Characteristics Of Pipe Scale Of Drinking Water Distribution Systems With Different Water Quality And Effect Of Microbial Community On The Pipeline Corrosion

Unstable corrosion scales might trigger“red water”issues when water quality entering distribution systems changed significantly.The morphology and physico-chemical characteriscs corrosion scales formed under different source water history were systematically investigated in this work.and the effect of corrosion scales characteristics on iron release was investigated through simulation experiments with the same water quality parameters and hydraulic regime.It was found that the thickcontinuous scale layer which was formed as the connection of many growing tubercles wasmostly found in pipes transporting surface water,but the thin surface layer was mostly discovered in pipes transporting groundwater.Corrosion scales on groundwater pipes with low magnetite content had highersurface area and higher sorption capacity.Corrosion scales higher percentage of Fe3O4,porosity and surface area in comparison with that in L city The concentrations of iron released from corrosion scales with lower percentage of Fe3O4,higher porosity and surface area was greater.In order to understand the bacterial community characteristics of biofilms developed in a real drinking water distribution systems,biofilm samples from G-1 and S-1 in the northern city were collected and systematically investigated using Roche 454 pyrosequencing of 16S rRNA gene.The abundance variation of the functional genes(BAC,nirK,nirS and nosZ)was investigated using the real-time polymerase chain reaction in different iron pipes from different distribution systems.The results showed that slightly differences in bacterial diversity and composition of the dominant bacteria were observed,but the relative abundance the species exist significant differences.The dominant bacteria at genus level were classified and analyzed,including sulphate reducing bacteria(SRB),sulfur oxidizing bacteria(SOB),iron reducing bacteria(IRB),iron oxidizing bacteria(IOB)and nitrate reducing bacteria(NRB).This research results to ensure the stable operation of the water pipe network and safety and high quality of water supply provide theory basis.