The control of particulates and VOCs is mostly accomplished by physical processes (cyclones, ESPs, filters, leakage control, vapor capture, condensation) that do not involve changing the chemical nature of the pollutant. Some particles and VOCs are chemically changed into harmless materials by combustion. This chapter and the next concern pollutants--sulfur oxides and nitrogen oxides that cannot be economically collected by physical means nor rendered harmless by combustion. Their control is largely chemical rather than physical. For this reason, these two chapters are more chemically oriented than the rest of the book

7-1 Introduction to the Activated-Sludge Process Historical Development The activated-sludge p now used routinely for biological treatment of municipal and industrial dge process date back to the early 1880s to the work of stewater in tanks and the hastening of the oxidation quently by a number of investigators, ility could be secured by e Experiment Station

第一节：化肥对环境的影响 第二节：农药对环境的影响 第三节：农用化学物质的污染控制 重点：农用化学物质的控制

一、大气圈与大气环境 二、农业生态系统对大气环境质量的影响 三、农业系统中温室气体的排放 四、温室效应与全球变暖

Treatment methods in which the application of physical forces predominate are known as physical unit operations. Examples of physical unit operations include screening, mixing, sedimentation, gas transfer, filtration, and adsorption. Treatment methods in which the removal or conversion of constituents is brought about by the addition

一、工程学及其与基础科学的关系 人类的一切科学活动不外乎有两个目的：一是认识自然，一是适应自然、保护自然 和改造自然。前者对应着自然科学中的基础科学，也称为理学，后者则对应着自然科学 中的工程技术科学，也称为工程学或工学；工程学和基础科学之间的这种目的的差异是 它们相互区别的根本所在，也反应了这二大学科的变质所在

Every community produces both liquid and solid wastes and air emissions. The liquid waste-wastewater, is essentially the water supply of the community after it has been used in a variety of applications. From the standpoint of sources of generation, wastewater may be defined as a combination of the liquid or water-carried wastes removed from residences

Volatile organic compounds (VOCs) are liquids or solids that contain organic carbon (carbon bonded to carbon, hydrogen, nitrogen, or sulfur, but not carbonate carbon as in CaCO3 nor carbide carbon as in CaC2 or CO or CO2), which vaporize at significant rates. VOCs are probably the second-most widespread and diverse class of emissions after particulates

Solid wastes comprise all the wastes arising from human and animal activities that are normally solid and that are discarded as useless or unwanted. The term solid waste as used in this text is all-inclusive, encompassing the heterogeneous mass of throwaways from the urban community as well as the more homogeneous accumulation of agricultural, industrial

The control of particulates and VOCs is mostly accomplished by physical processes (cyclones, ESPs, filters, leakage control, vapor capture, condensation) that do not involve changing the chemical nature of the pollutant. Some particles and VOCs are chemically changed into harmless materials by combustion. This chapter and the next concern pollutants--sulfur oxides and nitrogen