Recovering nutrients and unblocking the cake layer of an electrochemical anaerobic membrane bioreactor

Abstract

Abstract The sustainable development strategy shifts water treatment from pollution removal to resource recovery. Here, an electrochemical resource-recovery anaerobic membrane bioreactor (eRAnMBR) that employed a magnesium plate and conductive membrane as dual anodes is presented and shows excellent performance in carbon, nitrogen, and phosphorus recovery, as well as 95% membrane anti-fouling. The Mg2+ released alters the physicochemical properties of sludge, unblocking the cake layer, and recovers ammonium and phosphate, yielding 60.64% purity and 0.08 g d−1 struvite deposited onto cathode to be separated from sludge. The enhanced direct interspecies electron transfer, along with hydrogen evolution and alkalinity increase due to the electrochemical reactions, significantly increase methane yield and purity (93.97%) of the eRAnMBR. This increased internal energy can cover the additional electricity and electrode consumption. This integrated eRAnMBR reactor boasts the benefits of short process, low maintenance, and low carbon footprint, introducing a concept for the next generation of wastewater treatment.