摘要:

In recent years, concern about the physical environment and its management has grown rapidly. This is reflected in the increasing attention given to the planning process. The growth and expansion of urban agglomerations represent a typical aggregation of some of man's activities having a marked environmental impact, such as air pollution, noise pollution, etc. Perhaps most vital among the different aspects of impact remains the water pollution. Urban hydrology studies portions of the hydrologic cycle, as modified by the presence of urban environments. Urbanization accounts for an increase in the total amount of runoff due to the increase of imperviousness of the drainage basins, thus aggravating the situation in flood‐prone areas. Equally important, the quality of the runoff waters is a concern, and more specifically its pollution effect on the receiving bodies of water, rivers, lakes, and groundwater recharge. The important recent research effort on the various aspects of these problems can be traced in the large specialized literature. This review summarizes the major works that have contributed to the state‐of‐the‐art. An important feature in urban runoff processes is the interrelationship between physical processes and man‐made structures and systems. The proposed discussion follows this classification rather than any historical sequence in three major sections as follows: physical models, simulation models, and problem areas — research needs. In the first section, the more important among the quantity and quality models of the corresponding physical processes are presented and the assumptions made in their development critically reviewed. Such physical models are interchangeably used for simulating the performance of storm‐drainage systems. The most popular among these models simulating the performance of man‐made systems are reviewed in the second section. Finally the potential problem areas and research needs for both physical and simulation models are summarized in a third section.

ISSN:0007-8999    

DOI:10.1080/10643388009381676

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

More than 100 different enteric viruses are known to be excreted in human feces. More than 1 million viruses may be excreted per gram of feces, and concentrations as high as 500,000 infectious virus particles per liter have been detected in raw sewage. Certain enteric viruses can persist for long periods of time in the environment. Reported survival times range from 2 to 168 days in tapwater, 2 to 130 days in seawater, 25 to 125 days in soil, and up to 90 days in oysters. There are many potential routes of transmission back to man. An evaluation of the problems associated with viruses in water was prepared recently by the World Health Organization Scientific Group on Human Viruses in Water, Wastewater, and Soil which met in Geneva in October, 1978. Among its conclusions, four are pertinent to this article: (1) Viruses have been detected in the drinking water supply systems of a number of cities (including Paris and Moscow), despite the fact that those waters have received conventional water treatment considered adequate for protection against bacterial pathogens. (2) Conventional bacterial pollution indicators used to evaluate the safety of potable water supply have been shown to be significantly less resistant than viruses to environmental factors and water and waste‐water treatment processes. This leads to a situation where the more resistant enteric viruses can be present in water manifesting little or no signs of bacterial pollution. (3) Regular virus monitoring should be carried out to assure the freedom from enteric viruses in 100‐ to 1000‐/ samples in large urban centers where the water supply is derived from virus‐polluted surface water, a significant portion of which is untreated waste‐water or effluent insufficiently treated to inactivate viruses. (4) The constant exposure of large population groups to even relatively small numbers of enteric viruses in large volumes of water can lead to an endemic state of virus dissemination in the community which can and should be prevented.

ISSN:0007-8999    

DOI:10.1080/10643388009381677

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor