“The changes of microbial reactive oxygen species production, … activity and superoxide dismutase activity demonstrated that Cu(II) at 10 and 30 mg/L broke the equilibrium between the oxidation and … cells and also damaged the cytomembrance integrity, which could affect the COD and nitrogen removal performance and … cell morphology.”
“The inhibitory effects of Cu(II) at 10 and 30 mg/L on the nitrogen removal rate, OUR, and microbial enzymatic activity of SBR increased with an increment in operation time due to the Cu(II) biotoxicity and the Cu(II) accumulation in activated sludge.”