Abstract: The use of an inorganic azide compound as an inhibitor for a wastewater treatment bacterial additive composition. The inorganic azide compounds used in the invention serve to confer a useful life for the bacterial additive composition, yet a relatively short reactivation time which is of great advantage in wastewater treatment systems with short detention times. The inorganic azide compounds employed as an inhibitor in the bacterial composition additives of the invention include alkali metal azides, alkaline earth metal azides, lead azide and hydrazoic acid.