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 cau，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 caus 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 quantify 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 complex 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 current technology，but which are not dealt with becau of society’s lack of will to do so，or in many instance becau 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。
Some important definitions 一些重要的定义
Where they are first ud in this book，definitions are introduced in block form，as shown here，or printed in bold type.
如果他们是第一次使用这本书，定义介绍采用块形式，像这里显示的一样，或印成黑体字。
Environment is the physical and biotic habitat which surrounds us；that which we can e，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。
System，according to webster’s dictionary，is defined as “a t or arrangement of things so related or connected as to form a unit or organic whole；as，a solar system，irrigation system，supply system，the world or univer”.
系统，依据韦伯斯特的字典，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;比如，太阳系统，灌溉系统，供水系统，世界或宇宙” 。
Pollution can be defined as an undesirable change in the physical，chemical，or biological characteristics of the air，water，or land that can harmfully affect the health，s
urvival，or activities of humans or other living organisms.
污染可以被定义为有害影响健康，生存，活动的人或其它生物体的空气，水，或土地的物理，化学或生物特性的不应该有的变化，。
When the goal of improving environmental quanlity is taken to be improving human wellbeing，the word “environment” broadens to include all kinds of social，economic，and cultural aspects. Such broadness is unworkable in many real situations and impractical in a text book designed for a one mester cour. Our examination of environmental problems is therefore limited by our definition of “environment”.
当改善环境质量的目标是用来改善人类的福祉， “环境” 这个词扩大到包括社会，经济，文化等所有方面的内容。这种扩大化在许多实际情况下是不可行的，在本被设计为一学期课程的教科书中也是不切实际的。因此，我们对环境问题的考察限于我们定义的“环境”。
Interaction of Systems互动系统
A number of different environmental problems are associated with water, air, or land syste
ms. 许多不同的环境问题都涉及到水，空气，或土壤。
Many of the problems will apply only within one of the systems, justifying the breakdown into the categories.许多这些问题只适用于在其中一个系统，这为这些种类中的细目分类提供了充分的理由。
Such a classification is also uful for easier comprehension of related problems within one system.这种分类也有助于更容易理解一个系统里的相关问题。
Moreover, it is nsible becau, for manager and administrative reasons, such subfields as air pollution, water supply, wastewater disposal, and solid waste disposal are often dealt with parately by governmental agencies.
此外，这样做是明智的，因为是行政管理的原因，空气污染，水供应，固体废物处置和废水处理，往往是由政府机构分别处理的。
