Towards advanced nitrogen removal and optimal energy recovery from leachate: A critical review of anammox-based processes

Abstract

Anaerobic ammonium oxidation (anammox), a promising technology for bio-nitrogen removal, has been a research hotspot in the field of leachate treatment. However, the inhibitory effect of organic matter and high-strength nitrogen on anammox bacteria and the limitation of the theoretical total nitrogen removal efficiency of anammox (<90%) are obstacles to its wider application. The mechanisms of the inhibitory effects of organic matter, ammonium, and nitrite on anammox bacteria, and the corresponding control strategies are summaries. The anammox-based processes developed for advanced nitrogen removal (ANR) in recent years, including anammox-based heterotrophic denitrification, anammox-based partial denitrification, and anammox-based constructed wetlands are systematically discussed. An integrated anaerobic system of simultaneous denitrification and methanogenesis (anaerobic membrane bioreactor) + anammox-based processes was proposed for the ANR and optimal energy recovery from leachate. This process showed a 16% increase in biogas yield, a 64% decrease in aeration energy consumption, and the decrease in the external carbon source is expected to be 100% compared to conventional leachate treatment processes such as anoxic/oxic-membrane bioreactors. Finally, a few research perspectives on leachate treatment using anammox-based processes are reviewed. The conclusions drawn from the studies presented herein provide guidance for further research and engineering applications in the field of leachate treatment.

Highlights

• AnMBR pretreatment is proposed for energy recovery and elimination of inhibition of anammox bacteria by organics.

• Anammox-based heterotrophic denitrification, partial denitrification, and anammox-based constructed wetlands are discussed for ANR.

• SDM is proposed for ANR from leachate via anammox effluent recirculation.

• An SDM(AnMBR)+anammox based process is proposed for energy saving and recovery.

Graphical Abstract

Keywords:

• Leachate
• advanced nitrogen removal
• anammox
• heterotrophic denitrification
• partial denitrification
• simultaneous denitrification and methanogenesis (SDM)