论文部分内容阅读
目的研究城镇污水处理厂进出水中特征性致病菌E.coli O157:H7和沙门菌的浓度水平以及次氯酸钠对其及病原指示菌的灭活特性。方法于2012年2—12月,采集北方A污水处理厂的进水及二沉池出水水样,分离、纯培养总大肠菌群(TC)、粪大肠菌群(FC)、E.coli O157:H7和沙门菌;分别加入有效氯浓度为0(溶剂对照)、0.5、1.0、1.5、2.0 mg/L的次氯酸钠溶液接触5、15、30、45、60 min。测定TC、FC、E.coli O157:H7和沙门菌的浓度。结果污水处理厂进水中E.coli O157:H7为105~107 cfu/L,沙门菌为106~108 cfu/L;出水中微生物数量均有所下降,但E.coli O157:H7仍高于102 cfu/L,沙门菌高于104 cfu/L。纯培养的E.coli O157:H7和指示菌可被0.5 mg/L有效氯作用60 min灭活,而同条件下沙门菌只能部分被灭活。结论沙门菌在本次调查的污水中浓度水平较高,且比病原指示菌大肠杆菌难以灭活。若单以病原指示菌监测出水水质,存在指示菌达标而其他病原微生物造成环境二次污染的可能。
Objective To study the concentration of E.coli O157: H7 and Salmonella in urban sewage treatment plants, and the inactivation characteristics of sodium hypochlorite and its indicator bacteria. Methods From February to December in 2012, the influent water of secondary A sewage treatment plant and the water sample of secondary sedimentation tank were collected, and the total coliforms (TC), fecal coliforms (FC), E. coli O157 : H7 and Salmonella; respectively, adding effective chlorine concentration of 0 (solvent control), 0.5,1.0,1.5,2.0 mg / L of sodium hypochlorite solution contact 5,15,30,45,60 min. The concentrations of TC, FC, E. coli O157: H7 and Salmonella were determined. Results The water quality of E.coli O157: H7 was 105-107 cfu / L and the concentration of Salmonella was 106-108 cfu / L. The number of microorganisms in effluent decreased, but E. coli O157: H7 was still higher than 102 cfu / L, Salmonella higher than 104 cfu / L. Pure cultures of E. coli O157: H7 and indicator bacteria could be inactivated by 0.5 mg / L available chlorine for 60 min, whereas Salmonella could only partially be inactivated. Conclusions Salmonella is highly concentrated in the sewage collected from this survey and harder to inactivate than the pathogen indicator E. coli. If the pathogen indicator bacteria to monitor the water quality, there are indicators of bacteria and other pathogenic microorganisms cause secondary pollution of the environment.