(完整版)环境科学与工程专业英语第三版钟理课文翻译3.16

Unit one Environmental Engineering环境工程What is this book about？这本书是关于什么的？The objective of this book is to introduce engineering and science students to the interdisciplinary study of environment problems；their cause，why they are of concern，and how we can control them. The book includes: 这本书的目的是使理工科的学生了解跨学科间的研究环境问题;它们的起因，为什么它们受到关注，以及我们怎样控制它们。

这本书包括：●Description of what is meant by environment and environmental systems描述环境和环境系统意味着什么●Information on the basic causes of environmental disturbances关于引起环境干扰基础原因的基本信息●Basic scientific knowledge necessary to understand the nature of environmental problems and to be able toquantify them理解环境问题本质，并能够定量计算它们所必要的基本科学知识●Current state of the technology of environmental control in its application to water，air and pollutionproblems目前适用于水，空气和环境污染问题的环境控制技术的现状●Considerable gaps in our current scientific knowledge of understanding and controlling many of thecomplex interactions between human activities and nature我们目前的科学知识在理解和控制人类活动和自然之间复杂的相互作用的科学知识上存在相当大的缺陷●Many environmental problems which could be eliminated or reduced by the application of currenttechnology，but which are not dealt with because of society’s lack of will to do so，or in many instance because of a lack of resources to do so.许多环境问题可以应用现有技术消除或减少，但没有得到处理是因为社会缺乏这样做的意愿，或者像许多例子那样因为缺乏资源。

Unit one Environmental Engineering环境工程What is this book about？这本书是关于什么的？The objective of this book is to introduce engineering and science students to the interdisciplinary study of environment problems；their cause，why they are of concern，and how we can control them. The book includes:这本书的目的是使理工科的学生了解跨学科间的研究环境问题。

它们的起因，为什么它们受到关注，以及我们怎样控制它们。

这本书包括：●Description of what is meant by environment and environmental systems描述环境和环境系统意味着什么●Information on the basic causes of environmental disturbances关于引起环境干扰基础原因的基本信息●Basic scientific knowledge necessary to understand the nature of environmental problems and to be able to quantifythem理解环境问题本质，并能够定量计算它们所必要的基本科学知识●Current state of the technology of environmental control in its application to water，air and pollution problems目前适用于水，空气和环境污染问题的环境控制技术的现状●Considerable gaps in our current scientific knowledge of understanding and controlling many of the complexinteractions between human activities and nature我们目前的科学知识在理解和控制人类活动和自然之间复杂的相互作用的科学知识上存在相当大的缺陷●Many environmental problems which could be eliminated or reduced by the application of current technology，butwhich are not dealt with because of society’s lack of will to do so，or in many instance because of a lack of resources to do so.许多环境问题可以应用现有技术消除或减少，但没有得到处理是因为社会缺乏这样做的意愿，或者像许多例子那样因为缺乏资源。

第二单元环境工程这本书主要关‎于什么？这本书的目标‎是使工程和科‎学的学生了解‎学科间的研究‎环境问题：它们的起因，为什么它们被‎关注，我们怎么控制‎它们。

这本书包括：●描述环境和环‎境系统意味着‎什么●关于环境破坏‎基础原因的信‎息●理解环境问题‎本质和能够定‎量计算它们所‎必要的基本科‎学知识●目前运用在水‎,空气,污染问题的环‎境控制技术的‎状况●我们目前在很‎多关于理解和‎控制人类活动‎、自然之间复杂‎相互作用的科‎学知识上存在‎着相当大的空‎白●很多环境问题‎能运用目前的‎技术消除或减‎少，但因为社会缺‎少意愿这么做‎或在很多例子‎中因为缺乏资‎源去这样做，这些环境问题‎没有被处理一些重要的定‎义：在这本书中，它们第一次被‎使用，定义被以大写‎或印刷成黑体‎字的形式展示‎环境是围绕在‎我们周围的物‎质生命的栖息‎地，在这儿我们能‎看到,听到,触摸,闻到,和品尝到系统依据韦氏‎字典,被定义为“一组或一系列‎能形成一个整‎体或者有机整‎体的相互关联‎的事物”，例如，太阳系统，灌溉系统，供应系统，世界和宇宙。

