Study On The Identification And Control Method Of Antibiotic Resistant Bacteria In Municipal Wastewater Treatment Plants

The accumulation of antibiotics will leasd to the health risks to marine and terrestrial creatures in the environment.In recent years,the certain concentration of antibiotics have been detected in the domestic and foreign municipal wastewater treatment plants(MWTPs).The occurrence of antibiotics may promote selection of bacteria resistance to antibiotics,which will be transmitted to humans through the food chain.MWTPs are among the main sources of antibiotic resistant bacteria and antibiotics released into the environment.A method for the determination of fourteen target antibiotics(ofloxacin,ciproflo--xacin,penicillin,amoxicillin,cefuroximeaxetil,tetracycline,oxytetracycline,Sulfa--methoxazole,sulfadiazine,erythromycin,roxithromycin,azithromycin,Tinidazole,chloramphenicol)in water sample using solid phase extraction and high performance liquid chromatography-tandem spectrometry(SPE-HPLC-MS/MS)has been establish--ed and successfully applied in the survey of taget antibiotics in A MWTPs in shenyang.Result indicated that the detection rate of fourteen kinds of antibiotics as high as 92.86%,the concentration of antibiotics in raw influent and final effluent from A MWTPs range from 0.234 to 830.9 ng-L-1and from 0.1988 to 732.2 ng-L-1,respectively.According to the analysis of mass balance calculation,MWTPs treatment process for the removal efficiency of antibiotics in MWTPs treatment process was low.The resistance to bacterial colonies and the total number of colonies counted by plate count method,comparing the MWTPs' bacterial resistance to different types of antibiotics under four seasons.Results indicated that less impact on the bacterial resistance and the proportion of resistant bacteria with the seasonal variation and more related to the treatment process,water quality and other operating parameters are related.MWTPs are huge library of antibiotic resistant bacteria.Although the biochemical treatment in the sewage treatment process to reducing antibiotic resistant bacteria play a crucial role,there are still considerable number of antibiotic resistant bacterias with municipal wastewater treatment plant effuent discharged into the receiving water.The raw influent and final effluent of the A MWTPs as the research samples were screened for antibiotic resistant bacteria,the separation and purification of antibiotic resistant strains were analyzed and identified by 16SrDNA.The results showed that isolated 25 strains of resistant bacteria belonging to six genus,the strength of resistance:Acinetobacter>Pseudomonas>Escherichia>Enterococcus,Staphylococcus,Bacillus;the proportion of multi-resistant bacteria reach as high as 88%.The study on the disinfection efficiency of ozone,ultraviolet,sodium hypochlorite and combined UV with sodium hypochlorite disinfection on antibiotic resistant bacteria in MWTPs secondary effluent were carried out.Under the optimum processing conditions by analyzing the results:contact time for 5 min(initial ozone dose of 10 mg/L),UV dose of 15.6 mJ/cm2,contact time for 5 min(initial chlorine dose of 3 mg/L),initial chlorine dose of 1 mg/L and UV dose of 7.8 mJ/cm2.