA aggregates results in a tighter fouling layer and a lowerﬁnalﬂux(Fig.5)[29].We note that the SA–SA aggregate does not follow the trend of a decrease in aggregate size with increasing adhesion force because alginate molecules tend to form extended gel networks in the presence of calcium ions[29],as opposed to the other combinations of foulants.3.2.2.Proposed structure of fouling layerThe fouling experiments reveal that membrane fouling in the presence of Ca2+is controlled by alginate.From the AFM force mea-surement analysis and the DLS experiments,the proposed structure of the fouling layer when severe fouling occurs under various solu-tion chemistries is schematically shown in Fig.5.The top drawing shows the likely conformation of the cross-linked alginate fouling layer when the feed contains alginate in the presence of Ca2+.In this case,the fouling layer has the typical structure resulting from the formation of an‘egg-box’shaped gel network on the mem-brane surface[29].The middle drawing shows the proposed fouling layer formed by a feed solution containing a mixture of alginate, BSA,SRNOM,and octanoic acid(each foulant has the same concen-tration).The DLS experiments show that the aggregates of foulant mixtures containing alginate as a co-foulant have smaller effective feed solution in which alginate is the sole foulant.When the algi-nate concentration is increased while maintaining the same total foulant concentration,the fouling layer becomes more porous due to the increase in the highly ordered alginate–calcium complexes on the membrane surface.The state of the fouling layer would affect the transfer of a cleaning agent to the fouling layer,and hence,the cleaning efﬁciency of the cleaning agent as delineated in the next sections.3.3.Cleaning of fouled membranes3.3.1.Type of cleaning agentFig.6presents the cleaning efﬁciencies of various cleaning agents on membranes fouled by combined foulant types compris-ing alginate,BSA,SRNOM,and octanoic acid in the presence of 0.5mM Ca2+.Cleaning was performed for15min without an oper-ating pressure(i.e.,no permeate)and at a crossﬂow velocityﬁve times higher than that during fouling.Cleaning the fouled mem-brane with DI water resulted in19%cleaning efﬁciency,which implies that the fouling layer on the membrane surface was largely irreversible.Conventional cleaning agents,such as NaOH(pH11),Fig.6.Cleaning efﬁciencies of various cleaning agents on membranes fouled by combined foulant types comprising alginate,BSA,SRNOM,and octanoic acid,with the concentration of each foulant type at25mg/L,in the presence of0.5mM Ca2+.Cleaning conditions:time,15min;temperature,21±0.5◦C;and no applied。

建筑给水排水外文翻译文献

建筑给水排水外文翻译文献(文档含中英文对照即英文原文和中文翻译)原文：Supplying and draining waterin hospital constructionWith the fact that modern medicine science promptness develops,new technique , the new armamentarium are continuing without end , modernized medical treatment thereby consonant with that is building a hospital , are also are confronted with new design idea and new technology applying. Disregarding secondary hospital building function , what whose gets along environment, still , finclause the hospital builds equipment and is equipped with system, the request is without exception higher and higher. Because of it is to ensure daily work living not only need the rapid and intense life relevance recovering from the illness , avoiding crippling , rescuing, and promote with giving treatment to a patient. Not only the design accomplishing to the special field draining away water need to satisfy the request being unlike a function in hospital building on equipment , but also safety is be obliged to reliable. Following is built according to the hospital.一HOSPITAL GIVES A SEWERAGE1) Modernized hospital equipment and equipment system content is numerous , the function is peculiar , the request is very high. Except demanding to swear to continue supplying with the use water according with quality level sufficiently, need more according to demand of different medical treatment instrument and different administrative or tehcnical office to water quality , water pressure , the water temperature, classify setting up water treatment system and be in progress to system to increase pressure reduction.2) The hospital operating rooms , the delivery room operation the water hygiene, saliva washing hands by shower bath water , the dentistry dentistry chair ought to adopt the water purifying degassing. In the homeland few are large-scale , the high rank hospital centre supplies a room, the centre disinfecting has also adopted to purify the water disinfecting, now that swear to there be no dust , the sterility , to remove the pathopoiesia source , to avoid the blockage infecting , cutting down equipment microtubule.3) Hospital preparation rooms preparation uses water to adopt distilled water, and sets up in making distilled water system to have part pressure boost facilities. The handicraft responds to according to different hospital preparation handicraft but fixes concrete system distilled water, should satisfy demand of whose handicraft to water quality , water yield , water pressure act in close coordination that the preparation handicraft reserves corresponding to drain-pipe and allocation chilled water circulatory system by the special field draining away water.4) Hospital operating rooms , delivery rooms , baby rooms , supply rooms , medical treatment of the dermatological department wards, door emergency call, cures skill every administrative or tehcnical office and the request difference that the staff and worker logistics branch supplies to hot water need to set up hot water respectively supplying system more. Ordinary circumstances door emergency call, cures skill administrative or tehcnical office , centre supply a room , the staff and worker logistics branch supplies hot water to water supply the regular time, the comparison supplying time is consistent. The hospital is based on major part at present financial resources, ward building hot water supplies basic to the regular time , ought to be that 24 hs supply hot water judging from long-term angle but. Operating room , the delivery room operation wash hands, the hygiene h by the fact that the shower bath ought to be 24 supplies hot water, moreover the block of wood5) Considers beautification to the environment , is inadvisable to adopt the steam boiled waterstove , completely eradicates occurrence aroused the ward building pantry inner floor moistness , avoided interior wall mustiness phenomenon by leak or sparse steam water implement aerofluxus thereby. The hospital disregards size , boiled water supplies to should adopt automation volume or the electricity boiled water stove, a general disease area considers one , volume ascertains that according to using condition. The first easy to protect labor is managed, two is supplying ensuring that to the patient , improves the internal environment of ward at the same time.6)Especially infecting the section ward every door emergency call administrative or tehcnical office, every consulting room , the hand movement water curing a room , washing a basin should set up mistake chew , may adopt elbow style , knee style or dyadic switch of pedal. If using the dyadic switch of pedal to must use the product guarding against leakage, the floor is to avoid using a place often damp , makes the patient , the medical personnel slip down , an accident happened. Operation waits for the operating room , the delivery room to wash hands should adopt the constant temperature muddy water valve , the constant temperature to produce water, taking as an example infrared ray induced electromagnetic valve control mode for fine. Cure skill part control laboratory , laboratory of administrative or tehcnical office have the peculiar request , water chews the form should ascertain whose water according to every administrative or tehcnical office coming functional request chewing.7)Many administrative or tehcnical office, especially downstream pipelines such as pickling bath , the pool disinfecting , develop pool in administrative or tehcnical office such as checking the room , the control laboratory , emitting section responds to of hospitals are adopt to be able to bear the rotten PVC2U draining off silent stock tube.8) Pair of filth , waste water of all kinds must classify strictly according to the country in connection with the effluent standard , the field carrying out a pertinency with different treatment handicraft deals with and handles.9) Uses a function to need since the modern hospital needs to be satisfied with not only , wants to think that the interior outside environment is beautiful too at the same time. The building needs especially door emergency call, cures skill sometimes because of medical treatment function , give the horizontal stroke draining away water , erect a tube arrange to lie scattered comparatively, more bright dew is in interior, warm the pipeline exchanging special field up in addition sometimes , make the pipeline that the room inner clearly shows more than the correct or required number , both inelegant, and affect hygiene. This demands right away in the process ofengineering design , the rational arrangement the structure form should fully utilize not being the same as is carried out, needs to make the various pipeline conceal arrangement to the full according to the function , pays attention to beautiful befitting one's position or suited to the occasion under not affecting the premise being put into use. Certainly, these require that building structure special field is dense. Tier of furred ceilings and the basement top sometimes are every special field pipeline aggregation field , every special field norm and request having every special field , each sometimes arranges if the building designs middle in the ward,whose result either increase building storey height, or cannot attend to one thing without neglecting another. For overcoming this one abuse, should think in general that bigger flue pipe arrangement be in the most superjacent, it's on the down part is that several special field arrangement props up the public space being in charge of , down part is to arrange to give draining off , driving force , strong , weak electricity every system to do a tube again. Such is arranged than form arrangement is other comparatively economical , pragmatic.10) Exchangers forms choice. In the system the tradition hospital hot water is supplied, people adopt volume mainly dyadic exchanger. Have been to think that what be provided steam amounts and hot water supplies the adjustment amounts dispatching value between maximum value mainly , have diminished a steam boiler designing amounts , have decreased by boiler room Zhan field area , have saved one time investment. People demands but more highly, and more highly, especially the example discovering army group bacterium pathopoiesia in life hot water to water quality now , the altitude arousing people takes seriously. Be a bacterium mainly because of in the water 55 ~C is the easiest to breed an army group in 30 ~C ~, WHO (WHO) is recommended by for this purpose: "Hot water responds to in 60 ~C use And cycle at least above 50 ~C. Come if some users, need to fall to 40 ~C or 50 ~C or so with the faucet water temperature, to come true being able to use a thermoregulation to blend a valve at this time. The growth being a temperature Bu Li Yu pneumonia diplococcus swear to store water, is a regulating valve's turn to should set up the place closing down and suspending operation of point in drawing near". This be especially important to the hospital. Because of being in hospital the weak having disease,if bacterium of army group happened within the hospital is to be harmful for patient to treat and recover from the illness,the hospital has a grave responsibility. At present small hospital within the hospital especially a little condition is relatively poor , include the part area level hospital, 24 unable hs supply hot water, and volume the dyadic converter inner water temperature is to useechelon in inside of exchanger, the water temperature very difficult to make keeps in 60 ~C or so. Thereby, lead to volume produce the bacterium of army group in the pipeline supplying hot water system within dyadic exchanger , change a hospital using the exchanger form to respond to be a task of top priority. Adopt half to be to heat up style or be a dyadic hot exchanger , make whose hot water supply the system water temperature keeping the water supply being in progress in all above 60 ~C area all the time, occurrence propagating , completely eradicating the bacterium of army group in order to avoiding the bacterium of army group.二MULTILAYER WATER SUPPL Y SYSTEMAt present, great majority cities municipal administration pipe network pressure can maintain above 2 kilograms in the homeland , take place individual small town water pressure can reach 4 kilograms even. The pressure therefore, building the municipal administration pipe network's to the same multilayer has been already sufficient , has been in a small town especially since but municipal administration pipe network water yield supplying water , water pressure fluctuation are bigger. Have several kinds the following types mainly for overcome these shortcomings , multilayer water supply system design.1) Direct water supply type is that pressure , direct water supply , sort making use of municipal administration pipe network directly apply to slightly high area of municipal administration pipe network pressure or higher range of water works vicinity pressure inner. The shortcoming it is water yield , water pressure to be able to not ensure that. This water supply scheme economy function is very good but, to less pipe network of scale , does not need any other equipment or measure.2) Water box water supply types have led municipal administration pipe network water to roof water box , discrepancy in elevation , gravity depending on a water box and using the water appliance have supplied water , have overcome water pressure water yield block of wood stability and then. Since but, secondary pollution, moreover, water box volume that the water box there exists in possibility is bigger,this way does not encourage therefore.3) Water boxes , pipe networks ally self with a type when the ordinary time water yield water pressure is sufficient , unnecessary water enters the roof water box when covering water supply , overpressure as with a net directly from municipal administration, think that the water box supplies water to the consumer by gravity automation when pressure or the water yield is insufficient. The main force who is that regular directness supplies water on physics structurestretches the top cut-over water box , sets up and one exhalent siphon from the water box. Owe a scheme the volume having diminished a water box, and make water not need to enter a water box staying this one step , hygiene reliability increase by. The problem is (that the municipal administration now pipe network can accomplish) but if longtime stabilivolt supplies water , the water sojourn time in water box is on the contrary greatly increase by , easier to be contaminated. And, the water box all must readjust oneself to a certain extent in the building in all usage water boxes system most higher place, attractive looks being able to affect a building in some occasion , the physical design building even.4) Pressure jars supply water since insecure water box factor , reason why use the jar sealing off reliable pressure to replace, and the pressure jar does not need, high position lay down, attractive looks and structure not affecting a building bearing , go down well very much over the past few years. Pressure jar system requires that the water pump and autocontrol system have to fit but , feasible cost increases by to some extent. However, in the late years whose market price already lets many consumers be able to choose.Systematic pressure jar principle is to make use of a water pump water compression to be sent to receive the pipe network building the inside , thinks that water enters the pressure jar , reaches certain pressure time , water pump motor stoppage or reduces the speed when pressure is too big,While pressure is smaller than regulation value, the pressure jar conveys water to the outside and starts the water pump or acceleration at the same time (frequency conversion water pump).5) Two time of compression types can make do for to small-scale consumer ,if the building , the pressure jar are only systematic. The direction that the dwelling house spends at present to housing estate develops but, shows for the cluster arrangement that multilayer builds , concentrates stabilivolt mainly. The ability can not satisfy a request with pressure jar volume , the water pump concentrates compression therefore having appeared give first place to, pressure jar stabilivolt (remove the system water hammer) is subsidiary way. Economy cost rises only , also needs the specially-assigned person upkeep. Besides, pipe network system belongs to low pressure since tier of numbers are not many, pipeline, the direct cut-over without exception with layers consumer is be OK , comparatively simple. The steel tube prepares pipeline material with low pressure low pressure PPR silent stock tube give first place to.译文：医院建筑给水排水随着现代医学科学的迅速发展,新技术、新医疗设备层出不穷,从而与之相符的现代化医疗建筑———医院,也面临着新的设计理念和新技术的运用。