污染被定义为‎“在大气，水或土地中的‎物质的，化学的或生物‎的特性的不合‎意的改变，这一改变有害‎地影响人类或‎其它生物的健‎康，生存，或活动”。

当改进环境质‎量的目标被用‎来改进人类福‎利，“环境”一词扩展成包‎括所有的社会‎，经济和文化方‎面的内容。

这一扩展在许‎多真实情况下‎是不可行的以‎及在一本被设‎计为一学期课‎程的教科书中‎也是不实际的‎。

我们对环境问‎题的考察因此‎限于我们对“环境”的定义。

系统的相互作‎用许多不同的环‎境问题都与水‎，空气或土地系‎统有关联。

许多这些问题‎都只适用于这‎些系统中的一‎个，这为这些种类‎中的细目分类‎提供了充分的‎理由。

这样的分类也‎更有用于及易‎于理解一个系‎统内的相关问‎题。

而且，这样做是明智‎的，这是因为由于‎管理上的和行‎政上的原因，这些有关空气‎污染，水供应，废水处理和固‎体废物处理的‎子域通常由政‎府机构分别处‎理。

环境科学与工程专业英语第一篇：环境科学与工程专业英语一、单词/词组（考试时要求：中译英/英译中）环境科学：environmental science环境工程：environmental engineering定量环境科学：quantitative environmental science 定性环境科学：qualitative environmental science 衰减再生：decay and recycling新陈代谢率：metabolic rates外来物质：foreign matter研究和发展：Research and Development一次大气污染物：primary air pollutant 二次大气污染物：secondary air pollutant氧含量：Oxygen content点源：point sources沥青残留物：asphaltic residue酸雨：acid rain设备维护：facilities maintenance废物最小化：waste minimization正常浓度：normal concentration胡乱收集：magpie collection需氧量：oxygen demand/the amount of oxygen required 闭合回路：closed-loop微生物：microbe/microorganisms揭示大的差别;expose the considerable gaps空气质量监测：air-quality monitoring氧化剂：oxidizer石油精炼:petroleum refining活性炭：activated carbon质量控制：quality control海轮：ocean liner挥发性化学物质：volatile chemicals沙漠化：desertification火山喷发：volcanic eruption间歇源：intermittent sources衡量浓度：trace concentrations氯化物和硫化物：chlorides and sulphates风化：wind erosion不完全燃烧：incomplete combustion化石燃料：fossil fuels液滴：liquid dropletsSO3:sulfur trioxidefor managerial and administrative reasons行政管理上的原因stacks of generating stations许多发电站Roman empire罗马皇帝Cloaca maxima 古罗马的大排泄沟Wate phosphorous 亚磷的（三价磷）phosphorous acid亚磷酸phosphoric磷的（五价）carbonates，bicarbonates碳酸盐，碳酸氢盐carbohydrates碳水化合物，主要含氢和碳TOC(total organic carbon)总有机碳COD(chemical oxygen demand)化学需氧量BOD(biological oxygen demand)生化需氧量Biodegradable organic可生物降解的有机物BOD5BOD的测试标准化rborne diseases 水传染的疾病epilimnion 表层水hypolimnion深水层thermocline热变形层become depleted of oxygen 缺氧二、重点句子翻译UNIT21.Environment is the physical and biotic habitat which surrounds us；that which we can see，hear，touch，smell，and taste.环境是围绕在我们周围物质生命的栖息地，在那里我们可以看到，听到，触到，闻到和品尝到。

