环境工程、给排水专业外文参考文献译文
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
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。
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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。
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，化学稳定性咼而难以去除。
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。