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This study reports an investigation of the concept, application and performance of a novel bioelectrochemical nitritation-anammox microbial desalination cell (MDC) for resource-efficient wastewater treatment and desalination. Two configurations of anammox MDCs (anaerobic-anammox cathode MDC (AnA_moxMDC) and nitration-anammox cathode MDC (NiA_moxMDC)) were compared with an air cathode MDC (CMDC), operated in fed-batch mode. Results from this study showed that the maximum power density produced by NiA_moxMDC (1,007 mW/m³) was higher than that of AnA_moxMDC (444 mW/m³) and CMDC (952 mW/m³). More than 92% of ammonium-nitrogen (NH₄⁺-N) removal was achieved in NiA_moxMDC, significantly higher than AnA_moxMDC (84%) and CMDC (77%). The NiA_moxMDC performed better than CMDC and AnA_moxMDC in terms of power density, COD removal and salt removal in desalination chamber. In addition, cyclic voltammetry analysis of anammox cathode showed a redox peak centered at −140 mV Vs Ag/AgCl confirming the catalytic activity of anammox bacteria towards the electron transfer process. Further, net energy balance of the NiA_moxMDC was the highest (NiA_moxMDC-0.022 kWh/m³>CMDC-0.019 kWh/m³>AnA_moxMDC-0.021 kWh/m³) among the three configurations. This study demonstrated, for the first time, a N-E-W synergy for resource-efficient wastewater treatment using nitritation-anammox process.

 

Current wastewater treatment processes such as activated sludge process and other aeration technologies are resourceconsuming and are unsustainable. Novel and integrated processes are crucial to the development of sustainable wastewater treatment systems. In this context, anaerobic treatment technologies provide numerous opportunities for minimization of energy and resource consumption and maximization of beneficial products. Further, integration of anaerobic digestion augmented by co-digestion, fermentation, dark fermentation or photo-fermentation and other bioelectrochemical systems may result in resource-efficient waste management and environmental protection. This mini-review discusses various possibilities and highlights recent developments of integrated aerobic and anaerobic technologies with bioelectrochemical systems for sustainable wastewater treatment.