Waterborne Diseases in Shimla City an Analysis of Water Supply Scheme

Abstract

Shimla is a beautiful city and a rapidly growing hill station, attracting a large number of people from various parts of the world since British period. Sudden increase in population has triggered many problems like water shortage, poor sewage network and lack of quality drinking water. Outbreaks regarding waterborne disease are common in densely populated and water-scarce cities like Shimla. Mass level Jaundice was reported in Shimla City during 2015-16 affecting about 1680 people within 3 months which was of great concern. Cases peaked in January 2016 and decreased rapidly, suggesting a common source outbreak. Through studies it was found three major zones supplied by a common water supply i.e., Ashwani Khud was severely affected. The water after being pumped from the source was treated using conventional water treatment process. Since branch of this stream was receiving treated sewage effluent from a nearby Sewage Treatment Plant, which might have increased the bacterial load of the source water and thus leading to the outbreak. The efficiency of WTP and Water quality of AshwaniKhad water supply system was analyzed to check it's suitability for drinking purposes. The objectives of the investigation were to (i) Determination of the cause of problem and population at risk. (ii) Assessment of water quality variables in drinking water sources, Water Treatment Plant and Distribution Systems. (iii) Determine the degree of contamination at different stages of water supply. (iv) Identification of Pathogens in Drinking Water Supplies. The present study was aimed to identify pathogens in the water supply. For this, various bacteriological tests like colony forming units, MPN, selective isolation of bacteria and biochemical tests were performed. The water samples were found negative for any sort of fecal contamination. Biochemical tests lead to the presence of Alcaligenes faecalis, Pseudomonas spp., Streptococcus spp.in the water samples. All of the species discovered showed persistence in water supply and distribution system which can be a result of lack of proper disinfection process and maintenance of piped systems.