Study on Phosphorus and Bacterial Regrowth in Drinking Water

Phosphorus limitation on bacterial regrowth was studied in source water, water treatment process and water distribution system of J Water Supply Plant in T city, by modified AOC method and MAP analysis. Based on the study, the follows can be concluded: (1)MAP(Microbially Available Phosphorus) concentration was higher in source water and water treatment process, which was 5 38 mu g PO43--P/L. However in water distribution, MAP concentration was lower, which was less than 5 mu g PO43--P/L. (2)Coagulation and sedimentation can remove MAP efficiently. 31%similar to 68% of MAP can be removed in these process. (3)In source water and water treatment process, there was no evident difference between AOC(potential), AOC(p) and AOC(native). So assimilable organic carbon (AOC) was the most important factor of bacterial regrowth. In water distribution system, the concentration of AOC(potential) and AOC(p) were 2 similar to 8.7 times of the concentration of AOC(native). So phosphorus limited bacterial regrowth.