Study On The Effect Of Different Urban Sewage Treatment Systems On Emerging Pollutants

In recent years,emerging pollutants has aroused wide public concern.As a kind of persistent and cumulative pollutants in the environment,it can cause harm to human body at low concentrations.the sources of Emerging pollutants including antibiotics,estrogen,medicines and cosmetics are wide,but most of the emerging pollutants can enter the wastewater treatment plants with the sewage.Urban sewage treatment plants,as a key point in water circulation and pollution control,are important sources of migration and transformation of emerging pollutants to the environment.Therefore,urban sewage treatment plants play a vital role in the removal of emerging pollutants.In this paper,the removal efficiency of ten typical emerging pollutants via three different urban sewage treatment system: MSBR,BAF,and multi-stage A/O-MBBR was investigated.The concentration levels of emerging pollutants in wastewater treatment systems were detected by HPLC-MS.the removal efficiency of emerging pollutants via different treatment processes and the effect of temperature are evaluated.The sludge adsorption property of emerging pollutants was evaluated by detecting the concentration of emerging pollutants in the sludge.The Concentration level of antibiotic-resistant bacteria was detected to clarify its change in sewage treatment process.The details are as follows:1.Establishment of HPLC-MS detection methodMass spectrometry and chromatographic conditions were optimized by using HPLC-MS to build A method platform for the detection of ten typical emerging pollutants(including antibiotics,estrogen,and generic drugs)in sewage.the detection limit of the target was 6 ng / L after optimization.The external standard method was used to verify the recovery rate of the method.The result shows that the recovery rate of the target was between 82.23% and 97.08%,and the standard deviation was between 1.53 and 3.47.The method shows good repeatability so as to meet the requirements of the experiment.2.Study on the removal of antibiotics by different treatment systems(1)Removal of antibiotics by different treatment systemsBy analyzing the removal effect of five antibiotics in different sewage treatment systems,it was found that in the MSBR system in Haibohe wastewater treatment plant and the BAF systems in Maidao wastewater treatment plant,for the hydrophilic compound of sulfonamide antibiotics,the primary treatment of Haibohe wastewater treatment plant is more conducive to their removal.For the three TC,ROX and OFL compounds that are prone to adsorption,the primary treatment of Maidao wastewater treatment plant has better removal effect,especially the removal rate of ROX reached51.9%.Among the two-stage treatment,the multi-stage A/O-MBBR system has the best effect of removing five antibiotics.In the disinfection process,the treatment effect of ultraviolet disinfection is significantly better than sodium hypochlorite disinfection.(2)Study on removal of antibiotics under different temperature conditionsIn Haibohe sewage treatment plant,the removal effect of antibiotics at room temperature is significantly better than low temperature conditions.The temperature change has a greater impact on the removal effect of Haibohe Sewage Treatment Plant.In Maidao wastewater treatment plant,the removal effect of most antibiotics is greatly affected by temperature.Except OFL,its removal rate reached 91.7% under low temperature conditions.In the multi-level A/O-MBBR system,the removal rate of OFL under low temperature conditions is only 57.4%,and the removal effect of other antibiotics is less affected by temperature.(3)Study on adsorption of antibiotics by sludgeBy analyzing the content of the five antibiotics in the sludge,it was found that the concentrations of TC,ROX and OFL in the sludge were relatively high,especially the concentration of OFL in the remaining sludge reached 737.9 ng/g,indicating that they mainly pass through sludge adsorption removes them.The concentration of SM1 and SMZ in sludge is low,and the adsorption effect of sludge on them is poor.(4)Removal of antibiotic-resistant bacteria by different treatment systemsThe MSBR system in Haibohe wastewater treatment plant and the BAF systems in Maidao wastewater treatment plant have a good effect on the removal of TC and SMZ resistant bacteria,which can remove 4-5 orders of magnitude of resistantbacteria,and there is a certain correlation between the concentration of antibiotics and resistant bacteria.3.Study on the removal of estrogen by different treatment systems(1)Removal of estrogen by different treatment systemsBy detecting the concentrations of E1,E2,and EE2 in different sewage treatment systems,it was found that the concentration of the three estrogen in the influent water was above 45.9 ng/L.The primary treatment of Haibohe sewage treatment plant has a good effect on the removal of E1,the removal rate is 37.8%,while the removal effect of the other two estrogen is average.In the two-stage treatment,the removal effect of the multi-stage A/O-MBBR system on E1 and E2 is better than that of the MSBR process,and the removal rate of EE2 in the MSBR process reaches 60.3%,and the treatment effect is significantly better than the multi-stage A/O-MBBR system.The disinfection process can also remove some estrogen,and the removal rate of E2 has reached 31.7%.(2)Study on estrogen of antibiotics by sludgeBy detecting the concentration of estrogen in primary sludge and residual sludge in Haibohe wastewater treatment plant,it was found that the concentration of EE2 in the sludge was relatively high,reaching 75.5 ng/g,and the concentration of E2 was the smallest,only 42.3 ng/g,indicating that the adsorption effect of sludge adsorption on EE2 and E1 is better,but the adsorption capacity on E2 is poor.4.Study on the removal of generic drugs by different treatment systems(1)Removal of generic drugs by different treatment systemsBy analyzing the distribution of CF and AP in different sewage treatment systems,it was found that in the primary treatment,the Haibohe sewage treatment plant had a good removal effect of the two drugs,and the removal rate was more than47%.The Maidao wastewater treatment plant has a poor AP removal effect.In the secondary treatment,the biofilm method is better than the activated sludge method in removing two drugs,especially the removal rate of the two drugs in the multi-level A/O-MBBR system is more than 90%.(2)Study on removal of generic drugs under different temperature conditionsAlthough the concentration of CF and AP in the inlet water of the treatment system has increased under low temperature conditions,especially the concentration of CF under low temperature conditions has more than doubled compared with normal temperature conditions.Among them,the MSBR system in Haibohe wastewater treatment plant reached 1436.6 ng/L,but the sewage treatment system still maintained a good removal effect on them,and the removal rate was above 94.9%.(3)Study on estrogen of generic drugs by sludgeThe concentration of CF and AP in sludge is relatively low.The concentration of CF is about 348 ng/g,while the concentration of AP is only 87 ng/g.Compared with other pollutants,the adsorption effect of sludge on CF and AP is poor,and they are mainly removed by biodegradation.