3给水排水外文翻译外文文献英文文献

3给水排水外文翻译外文文献英文文献Relations between triazine flux, catchment topography and distancebetween maize fields and the drainage network F. Colina,*, C. Puecha, G. de Marsilyb,1aUMR “Syste`mes et Structures Spattiaux”, Cemagref-ENGREF 500, rue J.F. Breton 34093, Montpellier Cedex 05, FrancebUMR “Structure et Fonctionement des Syste`mes Hydriques Continentaux”, Universite´ P. et M. Curie 4, Pl. Jussieu 75252, Paris Cedex 05, FranceReceived 5 October 1999; revised 27 April 2000; accepted 19 June 2000AbstractThis paper puts forward a methodology permitting the identification of farming plots contributing to the pollution of surface water in order to define the zones most at risk from pesticide pollution. We worked at the scale of the small agricultural catchment (0.2–7.5 km2) as it represents the appropriate level oforganisation for agricultural land. The hypothesis tested was: the farther a field undergoing a pesticide treatment is from a channel network, the lower its impact on pollution at the catchment outlet.The study area, the Sousson catchment (120 km2, Gers, France), has a “herring bone” structure: 50 independent tributaries supply the main drain. Pesticide sales show that atrazine is the most frequently used compound although it is only used for treating maize plots and that its application rate is constant. In two winter inter-storm measurement exercises, triazine flux values were collected at about 30 independent sub-basin outlets.The contributory areas are defined, with the aid of a GIS, as different strips around the channel network. The correlation between plots under maize in contributory zones and triazine flux at related sub-basin outlets is studied by using non-parametric and linear correlation coefficients. Finally, the most pertinentcontributory zone is associated with the best correlation level.A catchment typology, based on a slope criterion, allows us to conclude that in steep slope catchments, the contributory area is best defined as a 50 m wide strip around the channel network. In flat zones, the agricultural drainage network is particularly well developed: artificial drains extend the channel network extracted from the 1/25.000 scale topographic map, and the total surface area of the catchment must be taken to account. q 2000 Elsevier Science B.V. All rights reserved.Keywords: Pesticide catchment; GIS artificial network1. IntroductionThe use of pesticides in western agriculture dates back to the middle of the 19th century (Fournier,1988). Since then, because of their intensive use,yields have increased and the demand for agricultural products has been satisfied. However, the pollution created by theiruse threatens both drinking water resources and the integrity of ecosystems. Therefore, there is a great demand for the reduction of pollution.The remedies lie in changes in the way that agricultural land is managed. The problem of agricultural Journal non-point source pollution by pesticides must be taken from the field, the level of action, to the catchment,the level of control of the water resource.Between these two spatial scales, different levels of organisation can be found. Fields, groups of fields,basins and main catchment, can be viewed together as nested systems (Burel et al., 1992). For each scale level, the main processes governing water movement and soluble pollutant transport are different, as are the variables characterising the system (Lebel, 1990):flow in macropores at local scale, preferential flowpaths at the hillslope scale, flows in connection withthe repartition of different soils at the catchment scale,geology influence at the regional scale(Blo¨sch and Sivapalan, 1995).At the field level, an experimental approach can be used and the relative weight of each variable can be experimentally tested (Scheunert, 1996; Bengtson et al., 1990). The major factors that concern agricultural practices have been identified and many agricultural management indicators have been developed (Bockstaller et al., 1997). Nevertheless, this approach cannot be applied at the catchment scale for several reasons: the need to measure the pollution and the environmental factors simultaneously, multiple measurement difficulties, the complexity of analysis. The variability of observations has temporal and spatial components. Rain induces pesticide leaching and therefore causes temporary high pesticide concentrations in the water; the closer the pesticide spreading date in thefield is to the measurement, the greater the concentration levels (Seux et al., 1984; Reme,1992; Laroche and Gallichand, 1995). The extensive use of Geographical Information System (GIS) has made it possible to analyse the impact on the pollution of the spatial characteristics of agricultural zones (Battaglin and Goolsby, 1996). But so far, the results of these experimentshave only led to an approximate estimate of the risks (Tim and Jolly, 1994).In order to progress in the search for ways to reduce pesticide pollution, it would be worthwhile to improve our assessment of how spatial structure and organisation affects the levels of pollutants measured.This paper presents the results of a study that concerns a particular aspect of the influence of spatial organisation on pesticide transfer: the effects of the distance between the cropland and the channel network. The longer the distance between a cultivated field and a river, the greater the retention and degradation processes (Leonard, 1990; Belamie et al.,1997). One mighttherefore imagine that the greater the distance, the lower the pollution level. However,few studies have given a numerical value to the critical distance at which a field does not influence river pollution significantly. Usually, when dealing with risk zone definition, experts establish an arbitrary distance (Bouchardy, 1992). Our main goal is to determine through spatial analysis the critical distance from a hydrographic network. The zones most at risk from pesticides, including the plots, which contribute most of the pollution, can then be determined.The study area, the Sousson catchment (Gers,France) has certain physical characteristics, which allows sampling of most of the independent subbasins, defined here as agricultural production zones. Its particular morphology made the comparative study of the production zones possible. The method involves a statistical comparison between pollution measurements and spatial characteristics of thecatchments. In order to establish the boundaries ofthe contributing areas, the pollution flux measured at the production zone outlet is compared to the landcover, estimated within strips of variable width around the channel network. Results are shown and discussed from a mainly practical viewpoint.2. The study area and collected data2.1. Study area descriptionThe study area is the Sousson catchment, in southwestern France (Gers). The Sousson River is a tributary of the river Gers. The catchment area is 120 km2. The 32 km long hydrographic network has a ‘herringbone’pattern: 53 sub-basins with fairly homogeneous surfaces areas ranging from 0.2 to 7.5 km2 serve the central drain (Fig. 1).The wide, gently sloping and heavily cultivated left bank, differs from the right bank, which is narrow, steep and mainly made up offorest and pastureland.The Sousson catchment area is exclusively agricultural.There is no industry or settlement of more than 200 inhabitants. The two main crops cultivated aremaize and winter wheat (17 and 15% of the catchment surface area, respectively). The maize fields are usually situated, on the left bank, in the upstream middle of the catchment area, and along the main river.There are two types of soil: a calcareous soil, which is quite permeable, and a non-calcareous soil called locally ‘boulbenes’ with an top limoneous layer and a lower silty layer. In order to avoid the stagnation of water in the upper layer caused by the silty impermeable layer, the fields on boulbene soil are artificially drained. Maize is cultivated for preference on thistype of soil.No significant aquifer has been found in the catchment, as the substratum is rather impervious (clays).2.2. Collected data2.2.1. Spatial dataA GIS was developed for the area, which contains the following information layers:²the hydrographic network and the catchment boundaries digitized from 1/25.000 scale topographic map;² a gridded Digital Elevation Model (DEM) of the zone providing landsurface slopes generated from DEM with a resolution of 75 m;²the boundaries of cultivated fields digitized from aerial photos at scale of 1/15.000;²landcover for both 1995 and 1996 was defined in detail in the study area. For 1997, landcover was identified by remote sensing. Knowledge of agricultural antecedents enhanced the classification of a SPOT (Satellite Pour l0Observation de la Terre) image. As a result, the maize areas for the entire Sousson catchment were determined for 1995, 1996 and 1997 (Fig. 2).GIS functions are capable of determining the landcover of each catchment by intersecting the two information layers “landcover” and “catchment boundaries”, or defining a zone of constant width around the hydrographic network, which is called the buffer zone.In order to evaluate the pesticide application rate, figures for local pesticide sales were collected. Atrazine, alachlor and glyphosate are the most commonly used compounds, atrazine far outstrips the others triazines as the most frequently used product (ten times less simazine is sold). In this region, atrazine is only used in maize cultivation. The application rate (mass of atrazine sold/maize surface area) does not vary from one municipality to another.To simplify the investigations, we chose to study the atrazine spread on maize plots in May. We assume that all the maize plots are treated with atrazine and that the application rate is uniform.2.2.2. Water pollution dataTwo series of measurements were made during the winter period: 23 sub-basins were sampled on December 3rd and 4th 1997, and 26 sub-basins were sampled March 17th to 19th 1998. Hence, the atrazine treatments were carried out 7 or 10 months before and the maize harvest was 1 and 4 months before the measurements were taken.To obtain stable hydrological conditions, the chosen measurement dates coincided with decreasing flow as shown in Fig. 3. The same operator collected the quality samples and gauged the river flow in order to limit measurement errors.The triazine concentration was measured with an ELISA water test (Transia Plate PE 0737). This measurement technique is less accurate than the classical chromatography technique, but it permits a faster analysis of a large number of samples (Rauzy and Danjou, 1992; Lentza-Rios, 1996). As atrazine is the mostwidely commercialised triazine product in this region, we will consider that observed triazine concentrations are representative of atrazine concentrations.December 1997 values, and March 1998 values were grouped together in order to assemble a large enough sample for statistical analysis (Fig. 4). The instantaneous triazine flux was obtained by multiplying the triazine concentration with the dischargevalue. As shown in Table 1, water flow in December 1997 was double that in March 1998, but the corresponding triazine flux are comparable.2.2.3. Quality assuranceTo control the quality of ELISA water-test measurements, each concentration was analysed 142 F. Colin et al. / Journal of Hydrology 236 (2000) 139–152 Fig. 2. Hydrographic network (topographic 1/25.000 map) and subcatchments, parcel limits and land-cover (example of maizeplots). twice. A maximum difference of 20% is tolerated between two duplicate samples, the median error is 10%, and mean values are used. It is possible that ELISA measurement induces a consistent error by comparing with gas chromatography measurements (Tasli et al., 1996), but this bias is compensated by comparative reasoning on all the samples.A few points were measured two or three times during the exercise in order to evaluate the daily variations during the sampling period. Table 2 shows that the flux variation between different days of a sampling period ranges from 2 to 49%. It is therefore possible to compare the different samples from the period in question. All the measurements from each period are then grouped together.The uncertainty on the triazine flux is the sum of the uncertainty of discharge and concentration measurements. The uncertainty on the discharge measurements ranges from 15 to 20%. Therefore, the triazine flux value isgiven with a maximum uncertainty of 40%.3. MethodTo define the zones most at risk we tested how the distance to the river of the areas where pesticides are applied influence pollution levels. Thus, we have to determine the relative position of the hydrographic network and the contaminating plots.In our case, the data on pollution is provided by triazine flux measurements taken at basin outlets and the potentially contaminating fields are maize plots.3.1. Efficiency curve and spatial partitionThe basic hypothesis is that the impact of the field as a contributor to pollution decreases the further it is from the channel network. Thus, there is a critical distance at which the field makes little contribution to outlet pollution. In other words, we assume that plot contribution to pollution level can be modelled through adecreasing efficiency curve. This hypothesis will be tested with a very simple curve: a step function. This curve is defined using only one parameter, the threshold limit distance, d, beyond, which a plot stops contributing to river pollution.In practice, this hypothesis implies a three-step approach:²determination of the location of the maize fields;²definition of a buffer of width d, equal to the threshold distance and, which surrounds the channel network;²determination of the contaminating fields inside these limits.The fields define the contributing maize areas depending on the buffer width (Fig. 5). At this stage, GIS functionality is required, particularly for the buffer function.3.2. Correlation between contributing area and pollution at the catchment outletWe studied the correlation level between triazine flux measured at the catchment outlet and the different contamination contributing areas defined by strips of variable width. Three parameters are used to determine the correlation level (further information is provided on this point in Appendix A):²The Kendall rank correlation coefficient (Siegel, 1956) t gives a measure of the degree of association or correlation between two sets of ranks. It expresses the difference between the probability that the two data sets are ranked according to the same order and the probability that they are ranked according to a different order. If t . 