1.The Environment and Environmental Engineering
环境和环境工程学
Simply said, the environment can be defined as one's surroundings. In terms of the environmental engineer's involvement, however, a more specific definition is needed. To the environmental engineer, the word environment may take on global dimensions, may refer to a very localized area in which a specific problem must be addresd, or may, in the ca of contained environments, refer to a small volume of liquid, gaous, or solid materials within a treatment plant reactor.
简单的说，环境可以定义为我们的周围。但是就环境工程师参与的角度来说，需要一个更加明确的定义。对于环境工程师来说，环境这个词可能包含全球范围；也可能专指非常局部的一个地区，在这个地区中涉及到一些具体要解决的问题；或者也可能在密闭的环境中，指处理厂反应器内的一小块液体、气体或固体。
The global environment consists of the atmosphere, the hydrosphere and the lithosphere in which the life-sustaining resources of the earth are contained. The atmosphere, a mixture of gas extending outward from the surface of the earth, evolved from elements of the earth that were gasified during its formation and metamorphosis. The hydrosphere consists of the oceans,the lakes and streams and the
shallow groundwater bodies that interflow with the surface water.The lithosphere is the soil mantle that wraps the core of the earth.
全球环境由大气圈、水圈和岩石圈所组成，其中包含了维系地球上生命的资源。大气圈，从地球表面向外延伸的一种混合气体，它从地球的形成和变化过程中气化产生的元素演变而来。水圈由海洋、湖泊、溪流以及与地表水互通的浅层地下水体所组成。岩石圈是指包围地核的土质地幔。
The biosphere, a thin shell that encapsulates the earth, is made up of the atmosphere and lithosphere adjacent to the surface of the earth, together with the hydrosphere. It is within the biosphere that the life forms of earth, including humans, live.Life-sustaining materials in gaous, liquid, and solid forms are cycled through the biosphere, providing sustenance to all living organisms.焦糖玛奇朵
生物圈是包裹住地球的薄薄的外壳，是由大气圈和地表附近的岩石圈，以及水圈组成的。地球上的生命形式，包括人类、动物存在于生物圈内。气态、液态和固态形式的生命维持物在生物圈内循环，向所有生命体提供营养物质。创新意义
Life-sustaining resources——air, food, and water——are withdrawn from the biosphere. It is also into the biosphere that waste products in gaous, liquid, and solid forms are discharges. From the b
eginning of time, the biosphere has received and assimilated the wastes generated by plant and animal life. Natural systems have been ever active, dispersing smoke from forest fires, diluting animal wastes washed into streams and rivers, and converting debris, of past generations of plant and animal life into soil rich enough to support future populations.
维持生命的资源——空气、食物和水——是从生物圈内提取的。废物也是以气态、液态和固态形式排放到生物圈中的。从刚开始的时候起，生物圈就接受和消化植物和动物产生的废弃物。自然生态系统已经空前活跃，将森林大火产生的烟扩散，稀释冲入小溪和河流中的动物排泄物以及把过去几代植物和动物的残骸转化成足以供养后续生物的肥沃土壤。
For every natural act of pollution, for every undesirable alteration in the physical, chemical or biological characteristics of the environment, for every incident that eroded the quality of the immediate, or local environment, there were natural actions that restored that quality. Only in recent years has it becomes apparent that the sustaining and assimilative capacity of the biosphere, though tremendous, is not, after all, infinite.Though the system has operated for millions of years, it has begun to show signs of stress, primarily becau of the impact of humans upon the environment.
对于每种自然行为的污染，对于环境在每种物理、化学、生物特性上不可取的变化，对于每种侵蚀当老鹅汤
下或当地环境质量的事件，有自然行为会恢复那种质量。只是到了近几年，生物圈的维持和消化能力尽管巨大，但毕竟不是无限的这一事实才变得明显。尽管系统运行了几百万年，但它开始发出有压力的信号，主要是由于人类对环境的影响。
Environmental engineering has been defined as the branch of engineering that is concerned with protecting the environment from the potential, deleterious effects of human activity, protecting human population from the effects of adver environmental factors, and improving environmental quality for human health and well-being.
中年女头像环境工程被定义为工程学的一个分支，其主要关注保护环境不受人类活动的潜在有害影响，保护人类不受不利环境因素的影响以及为人类的健康和幸福而改善环境质量。
As the above definition implies, humans interact with their environment——sometimes adverly impacting the environment and sometimes being adverly impacted by pollutants in the environment. An understanding of the nature of the environment and of human interaction with it is a necessary prerequisite to understanding the work of the environmental engineer.
上述定义表明，人类与环境相互影响——有时对环境造成不利影响，有时受到环境污染物的不利影响。了解环境的本质以及人类与环境的相互作用，是了解环境工程师工作的一个必要的先决条件。
2.Ecology
生态学
The recognition that all life forms are inextricably dependent on one another and on the physical environment is a fairly recent phenomenon. The word “ecology” was not even invented until the mid-1800s, and the study of ecology as a branch of natural sciences was not widespread until a few decades ago.
