Investigating the Changes in Chlorine-free Concentration Remaining in the Consumption Point and Drinking Water Distribution Network of Parehsar City and the Factors Affecting it in 1400

Controlling biological parameters is a crucial aspect of disinfecting drinking water. As such, a study was conducted in 1400 to examine the changes in the concentration of residual free chlorine at the point of consumption and distribution network of drinking water in Parehsar city, as well as the factors that influence it.

This study was conducted in Parehsar City, taking samples daily from 10 different points. In this cross-sectional study, according to the population of the city and based on the existing guidelines, sampling was done daily from 10 points in the city. Samples were taken during one season, one week every month, and daily, with ten samples from the point of consumption and ten samples from the distribution network (10 points in the city). A total of 420 samples were taken, and the parameters of residual free chlorine, temperature, turbidity, pH, and coliform were measured according to the standard method. Data analysis was also done using SPSS software.

The minimum and maximum concentration of residual free chlorine at the point of consumption and distribution network were measured, 0.2-0.5 and 0.5-1 mg/liter, respectively. It was determined by the analysis that there is no significant relationship between the residual free chlorine concentration at the consumption point and the distribution network. The changes in the concentration of residual free chlorine at the point of consumption and in the distribution network were independent of changes in temperature, turbidity, coliform, and pH (distribution network). There was only a positive relationship between the concentration of residual free chlorine at the point of consumption and pH at the point of consumption.

Out of the 210 cases measuring residual free chlorine concentration, only one case at the consumption point and ten cases in the distribution network did not meet the standards. However, all other residual free chlorine concentration measurements, temperature, turbidity, and pH were within the standards and guidelines.