The joint inhibitory effects of phenol, copper (II), oxytetracycline (OTC) and sulfide on Anammox activity

A batch test was employed to analyze the joint toxicity of copper (II) and oxytetracycline (OTC), OTC and sulfide, phenol and sulfide (S2−), phenol and copper (II), and OTC, copper (II) and substrate on an Anammox mixed culture. The joint toxicity of OTC and copper (II) on the Anammox mixed culture was antagonistic, whereas the interaction between OTC and S2− and between phenol and S2− was generally synergistic. The joint toxicity of phenol and copper (II) was dependent on the level of phenol: the joint toxicity was antagonistic at a high phenol level of 300 mg L−1, whereas the joint toxicity was synergistic at a low phenol level of 75 mg L−1. The joint toxic effect of OTC, copper (II) and NO2−–N on the Anammox activity can be ranked in the following order: NO2−–N > copper (II) > OTC.

► The combination of two or three factors had varying effects on the Anammox activity.
► The joint toxicity of OTC and copper (II) on the Anammox activity was antagonistic.
► The toxicity of the combinations of OTC and S2− or of phenol and S2− was synergistic.
► The joint toxicity of phenol and copper (II) was dependent on the level of phenol.
► The activity inhibition can be ranked in the order: NO2−–N > copper (II) > OTC.