所有生命形式不可避免的相互依赖且依赖自然环境是一个最近认识到的现象。“生态学”这个单词直到19世纪中叶才发明，而直到几十年前生态学才作为一门自然学科流传开来。
The science of ecology defines “ecosystems” as groups of organisms which interact with each other and the physical environment, and which affect the population of the various species in the environment. For example, the simplest type of ecosystem consists of two animals such as the hare and the lynx. If the hare population in a specific locality is high, the lynx have an abundant food supply, procreate, and increa in population until they outstrip the availability of hares. As the lynx population decreas due to the unavailability of food, the hares increa since the number of predators is fewer, and the cycle repeats. Such a system is dynamic in that the numbers of each pop
ulation are continuously changing, but over a long time span is at a steady state
滔滔不绝condition, known as “homeostasis”.
生态科学将“生态系统”定义为生物体群组，它们与自身以及自然环境相互作用，且影响着环境中不同物种的总量。例如，最简单的一种生态系统由两只动物组成，比如野兔和山猫。如果在一个特定的地方野兔总数多，山猫有充足的食物供应，繁殖，然后总数增长直到超过可获得的野兔。当山猫由于缺乏食物而总数减少时，野兔则因为捕食者数量的减少而增多，然后循环重复（图2-1）。这样一个系统是动态的，因为每个种群的数量是不断变化的，但是在很长时间里是处于稳定状态，称为“动态平衡”。
A slightly more complex example includes three species: the a otter, the a urchin and kelp. The kelp forests along the Pacific coast consist of 60m streamers fastened to the ocean floor. Kelp is an economically valuable plant since it is the source of algin (ud in foods. paints, cosmetics, etc.) and its harvesting is regulated to rerve the forests.
一个稍微复杂的例子包括三个物种：海獭、海胆和海藻。太平洋沿岸的海藻丛包括牢固生长在海底的60米飘烟带。海藻是一种具有经济价值的植物，因为它是藻朊（酸）（用于食品、绘画、化妆品等）的来源，种植并收获这些植物用来保护森林。
A few years ago, kelp started to mysteriously disappear, leaving barren ocean floors. The puzzle was solved when it was recognized that a urchins feed on the kelp, weaken the stems, and cau them to detach and float away. The a urchins population had incread becau the population of their predators, the a otters, had been reduced drastically. The solution to the problem was to protect the a otter and allow its population to increa, thus reducing the number of a urchins, and save the kelp forests.
几年前，海藻开始神秘地消失，留下光秃秃的海底。当人们认识到，海胆吃海藻，削弱它的茎，又使他们分开并漂离时，这个谜底被揭开了。由于其天敌海獭的总量大幅减少，海胆总数增加了。问题的解决方法是保护海獭并使其总数增加，从而减少海胆的数量，保护海藻丛。
Some ecosystems are fragile, while others are resilient and able to withstand even rious perturbations. One characteristic of a resilient ecosystem is that more than one species fills a “niche” within that system, that is many species perform the same function. For example, in the hare/lynx system, if the hare were the only source of food for the lynx (a niche), the destruction of de hares would result in the eventual eradication of the lynxes as well. If, however, the lynx ud other small animals for food, the system might survive the loss of the hares.
一些生态系统很脆弱，而另一些具有弹性，能承受更严重的骚扰。有弹性的生态系统所具有的一个特征是该系统中的一个位置可由不止一个生物种来占据，即许多物种能执行相同的职能。例如，在野兔、山猫系统中，如果野兔是山猫唯一的食物来源，野兔的灭亡也会导致最终山猫的灭亡。然而，如果山猫以其他小动物为食，这个系统即使失去野兔也能生存。
Engineers must appreciate the fundamental principles of ecology, and design with the environment, so as not to impact adverly an especially fragile ecosystem. For example, one of the most fragile of all ecosystems is the deep oceans, yet ocean disposal of hazardous waste is riously advocated by some engineers. The inclusion of ecological principles in engineering decisions is a major component of the environmental engineering profession.
工程师必须评价生态学的基本法则，并且设计环境，以免对一个特别脆弱的生态系统造
成不利影响。例如，最脆弱的生态系统之一深海，但一些工程师极力主张用海洋来处理有害的废物。把生态原理列入工程决策中是环境工程专业的一个重要组成部分。
3.Environmental Problems
环境问题
小孩谜语
1 Our Fragile World
Anyone who has had an opportunity to obrve even a small fraction of the natural wonders of our planet would agree that we live in a marvelous world. The majesty of the Rocky Mountains, the beauty of the Maine coast on a clear summer day, and the colors of a dert sunt are all impressive sights. On a more mundane level, we are reminded of the Earth’s bounties by the smell and feel of freshly plowed Iowa farmland, by a breath of fresh air on a brisk fall day, or the taste of fresh, clean water on a hot summer day.
