The impacts of silver nanoparticles and silver ions on wastewater biological phosphorous removal and the mechanisms

► Effects of nano and ionic Ag on biological P removal have never been reported. ► The presence of either AgNPs or Ag+ did not cause cell leakage and membrane damage. ► Ag+ had serious inhibition on P removal, while AgNPs showed no adverse effects. ► The enhanced ROS production caused the decrease of enzymes related to P removal. ► The decreased P removal was also caused by the suppressed energy generation.