tailieunhanh - Environmental Pollution Control Microbiology - Chapter 10

ĐẶC ĐIỂM VÀ THU NƯỚC THẢI Một khi nước đã được sử dụng, nó sẽ trở thành nước thải. Kể từ khi người ta bắt đầu sống trong bộ sưu tập, thành phố và quay trở lại nước thải ra môi trường là một vấn đề. Có ba nguồn cơ bản của nước thải được xử lý. Một nguồn nước thải từ lượng mưa và được gọi là nước mưa. Nguồn thứ hai của nước thải được tạo ra trong mỗi nhà và được gọi là nước thải trong nước hoặc nước thải sinh hoạt. Nguồn thứ ba của nước thải. | Chapter 10 WASTEWATER CHARACTERISTICS AND COLLECTION Once water has been used it becomes wastewater. Ever since people began to live in cities collection and return of wastewater back into the envfronment has been a problem. There are three basic sources of wastewater to be handled. One source of wastewater is from precipitation and is called storm water. The second source of wastewater is generated in each house and is called domestic sewage or domestic wastewater. The thfrd source of wastewater is from the manufacture of industrial products and is called industrial wastewater. Each of these three wastewaters has its own characteristics and impact on the envfronment. Over the years concern for the pollution potential of wastewater has produced numerous methods for processing wastewaters prior to thefr discharge back into the environment. The growth of cities during the 19th century created a number of positive benefits and a number of negative problems. Construction of houses and buildings close together created large areas of impervious surfaces and a reduction in the area of land that absorbed water during rainfall events. Streets were constructed to permit easy traffic movement through the city. The streets went from dirt to gravel that was further crushed and compacted by use also increasing the impervious area. As the cities grew the storm water runoff volume increased. For the most part storm water runoff was a nuisance for everyone in the cities. Eventually private citizens began constructing drainage ditches along the edges of the roads to handle the storm water runoff. Over time the storm water runoff problems increased creating problems at an increasing frequency. Eventually municipal government Copyright 2004 by Marcel Dekker Inc. All Rights Reserved. stepped in and assumed responsibility for the drainage ditches. The major streets soon became paved with bricks or granite blocks and the storm water ditches were eliminated. The storm water collection .