Unit 13Text: Water Treatment ProcessesOne of the great achievements of modern technology has been to drastically reduce the incidence of waterborne of diseases such as cholera and typhoid fever. These diseases are no longer the great risks to pubic health that they once were. The key to this advance was the recognition that contamination of pubic water supplies by human wastes was the main source ci infection, and that it could be eliminated by more effective water treatment and better waste disposal.Tod ay’s water treatment plants are designed to provide water continuously that meets drinking water standards at the tap. There are four main considerations involved in accomplishing this1 source selection, protection of water quality, treatment methods to be used, and prevention of recontamination. Common precautions to prevent groundwater and surface water pollution include prohibiting the discharge of sanitary and storm sewers close to the water reservoir, installing fences to prevent pollution from recreational uses of water, and restrictions on the application of fertilizers and pesticides in areas that drain to the reservoir.Screening, coagulation/flocculation, sedimentation, filtration. and disinfection are the main unit operations involved in the treatment of surface water. Water treatment operationa fulfill one or more of three key tasks1 removal of particulate substances such aa sand and clay, organic matter, bacteria, and algae; removal of dissolved substances such as those causing color and hardness; and removal or destruction of pathogenic bacteria and viruses. The actual selection of treatment processes depends on the type of water source and the desired water quality.Occasionally, raw water with low turbidity can be treated by plain sedimentation (no chemicals) to remove larger particles and then filtration to remove the few particles that failed to settle out. Usually, however, particles in the raw water are too small to be removed in a reasonably short time through sedimentation and simple filtration alone. To remedy this, a chemical is added to coagulate/flocculate the small particles, called colloids, into large ones, which can then be settled out in sedimentation tanks or removed directly in filters.Removal of Particulate MatterThe unit operations employed for the removal of particulate matter from water include screening, sedimentation, coagulation/flocculation, and filtration.Screening to remove large solids such as logs, branches, rags, and small fish is the first stage in the treatment of water. Allowing such debris into the treatment plant could damage pumps and clog pipes and channels. For the same reasons, water intakes are located below the surface of the lake or river in order to exclude floating objects and minimize physical damage from ice.Sedimentation, the oldest and moat widely used form of water and wastewater treatment, uses gravity settling to remove particles from water. It is relatively simple and inexpensive and can be implemented in basins that are round, square, or rectangular. As noted earlier, sedimentation may follow coagulation and flocculation (for highly turbid water) or be omitted entirely (with moderately turbid water) .Particulates suspended in surface water can range in size from 10-1 to 10-7mm in diameter, the size of fine sand and small clay particles, respectively. Turbidity or cloudiness in water is caused by those particles larger than 10 mm, while particles smaller than 10 mm contribute to the color and taste.Coagulation/flocculation is a chemical-physical procedure whereby particles too small for practical removal by plain sedimentation are destabilized sod clustered together for faster settling©. A significant percentage of particulates suspended in water are so small that settling to the bottom of a tank would take days or weeks. These colloidal particles would never settle by plain sedimentation.Coagulation is s chemical process used to destabilize colloidal particles. The exact mechanism is not well understood, but the general ides is to add a chemical which has positively charged colloids to water containing negatively charged colloids. This will neutralize the negative change on the colloids and thus reduce the tendency for the colloids to repel each other. Rapid mixing for a few seconds is required to disperse the coagulant. Gentle mixing, called flocculation, of the suspension is then undertaken to promote particle contact. This is achieved by mechanical mixing through the use of slowly rotating paddles inside the coagulation/flocculation tank, or by hydraulic mixing which occurs when flow is directed over and around baffles in the tank. Detention time in the coagulation/flocculation tank is usually between 20—40 minutes in tanks 3—4m deep. Through the combined chemical/physical process of coagulation/flocculation, the colloidal particles which would not settle out by plain sedimentation are agglomerated to form larger solids called floe. These appear as fluffy growths of irregular shape that are able to entrap small noncoagulaed particles when settling downward. Aluminum sulfate is the most common coagulant but organic polymers may also be used alone or in combination with alum to improve flocculation. The floe suspension is gently transferred from the coagulation/flocculation tanks to settling tanks, or directly to filters where the floes are removed.DisinfectionTo ensure that water is free of harmful bacteria it is necessary to disinfect it. Chlorination® is the most common method of disinfecting public water supplies. Sufficient quantities of chlorine from chlorine gas or hypochlorites are added to treated water to kill pathogenic bacteria. Chlorination is a reliable, relatively inexpensive, and easy disinfection method to use. Other disinfectants include chloramines, chlorine dioxide, other halogens, ozone, ultraviolet light, and high temperature. Ozonation, which has been used extensively in France, is now gaining acceptance in North America, especially as an alternative to prechlorination where natural organics are present. Although effective, ozone does not leave a lasting residual for long-term disinfection.Ozoanation is the disinfection of water by adding ozone, which is a powerful oxidant of inorganic and organic impurities. Its advantages over chlorine are that it leaves no tastes or odors, and unlike chlorine, it apparently does not react with natural organics to form compounds hazardous to humans.Removal of Dissolved SubstancesAeration is used to remove excessive amounts of iron and manganese from groundwater. These substances cause taste and color problems, interfere with laundering, stain plumbing fixtures, and promote the growth of iron bacteria in water mains. By bubbling air through water, or by creating contact between air and water by spraying, dissolved iron or manganese (Fe2+ , Mn2+) is oxidized to a less soluble form (Fe3+ , Mn4+), which precipitates out and can be removed in s settling tank or filter. Aeration also removes odors caused by hydrogen sulfide (H2S) gas.Softening of water is a process that removes hardness, caused by the presence of divalent metallic ions, principally Ca2+ and Mg2+. Hardness in water is the result of contact with soil and rock, particularly limestone, in the presence of CO2.Activated Carbon is an extremely adsorbent material used in water treatment to remove organic contaminants. Activated carbon is produced in a two-stage process. First, a suitable base material such as wood, pest, vegetable matter, or bone is carbonized by heating the material in the absence of air. Then the carbonized material is activated by heating it in the presence of air, CO2 , or steam to burn off any tars it has and to increase its pore size. Adsorption of gases, liquids, and solids by activated carbon is influenced by the temperature and pH of the water as well the complexity of the organics being removed.In reverse osmosis (RO), fresh water is forced through a semipermeable membrane in the direction opposite to that occurring in natural osmosis. Because the membrane removes dissolved salts, the main application for RO has been in desalination. However, the process also removes organic materials, bacteria, and viruses, and its application in water treatment is growing.。

