Effects of nanoscale zero-valent iron particles on biological nitrogen and phosphorus removal and microorganisms in activated sludge

Abstract The use of nanoscale zero-valent iron (NZVI) particles in environmental remediation and wastewater treatment has recently increased. The effects of NZVI on nitrogen and phosphorus removal were examined under continuous aerobic/anaerobic conditions by employing activated sludge. NZVI did not display any measurable effect on nitrogen removal at the concentration of 50 mg/L and below. However, 200 mg/L of NZVI inhibited NH 4 + -N removal. The addition of NZVI at 20 mg/L and above significantly ( p