Behavior Analysis of Sanitary Indicator Bacteria in Treatment Process of Johkasou

Abstract

 In Johkasou, chlorine disinfection is carried out in order to discharge treated water as hygienically safe. However, adverse effects of residual chlorine and by-product on eco-system at discharged area are concerned. In addition, the total coliforms are used for environmental standard or effluent standard as an indicator; however, the total coliforms include a large number of spontaneous bacterial species. Therefore, nowadays, it is considered that total coliforms are not appropriate as an index for fecal contamination. In this research, we aimed to reveal the behavior of sanitary indicator organisms in each treatment process to develop a johkasou with the minimum amount of chlorine addition, and to clarify the relationship between the removal efficiency and the treatment performance. As a result of the on-site survey, it was suggested that removal efficiencies of total coliforms, Escherichia coli and Enterococcus are correlated with BOD removal in aerobic filter tank and that of anaerobic spore bacteria is correlated with SS removal in anaerobic filter tank, respectively.