Research on biological stability of water distribution system in northern area and correlative influencing factors

To study the correlation between traditional water quality indexes and BDOC, the biological stability of drink water in a northern city water system was investigated and evaluated by BDOC. When the conentration of BDOC is between 0.11 mg/L and 0.40 mg/L, the water is in biological steady level. BDOC changed a few from the entry to the end in the network. Among traditional water quality indexes, turbidity presents a positive correlation with BDOC, while pH shows a negative correlation. The charges of BDOC and residual chlorine should be combined together to control bacteria re-growth in the network, not merely depending on the biological index.