Impact Of Pipe Features On Bacterial Population Diversity Of Biofilm In Urban Water Supply Network

With the rapid development of social economy and urbanization,the safety of drinking water has increasingly aroused people’s attention. Compared with water resources and plants, stable water quality in drinking water distribution networks is the worst. Even though the source quality is good enough, but because of the pipe scale and biofilms, the drinking water quality is substandard. There are both bioventure and chemical risk in drinking water distribution systems, but at present, there is litte research on bioventure in our country. Biofilm is widely exist in drinking water distribution networks, which provide a good environment for bacteria to cope with the adverse conditions. In this paper, molecular biology was used to explore the microbial situation and compare the differences among microbial population diversity in pipes of different materials, ages and diameters. The results of the research are as follows:1) The microbial population diversity in five pipe materials was different:the number of total bacteria of grey cast iron pipe was the most among the five pipes, the next were nodular cast iron pipe, galvanized pipe and stainless steel pipe, while the plastic pipe had the least number of culturable bacteria and total bacteria. The observation of SEM was in keeping with the results above, and the main bacteria were coccus and bacillus. But the proportion of living bacteria in plastic pipe and nodular cast iron pipe were higher than other pipes. The highest species richness and diversity were found in the samples from nodular cast iron pipe, and the lowest was in the samples from plastic pipe. Overall, except nodular cast iron pipe,more than 90% of the diversity in all the samples was associated with the phyla Proteobacteria, and the bacterial community composition of biofilm from the pipes was significantly different.2) The microbial population diversity in different pipe ages was different:there was no obvious regularty between ages and total bacteria in grey cast iron pipe, but the total bacteria and culturable bacteria were increasing along with pipe ages in nodular cast iron pipe and galvanized pipe. The observation of SEM was in keeping with the results above, and the main bacteria were coccus and bacillus. Overall, the species richness and diversity were increasing with increasing pipe ages, and the main population of all the samples was associated with the phyla Proteobacteria. The bacterial community composition of biofilm from the pipes was significantly different.3) The microbial population diversity in three pipe diameters was different:the number of culturable bacteria and total bacteria of DN300 pipe was the most among the three pipes, while the DN150 had the least number of total bacteria and the DN200 pipe had the least number of culturable bacteria. The proportion of living bacteria was as same as the number of culturable bacteria. The observation of SEM was in keeping with the results above, and the main bacteria were coccus and bacillus. The highest species richness and diversity were found in the samples from DN150 pipe, and the lowest was in the samples from DN300. The main population in DN150 pipe and DN300 pipe was the phyla Proteobacteria, but in DN200 pipe,the phyla Firmicutes was the most. Overall, the bacterial community composition of biofilm from the pipes was different.