1.21.; a positive (negative) relation exists between the two data series, if t . 0; there is no relation between the two data series.²The Spearman rank correlation coefficient R (Siegel, 1956) requires that individuals under study be ranked in two ordered series. As the Kendall coefficient t , R expresses the existence of any one relation between two data series if itsvalue is close to 1.²The linear correlation coefficient r (Wonnacott and Wonnacott, 1991) expresses the intensity of a linear relation between two data series; r2 is the part of the variance explained by the linear model.The two first parameters evaluate if a relation exists between observed triazine flux and the different tested maize areas without hypothesis on the form of the relation. The linear correlation coefficient allows a special relation type to be tested. The squared value of the Spearman coefficient R, as the correlation coefficient r, expresses a part of total variance on the ranks. The Kendall coefficient represents the probability of two series being ranked in the same way against the probability of them being ranked in a different way. The use of non-parametric coefficients confers robustness to the method in relation to distributional skewing (Barringer et al., 1990).The most significant correlation levelcorresponds to the most accurate threshold distance d. This distance d defines the zone for which the relation between fields undergoing atrazine treatment and triazine flux is the highest. The buffer of width d will be defined as, “the zone most at risk”, even if plots outside this buffer zone may contribute in a small way to the pollution.3.3. Catchment typologyThe study of the slopes in the whole catchment shows a significant disparity between the upstream and downstream zones. The slopes in the upstream zone are gentle while those in the downstream zone are steep. In order to describe these morphological differences, the index Islope threshold was calculated for each basin: Islope . Sslope.5%=Stotal .1. where Sslope.5% is the basin surface area where the slope is steeper than 5% and Stotal the total surface area of the basin.The 5% threshold slope was chosen because itrepresents the upper limit at which mechanised agriculture can still be practised.The higher the Islope, the greater the proportion of steep slope zones in the basin. In order to sequence basins, a limit of Islope . 0:5 was chosen. This value corresponds to an equal part of flat and steep slope zones in a catchment. Furthermore, this typology separates the sampled basins into two groups of a comparable number of elements. This catchment typology shows a classification according to the position upstream and downstream in the Sousson catchment (Fig. 6).4. ResultsDuring the winter, in December 1997 and March 1998, water quality and discharge measurements were made to determine triazine flux. The network was digitized from the 1/25.000 scale topographic map. The buffers tested are 50 m, 100 m, and 200 m wide. The entire catchment corresponds to the maximumwidth, which is close to 500 m for the downstream group basins and 250 m for the upstream group, which has a more pointed shape. As it is noted by Barringer et al. (1990), the minimum used buffer width must be superior to that of the mapping unit. Here, maize field were determined using information provided by SPOT satellite imagery, (resolution 20 m), with field boundary definition based on 1/10.000 aerial photos (1 mm on the map is equal to 10 m on field).The area was divided into strips around the channel network. Then, the maize fields were putback into this division of space to obtain, for each basin, maize surface area within 50, 100 and 200 m of the hydrographic network, and within the whole catchment.4.1. Study of the whole set of basinsResults of regressions for 23 catchment areas in December 1997 and 26 in March 1998, whichinclude a Kendall rank correlation, a Spearman rank correlation and linear correlation coefficients are given with their significance level in Table 3. Calculated correlation coefficients do not seem to vary consistently as a function of the selected threshold distances: the number of coefficients increase in all cases when the buffer area is enlarged with the exception of December where they decreased in number for the whole catchment area. Considering these results, one might think that the distance of the field from the river has no effect on the pollution. However, if upstream and downstream basins are separated, according to the slope criterion Islope, the results are very different.4.2. Study of the downstream basins Regressions were carried out on nine basins in December 1997 and on 13 in March 1998, mean triazine concentrations are 42.0 and 123.0 ng/l, respectively. Results are shown in Table 4. Calculated correlation coefficients decreasewhen the strip width around the channel network increases. The best correlation levels are obtained for a distance d of 50 m (100 m for the linear correlation in December 1997). The Kendall and the Spearman correlation coefficients show the existence of a relation between maize area inside a 50 m wide buffer zone around the channel network and the triazine flux at the catchment outlet. The linear relation is quite adequate to model this variable association given that 69% of the total variance is explained in December 1997 and 56% in March 1998 considering that d equals 50 m. Resultsobtained for the two measurement dates are mutually coherent although differences exist. In December, whatever the value of d, the significance level is above the acceptance limit (p . 5%). The relation between maize area and triazine flux is optimal for d equal to 50 or 100 m but still exists for d equal to 200 m or considering the whole catchment surface area.The correlation between pollutant flux and maize areas far from the river can be explained by two ways. On the one hand, there is a correlation between the different maize areas (cf. Table 6). Indeed, if maize surface areas within different buffer zones were perfectly proportional, i.e. if linear correlation coefficients between the different maize surfaces areas were equal to one, no variation wouldbe detected in the correlation coefficients between maize surface areas and triazine flux. The sets of basins studied were not exactly the same during the two measurement exercises. For December 1997, the level of correlation between the different maize surface areas is higher than for March 1998 (as it is shown in Table 6). This difference between the two series is partly responsible for the slow decrease in the number of correlation coefficients concerning distance d for December 1997. On the other hand, as it is shown in Fig. 3, December 1997 measurements were made during the falling limb of thehydrograph and thus we can assume that, in these hydrological conditions, the area contributing to pollution is larger and includes zones distant from the hydrographic network for the whole catchment area. However, in March 1998, in lower water level conditions, only correlations where d is equal to 50 m are significant at the 5% threshold.We can conclude that the limit of 50 m is the most appropriate to define the zones most at risk for the two monitoring periods — seven and ten months after the triazine applications —even if hydrological conditions are also important when defining the contribution of the other maize plots located on the whole catchment area.4.3. Study of the upstream basinRegressions were made on 14 catchments for December 1997 and 13 basins for March 1998, mean triazine concentrations are 177.9 and 314.6 ng/ l, respectively. Results are shown inTable 5. The correlation coefficients become more numerous with strip width, while the opposite is true for the downstream basins. In most cases, the best results are obtained by considering the whole catchment area. The linear model is less accurate for the December data set .r2 . 38%. than the Spearman rank correlation .R2 . 70%.: It suggests an association between variables more complex than the linear relation does.Field investigations provide the explanation of the difference between the two catchment groups. For upstream catchments, the hydrographic network taken as the reference is irrelevant. In this flat zone, the artificial drain network around each plot extends the channel network; thus, the real active network is denser than that of the topographic 1/25.000 map. Fig.7 shows, for a particular catchment, the differences between the topographic 1/25.000 map network and the active one observed in the field. Moreover, this ditch network is connectedwith buried drains located under most of the fields in this upstream zone. The consequence is that each field is artificially connected with the catchment outlet.This difference in optimal width between the upstream and downstream catchments is the consequenceof man’s activities on the flat upstream area. In this case, the total catchment surface area must beconsidered as a contributing area.5. DiscussionWe chose to take the measurements in winter because it is easier to compare triazine flux at the catchment outlets. In spring, which is the atrazine spreading period, the differences in flux could be due to differences in the application dates. We used instantaneous inter-storm triazine flux measurements to maximise the stability of the transfer processes (Woods and Sivapalan, 1995). Thus, our resultsdo not necessarily apply to transfer during peak runoff. As the measurements were made between stormy periods our attention was focussed on the slow components of water movement such as subsurface runoff, drainage flow and water circulation in soil, where leaching favours the transport of soluble compounds such as atrazine. These conditions are not maximal from the point of view of instantaneous pollutant quantity export, but do represent a nonnegligible quantity and this over long periods of the year. However, this was a way to acquire comparable data sets at several basin outlets. Moreover, with these data sets it is possible to integrate the spatial diversity and give the results in a form that can be generalised.A simple model of contribution through buffers of stationary width around the hydrographic network was used, where each buffer defines a zone contributing to pollution. The degree of correlation between thecontributing areas and the pollution at the basin outlet was determined.The results show that a critical contribution distance cannot be defined for all basins studied. However, basin typology based on morphology criteria permitted the identification of two groups of basins.These basins have to be considered separately as their water movement characteristics are very different.For the downstream basins, which have a marked relief, the channel is well defined by the network that figures on the 1/25.000 scale topographic map. The model identifies a critical contribution distance, which ranges from 50 to 100 m. Atrazine is little adsorbed by soil, very soluble and easily leached. In inter-storm periods, it is not surface runoff, which causes the water transfers but sub-surface runoff and the draining of local aquifers surrounding the hydrographic network. The area of strongest influence ranges from 50 to 100 m and gives a good representation of the zone where atrazinetransport processes are active. This optimal distance should be determined for different climatic conditions and different periods of the agricultural year. Then we would know if the contributing area possesses temporal dynamics or if it remains stable.The upstream basins have higher triazine concentrations. These areas are characterised by the high proportion of flat zones (slopes of less than 5%), and an artificial drainage network connecting each plot to the main drain in order to avoid flooding. Thus, each plot contributes to the pollution measured at the basin outlet. The topographic 1/25.000 map network does not include this effect of the human intervention on the water circulation, and it is not pertinent in a drained region to evaluate the distance between cropland and the river.How the hydrographic network is defined is critical to the success of this analysis. The initial choice was based on the network digitized from the 1/25.000 scale topographic map. The mainbenefit to be derived from using such a network is its availability, which allows us to easily transpose the methodology. It represents the perennial flow network, stable in time. But, from the point of view of water movement, it lacks locations of manmade drains that can accelerate he transport of solute pollution. From a practical point of view, it is preferable to study the farmlandand identify zones with intensive artificial drainage before defining the boundaries of contributing areas around the channel network.6. ConclusionsIn order to reduce surface water pollution, the application of pesticides has to be controlled and agricultural practices must be such that they respect the environment. But the proper management of cropland must not be neglected either. The spatial organisation of fields has an impact on river pollution.The effect of the distance between fields contributing to the。