Unit 3 What is Waste Reduction/Waste Minimization?什么是废物减量化，废物最少化美国花费了大量的时间在讨论像资源减量化，废物最小化，循环和阻止污染这些术语上，EPA已经提供了以下的定义。

资源减量化：减少在于一个过程中的大量废物的任何行为。

它包括，例如，过程调整，原料调整，提高管理和回收内在循环。

废物最少化：产生的废物最大程度减少，然后处理，存储，或者处置。

它包括了被导致了只要减量化与现在或将来威胁到人类健康和环境的最小化的目标一致的总容量或废物数量的减少或者废物毒性的减少，或者两方面兼备的发生器承担任何资源减量化或循环的活动。

回收：作为一个商业产品的代替品，或作为一个工业过程的原料的利用或再利用。

它包括了废物的有用的小部分或来自允许再用的去除了污染物的废物的在现场或离开现场的回收利用。

污染的防止：污染可能在生产过程之中产生，或者在当一个产品被用作商业用途或被消费者使用的时候产生。

这样可能在三个方式上被阻止：改变投入/减少依赖有毒物或有害的原材料；改变过程/增加效率/提高类似设备修改的维修保养，更好的管理，在过程中闭环循环；或者改变产出/减小对有毒或者有害产品的依赖。

随着1984年危险废物和固体废物修正案资源保护和恢复法的通过，美国国会建立一个国家政策来表明回收或消除危险废物的产生重要性。

美国国会宣称它是一项无论在美国哪里都可行的国家政策，要尽可能迅速地回收或消除危险废物的产生。

然而产生的废物还是应被处理、储存或处置，从而尽量减少现在和将来对人类健康和环境的威胁。

在1990年，美国国会通过污染防治法，建立了一个全国废物管理政策。

表明第一污染应该被预防或回收；;第二，废物应该用一种环保安全的方式进行循环利用；第三，废物应该被处理;最后，废物应该被除去或降解到环境。

在美国，随着这些和其他环境法规的通过，废物最少化成为一种重要的工作理念.废物回收/废物最少化技术同时，对于一些特定的工厂，废物最少化的当然是在具体的工厂或在实地，能用的技术能被分为以下主要几类：●product changes产品改变●process changes过程改变●equipment modifications设备改造●operating practices操作训练●recycling and reuse回收和再利用在实践中，尽量减少废物的机会是有限的，只有被工厂人员的聪明才智所利用. 这种技术已经被运用与大数量的工业和工业化生产过程，同时也被应用于有危险性和非危险性的废物。

