土木工程专业语英教学课件.ppt

Lesson 5 Environmental Engineering 环境工程; Environmental engineering is a branch of engineering that is concerned with pollution by the structures, machines, systems, and processes that are involved in human activities. 环境工程是和结构、机械、系统，以及涉及到人类活动的过程所产生的污染有关的一个工程学的分支。 The development of civilization has caused perturbation of much of the Earth’s ecosystem, resulting in pollution of the air, land and water. 文明的发展已经引起许多地球生态系统的紊乱，造成空气、陆地和水的污染 。 It is the task of the environmental engineer not only to design systems to assuage this pollution but also to educate people in protecting their surroundings from additional pollution. 环境工程师的任务不仅是设计出一些系统来减轻这个污染，而且还要教育人们保护他们周围的环境免遭额外的污染。 The practice of environmental engineering is divided into various subdisciplines. 环境工程专业又被分为了不同的分支学科。 ; In many cases, rivers, lakes, and oceans have become polluted from discharges of liquid wastes from residential, commercial, and industrial sources. 在许多情况下，河流、湖泊和海洋已经被由住宅、商业、和工业源点排放的废液所污染 。 Many of these bodies of water have been reclaimed because of a movement in the 1970s to construct new wastewater treatment facilities and to improve old ones. 许多这些水体已经被回收了是因为20世纪70年代的一场修建新的废水处理设施和改进旧的设施的运动。 Both physical-chemical and biological processes are used to remove from the liquid wastewater stream. 可以采用物理化学方法和生物学方法从废液中除去污染物。 ; It is this organic matter that causes a depletion of oxygen in rivers and lakes, with consequent anaerobic conditions leading to fish kills and noxious odors. 正是这种有机物会使江河湖泊中的氧气耗尽，形成导致鱼类死亡的厌氧环境并产生有害气体。 The physical-chemical and biological processes remove an abundance of the organic matter along with floatable scum and grease from the waste stream. 物理化学方法和生物学方法消除了大量的有机物质连同来自废水中的漂浮的浮渣和油脂。 Chemical disinfection inactivates bacteria, viruses, and protozoa in the waste stream. 化学消毒可使废水中的细菌、病毒和原生动物钝化。 The physi