Water Quality Assessment of Public Wells of Madhyapur Thimi Municipality

Abstract

Madhyapur Thimi Municipality with an area of 11.47 sq. km is situated exactly inbetween Kathmandu, Lalitpur and Bhaktapurandhas total population of 47751(CBS2001). Important physico-chemical parameters were studied monthly over the period ofeight months from February to September 2006 andmicrobiological parameters werestudied for the month September. The physico-chemical features such as pH, electricalconductivity, total dissolved solids, dissolved oxygen, free carbondioxide, total alkalinity,total hardness, calcium, magnesium, chloride and phosphate vary significantly from sites1 to 20 whereas the monthly variation of only water temperature, pH, dissolved oxygen,free carbondioxide, total alkalinity, nitrate and phosphate were significant over theinvestigation period. The Nitrate-nitrogen content of all Well water samples were foundwithin WHO limit during the investigation period. The iron content of Sites 1(Kumhalachi), 2 (Bahanani), 4 (Gungachiwa), 9 (Tigani), 11 (Tahanani), 12(Bhulankhel), 13(Bramhanani), 15(Tachutole), and 16(Bamune tole) crosses the WHOlimit for iron content. The maximum iron content was found in site 11 in the month Juneduring the investigation period. Similarly, the electrical conductivity of sites 2(Bahanani), 3(Dhwakasi), 4 (Gungachiwa), 5(Kasmatuthi), 8(Nachutole), 9(Tigani),10(Lokanthali), 11(Tahanani), 12(Bhulankhel), 13(Bramhanani), 14(Tulanani), 15(Tachutole), 16 (Bamune tole), 17(Parsikomarga), 18(Gachen marga), 19(Shiva tole)and 20(Chode marga) crosses the WHO limit for electrical conductivity. The maximumelectrical conductivity of 2330 µS/cm was found in site 9. From MF Test all Well waters contained faecal coliform per 100 ml of water sample greater than 300. So, all Wells arecontaminated with faecal coliforms. But from MPN Test, out of 10 sites in which MPNTest were performed maximum coliforms were found in site 20 (1600/100ml) andminimum were found in site 7 (2/100 ml). All thewell water samples gave positivecompleted coliforms test confirming the detection of coliform bacteria in the water sample, indicating the faecal contamination of water except site 7. Thus,all well water sare considered as non potable from microbial point of view. Necessary treatment should bedone before drinking such water