环境工程专业英语钟理翻译第三部分水及废水处理第十六单元废水的生物处理法（1）微生物降解和去除工业废水以及城市废水中的不希望存在的成分的应用，并不是一个新的概念。

它是一般废水处理活动的常用过程，而且已经使用了许多年。

随着我们认识到化学品对于环境的污染，许多关于有毒化学物的生物降解方面的研究便出现了。

在这些处理技术之中，生物降解是最有效的。

通过废水的生物处理法，跟其他化学和热处理过程联合使用，使得其在管理方面的应用得以提高。

活化的生物过滤池生物过滤池为第一阶段，随后活性污泥池为第二阶段，之后是沉淀池。

污泥会循环到生物膜阶段和活性污泥池。

这种方式结合了生物膜和悬浮生长的特性。

活性污泥活性污泥过程是一种典型的悬浮生长的生物处理系统，是用于处理有机和工业废水的最广泛的生物处理过程。

然而，它只能处理含有小于1%悬浮固体的有机废水流，但不能承受浓缩的有机物的冲击式负荷。

因此，加入这个工序的废水流通常是必须经过包含沉淀池(初沉池)和调节池的预处理过程。

初沉池用来处理沙砾、油和脂肪以及总固体物，而调节池则对废水流率的变化进行缓冲同时使活性污泥系统的有机负荷更加均匀。

活性污泥过程用来处理城市和工业废水，因为它们是丰富多样的、灵活的，以及通过调整工艺参数来达到一个我们所希望的水质出水。

这样来命名这个过程，是因为有氧的稳定化处理的废水中，能产生能大量的起作用的微生物。

基础工序有很多的版本，但它们基本上是相同的。

术语“活性污泥”是被应用于工序和在处理单元中生物固体两步的。

混合液悬浮固体或活性污泥，包含各种各样异养的微生物，例如细菌、原生动物、真菌和更大的微生物。

特殊微生物种的主导优势取决于被处理的废物及操作过程中的方法。

活性污泥法是当前最广泛使用的生物处理法。

这部分是基于生物质循环这一结果，生物质循环是整个工艺的一部分，它可以使微生物在相对较短的驯化时间内适应废水组分的变化，并能在较大程度上控制驯化菌的数量。

活性污泥系统包括调节池、沉淀池、曝气池，澄清池、和污泥回流过程。

Unit one Environmental Engineering环境工程What is this book about？这本书是关于什么的？The objective of this book is to introduce engineering and science students to the interdisciplinary study of environment problems；their cause，why they are of concern，and how we can control them. The book includes:这本书的目的是使理工科的学生了解跨学科间的研究环境问题;它们的起因，为什么它们受到关注，以及我们怎样控制它们。

这本书包括：●Description of what is meant by environment and environmental systems描述环境和环境系统意味着什么●Information on the basic causes of environmental disturbances关于引起环境干扰基础原因的基本信息●Basic scientific knowledge necessary to understand the nature of environmental problems and to be able toquantify them理解环境问题本质，并能够定量计算它们所必要的基本科学知识●Current state of the technology of environmental control in its application to water，air and pollution problems目前适用于水，空气和环境污染问题的环境控制技术的现状●Considerable gaps in our current scientific knowledge of understanding and controlling many of the complexinteractions between human activities and nature我们目前的科学知识在理解和控制人类活动和自然之间复杂的相互作用的科学知识上存在相当大的缺陷●Many environmental problems which could be eliminated or reduced by the application of current technology，butwhich are not dealt with because of society’s lack of will to do so，or in many instance because of a lack of resources to do so.许多环境问题可以应用现有技术消除或减少，但没有得到处理是因为社会缺乏这样做的意愿，或者像许多例子那样因为缺乏资源。

