Relationship Between Heterotrophic Bacteria and Some Physical and Chemical Parameters in a Northern City's Drinking Water Distribution Networks of China

In order to study the relationship between heterotrophic plate counts and some physical and chemical parameters, long-time detection was made on the parameters such as total chlorine, free chlorine, turbidity, water temperature, pH, total organic carbon (TOC), assimilable organic carbon (AOC), biodegradable organic carbon (BDOC) in a northern city distribution network of China. Bacteria were identified by Analytic Products inc. (API) bacteria identification systems, and most of them were opportunistic bacterial pathogen. Biofilms on the inner face of pipe were detected by environmental scanning electron microscope (ESEM). Free chlorine had a good negative correlation with heterotrophic plate counts (HPC). The results of turbidity and total Fe have good correlation with HPC. TOC has a good correlation with HPC. In distribution network of the city, AOC content was less correlative with amount of heterotrophic bacteria, BDOC content has a positive correlation with amount of heterotrophic bacteria. These indicate that the microbiological water quality of this area is not good, and BDOC is the better index to indicate the biological stabilization of this area. And there are many parameters affecting biological water quality especially in the residential area with complex water power condition, it can't be represented by one parameter and it should be thought about with all parameters synthetically.