Removal Characteristics And Risk Assessment Of Typical Trace Organic Pollutants In Guiyang Municipal Sewage Treatment System

The trace organic pollutants have the characteristics of low concentration,toxic and harmful,and difficult to be degraded.The tail water of municipal sewage treatment plant is an important input source of trace organic pollutants in the water environment.With the frequent detection of trace organic pollutants in the water environment,the source emission reduction of trace organic pollutants and the efficient removal of sewage treatment plant have become a research focus in the field of environmental science and engineering.This study choose guiyang four city sewage treatment plant as the research object,explore 10 kinds of antibiotics in sewage and 6kinds of phthalic acid esters(PAEs),two kinds of alkylphenol(APs)and 2 kinds of bisphenol A total of 20 kinds of trace organic pollutants in wastewater treatment system of distribution features,and to evaluate the risk of receiving waters.The results of this study can provide support for the efficient removal of trace organic pollutants in sewage treatment plants on the basis of mastering the law of removal of trace organic pollutants,and also provide an important reference for the standard formulation of trace organic pollutants in water environment in China.The main results are as follows:The average total concentration of antibiotics in the inflow of 4 sewage treatment plants in guiyang city was 652.16 ± 80.11 ng/L,and ofloxacin was the antibiotic with the highest concentration detected.The average removal rate of antibiotics in 4 sewage treatment plants was 61.64±22.20%.The removal rate of antibiotics in 4 sewage treatment plants was as follows: primary treatment(physical precipitation)<secondary treatment(biochemical treatment)< tertiary treatment(flocculation precipitation + disinfection).The total removal rate of EDCs in 4 sewage treatment plants in guiyang reached more than 57.71%.The average removal rate of EDCs was as follows: primary treatment(physical precipitation)< tertiary treatment(flocculation precipitation + disinfection)< secondary treatment(biochemicaltreatment).The removal rate of antibiotics and EDCs was higher in winter than in summer.The biodegradation of W1 plant,W3 plant and W4 plant had a poor effect on the overall removal of antibiotics.In W2 plant,biodegradation was the main removal pathway,and sludge adsorption was the secondary removal pathway.The removal effect of EDCs by W1 biodegradation was poor.In W2 and W4,sludge adsorption was the main removal pathway and biodegradation was the secondary removal pathway.The ratio of EDCs sludge adsorption and biodegradation removal in W3 was similar.The antibiotic oxytetracycline has a medium risk to aquatic organisms in the receiving water,and ofloxacin has a high risk to the receiving water.Octyl phenol is a high risk EDCs for aquatic organisms in polluted rivers.