Study On Distribution Characteristics And Environmental Returns Of Phenolic Endocrine Disruptors Chemicals In Sewage Treatment System With Different Processes

Environmental endocrine disrupting(EDCs)refers to exogenous chemicals that influence biological processes such as the formation,reaction,metabolic transport,and elimination of hormonal substances that maintain their functionally and promote the development of the organism.At present,animals living on earth,including humans,whose endocrine systems are affected by such substances,produce problems such as dysplasia,reproductive disorders and reduced immunity.In these EDCs,phenolic EDCs are the most widely used,and their pollution characteristics in urban sewage are one of the hot issues in environmental science and public concern.As the environmental sample composition is very complex,making trace phenolic EDCs accurate analysis of detection is more difficult.Therefore,it is necessary to monitor and analyze the distribution characteristics,removal effect and environmental return of phenolic EDCs in urban sewage,which is an urgent problem to be solved in the study of phenolic EDCs pollution characteristics.Activated sludge method as a sewage treatment technology,has been widely used at home and abroad.At present,the research on the removal of conventional pollutants in wastewater by activated sludge has achieved more results,but there are few studies on the organic micro-pollutants with a large amount of organic pollutants in the environment.Phenolic EDCs compounds are the most common class of environmental hormones that pose a potential hazard to humans.In this paper,the technological units of the fifth,sixth and seventh sewage treatment plants in Xi’an were sampled as sampling points,collected samples of water samples and excess sludge.Four kinds of phenolic compounds(phenol,PCP,2,4-DCP And BPA)were used as targets to analyze the concentration of water and effluent in each process unit.The distribution characteristics of four phenolic EDCs compounds in three kinds of wastewater treatment processes,the removal efficiency of each treatment unit and the phenol and the environmental fate of EDCs in three processes were analyzed..The main findings include:(1)The samples were pretreated by solid phase extraction,and the samples were pretreated by ultrasonic extraction and silica gel column.The HPLC conditions were as follows: C18 column(4.6 * 250 mm,5um),UV detector,detection wavelength 265 nm,methanol-water as mobile phase,methanol-water(80:20,v / v),Injection volume 20 ul.The recovery rate of the samples was 90.50% ~ 95.00%,the recovery rate of the experimental method was higher,and the accuracy and precision were better.(2)The removal efficiency of phenolic compounds was studied by using the treatment units in the three processes.The primary treatment tank,biological treatment unit,secondary sedimentation tank and deep treatment process have certain removal effect on four phenolic EDCs.The removal of pentachlorophenol and bisphenol A from the primary settling tank was better than that of the other two kinds of phenolic compounds with relatively low octanol-water partition coefficient.The removal efficiency of four kinds of phenolic EDCs in biological treatment unit was better.And the removal efficiency of phenol and 2,4-dichlorophenol was better in the secondary sedimentation tank.The treatment effect of four kinds of phenolic EDCs was better in depth treatment process.DE oxidation efficiency was slightly lower than that of A2/O process on the four kinds of phenolic EDCs,but there was no significant difference between them.(3)The environmental attribution of phenolic EDCs in three kinds of sewage treatment processes was analyzed.The removal rate of EDCs in the four processes was higher than 75%,and the total removal rate of A2/O process and modified A2/O process was higher than that of DE oxidation ditch process,and the sludge adsorption ratio was higher than DE oxidation Ditch craft.(4)Comparison between A2/O process and sewage treatment model simulation results.There are some differences between the simulation results of the environmental attribution model of the four phenolic EDCs in the A2/O process and the actual monitoring results.Because the values of the biodegradable half-lives of the four phenolic EDCs in different treatment units are within a range,there is uncertainty that leads to differences in the simulation results from the actual monitoring results.