A Novel Water Reclamation Plant Configuration for Enhanced Energy Efficiency and Removal of CEC

Presentation Description: Indirect potable reuse (IPR) is increasingly popular for communities to expand their water sources. It, however, requires advanced water treatment, often including microfiltration (MF) or ultrafiltration (UF), followed by reverse osmosis (RO) and advanced oxidation with ultraviolet radiation and hydrogen peroxide addition (UV/AOP). These processes are usually installed downstream of an existing secondary or tertiary wastewater treatment plant. While this method effectively produces high-quality product water, it more than doubles the treatment plant's electrical energy use, and chemicals of emerging concern (CECs) become concentrated in the RO concentrate stream, which is typically returned to the environment rather than permanently removed. A new process configuration incorporating UF, RO, and microbial fuel cell (MFC) as key components is expected to cut overall energy consumption while reducing the release of harmful compounds. The feasibility of this setup was tested through piloting at San Jacinto Valley Regional Water Reclamation Facility (SJVRWRF). The main goal was to operate the pilot on primary effluent and generate a product suitable for indirect potable reuse without relying on an activated sludge process, thus lowering energy needs. Another objective was to show that the MFC can run continuously and help lower the high concentration of dissolved organic matter in the RO concentrate, along with removing some CECs, including per- and polyfluoroalkyl substances (PFAS) compounds. The pilot was successful, with all three units operating steadily and the product water showing very low total dissolved solids (TDS) ( < 40 mg/L), chemical oxygen demand (COD) ( < 12 mg/L), total suspended solids (TSS) ( < 3 mg/L), ammonia ( < 5 mg/L), and total phosphorus ( < 0.05 mg/L). The MFC worked very well, significantly reducing conventional pollutants (BOD5 – 77%, COD – 50%, ammonia - 28%, phosphorus - 40%) and CECs (30–45%, including perfluorooctane sulfonate (PFOS) removal of 39%).