[Growth Features of Water Supply Pipeline Biofilms Based on Active Microorganisms]

Biofilm in the water distribution system is composed of various active microorganisms, microbial residues, and organic and inorganic impurities. The growth of pipeline biofilms causes several drinking water hygiene problems, such as the colonization of opportunistic pathogens, corrosion of pipelines, and deterioration of water quality. To investigate the biofilm formation process and the distribution characteristics of live microorganisms attached to drinking water pipe walls, heterotrophic plate count (HPC), flow cytometry (FCM), and high-throughput 16S rRNA sequencing were analyzed to examine the growth characteristics and diversity of active microorganisms on the wall of three typical building water supply pipeline materials:polyvinyl chloride (PVC), polypropylene random (PPR), and stainless steel (STS). The results showed that after 73 d, the biomass on the PVC pipe wall was firstly up to peak. The relationships between the maximum biomass and mature biofilm biomass per unit area among the three pipelines were both PVC > PPR > STS. Regarding the composition and structure of the biofilm active bacterial community on the three different pipelines, the predominant phylum on PVC was Nitrospirae, while Verrucomicrobia was predominant on PPR and STS. The species richness and diversity of biofilm on STS were smallest, and thus the community structure was the simplest. Compared to STS, there were more Cyanobacteria and Actinomycetes on PVC and PPR-hence, odor is more likely to be an issue. The results demonstrated that pipe material can affect the community structure of the attached biofilm.