Study On Occurrence Characteristics Of Typical PPCPs In Excess Sludge

With the rapid development of the detection technology of trace pollutants and the strengthen of environmental consciousness,pharmaceuticals and personal care products?PPCPs?have attracted much attention.Although the concentration of PPCPs that is a class of compounds closely related to human activities is usually ng/L to g/L in water environment,with the continuous use of human beings,a large number of PPCPs are discharged continuously into the environment,causing potential risksfor human health and ecological environment safety.Water pollution control action plan,enacted by the State Council in april,2015,emphasizes that excess sludge produced by wastewater treatment plants?WWTPs?should be treated stably,harmlessly,and resourcefully,and the substandard excess sludge is prohibited to enter the farmland.Therefore,it is of great importance to investigate the occurrence of trace organic pollutants such as PPCPs in excess sludge.At present,few study is carried out for the influence factors and mechanisms of PPCPs in excess sludge from WWTPsFirstly,on the base of previous literatures solid-liquid partition coefficients?Kd?of 152 PPCPs were collected in sludges such as primary sludge,aeration tank sludge,secondary sludge,digested sludge and MBR sludge.and the concentrations of 48 PPCPs were obtained from 9 provinces and cities of China.The concentrations,contents and adsorption removal rates of PPCPs in excess sludge from WWTPs of China were evaluated based on some basic assumptions,to reveal pollution levels of PPCPs.The results indicated that there are a lot of PPCPs in excess sludge in China.Hence,the government departments and scientific researchers should pay attention to the trace organic pollutants in the sludge.To explore the occurrence and influence factors of PPCPs in excess sludge,three drugs such as acetaminophen,sulfamethoxazole,ciprofloxacin were selected to evaluate the effects of p H,extracellular polymers and metal ions on the adsorption of PPCPs onto excess sludge.It was obtained that the adsorption of ciprofloxacin and sulfamethoxazole decreased,however,that of acetaminophen increased with increasing p H;because the speciation of a pharmaceutical in aqueous solution and zeta potential of biosolid are as a function of p H.EPS could enhance the adsorption of three typical pharmaceuticals onto the sludge,independent of p H;because the metal ions and organic substances contained in EPS determine the adsorption of pharmaceutical onto the sludge.Through ultrasonic extraction,solid-phase extraction and high performance liquid chromatography-mass spectrometry?UPLC-MS/MS?,a highly selective and sensitive analytical method was developed for simultaneous determination of 10 antibiotics in the excess sludge of WWTPs.The antibiotics in actual excess sludge were detected using this method,and the results were similar to that in previours literatures,which confirmed that the sludge adsorption is one of the main fate of antibiotics in WWTPs.The Kd of 7 quinolones in the excess sludge were investigated under different p H?= 4 11?.With increasing p H,the 7 quinolones showed similar the regularities of adsorption,and the adsorption capacity was the highest one at pH = 5.The concentrations of metal ions in the water before and after p H regulation were inversitigated and it was revealed that that the desorption of metal ions(K⁺,Mg²⁺,Ca²⁺)on the surface of the exces sludge could be the reason of the variation of Kd.On the basis of FTIR spectra,it was understood that the quinolones were mainly combined with the phenolic hydroxyl groups by cation exchange,rather than carboxylic groups on the surface of excess sludge.