eng
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practice 38

created Mar 14th, 17:54 by Heartking001


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404 words
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A significant challenge confronting engineers and scientists in developing  
countries is the search for appropriate solutions to the collection, treatment,  
and disposal or reuse of domestic waste. Technologies of waste collection  
and treatment that have been taught to civil engineering students and  
practiced by professional engineers for decades are, respectively, the water  
borne sewerage and conventional waste treatment systems such as  
activated sludge and trickling filter processes. However, the above systems  
do not appear to be applicable or effective in solving sanitation and water  
pollution problems in developing countries. Supporting evidence for the  
above statement is the result of a World Health Organization report which  
showed that in the year 2000 some 1.1 billion people did not have access to  
improved water supply, and 2.4 billions were without access to any sort of  
improved sanitation facility. For both the water supply and sanitation services,  
the vast majority of those without access are in Asia. Although the  
percentages of population served with adequate water supply and sanitation  
increased during the past decade, due to rapid population and urban growth,  
these percentages for the urban areas are not expected to increase much in  
the next decade, while a lot of improvement is needed for the rural areas.  
Sanitation conditions in both urban and rural areas need to be much  
improved as large percentages of the population still and will lack these  
facilities. Polprasert cited several reasons for the failure to provide sewerage  
to the population of the cities of the developing countries. The construction of  
sewerage systems implies large civil engineering projects with high  
investment costs. Soil is the most important renewable natural resource. It is  
the medium of plant growth and supports different types of living organisms  
on the earth. The soil is a living system. It takes millions of years to form soil  
upto a few cm in depth. Relief, parent rock or bed rock, climate, vegetation  
and other forms of life and time are important factors in the formation of soil.  
Various forces of nature such as change in temperature, actions of running  
water, wind and glaciers, activities of decomposers etc. contribute to the  
formation of soil. Chemical and organic changes which take place in the soil  
are equally important. Soil also consists of organic and inorganic materials.  
On the basis of the factors responsible for soil formation texture, age,  
chemical and physical properties, the soils of India are classified in different  
types

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