环境工程专业英语文献中英双语版

Treatment of geothermal waters for production ofindustrial, agricultural or drinking waterDarrell L. Gallup ∗Chevron Corporation, Energy Technology Company, 3901 Briarpark Dr., Houston, Texas 77042, USAReceived 14 March 2007; accepted 16 July 2007Available online 12 September 2007AbstractA conceptual study has been carried out to convert geothermal water and condensate into a valuable industrial, agricultural or drinking water resource. Laboratory and field pilot test studies were used for the conceptual designs and preliminary cost estimates, referred to treatment facilities handling 750 kg/s of geothermal water and 350 kg/s of steam condensate. The experiments demonstrated that industrial, agricultural and drinking water standards could probably be met by adopting certain operating conditions. Six different treatments were examined. Unit processes for geothermal water/condensate treatment include desilication of the waters to produce marketable minerals, removal of dissolved solids by reverse osmosis or evaporation, removal of arsenic by oxidation/precipitation, and removal of boron by various methods including ion exchange. The total project cost estimates, with an accuracy of approximately ±25%, ranged from US$ 10 to 78 million in capital cost, with an operation and maintenance (or product) cost ranging from US$ 0.15 to 2.73m−3 of treated water.© 2007 CNR. Published by Elsevier Ltd. All rights reserved. Keywords:Geothermal water treatment; Water resources; Desilication; Arsenic; Boron1. IntroductionWith the world entering an age of water shortages and arid farming land, it is increasingly important that we find ways of recycling wastewater. The oil, gas and geothermal industries, for example, extract massive amounts of brine and water from the subsurface, most of which are injected back into underground formations. Holistic approaches to water management are being adopted ever more frequently, and produced water is now being considered as a potential resource. In the oil and gas arena, attempts have been made to convert produced water for drinking supply or other reuses (Doran et al., 1998). Turning oilfield-produced water into a valuable resource entails an understanding of the environmental and economic implications, and of the techniques required to remove dissolved organic and inorganic components from the waters. Treatments of geothermal water and condensate for beneficial use, on the other hand, involve the removal of inorganic components only.We have explored the technical and economic feasibility of reusingwaters and steam condensates from existing and future geothermal power plants. Produced geothermal fluids, especially in arid climates, should be viewed as valuable resources for industry and agriculture, as well as for drinking water supplies. This paper presents the results of laboratory and field pilot studies designed to convert geothermal-produced fluids into beneficially usable water. The preliminary economics of several water treatment strategies are also provided.2. Design layoutThe layout for the treatment strategies (units of operation) have been designed specifically for a nominal 50Mwe geothermal power plant located in an arid climate of the western hemisphere, hereafter referred to as the test plant. The average concentration of constituents in the produced water is shown in Table 1. The amount of spent water from the test flashplant is ∼750 kg/s. The potential amount of steam condensate that could be produced at the plant is ∼350 kg/s. Table 1includes the compositionof the steam condensate derived from well tests. The six treatment cases considered in the study are given in Table 2, together with product flows and unit operations of treatment. Fig. 1 provides simplified schematic layouts of the unit operations for each case.3. Evaluation of treatment optionsIn this section the various operations considered for each case are described.3.1. Arsenic removalT he techniques considered viable for removing traces of arsenic (As) from condensate or from water are ozone oxidation followed by iron co-precipitation or catalyzed photo-oxidation processes (Khoe et al., 1997). Other processes for extracting As from geothermal waters (e.g. Rothbaum and Anderton, 1975; Umeno and Iwanaga, 1998; Pascua et al., 2007) have not been considered in the present study. In the case of the test plant, ozone (O3) would be generated on-site using parasitic power, air and corona-discharge ultra-violet (UV) lamps, and iron in the form of ferric sulfate [Fe2(SO4)3] or ferric chloride (FeCl3) that would be delivered to the geothermal plant. The photo-oxidation processes consist of treating the condensate or water with Fe2+ in the form of ferrous sulfate (FeSO4) or ferrous chloride (FeCl2), or with SO2 photo absorbers. The latter is generated from the oxidation of H2S in turbine vent gas (Kitz and Gallup,1997).The photo-oxidation process consists of sparging air through the photo- adsorber-treated fluid, and then irradiating it with UV lamps or exposing it to sunlight to oxidize As3+ to As5+. In the Fe photo-oxidation mode, the Fe2+ is oxidized to Fe3+, which not only catalyzes the oxidation reaction, but also co-precipitates the As. In the SO2 photo-oxidation mode,after oxidizing the As, FeCl3 or Fe2(SO4)3 is added to the water to precipitate the As5+ as a scorodite-like mineralTable 1Approximate geothermal water and steam condensate compositions assumed in the studya Total dissolved solids.Table 2Summary of the six cases of geothermal fluid treatment to produce marketable watera On treatment of water, clays are produced at a rate of 7.4 ton/h.(FeAsO4·2H2O). In the laboratory and field pilot tests, the photo-absorber and UV dosages were varied to decrease the As concentration in geothermal fluids to below the detection limit of 2 ppb (Simmons et al., 2002). Residual As in the precipitate may be slurry-injected into a water disposal well or fixed/stabilized for land disposal to meet United States Environmental Protection Agency (USEPA) Toxicity Characterization Leach Procedure (TCLP) limits using special cement formulations (Allen, 1996).3.2. Ion exchangeStrong-base anion exchange resins have been shown to remove traces of As in geothermal fluids provided that the amorphous silica is decreased below its saturation point or the water stabilized against silica scaling by acidification. The ion exchange alternative to As removal by oxidation/precipitation has proven successful in reducing the concentrations of this element to below the limits set for drinking water standards. As part of the present study, laboratory and field columnar tests were successfully conducted with geothermal hot spring water containing 30 ppm As. Pre-oxidation of As3+ is required to achieveacceptable As removal by ion exchange. In these columnar tests, NaOCl and H2O2 were used to pre-treat the hot spring water to oxidize As3+ to As5+. Chloride-rich water, which had been treated with lime (CaOH2) and filtered to reduce amorphous silica to well below its saturation point, successfully regenerated the resin. In the field, and for simplicity of operation, we concluded that ozone/Fe co-precipitation or catalyzed photo-oxidation would be preferred for water treatment over ion exchange as this would eliminate the need to purchase and transport additional chemicals. On the other hand, ion exchange is an attractive option for extracting As from condensate.Special ion-exchange resins have proven successful in removing boron (B) from geothermal fluids (Recepoglu and Beker, 1991; Gallup, 1995). Hot spring water from the geothermal field, containing 25 ppm B, had its B content decreased to <1 ppm in a laboratory columnar test. The resin was regenerated with sulfuric acid (H2SO4). No deterioration in resin performance was observed up to 10 loading and regenerationcycles.Fig. 1. Flow chart of the basic unit operations involved in treatment cases 1–6.3.3. pH adjustmentThe majority of the cases considered in this study require adjustment to pH. Adding soda ash (Na2CO3) can increase the buffering capacity of the water and condensate. Soda ash or lime treatment can also be used to enhance precipitation of certain species. Purchased H2SO4, on-site generated sulfurous acid (H2SO3) or on-site generated hydrochloric acid (HCl) can be used to acidify waters to meet reuse requirements or to inhibit silica scaling (Hirowatari, 1996; Kitz and Gallup, 1997; Gallup, 2002). A number of geothermal power plants around the world utilize water acidification to inhibit silica scaling. Unocal Corporation commenced this practice of pH adjustment of hot and cold geothermal fluids in commercial operations in the early 1980s (Jost and Gallup, 1985; Gallup et al., 1993; Gallup, 1996). In water acidification the pH is reduced slightly so as to slow down the silica polymerization reaction kinetics without significantly increasing corrosion rates.3.4. Cooling pondsIn this water processing option, the water is cooled in open, lined ponds prior to injection or treatment for beneficial use. The flashed water is allowed to flow into the pond where it “ages” for up to 3 days; this is a sufficient length of time to achieve amorphous silica saturation at ambient temperature, which is assumed to be below 20 ◦C most of the year. Adjustment of the water pH to 8.0±0.5 with soda ash or lime enhances water desilication, resulting in undersaturation with respect to amorphous silica (Gallup et al., 2003). At 15 ◦C, the solubility of amorphous silica in the water in our test field is predicted to be about 90 ppm (Fournier and Marshall, 1983). In a large bottle, field water wasadjusted from pH 7.2 to 8.1 with soda ash and allowed to cool to 15 ◦C over a period of 90 min. The resultant dissolved silica [Si(OH)4] concentration in the supernatant fluid was 54 ppm (undersaturated by about 40%).3.5. FiltrationSand and plate/frame filters were adopted in this study to polish water and dewater sludges, respectively. This does not mean that other filters could not be used in the water treatment project. At the Salton Sea (California, USA) geothermal field, for example, flocculated secondary clarifiers and pressure or vacuum filters have been adopted with success for many years as alternatives to media and plate/frame filters, respectively (Featherstone et al., 1989).3.6. Multi-stage vacuum-assisted evaporatorIn this unit of operation, cool, ponded water is combined with cooled and re-circulated water (from the evaporator heat rejection stages), and pumped to the heat recovery portion of the evaporator system. The cool water provides the thermal sink for the vapors from the final stages of the evaporator concentrate. The inlet water and concentrate flow countercurrent in the evaporator. After flowing through the heat recovery stages, the water temperature has increased somewhat. Most of this heated water is sent to a separate cooling pond before returning to the heat recovery stages. A portion of the heated water continues on through the heat recovery stages; the water also functions as the heat sink for this portion of the process.After the heat recovery stages, the water is heated with steam and returned to the heat recovery stages for flashing. The water proceeds through the heat recovery and rejection stages until it is fully concentrated. The concentrate is sent to an injection well, while the distillate is collected and re-routed for pH adjustment, as required, before passing to other treatments discussed here. The evaporator has not yet been tested at the field; the present discussion is provided for conceptualization only.3.7. Reverse osmosisThe reverse osmosis (RO) process removes dissolved salts through fine filtration at the molecular level of water. The RO membrane allows water to pass through but blocks 98% of the salts. The typical RO operating pressure is 2760–3100 kPa, which is achieved by gravity flow from the power plant to the RO unit located 300m downhill. The RO feed is pre-treated with a 2 _m cartridge filter. The rejected fluid is injected into a disposal well, while the permeate can be sent to other treatment units for polishing.The RO unit has not yet been tested at the field; the present discussion is again provided for conceptualization only. However, RO has been successfully tested at the Mammoth Lakes, California, USA, field to recover useable silica (Bourcier et al., 2006).3.8. Desilication and production of claysSilica can be eliminated from the water by holding the latter in cooling ponds for up to 3 days. Soda ash or lime can be added to the water to enhance silica precipitation. Laboratory and field jar test experiments showed that desilication of the water can also be achieved by treating with various metal cations at elevated pH to precipitate metal silicates. Below ∼90 ◦Cand at elevated pH (typically 9–10) treatments with caustic soda (NaOH), magnesium hydroxide [Mg(OH)2], lime, strontium hydroxide [Sr(OH)2], barium hydroxide [Ba(OH)2], ferric hydroxide [Fe(OH)3], birnessite [(Na,Ca)0.5(Mn4+,Mn3+)2O4· 1.5H2O], copper hydroxide, [Cu(OH)2] and zinc hydroxide [Zn(OH)2] precipitated only amorphous or poorly crystalline metal-rich silicates of little commercial value. Treatment of water with alkaline-earth metals below ∼90 ◦C, except magnesium, tended to co-precipitate metal carbonates. Laboratory reactions conducted at ∼130 ◦C demonstrated that certain metal ions may react with the silica in the water to precipitate crystalline compounds of commercial value. For example, kerolite1 clay was precipitated upon treating synthetic and field waters with magnesium at 130 ◦C, whereas, under similar conditions, sodalite (Na4Al3 Si3O12Cl) and Zeolite P2 were precipitated upon treatment with aluminum hydroxide or sodium aluminate (Gallup et al., 2003; Gallup and Glanzman, 2004). Treatment of waters with a combination of magnesium and iron precipitated hectorite (i.e. a lithium-rich clay mineral of the montmorillonite group).The desilication process designed for the field consists of a crystallizer-clarifier similar to those used at the Salton Sea field (Newell et al., 1989). For kerolite production, magnesium chloride (MgCl2) is added at slightly above stoichiometric proportions (3Mg:4Si) and the pH is increased to ∼10.0 with caustic soda or lime. The crystallizer and clarifier include sludge recirculation to maximize the “seed crystal” effect, thus providing a high surface area for precipitation. After precipitation, the water is clarified, possibly treated further to meet industrial water specifications, cooled to pipeline specifications, and finally sent to a pipeline for transport to the industrial site. The kerolite sludge is dewatered using a filter, as discussed earlier. The dewatered sludge can be dried in a steam-heated kiln or in an arid, but cool environment at the power plant. Dried kerolite is transported off-site for commercial refining and use. In zeolite manufacture, sodium aluminate (NaAlO2) is used both as the Al and base source. Hectorite or saponite (i.e. a magnesium-rich clay mineral of the montmorillonite group) are made1 Kerolite is a disordered form of talc.2 Zeolite P refers to various forms of gismodine.Table 3Quality of the water end-product estimated from actual testing and from vendor treatment specifications for the six treatment cases described in Table 2a TDS: total dissolved solids.in a similar fashion by treating water with Mg2+ and Fe2+ salts and a base (Gallup et al., 2003). Adding a little brucite [Mg(OH)2] or MgCl2 will also produce a nearly pure silica by-product for industrial uses (Lin et al., 2001). Desilication of water with precipitation of valuable minerals is a preferred option as opposed to simply allowing the silica to deposit in cooling ponds as it adds value to the geothermal power project by simultaneously controlling scale deposition and producing marketable products. Once the water is treated for desilication, any metals of commercial value can be extracted by means of well-documented processes (Maimoni, 1982; Featherstone, 1988; Duyvesteyn, 1992; Featherstone and Furmanski, 2004). This approach is particularly important if ion exchange or solvent extraction techniques have been used to concentrate and recover lithium, base and precious metals.4. Quality of the water end-productTable 3 gives details on the estimated quality of the water produced after each of the six treatment cases (see Table 2 for initial concentrations). The water qualities meet or exceed perceived drinking, agriculture and industrial standards at the location of the test plant.5. Preliminary cost estimatesTable 4 is a summary of the estimated capital and operating (product water) costs, based on construction of the geothermal power plant for the six treatment processes. Local market prices for chemicals such as H2SO4, CaO, flocculents, NaCl, Na2CO3, FeSO4, MgCl2, NaAlO2, etc., were used in the calculations. The product cost does not include a productstorage reservoir at the end of the pipeline where the treated water can be made available for industrial, agricultural or drinking uses. The anticipated selling price for finished minerals, such as kerolite, saponite, sepiolite (a magnesium-rich clay mineral), etc. was set at US$ 0.45 kg −1. For comparison, the cost of injecting all of the waste geothermal fluids back into the field (using wells with gravity feed) is ∼US$ 10,000,000. The latter is the estimated capital cost of drilling sufficient injection wells for water disposal, but does not include poten- Table 4Preliminary cost estimates (US$) for the six treatment cases described in Table 2a Water treatment cost offset by 7.5 ton/h of clay sales.tially high maintenance costs for acidification treatment and/or for re-drilling these injection wells.6. ConclusionsA preliminary study has been made of combining water treatment/reuse and electricity generation in a geothermal power plant located in an arid region of the western hemisphere. It has been assumed that good-quality water is scarce in the area and that there is a local demand for potable, agricultural and industrial water resources. Geothermal water and steam condensate require treatment prior to reuse. A variety of treatment scenarios have been considered to achieve water quality ranging from potable to industrial standards. Some proof-of-concept testing in the laboratory and the field has been conducted to ensure that certain qualities can be attained. Preliminary cost estimates have been made for the treatment schemes considered in the study. Promising processes have been developed to produce marketable water and silicate minerals. Desilication and removal of arsenic and boron from the water have also proved useful with a view to subsequent extraction of lithium, base and precious metals.AcknowledgmentsThe authorwould like to thank Chevron Corporation management for permission to publish this paper. CH2MHILL, Irvine, CA, provided many of the process ideas and cost estimates included here. The author appreciates the many useful comments and suggestions provided by the editors and by Mr. Paul Hirtz in his review of the manuscript.ReferencesAllen, W.C., 1996. Superplasticizer-cement composition for waste disposal. US Patent 5,551,976.Bourcier, W., Ralph, W., Johnson, M., Bruton, C., Gutierrez, P., 2006. Silica extraction at Mammoth Lakes, California.Lawrence Berkeley National Laboratory Report UCRL-PROC-224426. Livermore,CA, USA, 6 pp.Doran, G.F.,Williams, K.L., Drago, J.A., Huang, S.S., Leong, L.Y.C., 1998. Pilot study results to convert oil field producedwater to drinking water or reuse. Paper presented at 1998 SPE Annual Technical Conference and Exhibition, 27–30September. New Orleans, LA, USA, SPE Paper 49124, 15 pp.Duyvesteyn, W.P.C., 1992. Recovery of base metals from geothermal waters. Geothermics 21, 773–799.Featherstone, J.L., 1988. Process for removing silica from silica-rich geothermal water. US Patent 4,765,913.Featherstone, J.L., Furmanski, G., 2004. Process for producing electrolytic manganese dioxide from geothermal brine.US Patent 6,682,644.Featherstone, J.L., Spang, T., Newell, D.G., Gallup, D.L., 1989. Process and apparatus for reducing the concentration ofsuspended solids in clarified geothermal water. US Patent 4,874,529. Fournier, R.O., Marshall, W.L., 1983. Calculation of amorphous silica solubilities at 25◦ to 300 ◦C and apparent cationhydration numbers in aqueous salt solutions using the concept of effective density of water. Geochim. Cosmochim.Acta 47, 587–596.Gallup, D.L., 1995. Agricultural uses of excess steam condensate—Salton Sea geothermal field. Geotherm. Sci. Technol.4, 175–187.Gallup, D.L., 1996. Water pH modification scale control technology. Geotherm. Resour. Counc. Trans. 20, 749–755.Gallup, D.L., 2002. Method for simultaneously abating H2S and producing acid for water treatment. US Patent 6,375,907.Gallup, D.L., Barnes, M.L., Cope, D., Kolimlim, Q.S., Leong, J.K., 1993. Water heat exchanger treatment method. USPatent 5,190,664.Gallup, D., Sugiaman, F., Capuno, V., Manceau, A., 2003. Laboratory investigation of silica removal from geothermalwaters to control silica scaling and produce usable silicates. Appl. Geochem. 18, 1597–1612.Gallup, D.L., Glanzman, R.K., 2004. Method for synthesizing crystalline magnesium silicates from geothermal water.US Patent 6,761,865.Hirowatari, K., 1996. Scale prevention method bywater acidification with biochemical reactors. Geothermics 25, 259–270.Jost, J.W., Gallup, D.L. 1985. Inhibiting scale precipitation from high temperature water. US Patent 4,500,434.Khoe, G.H., Emett, M.T., Robins, R.G., 1997. Photoassisted oxidation of species in solution. US Patent No. 5,688,378.Kitz, K.R., Gallup, D.L., 1997. pH modification of geothermal water with sulfur-containing acid. US Patent 5,656,172.Lin, M.S., Premuzic, E.T., Zhou,W.M., Johnson, S.D., 2001. Mineral recovery: a promising geothermal power productionco-product. Geotherm. Resour. Counc. Trans. 25, 497–500.Maimoni, A., 1982. Mineral recovery from Salton Sea geothermal waters: a literature review and proposed cementationprocess. Geothermics 11, 239–258.Newell, D.G., Whitescarver, O.D., Messer, P.H., 1989. Salton Sea Unit 3;47.5MWe geothermal power plant. Geotherm.Resour. Counc. Bull. 18 (5), 3–5.Pascua, C.S., Minato, M., Yokoyama, S., Sato, T., 2007. Uptake of dissolved arsenic during the retrieval of silica fromspent geothermal brine. Geothermics 36, 230–242.Recepoglu, O., Beker, U., 1991. A preliminary study of boron removal from Kizildere/Turkey geothermal waste water.Geothermics 20, 83–89.Rothbaum, H.P., Anderton, B.H., 1975. Removal of silica and arsenic from geothermal discharge waters by precipitationof useful calcium silicates. Geothermics 2, 1417–1425.Simmons, M., Gallup, D., Harden, D., 2002. Photo-oxidation, removal and stabilization of arsenic residuals in drinkingwater, wastewater and process water systems. Trends Geochem. 2, 73–84. Umeno, J., Iwanaga, T., 1998. A study on the abatement technology of the harmful chemical components in geothermalhot water. In: Proceedings of the 20th New Zealand Geothermal Workshop, pp. 209–213.处理地热废水来生产工业用水、农业用水或生活饮用水达雷尔L.盖洛普能源技术公司，雪佛龙公司Briarpark博士，美国德克萨斯州休斯顿摘要：一个概念的研究已经进行了转换成有价值的工业、农业和饮用水资源地热水和凝析油。

