Water quality analysis and corrosion potential of the distribution network of Patna, Bihar, India

Abstract

Drinking water distribution system water quality can be affected by chemical and microbial processes. A change in the chemical concentration of water is a result of pipe scaling and corrosion. It causes insignificant deterioration of water quality. This study determined the corrosion and scaling potential of the drinking water in the distribution networks of the water supply in Patna City, Bihar, India. For the determination of the physico-chemical parameters, 92 water samples were collected from 46 points of the distribution network. Four parameters were analysed in situ – namely, temperature, electrical conductivity, pH and total dissolved solids – and the remaining parameters – alkalinity, total hardness, calcium, magnesium, chloride, sulfate, nitrate and iron – were measured in the laboratory. Various widely used indices – namely, Langelier saturation index (LSI), Ryznar stability index (RSI), Puckorius scaling index (PSI), Larson–Skold index (LS) and aggressive index (AI) – were used to calculate corrosion and scaling potential of water samples. A result of the LSI and RSI, show that 86.96% of water samples are corrosive and only 13.04% are scaling tendency. PSI shows 30.43% of water samples are corrosive. LS shows all water samples are mildly corrosive. AI shows 71.74% of the water samples are moderately corrosive and only 28.26% of the water samples are scaling tendency.