Breaking the limits of continuous operation: Energy‐efficient methane production in iron–carbon MEC ‐ AD via short‐term electrochemical input

The current study was conducted to anaerobically digest swine manure wastewater using iron carbon as the electrode and three types of short‐time on‐load voltages, namely, 0.6, 0.9, and 1.2 V, in order to solve the challenging problem of microbial electrolysis cell (MEC) to improve the efficiency of anaerobic digestion (AD) but with high energy consumption. According to the results, the short‐time energized MEC‐AD significantly increased the hydrolysis and acidification efficiency of swine manure wastewater, shortened the anaerobic digestion cycle, and effectively increased methane production. It also realized the system's positive energy gain and showed a stronger ability for anaerobic digestion to self‐regulate. In addition to enriching the electroproducing microbes Clostridium_sensu_stricto_1 and the common methanogenic bacterium Methanosarcina , the short‐time energized treatment group at 0.9 V also exhibited the maximum energy gain and methane production. The short‐time energization approach provided a new avenue for the energy exploitation of swine manure wastewater with high efficiency and low energy consumption, and it significantly reduced energy consumption compared to continuous energization.