环境工程、给排水专业外文参考文献译文

浮选柱处理含油废水的研究摘要：本文介绍了一种为处理含油废水而开发的新型溶气浮选柱装置。

溶气浮选柱将溶气气浮法和浮选柱巧妙的加以结合运用，溶解空气在柱体分离系统中释放。

本文对这种具有潜在应用价值的柱体系统分离含油废水中油分的效果进行了研究，在一系列的实验中该装置均取得了理想的分离效果，同时还对溶气浮选柱中采用的气泡产生器的曝气效果进行了专门研究。

关键词：含油废水；分离；气浮；气泡发生器；溶气浮选柱一、引言含油废水是石油开发利用过程中产生的面积广，数量大的污染源。

废水中的油分包括浮油，分散油，乳化油，溶解油和油-固结合物。

含油废水常用的处理技术有物理法、物理化学法、化学破乳法、生物化学法和电化学法。

分离难易程度取决于油分在水体中的存在形式。

含油废水中的浮油一般可以采用重力分离技术予以去除，溶解油可以通过生物处理法将其去除，而以胶体状态存在的分散油和乳化油由于其平均粒径小，化学稳定性高而难以去除。

近年来，浮选技术由于具有分离效率高，资金投入少，运行费用低的特点而吸引了众多学者的关注，并且已经开发出一些新型的快速高效的含油废水处理装置。

Feng P B 和其合作者开发出一种高效节能浮选柱进行含油废水处理，其油分的去除率可以达到90%左右。

Gu Xuqing等人开发出一种新型多级环流式浮选柱可处理含油废水，其独特的流体环流模式极大的提高了油珠和气泡之间的接触几率，分离效果显著，5分钟，分离效率可以达到96%-97%。

