Are you well known about water you consume?by Asmita Gaire | 30-01-2020 04:40 |
|---|
 Microbiological standards of Water Bacteriological standard of pure water- 1.No sample should contain E. coli in 100ml. 2.No sample should contain more than 3 coliform organisms per 100ml. 3.Not more than 5% samples throughout the year should contain coliforms in 100ml. 4.No two consecutive samples should have coliform organisms in 100ml. It may not be possible to attain the standards mentioned above in case of small community water supplies such as wells. In such cases isolated samples should not have more than 10 coliforms per 100ml, if E.coli is repeatedly found, the water is unfit for drinking. The finding of faecal Streptococci in water is regarded as an important confirmatory evidence of recent faecal pollution of water. Bacteriological examination is carried out to detect contamination of water by sewage or human or animal excreta which may contain pathogenic organisms of cholera, typhoid fever or dysentery. Human or animal excreta contains three types of organisms e.g., faecal coliform (E.coli), faecal Steptococci and Cl.perfringens. If any of them can be isolated from the water sample, it serves as an indirect evidence of faecal contamination. For routine examination coliform organisms are taken as bacteriological indicators, because their abundance in faeces, live longer period in the environment and can be grown rather easily. The tests employed are presumptive coliform count and plate count methods. The test results are expressed per 100 ml of water. No coliform in 100ml- excellent quality 1-2 coliforms in 100ml- satisfactory 3-10coliforms in 100ml-suspicious More than 10coliform in 100ml- unsatisfactory.. Viral standard- New recommendations are that faecal bacteriophages and enteropathogenic viruses should be absent. (Disinfection with 0.5mg/litre of free chlorine residual after contact period of at least 30minutes at a pH of 8 is sufficient to inactivate virus). Biological aspects- Protozoa parasite- These are E.histolytica, Giardia, Balantidium etc. Helminth parasite- Taenia, echinococcus, H. nana etc. Free living organisms- fungi, algae, etc. And turbidity, taste, odour etc. It's very simple way to test the microbiological standard. Get aware about microbiological properties of water and protect yourselves from several water borne diseases.
|
