Reversible and irreversible inhibition of metabolic activity in biological phosphorus removal systems

Biological phosphorus removal was inhibited to varying degrees by short-term exposure to copper, cyanide and phenol. Anaerobic phosphorus release was either unaffected or stimulated in the presence of inhibitory agents. Both copper and cyanide severely inhibited aerobic phosphorus uptake. Inhibitory metabolic effects associated with cyanide could be reversed by removing the compound from solution. Copper-induced inhibition could not be reversed by simple washing, even after prolonged aeration. Short-term exposure to phenol, at concentrations up to 150 mg l-1, had relatively little effect on the phosphorus accumulating cultures.