Study On Removal Efficiency And Correlation Coefficient Of Host-specific Markers And Enteric Pathogenic Bacteria By Municipal Wastewater Treatment Processes

Fecal pollution from nonpoint sources has a significant impact on watershed waterquality and affects human and environmental health.The fecal of human and animalmay carry enteric pathogenic bacteria including Salmonella,Shigella,and pathogenicEscherichia coil.If wastewater inflows into drinking water,the enteric pathogenic willspread,result in impacting the healthy of people.Bacteroides,Bifidobacterium and gascapsule bacillus are the three mian types of anaerobic bacteria in fecal.The researchuseed Bacteroides and Bifidobacterium as fecal indicator bacteria,studying the removalefficiency of host-specific markers and enteric pathogenic bacteria by municipalwastewater treatment processes,and studying the correlation coefficient by collectingdifferent sources of fecal pollution.The small experimental reactors were used to investigate the removal efficiency ofhost-specific markers for human and dog, and enteric pathogenic bacteria includingSalmonella, Shigella,and pathogenic Escherichia coil by activated sludge process(SBR),coagulation and filtration, respectively. The results showed that the removal efficiencyof host-specific markers and enteric bacteria by SBR process were approximately98%,which were significantly higher than coagulation and filtration.The removal efficiencyof host-specific markers and enteric bacteria by coagulation and filtration wererespectively60%and30%.There are three kinds of wastewater samples for analysing the correlationcoefficient.The first sample is collected from campus wastewater of Xi’an SiyuanUniversity and the wastewater treatment plant in the university,the sources of pollution is human fecal.The second sample is collected from an urban village nearby Xi’an,thesources of pollution is very complex,including human fecal，fowl fecal and livestockfecal.The third sample is collected from Xi’an wastewater treatment plant and effluentfrom SBR reactor,which sample’pollution source is primary human fecal,but affectedby other fecal.The result showed that the correlation coefficient between the removalefficiency of host-specific markers and that of pathogenic Escherichia coil is about0.75,no matter how complex the water pollution sources.For the pollution of the humanfecal,the correlation coefficient between the removal efficiency of host-specificmarkers and that of enteric bacteria is very good,ranged from0.66to0.99,whichindicated that the host-specific markers could to some extent reflect the concentration ofpathogenic bacteria in wastewater treatment process.