Xiao K L等人用多级浮选柱处理含油废水，空气分散在装置的柱体托盘底部，含油废水在柱体的各个托盘中进行处理，除油率达94%。

含有乳化油的废水处理较为困难，为保证浮选效率，分离时要求气泡粒径小，并且在分离区域中形成安静的水力学环境。

分离区应当又长又窄这一概念引发了利用柱状体作为分离设备这一设计理念。

由此产生了一种叫做溶气浮选柱的新型设备，溶解空气在该装置的柱体分离系统中析出，以此来处理含油废水。

给水排水工程专业英语文献翻译译文第三篇

污水的有机污垢物污染的反渗透膜的污染和清洗摘要：被模拟的混合有机废水污水污染反渗透膜的结垢和随后的清洗已经有了系统的研究。

有机污染研究包括海藻，牛血清白蛋白（BSA），萨旺尼河天然有机物，与辛酸,分别代表多糖、蛋白质、腐殖酸和脂肪酸，在出水有机物中它们是无处不在的。

建立了存在或缺乏钙离子的混合有机污染物的结垢行为和机制后，我们的研究集中在被有机污染物质的混合物污染的渗透膜的清洗机制。

化学清洗剂代理包括碱（氢氧化钠），金属螯合剂（乙二胺四乙酸），阴离子表面活性剂（十二烷基硫酸钠），和浓缩盐溶液（氯化钠）。

具体来说，我们研究清洁剂型，清洁液，清洗时间，和结垢层组成对膜清洗效率的影响。

在有机污染物质的混合物污染的污染膜的的条件下模拟的化学清洗的调查时，粘附力值测量值提供了深入了解化学清洗机制。

结果表明，在单用碱性溶液（氢氧化钠）不能有效的破坏含钙有机污染形成的配合物，较高的pH值会导致有效的清洁，如果有足够的流体剪切力（由横向表面流提供）存在。

表面活性剂（十二烷基硫酸钠），一个强大的螯合剂（乙二胺四乙酸），和盐溶液（氯化钠）可以有效的清洗混合污染的反渗透膜，尤其是如果应用在高pH值和更长的清洗时间。

观察各种清洁剂的清洗效率均符合相关测量–分子间力值值。

此外，我们已经表明，最佳的清洁剂浓度可以从绘制的还原百分比–粘附力的值与清洗剂浓度的对比中推出。

1 景区简介全球范围对饮用水需求的增加，选择水源满足这一需求的方式从传统的来源，如水库、湖泊，转换到较常规来源，如污水二级污水处理。

为生产优质用水，使用膜进行海水淡化和废水回收已应用的更广泛。

膜污染是利用膜技术等应用的一个主要障碍，因为污染是不可避免的。

尽管努力研究开发更好的防污膜[和改进控制方法策略，膜污染仍随时间发生。

因此，长期解决办法是通过化学清洗清除沉积膜。

在废水中，回收为了选择适当的清洁剂和采用有效的化学清洗规程，必须了解废水排放特性的对膜污染的影响。

给排水专业英文文献翻译

Sewage treatmentAbstract：Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff (effluents) and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants. Its objective is to produce a waste stream (or treated effluent) and a solid waste or sludge suitable for discharge or reuse back into the environment. This material is often inadvertently contaminated with many toxic organic and inorganic compounds.Key words: Sewage treatment,fixed-film and suspended-growth, Activated sludge Origins of sewageSewage is created by residences, institutions, and commercial and industrial establishments. Raw influent (sewage) includes household waste liquid from toilets, baths, showers, kitchens, sinks, and so forth that is disposed of via sewers. In many areas, sewage also includes liquid waste from industry and commerce. The separation and draining of household waste into greywater and blackwater is becoming more common in the developed world, with greywater being permitted to be used for watering plants or recycled for flushing toilets. A lot of sewage also includes some surface water from roofs or hard-standing areas. Municipal wastewater therefore includes residential, commercial, and industrial liquid waste discharges, and may include stormwater runoff. Sewage systems capable of handling stormwater are known as combined systems or combined sewers. Such systems are usually avoided since they complicate and thereby reduce the efficiency of sewage treatment plants owing to their seasonality. The variability in flow also leads to often larger than necessary, and subsequently more expensive, treatment facilities. In addition, heavy storms that contribute more flows than the treatment plant can handle may overwhelm the sewage treatment system, causing a spill or overflow. It is preferable to have a separate storm drain system for stormwater in areas that are developed with sewer systems.As rainfall runs over the surface of roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease. Some jurisdictions require stormwaterto receive some level of treatment before being discharged directly into waterways. Examples of treatment processes used for stormwater include sedimentation basins, wetlands, buried concrete vaults with various kinds of filters, and vortex separators (to remove coarse solids).Process overviewSewage can be treated close to where it is created (in septic tanks, biofilters or aerobic treatment systems), or collected and transported via a network of pipes and pump stations to a municipal treatment plant (see sewerage and pipes and infrastructure). Sewage collection and treatment is typically subject to local, state and federal regulations and standards. Industrial sources of wastewater often require specialized treatment processes (see Industrial wastewater treatment).Conventional sewage treatment may involve three stages, called primary, secondary and tertiary treatment. Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment. Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-bornemicro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment. Tertiary treatment is sometimes defined as anything more than primary and secondary treatment. Treated water is sometimes disinfected chemically or physically (for example by lagoons and microfiltration) prior to discharge into a stream, river, bay, lagoon or wetland, or it can be used for the irrigation of a golf course, green way or park. If it is sufficiently clean, it can also be used for groundwater recharge or agricultural purposes.Pre-treatmentPre-treatment removes materials that can be easily collected from the raw wastewater before they damage or clog the pumps and skimmers of primary treatment clarifiers (trash, tree limbs, leaves, etc).ScreeningThe influent sewage water is strained to remove all large objects carried in the sewage stream. This is most commonly done with an automated mechanically raked bar screen in modern plants serving large populations, whilst in smaller or less modern plants a manually cleaned screen may be used. The raking action of a mechanical bar screen is typically paced according to the accumulation on the bar screens and/or flow rate. The solids are collected and later disposed in a landfill or incinerated.Grit removalPre-treatment may include a sand or grit channel or chamber where the velocity of the incoming wastewater is carefully controlled to allow sand, grit and stones to settle.Primary treatmentIn the primary sedimentation stage, sewage flows through large tanks, commonly called "primary clarifiers" or "primary sedimentation tanks". The tanks are large enough that sludge can settle and floating material such as grease and oils can rise to the surface and be skimmed off. The main purpose of the primary sedimentation stage is to produce both a generally homogeneous liquid capable of being treated biologically and a sludge that can be separately treated or processed. Primary settling tanks are usually equipped with mechanically driven scrapers that continually drive the collected sludge towards a hopper in the base of the tank from where it can be pumped to further sludge treatment stages. Grease and oil from the floating material can sometimes be recovered for saponification.Secondary treatmentSecondary treatment is designed to substantially degrade the biological content of the sewage which are derived from human waste, food waste, soaps and detergent. The majority of municipal plants treat the settled sewage liquor using aerobic biological processes. For this to be effective, the biota require both oxygen and a substrate on which to live. There are a number of ways in which this is done. In all these methods, the bacteria and protozoa consume biodegradable soluble organiccontaminants (e.g. sugars, fats, organic short-chain carbon molecules, etc.) and bind much of the less soluble fractions into floc. Secondary treatment systems are classified asfixed-film and suspended-growth.Fixed-film OR attached growth system treatment process including trickling filter and rotating biological contactors where the biomass grows on media and the sewage passes over its surface.In suspended-growth systems, such as activated sludge, the biomass is well mixed with the sewage and can be operated in a smaller space than fixed-film systems that treat the same amount of water. However, fixed-film systems are more able to cope with drastic changes in the amount of biological material and can provide higher removal rates for organic material and suspended solids than suspended growth systems.Roughing filters are intended to treat particularly strong or variable organic loads, typically industrial, to allow them to then be treated by conventional secondary treatment processes. Characteristics include typically tall, circular filters filled with open synthetic filter media to which wastewater is applied at a relatively high rate. They are designed to allow high hydraulic loading and a high flow-through of air. On larger installations, air is forced through the media using blowers. The resultant wastewater is usually within the normal range for conventional treatment processes. Activated sludgeMain article: Activated sludgeIn general, activated sludge plants encompass a variety of mechanisms and processes that use dissolved oxygen to promote the growth of biological floc that substantially removes organic material.The process traps particulate material and can, under ideal conditions, convert ammonia to nitrite and nitrate and ultimately to nitrogen gas, (see also denitrification).Surface-aerated basinsMost biological oxidation processes for treating industrial wastewaters have in common the use of oxygen (or air) and microbial action. Surface-aerated basins achieve 80 to 90% removal of Biochemical Oxygen Demand with retention times of 1 to 10 days. The basins may range in depth from 1.5 to 5.0 metres and usemotor-driven aerators floating on the surface of the wastewater.In an aerated basin system, the aerators provide two functions: they transfer air into the basins required by the biological oxidation reactions, and they provide the mixing required for dispersing the air and for contacting the reactants (that is, oxygen, wastewater and microbes). Typically, the floating surface aerators are rated to deliver the amount of air equivalent to 1.8 to 2.7 kg O2/kW·h. However, they do not provide as good mixing as is normally achieved in activated sludge systems and therefore aerated basins do not achieve the same performance level as activated sludge units.Biological oxidation processes are sensitive to temperature and, between 0 °C and 40 °C, the rate of biological reactions increase with temperature. Most surface aerated vessels operate at between 4 °C and 32 °C.Filter beds (oxidizing beds)Main article: Trickling filterIn older plants and plants receiving more variable loads, trickling filter beds are used where the settled sewage liquor is spread onto the surface of a deep bed made up of coke (carbonized coal), limestone chips or specially fabricated plastic media. Such media must have high surface areas to support the biofilms that form. The liquor is distributed through perforated rotating arms radiating from a central pivot. The distributed liquor trickles through this bed and is collected in drains at the base. These drains also provide a source of air which percolates up through the bed, keeping it aerobic. Biological films of bacteria, protozoa and fungi form on the media’s s urfaces and eat or otherwise reduce the organic content. This biofilm is grazed by insect larvae and worms which help maintain an optimal thickness. Overloading of beds increases the thickness of the film leading to clogging of the filter media and ponding on the surface.Biological aerated filtersBiological Aerated (or Anoxic) Filter (BAF) or Biofilters combine filtration with biological carbon reduction, nitrification or denitrification. BAF usually includes a reactor filled with a filter media. The media is either in suspension or supported by a gravel layer at the foot of the filter. The dual purpose of this media is to support highly active biomass that is attached to it and to filter suspended solids. Carbon reduction and ammonia conversion occurs in aerobic mode and sometime achieved in a single reactor while nitrate conversion occurs in anoxic mode. BAF is operated either in upflow or downflow configuration depending on design specified by manufacturer.Membrane bioreactorsMembrane bioreactors (MBR) combine activated sludge treatment with a membrane liquid-solid separation process. The membrane component uses low pressure microfiltration or ultra filtration membranes and eliminates the need for clarification and tertiary filtration. The membranes are typically immersed in the aeration tank; however, some applications utilize a separate membrane tank. One of the key benefits of an MBR system is that it effectively overcomes the limitations associated with poor settling of sludge in conventional activated sludge (CAS) processes. The technology permits bioreactor operation with considerably higher mixed liquor suspended solids (MLSS) concentration than CAS systems, which are limited by sludge settling. The process is typically operated at MLSS in the range of 8,000–12,000 mg/L, while CAS are operated in the range of 2,000–3,000 mg/L. The elevated biomass concentration in the MBR process allows for very effective removal of both soluble and particulate biodegradable materials at higher loading rates. Thus increased Sludge Retention Times (SRTs) — usually exceeding 15 days — ensure complete nitrification even in extremely cold weather.The cost of building and operating an MBR is usually higher than conventional wastewater treatment. Membrane filters can be blinded with grease or abraded by suspended grit and lack a clarifier's flexibility to pass peak flows. The technology has become increasingly popular for reliably pretreated waste streams and has gainedwider acceptance where infiltration and inflow have been controlled, however, and the life-cycle costs have been steadily decreasing. The small footprint of MBR systems, and the high quality effluent produced, make them particularly useful for water reuse applications.There are MBR plants being built throughout the world, including North Librty, Iowa, Georgia, and Canada.Secondary sedimentationThe final step in the secondary treatment stage is to settle out the biological floc or filter material and produce sewage water containing very low levels of organic material and suspended matter.Rotating biological contactorsMain article: Rotating biological contactorRotating biological contactors (RBCs) are mechanical secondary treatment systems, which are robust and capable of withstanding surges in organic load. RBCs were first installed in Germany in 1960 and have since been developed and refined into a reliable operating unit. The rotating disks support the growth of bacteria and micro-organisms present in the sewage, which breakdown and stabilise organic pollutants. To be successful, micro-organisms need both oxygen to live and food to grow. Oxygen is obtained from the atmosphere as the disks rotate. As themicro-organisms grow, they build up on the media until they are sloughed off due to shear forces provided by the rotating discs in the sewage. Effluent from the RBC is then passed through final clarifiers where the micro-organisms in suspension settle as a sludge. The sludge is withdrawn from the clarifier for further treatment.A functionally similar biological filtering system has become popular as part of home aquarium filtration and purification. The aquarium water is drawn up out of the tank and then cascaded over a freely spinning corrugated fiber-mesh wheel before passing through a media filter and back into the aquarium. The spinning mesh wheel develops a biofilm coating of microorganisms that feed on the suspended wastes in the aquarium water and are also exposed to the atmosphere as the wheel rotates. This is especially good at removing waste urea and ammonia urinated into the aquariumwater by the fish and other animals.污水处理摘要自然或生活污水处理，是指清除包括家庭排放的和地面径流在内的污水废水和地面污染物的过程。

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浮选柱处理含油废水的研究摘要：本文介绍了一种为处理含油废水而开发的新型溶气浮选柱装置。

