Unravelling the economics behind mainstream anaerobic membrane bioreactor application under different plant layouts

This research evaluated the economic feasibility of anaerobic membrane bioreactor (AnMBR) as a mainstream technology for municipal sewage treatment. To this end, different wastewater treatment plant (WWTP) layouts were considered, including primary settler, AnMBR, degassing membrane, partial nitritation-Anammox, phosphorus precipitation and sidestream anaerobic digestion. The net treatment cost of an AnMBR-WWTP decreased from 0.42 to 0.35 ¿ m-3 as the sewage COD concentration increased from 100 to 1100 mg COD L-1 due to revenue from electricity production. However, the net treatment cost increased above 0.51 ¿ m-3 when nutrient removal technologies were included. The AnMBR and partial nitritation-Anammox were the costliest processes representing a 57.6 and 30.3% of the treatment cost, respectively. Energy self-sufficiency was achieved for high-strength municipal sewage treatment (1000 mg COD L-1) and a COD:SO42--S ratio above 40. Overall, the results showed that mainstream AnMBR has potential to be an economically competitive option for full-scale implementation