Life cycle costing of AnMBR technology for urban wastewater treatment: A case study based on a demo-scale AnMBR system

Abstract

This study aims at assessing the economic performance of a projected full-scale anaerobic membrane bioreactor (AnMBR) for urban wastewater (UWW) treatment at ambient temperature. To this aim, data from an AnMBR demonstration plant (industrial prototype, TRL 6) was used, which was operated for 3 years treating real UWW, allowing gathering a robust set of information for scaling-up to full scale. The obtained results revealed that reactor mixing (0.056–0.124 kWh·kgCODrem-1; 34–57%), and membrane scouring (0.048–0.120 kWh·kgCODrem-1; 22–48%) were the main contributors to the total energy demand; while net energy productions between 0.210 and 0.645 kWh·kgCODrem-1 were achieved. Capital expenditure was highly influenced by UF membranes (€0.029–0.073 kgCODrem-1; 31–49%), combined heat and power technology for energy recovery (€0.012–0.023 kgCODrem-1; 8–24%), and reactor construction (€0.07–0.014 kgCODrem-1; 8–13%); while the main contributors to operating expenditure were energy requirements (€0.042–0.069 kgCODrem-1; 41–46%), membrane replacement (€0.011–0.028 kgCODrem-1; 9–17%), and discharge fee (€0.010–0.020 kgCODrem-1; 9–12%). Total annualized costs showed high variability, between €− 0.003 and 0.188 kgCODrem-1. Results presents AnMBR as a competitive technology for UWW treatment compared to conventional aerobic technologies (e.g., CAS). Membrane fouling control; hydraulic retention time; biogas requirements for reactor mixing and membrane stirring; and energy recovery efficiency were identified as key parameters for improving economic sustainability of AnMBR technology.