溶气浮选柱将溶气气浮法和浮选柱巧妙的加以结合运用，溶解空气在柱体分离系统中释放。

关键词：含油废水；分离；气浮；气泡发生器；溶气浮选柱一、引言含油废水是石油开发利用过程中产生的面积广，数量大的污染源。

废水中的油分包括浮油，分散油，乳化油，溶解油和油-固结合物。

含油废水常用的处理技术有物理法、物理化学法、化学破乳法、生物化学法和电化学法。

分离难易程度取决于油分在水体中的存在形式。

含油废水中的浮油一般可以采用重力分离技术予以去除，溶解油可以通过生物处理法将其去除，而以胶体状态存在的分散油和乳化油由于其平均粒径小，化学稳定性咼而难以去除。

Feng P B和其合作者开发出一种高效节能浮选柱进行含油废水处理，其油分的去除率可以达到90% 左右。

GU Xuqing等人开发出一种新型多级环流式浮选柱可处理含油废水，其独特的流体环流模式极大的提高了油珠和气泡之间的接触几率，分离效果显著，5分钟内，分离效率可以达到96%-97%0Xiao K L等人用多级浮选柱处理含油废水，空气分散在装置的柱体托盘底部，含油废水在柱体的各个托盘中进行处理，除油率达94%。

含有乳化油的废水处理较为困难，为保证浮选效率，分离时要求气泡粒径小，并且在分离区域中形成安静的水力学环境。

分离区应当又长又窄这一概念引发了利用柱状体作为分离设备这一设计理念。

由此产生了一种叫做溶气浮选柱的新型设备，溶解空气在该装置的柱体分离系统中析出，以此来处理含油废水。

二、材料与方法（一）材料实验废水是用胜利油田的脱水脱气原油配制的乳化油经过稀释得到的。

水样经过三十分钟的高速搅拌混合以保证油珠完全地分散到水中。

采用激光粒度分析仪分析油珠的粒径分布；平均粒径为18.15微米，约有77.8%的粒子的粒径在25微米左右或更小（图I）O5.00405 I 2 4 5 10 20 40 50 IOO 200PaniCIe analyzer （μm）图1含油废水中油珠粒径的分布曲线（二）方法浮选分离装置为圆柱形，由树脂玻璃制成，高2000mm,直径50mm。

浮选柱的工作原理是气液逆流，清洁水和回流水在充满空气的加压罐中加压，由此水中溶解了饱和的空气，水流通过气泡发生器时快速减压，并且以超微气泡的形式释放出溶解空气，而后进入浮选柱中。

当气泡从发生器中释放出来的时候碰撞接触，逐渐形成了大量的微气泡。

用于废水处理的浮选法有很多种气泡产生的方式，它们在运行的原理上有较大的区别。

微气泡发生器主要有三种：溶气释放型微气泡发生器，加气微气泡发生器，电解低浓度水溶液气泡发生器。

携带气泡的水进入浮选柱，由于其动能大幅度降低，流速低到接近静态，近乎实现了浮选柱分离中静态分离的理想状态。

含油废水从浮选柱的上部进入，水流向下流动，气泡向上流动，形成了气液逆流。

气泡和油滴在此过程中产生碰撞，结合形成气泡-油珠复合物，并上浮到液面。

然后，这些复合物最终形成泡沫流进收集罐体。

浮选柱可以被分为三个区：a）位于底部的曝气点和顶部的废水-泡沫接触面之间的回收区；b）位于水-泡沫接触面到溢流堰之间的泡沫富集分离区；C）位于柱体底部到产生微气泡的曝气点之间的净化区（图2）o气泡和油滴在回收区碰撞接触，气泡在气泡富集分离区进行聚集，从而降低了回收油分中的含水量。

分离过程主要包括两个步骤。

第一步是破乳和混凝，即在含油废水中加入混凝剂进行破乳和絮凝，增大了絮凝体尺寸，有利于形成稳定的疏水基团。

第二步是浮选柱分离，在柱体中微气泡和絮凝体互相碰撞粘附形成气-絮团聚物，在浮力作用下上升到液面，油分因此从废水中得以分离去除。

实验中采用十二烷基硫酸钠（SDS ）作为表面活性剂，聚合氯化铝（PAC ）和聚丙烯酰胺（PAM ）作为混凝剂。

将药剂投加到装有实验水样的搅拌器中，混凝剂分散水解后产生絮凝反应，含油废水通过蠕动泵输送到浮选柱中。

处理水通过设有固定数值的转子流量计定量排出，回用处理水通过另一个蠕动泵输送到压力罐中。

三、结果与讨论（一）溶气浮选柱的曝气效果采用微气泡发生器将微气泡释放到溶气浮选柱中。

由碰撞与捕获效率理论可知，气泡与油珠的碰撞几率在气泡尺寸较小时达到最大。

实验废水水样的油珠平均粒径小于100 μm ,因此在实验中采用了微气泡产生法来释放溶解空气，气泡发生器的结构决定曝气方法。

气泡发生器是本实验系统中的关键环节，对浮选柱的曝气效果和分离效率有重要影响，含有饱和空气的水通过气泡产生器稳定的释放出大量的细小，均匀的气泡（图 3）。

溶气浮选柱中气泡的稳定性受到气泡在气液两相流中的停留时间的影响。

停留时间定义为气泡从气泡发生器释放到气泡上升至液体表面并破裂所经历的时间段。

停留时间StilrTed IarlkTleatetI Water TeCyCle BuibbI es ge⅛ιeralαrFIoatCIj Pro-IiUct* Forth range TniatCd ⅛a⅛∣Flcilalkm reagentPCri5U∣Uc PUrnPRceiI⅛cτy range SCaVCn^τ TaUgC Saturation Unk冋OUHan COIIJmn图2溶气浮选柱处理含油废水的工艺流程COmI>ι,c⅛s⅛d air J * W TrTeaIed wa⅛r P ROealIKter 卜∙ VaIVe 图3 溶气浮选柱中的曝气效果通过一个充满压力水的容积为1000mL 的圆柱形量筒进行测量，所需时间由气泡从量筒中分别测定。

溶解气压对停留时间的影响如图4所示5.5 丿 _______________ Jj - _______________ I ____________ J J__ ____________ ____________________ ______________ JO t l 0203 0,4 0.5■ DiSSolUtiOn air PreSSUrC (MPa)图4溶解空气压力对气泡停留时间的影响由图4可以看出，在压力小于0.4MPa 时，气泡的停留时间随气压的增加而增加，此后随气压的增加而减小。

因此，由本实验可以得出 0.3MPa-0.45MPa 为最合适的压力区间，在此区间内，产生的气泡数量最多，粒径最小，停留时间最长。

(二)影响除油效果的几个参数1. 压力的影响浮选过程需要足够的溶气量，以便提供足够数量的微气泡。

在溶气浮选柱实验系统中，空气在水中的溶解量随着压力罐中压力的增加而增加。

小气泡的上升速度小于大气泡，这确保了浮选柱系统有更长的停留时间，气泡和油珠之间有更多的机会碰撞。

溶气压力对除油率的影响如图5所示。

实验条件如下：PH=6.9,流量v=0.6L∕min ,回流比R=20%,P PAC)=20.0mg∕L , P SDS)=5.0mg∕L ,泡沫层厚度 δ =30mm的最底部上升到液面并破裂之间的时差来决定,停留时间在具有不同初始气压的压力罐90SO7060刃403020-丿——Il 1 P.0.5.0.5.0 067.7.6I6Γ ='≡)sq⅛q⅞u,il魁 IPPF —InitiaI oil concentration, 5 I Λhnfi∕L -∙- Initiaj ailconcentration, IoO,5mg∕L -* ' Tnidai Oil ConCentra时On lb ISO T 9mg∕L V -v . —9- Initial 。

订COnCentratiOTl t 20】.2mg∕l -10 l ~I --------------------- 1 --------------1- ---------- 1 ---------------- ' 0.1 0.2 03 0.4 0.5P(MPa)图5溶气压力对除油效果的影响从图5中可以看出，随着溶气压力的增加，含油废水中的残油浓度逐渐下降。

实验结果表明在压力为0.3MPa 的情况下，残油浓度为59.6mg∕L, 45.7mg∕L, 29.5mg∕L, 14.8mg∕L时，除油率分别为70.4%,69.7%,70.6%,71.0%。

但当压力增大到0.3MPa以后残油浓度的降低趋势减缓，在溶气压力大于0.35MPa以后含油废水中的残油浓度反而缓慢增加。

这是因为在合适的压力范围内，较高的溶气压力可以保证微气泡的尺寸小，数量多。

然而，当压力超过一定限值以后就会对分离过程产生不利影响，因为当压力过高时水中的溶气既无法消能，气泡的大小也无法保持均衡，这就造成了紊流，它会扰乱柱体中的水流流动并且破坏絮凝体。

絮凝体的破坏会造成浮选效率的降低，当溶气压力接近0.5MPa时在浮选柱中会出现“弹状流”。

因此，由实验所确定的最佳压力范围为0.25MPa-0.35MPa2. PH值的影响油珠和悬浮在水中的微气泡在其表面带有负电荷。

在分离过程中调整PH值对气泡、油珠以及它们所形成的絮凝体所带的表面电荷有重要影响，这有可能影响絮凝体在废水中的性质甚至存在形式，PH值可以通过添加盐酸或者氢氧化钠进行调整。

PH值对除油率的影响如表1所示。

实验条件如下：溶气压力p=0.3MPa,处理水量v=0.6L∕min ,回流比R=20%,进水含油浓度W0=100.9mg∕L, P (PAC=20.0mg∕L, P(SDS)=5.0mg∕L,泡沫层厚度δ =30mm从表1可以看出，当PH值介于6-9之间时，除油率为77.0%-78.6%o实验结果表明用溶气浮选柱处理含油废水时PH值应介于6-9之间。

3. 处理水量的影响处理水量也是对分离效率的重要影响因素。

增大处理水量会降低废水在柱体中的停留时间，从而导致除油率降低。

因此应通过研究确定合理的处理水量，处理水量过小，在经济上不划算，处理水量过大，废水在柱体中的停留时间过短，除油率降低。

实验条件如下：PH=7.4,溶气压力p=0.3MPa,回流比R=20%,进水含油浓度w°=101.1mg∕L,P (PAC=20.0mg∕L, P(SDS)=5.0mg∕L,泡沫层厚度δ =30mm从表可以看出，处理水量从增加到的过程中，除油率从降到了 38.5%。

柱体横截面上的流速随着处理水量的增加而增加，废水在柱体中的停留时间因此缩短，这减小了微气泡与油珠之间碰撞的几率，降低了分离效率。

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