Types of Water (Potable)
Potable water is defined as water fit for human consumption and domestic use, which is of sanitary quality and normally free of minerals, organic substances, and toxic agents in excess or in reasonable amounts for domestic usage in the area served, and normally adequate in quantity for the minimum health requirements of the persons served. Potable water is usually available in two forms
a) Surface Water
b) Ground water
Ground water is usually pumped by wells for human use. Of this massive amount of water only about 3% is fresh. Also, most of the minute percentage of fresh water the Earth holds is locked up in polar ice caps and in glaciers. The rest is held in lakes, in flows through soil, and in river and stream systems.
Only 0.027% of the Earth's fresh water is available for human consumption. Again, surface water is that water that is open to the atmosphere and results from overland flow i.e., runoff that has not yet reached a definite stream channel and in a way surface water is the result of surface runoff. For the most part however, surface refers to water flowing in streams and rivers, as well as water stored in natural or artificial lakes, man-made impoundments such as lakes made by damming a stream or river, springs that are affected by a change in level or quantity, shallow wells that are affected by precipitation, wells drilled next to or in a stream or river, rain catchments, and ponds. Specific sources of surface water include:
1. Rivers
2. Streams
3. Lakes
4. Impoundments (man-made lakes made by damming a river or stream)
5. Very shallow wells that receive input via precipitation
6. Springs affected by precipitation (flow or quantity directly dependent upon precipitation)
7. Rain catchments (drainage basins)
8. Ponds (peat bogs)
India receives annual precipitation of about 4000 km³, including snowfall. Out of this, monsoon rainfall is of the order of 3000 km³. Rainfall in India is dependent on the south west and north east, monsoons, on shallow cyclonic depressions and disturbances and on local storms. India is gifted with a river system comprising more than 20 major rivers with several tributaries. Many of these rivers are perennial and some of these are seasonal. The rivers like Ganges, Brahmaputra and Indus originate from the Himalayas and carry water throughout the year. The snow and ice melt of the Himalayas and the base flow contribute the flows during the lean season. More than 50% of water resources of India are located in various tributaries of these river systems. Average water yield per unit area of the Himalayan rivers is almost double that of the south peninsular rivers system, indicating the importance of snow and glacier melt contribution from the high mountains. Apart from the water available in the various rivers of the country, the groundwater is also an important source of water for drinking, irrigation, industrial uses, etc. It accounts for about 80% of domestic water requirement and more than 45% of the total irrigation in the country. As per the international norms, if per capita water availability is less than 1700 m³ per year then the country is categorised as water stressed and if it is less than 1000 m³ per capita per year India receives annual precipitation of about 4000 km³, including snowfall. Out of this, monsoon rainfall is of the order of 3000 km³.
Sources and Significance of Microorganisms in Water
Bacteria: Bacteria are the principal microorganisms in water. Bacteria convert carbonaceous materials into various gases and additional cell mass. One of the most common pathogens found in sewage is Salmonella. Shigella, the leading cause of recreational waterborne outbreaks in lakes and rivers, is also found. Some of the other bacteria that have been identified in sewage include Vibrio, Mycobacterium, Clostridium, Leptospira, Yersinia, Escherichia coli, and Campylobacter.
Viruses : Viruses are parasitic particles that consist of a strand of DNA o RNA. They invade living cells and redirect the cell to reproduce the vicus, which accumulates within the cell. When the host cell dies, the viruses are released. Viruses of concern in sewage include enteroviruses, rotaviruses, reoviruses, parvoviruses, adenoviruses, and hepatitis A virus. Protozoa. Protozoa are organisms that feed on bacteria and other microorganisms and are vital to the operation of biological treatment systems. Important protozoa in water treatment include amoebas, flagellates and ciliates. There are also pathogenic protozoa in sewage. Giardia lambia and Cryptosporidium are included in this category,
Pathogenic Organismes: Pathogens are organisms that are highly infesans. Par topen found in water are discharged by hammars who anr infected with or are carrier af a tseare Them pathogens typically cause typhoid fever, diarrhea, cholera, anu ethe discasis of the gastrointestinal tract
Indicator Organisms: There is large number and variety of pathogenic organisms in water. The time, cost, and difficulty of analysing for all of these organisms would be expany dea level of confidence in pathoger concentrations, runanute urgonis stable mund formas The ideal organism would be present when patlingenie orgtists are great he abent chemn pathogenic o ganisns are absent, be easy til inexpensive to analyze ans a pathogeritze|| An organism that meets these criterii cled a zboc gansa. The most widely used. indicator organism in water or sewage treatment is fecal coliform bacteria.
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Tags:
Water_Microbiology