Unit 13Text: Water Treatment ProcessesOne of the great achievements of modern technology has been to drastically reduce the incidence of waterborne of diseases such as cholera and typhoid fever. These diseases are no longer the great risks to pubic health that they once were. The key to this advance was the recognition that contamination of pubic water supplies by human wastes was the main source ci infection, and that it could be eliminated by more effective water treatment and better waste disposal.Tod ay’s water treatment plants are designed to provide water continuously that meets drinking water standards at the tap. There are four main considerations involved in accomplishing this1 source selection, protection of water quality, treatment methods to be used, and prevention of recontamination. Common precautions to prevent groundwater and surface water pollution include prohibiting the discharge of sanitary and storm sewers close to the water reservoir, installing fences to prevent pollution from recreational uses of water, and restrictions on the application of fertilizers and pesticides in areas that drain to the reservoir.Screening, coagulation/flocculation, sedimentation, filtration. and disinfection are the main unit operations involved in the treatment of surface water. Water treatment operationa fulfill one or more of three key tasks1 removal of particulate substances such aa sand and clay, organic matter, bacteria, and algae; removal of dissolved substances such as those causing color and hardness; and removal or destruction of pathogenic bacteria and viruses. The actual selection of treatment processes depends on the type of water source and the desired water quality.Occasionally, raw water with low turbidity can be treated by plain sedimentation (no chemicals) to remove larger particles and then filtration to remove the few particles that failed to settle out. Usually, however, particles in the raw water are too small to be removed in a reasonably short time through sedimentation and simple filtration alone. To remedy this, a chemical is added to coagulate/flocculate the small particles, called colloids, into large ones, which can then be settled out in sedimentation tanks or removed directly in filters.Removal of Particulate MatterThe unit operations employed for the removal of particulate matter from water include screening, sedimentation, coagulation/flocculation, and filtration.Screening to remove large solids such as logs, branches, rags, and small fish is the first stage in the treatment of water. Allowing such debris into the treatment plant could damage pumps and clog pipes and channels. For the same reasons, water intakes are located below the surface of the lake or river in order to exclude floating objects and minimize physical damage from ice.Sedimentation, the oldest and moat widely used form of water and wastewater treatment, uses gravity settling to remove particles from water. It is relatively simple and inexpensive and can be implemented in basins that are round, square, or rectangular. As noted earlier, sedimentation may follow coagulation and flocculation (for highly turbid water) or be omitted entirely (with moderately turbid water) .Particulates suspended in surface water can range in size from 10-1 to 10-7mm in diameter, the size of fine sand and small clay particles, respectively. Turbidity or cloudiness in water is caused by those particles larger than 10 mm, while particles smaller than 10 mm contribute to the color and taste.Coagulation/flocculation is a chemical-physical procedure whereby particles too small for practical removal by plain sedimentation are destabilized sod clustered together for faster settling©. A significant percentage of particulates suspended in water are so small that settling to the bottom of a tank would take days or weeks. These colloidal particles would never settle by plain sedimentation.Coagulation is s chemical process used to destabilize colloidal particles. The exact mechanism is not well understood, but the general ides is to add a chemical which has positively charged colloids to water containing negatively charged colloids. This will neutralize the negative change on the colloids and thus reduce the tendency for the colloids to repel each other. Rapid mixing for a few seconds is required to disperse the coagulant. Gentle mixing, called flocculation, of the suspension is then undertaken to promote particle contact. This is achieved by mechanical mixing through the use of slowly rotating paddles inside the coagulation/flocculation tank, or by hydraulic mixing which occurs when flow is directed over and around baffles in the tank. Detention time in the coagulation/flocculation tank is usually between 20—40 minutes in tanks 3—4m deep. Through the combined chemical/physical process of coagulation/flocculation, the colloidal particles which would not settle out by plain sedimentation are agglomerated to form larger solids called floe. These appear as fluffy growths of irregular shape that are able to entrap small noncoagulaed particles when settling downward. Aluminum sulfate is the most common coagulant but organic polymers may also be used alone or in combination with alum to improve flocculation. The floe suspension is gently transferred from the coagulation/flocculation tanks to settling tanks, or directly to filters where the floes are removed.DisinfectionTo ensure that water is free of harmful bacteria it is necessary to disinfect it. Chlorination® is the most common method of disinfecting public water supplies. Sufficient quantities of chlorine from chlorine gas or hypochlorites are added to treated water to kill pathogenic bacteria. Chlorination is a reliable, relatively inexpensive, and easy disinfection method to use. Other disinfectants include chloramines, chlorine dioxide, other halogens, ozone, ultraviolet light, and high temperature. Ozonation, which has been used extensively in France, is now gaining acceptance in North America, especially as an alternative to prechlorination where natural organics are present. Although effective, ozone does not leave a lasting residual for long-term disinfection.Ozoanation is the disinfection of water by adding ozone, which is a powerful oxidant of inorganic and organic impurities. Its advantages over chlorine are that it leaves no tastes or odors, and unlike chlorine, it apparently does not react with natural organics to form compounds hazardous to humans.Removal of Dissolved SubstancesAeration is used to remove excessive amounts of iron and manganese from groundwater. These substances cause taste and color problems, interfere with laundering, stain plumbing fixtures, and promote the growth of iron bacteria in water mains. By bubbling air through water, or by creating contact between air and water by spraying, dissolved iron or manganese (Fe2+ , Mn2+) is oxidized to a less soluble form (Fe3+ , Mn4+), which precipitates out and can be removed in s settling tank or filter. Aeration also removes odors caused by hydrogen sulfide (H2S) gas.Softening of water is a process that removes hardness, caused by the presence of divalent metallic ions, principally Ca2+ and Mg2+. Hardness in water is the result of contact with soil and rock, particularly limestone, in the presence of CO2.Activated Carbon is an extremely adsorbent material used in water treatment to remove organic contaminants. Activated carbon is produced in a two-stage process. First, a suitable base material such as wood, pest, vegetable matter, or bone is carbonized by heating the material in the absence of air. Then the carbonized material is activated by heating it in the presence of air, CO2 , or steam to burn off any tars it has and to increase its pore size. Adsorption of gases, liquids, and solids by activated carbon is influenced by the temperature and pH of the water as well the complexity of the organics being removed.In reverse osmosis (RO), fresh water is forced through a semipermeable membrane in the direction opposite to that occurring in natural osmosis. Because the membrane removes dissolved salts, the main application for RO has been in desalination. However, the process also removes organic materials, bacteria, and viruses, and its application in water treatment is growing.。

