Distribution And Migration Of Typical PPCPs In Municipal Sewage System

In recent years,the wide use of pharmaceuticals and personal care products(PPCPs)have been detected at various degrees to the natural environment,including surface water,groundwater,domestic sewage,drinking water,natural sediments,etc.,which has attracted much attention from the public.The environmental pollution caused by PPCPs has a close relationship with human habits and ways of production.Through the investigation on the occurrence state of PPCPs in urban sewage system,this thesis compares the concentrations and distribution characteristics of PPCPs in different regions and screens out the emission sources and typical substance of PPCPs.Meanwhile,sewage pipelines serve as the original collectors and transporters of the PPCPs in sewage and the exploration of the law of migration of typical PPCPs in sewage pipelines were explored to evaluate the removal efficiency of sewage pipelines.13 species PPCPs were selected as target substances and adopts HPLC-MS/MS and GC-MS analytic methods to measure and analyze the PPCPs in the samples of the sewage system,surface water in liquid state and suspended substance in a southern city of China.The results show,all target PPCPs were detected.The average concentration of PPCPs in liquid and suspended solids was 1.50ng/L-258.59ng/L and 11.00ng/g-917.94ng/g respectively.By investigating the PPCPs in the sewage pipelines of the residential area,the industrial zone and the periphery of the hospital,the investigation results show,the main PPCPs pollutants in the sewage are IM and D6 which mainly come from domestic sewage.By comparing the concentrations of PPCPs in the waters of passing in and out of sewage treatment plant,we can learn that sewage treatment plant plays an effective role in removing GF,D4,D5 and D6,but has a bad removal effect on PPN,SP,IM,KP,BF,CA and DEET,or even appears the phenomenon of negative removal.The thesis adopts the risk quotient method to conduct ecological risk assessment on the 7 species PPCPs in surface water and the effluent from sewage treatment plant.The results show,except for KP and GF,other PPCPs have different ecological risks to the environment.Among them,the ecological risk of D6 is more prominent.It is necessary to observe the D6 concentration in water environment for a long time.Then the thesis employs the methods of correlation analysis and linear regression analysis to conduct acorrelation analysis on PPCPs concentration,the total concentration of PPCPs as well as the conventional indicators of water samples.The results show,COD,total nitrogen,total phosphorus and PPCPs present significant positive correlation;PH,DO and some PPCPs have a significant negative correlation.D6 concentration and the total concentration of PPCPs show significant positive correlation and good linear relationship,which illustrates that D6 has certain representativeness and typicality among the 13 PPCPs.In order to further explore the law of migration and degradation of the PPCPs in sewage pipelines,the thesis constructs three sewage pipeline reactors and chooses D6 as the typical target substance to explore the law of distribution and migration of the typical PPCPs compounds in sewage pipelines.The experimental results show,HRT=12 hours of sewage pipeline has a certain removal effect on high concentration of D6,the removal rate is 57%.The absorption are the main migration means of D6 in sewage pipeline.The adsorption process has a good fitting effect with the pseudo first order kinetic model.Moreover,the absorption process of sediment on D6 and pseudo-second-order have a relatively good fitting effect.