Ecological Distribution And Characteristics Of Phage In Wastewater Treatment System

Phage is the largest component in the wastewater treatment system. In recent years, there have beensome researches about phage to control the microbial community in the sewage treatment system. Due todifficulty of culture, lackness of the phage information and the unclearness of the phage infectionmechanism and environmental factors impacting phage infection, the application is limited. Therefore, it isgreat supplement of microbiology and engineering to research about the abundance, distribution andcharacter of phage in the wastewater treatment system. In this study, we have obtained several aspects asfollowing:(1) This research selected different full scale of urban sewage treatment systems and industrialwastewater treatment systems, with the technology of fluorescence staining and microscopy to study thedistribution and abundance of the phage in sewage treatment system. The result we got of the general orderof magnitude is the108-10ml-1, where the phage abundance of industrial wastewater plant activated sludgeis109ml-1and urban sewage plant activated sludge is1010ml-1. Among all kinds of sewage treatmentsystems, the distribution trend of the phage generally in activated sludge tank is: anoxic> aerobic>anaerobic.(2) Using the statistical software to analyse the correlation between the phage abundance in sewagetreatment system and other factors, such as other microorganisms in wastewater treatment system, inflowquality, operation, sludge performance, technological process. The results show that phage abundance hascertain relevance with these factors, such as other microbial abundance, quality of inflow, sludge indexes,but no significant relevance to the operation. And phage’s infecting activity has certain correlation withother microbial abundance, technological process, the types of water, but with no significant correlationwith sludge concentration and operation of sludge.(3) Using the method of plate culture,15phage strains were isolated successfully from the urbanwastewater treatment system., and we identificated their hosts by molecular biology method, as the resultshows that they are mainly distributed in Bacillus tequliensis, Bacillus methylotrophicus, Bacillus subtillis,Bacillus licheniformis, Bacillus pumilus and Bacillus safensis and Citrobacter freundii, Citrobactermurliniae. These phages were mainly the type of head-long tail, head-short tail, spherical, filiform undertransmission electron microscope. Preliminary appraisal phages were in Inoviridae Inovirus, Caudovirales Siphoviridae, Caudovirales Myoviridae, Caudovirales Podoviridae; We can roughlg estimate the size ofthese pahges is23kb by extracted their DNA.(4) The preliminary research on the relationship between phages and the hosts shows that host age andconcentration ratio of phage to host all affect the phage infection. Besides,6strains of the15isolated andidentificated phage have obvious characteristics of wide host, which can infect different species of bacteria.