Effects of single and combined copper/perfluorooctane sulfonate on sequencing batch reactor process and microbial community in activated sludge.

•Cu and Cu/PFOS exposure reduced COD, NH4+-N, TN and TP removal in SBR process.•PFOS exposure deteriorated settleability of sludge due to abundant EPS produced.•Cu and Cu/PFOS posed more adverse impacts on microbial activity than single PFOS.•Cu and PFOS affected the structure and component of microbial community in sludge.•Antagonistic effect, rather than synergistic effect of toxicity existed in Cu/PFOS.