Effect of temperature on pH, turbidity, and residual free chlorine in Sanandaj Water Distribution Network, Iran

One of the parameters responsible for decreased water quality in a distribution system is temperature changes. This study was conducted to examine the effect of temperature on pH, turbidity, and residual chlorine in Sanandaj, Iran, Water Distribution System. The required water samples were taken from 85 stations during April to October 2014. Sampling was carried out over 6 months and twice per month. The average amount of residual chlorine measured at these stations was 0.58 and 0.52 mg/l, and turbidity was 0.86 and 0.98 nephelometric turbidity unit (NTU) in winter and spring, respectively. The temperature did not have any effect on pH, the amount of pH in winter and spring were 7.56 and 7.57, respectively. The results showed significant differences in the concentration of residual chlorine and turbidity of Sanandaj Water Distribution Network between winter and spring (P ≤ 0.01). Thus, the concentration of residual chlorine and turbidity varies in warm and cold seasons. However, no significant difference was observed in pH (P ≥ 0.01). The research results indicated that temperature does not have any effect on the qualitative parameters measured in the study area.