Unlocking the performance of anammox-coupled technologies for sustainable treatment of nitrogenous wastewater

Abstract

Wastewater from industries, municipalities, or the agricultural sector contains huge amounts of nitrogenous substances, causing serious risks to the immediate locality and public health. Anammox technology is recognized as a preferred option for treating nitrogenous wastewater due to its sustainability, cost-effectiveness, and eco-friendliness. In addition, this technique is characterized by the absence of organic carbon, lower sludge production, reduced energy consumption and greenhouse gas emissions, and high nitrogen removal efficiency. However, the efficacy of the wastewater treatment process is deterred by the presence of inhibitory pollutants, including microplastics, heavy metals, and antibiotics. Consequently, the coupling of anammox with other biological wastewater treatment processes, including partial nitrification (PN), partial denitrification (PD), simultaneous partial nitrification anammox and denitrification (SNAD), constructed wetlands (CWs), microbial electrolysis cells (MECs), and microbial fuel cells (MFCs), offers an effective approach to sustainable and improved nitrogen removal from wastewater. The addition of biochar, zeolite, graphene, metal ions, and hydrazine in the culture medium promotes anammox bacterial growth and catalytic activity, as well as pollutant removal efficiency. Therefore, this review provides insights into various anammox-coupled biological technologies for the efficient treatment of nitrogenous wastewater and elucidates strategies to optimize anammox performance. Some challenges that impede anammox activity, along with their respective antidotes, are also highlighted.