Residual Chlorine and Effect of Residual Chlorine on Reduction of Bacteria in Wastewater from Fish Landing Site

Abstract

The aim of this study was to determine the residual chlorine and effect of residual chlorine on the reduction of bacteria in wastewater from fish landing sites using a wastewater sample from Maeklong Fishery Cooperative Fish Market in Samut Songkhram province. Initial chlorine concentrations at 0-85 mg/L were determined at the 30 minute contact time. The results showed that the residual chlorine in the initial chlorine concentration in the range of 0-50 mg/L were not detected but could be detected at the initial chlorine concentration excess of 55 mg/L. The initial chlorine concentration at 85 mg/L was found to have the highest residual chlorine in wastewater, while the initial chlorine concentration at 70 mg/L was found to have the lowest. As regards the relationship between residual chlorine and the reduction of bacteria at the initial chlorine concentration in the range of 55-70 mg/L, at the 5 second and the 15, 30, 60 and 120 minute contact time found that increasing the contact time decreased the residual chlorine significantly (p < 0.05). Also, increasing the contact time and initial chlorine concentration further reduced the bacteria (p < 0.05).