UV Resistance of E. coli and Total Coliform in Raw and Secondary Treated Sewage

Abstract

In consideration of the changes in indicator bacteria in the environmental standard and wastewater effluent standard, fluctuations in the concentrations of E. coli and total coliform in raw sewage and secondary treated sewage at three wastewater treatment plants and fluctuations in the resistance to UV disinfection were investigated. Regarding the concentrations of E. coli and total coliform, there were no significant fluctuations in either raw or treated sewage with seasonal variation, water collection system, and treatment method. As a result of UV inactivation of secondary treated water, it was found that the UV resistance of E. coli was higher than that of total coliform. However, there was no significant difference in UV resistance calculated using the concentration after photo-reactivation. Moreove, no significant difference was found between seasonal variation, diurnal fluctuation, and treatment plants for these tolerances. According to the result of similar experiments on raw sewage, the UV resistances of E. coli and total coliform were equivalent, and the resistances calculated using the concentration after photo-reactivation were also the same.