Removal characteristics of coliform bacteria by certified structure type small-scale Johkasou

The removal characteristics of coliform bacteria by certified structure type small-scale Johkasou were studied. The results showed that among 25units of investigated Johkasou 24 units could meet the effluent quality standard of coliform bacteria count under 3,000cfu/mL before chlorination, and all units could remove coliform bacteria count less than 1,000cfu/mL after chlorination. However, about 200cfu/mL of coliform bacteria count was detected, in spite of having detected residual chlorine in effluent over 2mg/L. Coliform bacteria count in effluent before chlorination was negatively correlated with nitrifying ratio and positively correlated with SS, respectively. Therefore it was considered that highly removal of coliform bacteria was possible by advanced Johkasou which could remove nitrogen and SS.