Metabolic and kinetic changes of activated sludge because of failures in the aeration system in a WWTP

The classic question from wastewater treatment plant (WWTP) operators is, how long can a secondary reactor be kept unaerated after an aeration system failure? Therefore, in the present research, samples of activated sludge (AS) were taken WWTP and left without for 12, 18, 24, 36 h; simulating failure. Subsequently, activity AS lacking was evaluated batch cultures. results showed that lack oxygenation affected its metabolism. For example, heterotrophic stopped completely when not aerated 24 h. nitrifying activity, experiments 12 to h aeration, ammonium removal did change, but there increase nitrite concentration. In 36-h experiment consumption rate efficiency decreased by 56% 43%, respectively, regarding control. N2O produced period aerated, which could responsible these metabolic kinetic changes. Finally, this study suggested don't leave more than quick recovery or diminish damage.