Influence Of Amoxicillin On AAO Urban Sewage Treatment Process And Its Biodegradation Behavior

A wastewater treatment plant of Harbin accepted a large number of pharmaceuticalwastewater, which was up to10%of influent. A large number of drugs were flowed intothe wastewater treatment plant that high concentrations of drugs would affect sewagetreatment system. In addition, a series of environmental problems would be triggeredwhen the drugs entered the water after passing through sewage treatment plant.Amoxicillin was the largest consumption and production of antibiotic, which wasselected to study its impact on AAO process and its degradation behavior in wastewatertreatment processes.A laboratory-scale AAO process was used as the reactor. A simulation softwareGPS-X was used to optimizing the startup of AAO process. We studied the influence ofamoxicillin on nitrogen and phosphorus removal of sewage treatment plant, investigatedthe biodegradation of amoxicillin in AAO system, estabilished the adsorption andbiodegradation kinetics model of amoxicillin in AAO process, suggested thebiodegradation products of amoxicillin, explore the strengthening process measures toremova typical contaminant.The results show that the simulation software GPS-X was able to optimize thestartup of AAO process in a short term. Nitrogen and phosphorus removal of AAOsystem was affected by concentration of amoxicillin. Activity of sludge and nitritebacteria was inhibited by1~3mg/L amoxicillin that affect on the removal of COD andammonia, while3~5mg/L amoxicillin significant affect on the removal of COD、ammonia、total nitrogen, total phosphorus. AAO process got a certain ability to removalamoxicillin, where the degradation removal areas were mainly concentrated in theanaerobic and anoxic zone, wherein the remaval proportion of anaerobic zone was morethan50%. Amoxicillin in the AAO system was removal by hydrolysis, adsorption andbiodegradation. The adsorption process of amoxicillin in activated sludge could well fitLangmuir and Freundlich adsorption isotherm model. Biodegradation kinetics model ofamoxicllin in AAO process was established that could well predict the degradation ofamoxicllin in the actual AAO process. The detection mean of LC-MS was used toanalysis the degradation products of amoxicillin in activated sludge. we could speculated that the β-lactam ring of amoxicillin was opened by degrading enzyme,following by decarboxylation. Then it degraded into a kind of aldehydes in further, andfinally degraded into unknown substance. In addition, shortening the SRT of AAO to5dcould improve the removal of amoxicillin and phosphorus, while weaken the effect ofremoving nitrogen at the same time. This problem could be effectively solved byAAO-BAF combined process. Extension of HRT of BAF to4h both strengthen theremoval of amoxicillin, and inprove the efficiency of nitrogen and phosphorus removal.The typical pollutant index could achieve 《urban wastewater discharge standards》Astandard.In summary, the use of a large number amoxicillin brought certain challenges forwastewater treatment. AAO-BAF combined process provided certain reference value forenhancing the removal of typical contaminants, which had the practical engineeringsignificance.