5 Water Quality Parameters for drinking waterby | 14-12-2013 02:23 |
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The water quality parameters are the indicating factor that helps to determine the nature, property and constituents (i.e. physical, chemical, biological components) of the water to identify whether water is safe enough for drinking and other purposes or not. Quality parameters are selected on the basis of their source, location, geology and environmental condition and so on. Turbidity, colour, temperature, odour, conductivity are the physical parameter. Total hardness, Total alkalinity, iron, manganese, ammonia, chloride, nitrate, phosphate, calcium, magnesium etc are chemical parameter where as Coliforms and Faecal Coliforms are biological parameters. Therefore the brief discussions on the quality parametes are here below: a) Turbidity: No person likes to drink turbid water so it has an aesthetic significance. It is the measure of the fine suspended matter in the water , mostly caused due to colloidal matters. It has much significance also in water treatment unless water is turbid free treatment does not work effective. As bacteria will hide in the small pores of the turbid particles to protect themselves from the attack of disinfectants. It is measure using Nephelometry turbidity unit (NTU). The turbidity of water is measures with the help of Nephelometer / Turbidity meter. WHO GV for turbidity is 5 NTU. b) pH: The pH of the water indicates the extend of acidity and alkalinity condition. It is measured by an instrument pH meter (calibration in the buffer solution of pH-4, pH-7 and pH-9 is required), universal indicator solution, or a pH paper whose color changes in different pH, i.e. red to blue (acid to base) / blue to red (base to acid). WHO Guideline value for drinking water is 6.5 to 8.5 because the pH of natural water is considered to lie within this. c) Total Ammonia: Ammonia is the result of putrefaction of organic substances containing nitrogen and thus usually enters into water due to this process. It is the indicator of contamination of geological origin, domestic or agriculture wastes. In low pH it remains in ammonium form having no odor and in high pH slowly ammonium gets converted into ammonia giving unfavorable odor. The analysis of ammonia is done by Nesslerizatin method (Colorimetric/ Spectrophotometric). WHO guideline for ammonia is 1.5 mg/l in water. d) Nitrate: Nitrate enter into water through fertilizer use, decayed vegetables and animal matters, domestic effluents, industrial discharges, atmospheric washouts etc. Contamination may result from a direct or indirect discharge. Drinking of nitrate contaminate water may cause Blue Baby Syndrome (Methaemoglobinaemia). In this excessive accumulation of nitrate in human body displaces the hemoglobin from the blood resulting in the blue colour of the body. The WHO guideline value for nitrate is 50 mg/l
e) Bacteriological: Drinking of the bacteriological contaminated water affects the human instantly causing different diseases like Poliovirus, Norwalk virus, Hepatitis A, Protozoa?s like Entamoeba histolytica, Giardia lamblia, cholera, dysentery and Helminthes such as round worms, flat worms can be transmitted through contaminated and unsafe drinking water. The analysis for bacteria is difficult to test for the presence of all the species. In generalized form, coliform and E. Coli which are considered as indicator micro-organisms are performed. Water is cultured with nutrient media either solid or liquid example, Nutrient Agar, EMB Agar (Solid Media) where as McConkey Broth Purple (Liquid media) for 24 to 48 hour for incubation. Their colonies are counted if the incubation shows positive result.The measured in the different unit depending on the methodology like MPN/100ml, CFU. |