Research On Microbial Diversity Of Pipeline Biofilm In Water Distribution System

The distribution network is an important part in the whole water supply systems, and it plays a key role in protecting security of water supply. The recontamination during distribution network has been receiving considerable attention, and the conception of biosability of drinking water also has been bring forward. To control the bacterial regrowth is a key issue in attempt to increase the biosability of drinking water. Contamination and material in the biofilm may subsequently be released into the flowing water under various circumstances. As a result, biofilms can act as a slow-release mechanism for persistent contamination of the water.The study on the biota of distribution system is still few. The model pipeline which was used to simulate to the distribution system dynamically was designed to analyze the bacterial growth. And microbiological methods were used to identify the bacteria which grew in the biofilms in different periods. Then the bacterial species and their growth were analyzed to monitor the bacteria diversity of different pipelines biofilms in different periods.The scanning electron microscope (SEM) was used to observe the bacterial growth intuitively in the model pipeline biofilms, and analyzed the water quality target which affected its growth. The Analytic Products INC (API) was used to identify the bacteria which grew in the heterotrophic plate counts (HPC).The scanning electron microscope(SEM) and heterotrophic plate counts (HPC) of pipe tubercle samples collected in the model distribution system demonstrated that the inner wall of the pipe was not smooth, permitting crevice to exist and bacteria to grow. The bacterial regrowth was confirmed by the SEM results showing that most of them were bacteria and bacilli. However, the large quantity of bacterial growth was profit for pathogenic bacteria to grow. The water quality would deteriorate when water flow velocity or pressure were changed suddenly.Molecular biological technologies were innovational used in the study of bacteria diversity in distribution network biofilm.16SrDNA based PCR amplification and denaturing gradient gel electrophoresis (PCR-DGGE) was used to monitor the microbial diversity in different biofilms. It's proved that molecular biological technologies could be used in the research of bacteria diversity in drinking water, it is useful to protect the security of microbiology water quality, and helpful for ensure the health of people.