（完整版）（整理）环境工程专业英语翻译（中英对照）Unit one Environmental Engineering环境工程What is this book about？这本书是关于什么的？The objective of this book is to introduce engineering and science students to the interdisciplinary study of environment problems；their cause，why they are of concern，and how we can control them. The book includes:这本书的目的是使理工科的学生了解跨学科间的研究环境问题;它们的起因，为什么它们受到关注，以及我们怎样控制它们。

这本书包括：●Description of what is meant by environment and environmental systems描述环境和环境系统意味着什么●Information on the basic causes of environmental disturbances关于引起环境干扰基础原因的基本信息●Basic scientific knowledge necessary to understand the nature of environmental problems and to be able toquantify them理解环境问题本质，并能够定量计算它们所必要的基本科学知识●Current state of the technology of environmental control in its application to water，air and pollution problems目前适用于水，空气和环境污染问题的环境控制技术的现状●Considerable gaps in our current scientific knowledge of understanding and controlling many of the complexinteractions between human activities and nature我们目前的科学知识在理解和控制人类活动和自然之间复杂的相互作用的科学知识上存在相当大的缺陷●Many environmental problems which could be eliminated or reduced by the application of current technology，but which are not dealt with because of society’s lack of will to do so，or in many instance because of a lack of resources to do so.许多环境问题可以应用现有技术消除或减少，但没有得到处理是因为社会缺乏这样做的意愿，或者像许多例子那样因为缺乏资源。