1.我们脆弱的世界
任何一个人只要有机会去见证我们的行星，哪怕只是自然奇观的一个小片段，他都会认同我们正住在一个不可思议的世界。雄伟的落基山脉，清爽夏日里缅因州海岸的美丽，还有沙漠里日落的色彩都是能给人留下深刻印象的景观。在一个更为世俗的层次，我们会想起地球的恩赐——感受爱荷华州新耕土地的泥土清香，呼吸秋季凉爽的新鲜空气，在炎炎夏日品尝甘甜、洁净的饮水。
It goes without saying that all of the things are threatened by a broad range of human activities. In an effort to increa short-term agricultural production, farmland in many areas is cultivated improperly, resulting in extreme erosion that threatens its very existence. Many urban dwellers would
agree that a breath of fresh air is a rare commodity in the city. In many industrialized areas, ground water sources of drinking water are being threatened by the insidious movement of hazardous waste chemical leachates through ground water aquifers. The protection of our environment must be given the highest priority becau on it depends the prervation of human kind, itlf.
不用说，所有这些事物被大范围的人类活动所威胁着。努力去谋求农产品的短期增长，农田在许多地区的不合理耕耘，导致了威胁其生存的极端侵蚀。很多城市居民都认为新鲜的空气在城市里是稀有品。在许多工业地区，有害废物的化学沥滤液通过地下水潜移扩散，威胁着地下水饮用水源。必须给予环境最优先的保护，因为人类自身的保护依赖于此。
In order to combat threats to our environment, it is necessary to understand the nature and magnitude of the problems involved. Before discussing the problems further, it is esntial to recognize the fact that science and technology must play key roles in solving environmental problems. Only through the proper application of science and technology, under the direction of people with a strong environmental consciousness and a basic knowledge of the environmental sciences, can humankind survive on the limited resources of this planet.
为了应对那些对我们环境的威胁，我们有必要了解性质和所涉及的问题的大小。在进一步讨论这些问
题之前，必须承认科学技术在解决环境问题时起着关键作用这一事实。只有通过科学技术的正确应用，在具有强烈环保意识和环境科学基本知识的人的指导下，人类才能在这个资源有限的星球上生存。亲吻节
2. Classifying Environmental Problems
Environmental problems are always interrelated. Sometimes a solution to one problem actually creates another problem. For example, when people are sick and dying from dia, it is natural to want to improve human health. When health is improved and infant mortality is reduced, a population explosion may result. To feed this growing population, natural habitats are often destroyed by turning them into farmland. As natural habitats are destroyed, the wild plants, predatory animals, and parasites that once lived there are killed as well. Becau of the lack of predators and parasites, outbreaks of inct pests become more common. Farmers u pesticides to control the pests and protect the crops, but in the process the environment becomes polluted. The development of this entire cycle in itlf consumes fossil fuel supplies that are becoming scare. In addition, when fuels are burned, air pollutants are generated.
2.环境问题的分类
环境问题总是互相关联的。有时一个问题的解决实际上引起了另外一个问题的产生。例如，当人们因为生病或因病死亡时，自然想到要改善人们健康状况。当人类健康得以改善及婴儿的死亡率下降时，又可能会导致人口数量爆炸。为了养活这些不断增长的人口，自然栖息地常常被破坏变成耕地。当自然栖息地被破坏，曾经生长在那里的野生植物、掠夺性动物和寄生虫也被杀死。由于缺乏捕食者和寄生虫，病虫害的暴发变得越来越普遍。农民使用农药去抑制虫害保护庄稼，但在这一过程中污染了环境。经历这一完整循环，本身要消耗日渐不足的化石燃料供应。此外，燃料被燃烧的同时，空气污染产生了。
4.The Impact of Humans upon the Environment
人类对环境的影响
In a natural state, earth’s life forms live in equilibrium with their environment. The numbers and activities of each species are governed by the resources available to them. Species interaction is common, with the waste product of one species often forming the food supply of another. Humans alone have the ability to gather resources from beyond their immediate surroundings and process tho resources into different, more versatile forms. The abilities have made it possible for human population to thrive and flourish beyond natural constraints. But the natural and manufactured waste
棚改政策s generated and relead into the biosphere by the incread numbers of human beings have upt the natural equilibrium.
在一种自然状态下，地球上的生命体与所处的环境保持平衡.每个物种的数量和活动受控于他们所能得到的资源。物种间普遍存在相互作用，往往一个物种的废弃物能成为另一个的食物供应。唯独人类拥有从他们周围的环境之外收集资源的能力，并把那些资源加工成不同的、更加多功能的东西。这些能力使人类人口的兴旺和蓬勃发展有可能超出自然的限制。但是，由于增加的人口所产生和释放到生物圈的天然和人造的废物破坏了自然平衡。
Anthropogenic, or human-induced, pollutants have overloaded the system. The overloading came relatively late in the cour of human interaction with the environment ,perhaps becau early societies were primarily concerned with meeting natural needs, needs humans share in common with most of the higher mammals. The peoples had not yet begun to be concerned with meeting the acquired needs associated with more advanced civilizations.
人类产生的、人为引起的污染使系统超载。超载在人类与环境相互作用的过程中来的相对较晚，或许因为早期社会主要关注满足自然需求，人类和大部分较高等的哺乳动物共同分享的那些必需品。这些民族还没想到要把更先进的文明与所需求的联系起来。
