Attenuation And Risk Assessment Of Antibiotics In Wastewater From Key Industries

Since the discovery of antibiotics in the last century,they have played an unparalleled role in the treatment of human,animal and plant diseases.With the increasing production and use of antibiotics worldwide,the potential harm to the ecological environment and human health is becoming more and more serious.Now antibiotics have become a new type of environmental pollutants.The final effluent of the sewage treatment plant has become an important point source of antibiotics in the water environment.With the frequent detection of antibiotics in the water environment,it is urgent for us to deeply understand the removal mechanism of antibiotics by the wastewater treatment process in the sewage treatment plant.In this study,five sewage treatment plants and three pharmaceutical plant sewage treatment stations in five cities along the middle and lower reaches of the Yangtze River were selected as the research objects.The simultaneous separation and analysis method of antibiotics in sewage and sludge samples was established and improved.A total of 9 quinolones,8 macrolides,16 sulfonamides,5 tetracyclines and 1 beta-lactamases.The concentration distribution of lactam antibiotics in the sewage treatment system,and the COD,NH~3-N and p H of water samples were measured.The main results were as follows:(1)the overall concentration of 39 antibiotics ranged from ND to 2.14μg/L,the antibiotics with high detection rate are norfloxacin,ofloxacin,roxithromycin,clindamycin,lincomycin,SULFAPYRIDINE,sulfamethoxazole and trimethoprim,among which norfloxacin has the highest detection concentration.(2)Most antibiotics show varying degrees of reduction in sewage treatment system,and only a few antibiotics show difficult or negative removal effect.The overall removal rate of various antibiotics in the sewage treatment plant is roughly the same,the removal effect of sulfonamides is the best,and the removal effect of macrolides is the worst.The biological treatment unit has the highest removal rate of antibiotics.(3)According to the mass balance analysis,the total mass of various antibiotics in the sewage treatment system presents the following characteristics:microbial degradation>total mass in final effluent>total mass in sludge.Although the total quality of final effluent and sludge is relatively small,its risk can not be ignored.In addition,water quality parameters can affect the degradation effect of antibiotics,showing a better process for the removal rate of conventional pollutants,and the removal effect of antibiotics is also better.(4)Through the ecological risk assessment,most antibiotics in the final effluent of the sewage treatment plant have no risk to the ecological environment,a few antibiotics have high risk value to the ecology,and the antibiotics in the final effluent of the pharmaceutical plant are at high risk.Through the human health risk assessment,the risk values of 23 common antibiotics with high detected concentrations to human health are at a very low level.This paper mainly studied the distribution law and pollution characteristics of 39antibiotics in sewage treatment system,explored the reduction mechanism of antibiotics by biological treatment process,and analyzed the correlation between conventional water quality parameters and antibiotic concentration distribution.In addition,using the ecological risk assessment model and human health risk assessment model,this paper expounds the ecological environment risk and human health risk of23 kinds of antibiotics which are common and seriously polluted in the final effluent of sewage treatment plant.The results of this study not only enrich China’s antibiotic pollution database,but also provide technical support for antibiotic pollution control in sewage treatment plants and water environment,and provide a theoretical basis for formulating new pollutant treatment processes in sewage treatment plants and pharmaceutical plants.