Effect of Microbial Community on Iron Release under Low Velocity in Drinking Water Supply Pipes

Iron release from water supply network affects water quality safety. To investigate the change of microbial community structure and its effect on iron release in water supply pipes under leakage condition, the research was carried out based on the pilot platform used in actual water supply system. Microbial community structure was analyzed using high-throughput sequencing and the total iron index was measured by atomic flame absorption spectroscopy. The results showed that Proteobacteria had a large competitive advantage in the laminar flow rate, the average relative content increased more than 60%. At the level of class, the relative content of Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria increased larger than others. When the velocity was close to the critical flow rate, the microbial community was gradually stabilized. The total iron concentration decreased with the increase of flow rates, when the flow rate was 40% of the critical flow rate, the total iron concentration tended to be stable, and the promotion of total iron release was mainly iron-oxidizing bacteria and sulfate reducing bacteria, and the inhibition effect was mainly nitrate reducing bacteria. It has important reference significance for further controlling the microbial community and iron release in the water at the end of the pipe network.