苏南太湖流域农村污水PFASs现状及分散式处理设施去除效能

以常州市武进区洛阳镇6座分散式农村污水处理设施为研究对象,分别采集了处理设施总进水、总出水及湿地土壤,共检测出样品中11种PFCAs(全氟羟酸类物质C4?C14)和4种PFSAs(全氟磺酸类物质C4、C6、C8、C10)及MeFOSA(N-甲基全氟辛基磺酰胺)、EtFOSA(N-乙基全氟辛基磺酰胺)、MeFOSE(N-...

Status of PFASs in rural sewage from the Taihu Basin in southern Jiangsu and their removal efficiency in decentralized treatment facilities

In this study, six decentralized rural sewage treatment facilities in Luoyang Town, Wujin District, Changzhou City were used as the research objects. The total inlet water, total outflow water and wetland soils from six dispersed rural sewage treatment facilities were sampled. And the mass concentrations of 11 PFCAs (perfluorohydroxyl acid substances, C₄-C₁₄), 4 PFSAs (perfluorosulfonic acid substances, C₄, C₆, C₈, and C₁₀),MeFOSA (n-methyl perfluorooctyl sulfonamide), EtFOSA (n-ethyl perfluorooctyl sulfonamide), MeFOSE (n-methyl perfluorooctyl sulfonamide)and other PFOS(perfluorooctane sulfonic acid)precursors were detected in these samples. The results showed that the detection rates of 6 PFCAs and 3 PFSAs in the influent water of 6 sewage treatment facilities were over 83.33%. In PFSAs, PFOS (perfluorooctane sulfonic acid) had the highest concentration, and the concentration range was from N.D. to 79.89 ng/L. In PFCAs, PFOA (perfluorooctanoic acid) had the highest concentration, and the concentration range was from 3.87 to 8.60 ng/L. The concentration characteristics of perfluorinated and polyfluorinated compounds (PFASs) in three different wastewater collection methods was: rainwater and sewage confluence and enterprise drainage > rain and sewage diversion > rainwater and sewage confluence. In the process of A/O contact oxidation and the multistage A/O process, the total concentration of PFASs in the outlet water was higher than that in the inlet water. So these two processes had no removal effect on PFASs. But A/O-MBR process had good removal effect on the medium-chain PFASs, and the removal rate was 81.27%.The removal of PFOS was the most obvious,the concentration of PFOS decreased from 64.45 to 15.41 ng/L, and the removal rate was about 74.90%. However, the process had no obvious removal on the short-chain PFASs. Constructed wetlands also had good removal effect on the medium-chain PFASs. And PFOS in outlet water of wetlands could be reduced from 15.41 ng/L to below the detection limit. The short-chain PFASs had low adsorption potential and hydrophobicity, which made it easier to exist in the liquid phase rather than in the solid phase,so that several processes have no obvious removal effect on them, even the concentration of effluent water is higher than that of inflow water.