Integrating electrochemical and biological phosphorus removal processes via electrokinetic-based technology

Abstract

Excessive phosphorus levels in aquatic environments create harmful algal bloom that produces cultural eutrophication and poor water quality. The phosphorus removal from municipal wastewater treatment plants (WWTPs) is required to control this undesirable phenomenon. Removing nutrients from influent wastewater necessitates the construction of various operating units to provide different conditions (i.e., anoxic and aerobic) to promote the removal efficiency of each single-nutrient compound. Unfortunately, such designs have a high energy consumption rate and leave a big carbon footprint. The present work investigates the possibility of simultaneous electrochemical and biological phosphorus removal in a single reactor. A bench-scale electro-bioreactor was fed synthetic wastewater containing phosphorus ranging from 14 to 18 mg PO4−P/L. At steady-state conditions, the phosphorus removal efficiency (PO4−P) reached over 99%. Furthermore, a single membrane electro-bioreactor (MEBR) created anoxic and aerobic conditions suitable for polyphosphate-accumulating organisms (PAOs) growth. The operation of electrocoagulation inside MEBR also generated Al3+ due to the electrolytic dissolution of aluminum anode, increasing the system’s electrochemical phosphorus removal. Therefore, findings suggest that such a high percentage of phosphorus removal was due to both the electrocoagulation process and proliferation of PAOs in the reactor. The developed MEBR is particularly suitable for small-scale plants for various applications, including mining, remote and rural communities, settlements, and temporary (e.g., exploration or military).