Maximizing anammox in mainstream wastewater treatment: An integrated nitrite producing approach

The discovery of anaerobic ammonium oxidation (anammox) opens a new window for turning the energy -intensive mainstream municipal wastewater treatment into energy self-sufficient or even energy-positive. Currently, anammox processes are mainly performed based on partial nitrification (PN) providing nitrite, while it highly depends on the operating conditions as well as strictly process control for the continuous sup-pression of nitrite-oxidizing bacteria (NOB). Partial denitrification (PD), the reduction of nitrate to nitrite, was recently demonstrated to be another pathway of nitrite production for anammox with strong robustness, high efficiency, and easy control. As such, a roadmap aiming to maximize anammox in mainstream wastewater treatment is outlined by integrated nitrite production via PN and PD approaches. Since organic carbon is needed to drive PD, the roadmap based on external carbon dosing, utilizing complex organic carbon from municipal wastewater, and sludge anaerobic fermented liquid is illustrated, with a critical analysis of their economy, ef-ficiency, and effectiveness in practical application. The presented roadmap is easy to implement without the requirement of strictly controlled PN. Moreover, a high effluent quality can be guaranteed with great engineering feasibility. Overall, this article offers a new avenue in going for mainstream nitrogen removal with maximizing anammox contribution, which will indeed facilitate the achievement of sustainable municipal wastewater treatment.

Automated summary

The discovery of anaerobic ammonium oxidation (anammox) offers a new opportunity for energy self-sufficiency in mainstream municipal wastewater treatment. Anammox processes can be enhanced by integrated nitrite production via partial nitrification (PN) and partial denitrification (PD). This article presents a roadmap for maximizing anammox in mainstream wastewater treatment by utilizing external carbon dosing and evaluating their economy, efficiency, and effectiveness.