Targeted pressure-based development of membrane biofilms improves anaerobic membrane bioreactor effluent quality

Abstract

Treated wastewater has been addressed as an alternative water resource to a great extent lately because of major water scarcity faced worldwide. Among wastewater treatment technologies envisaged, anaerobic membrane bioreactors (AnMBRs) have demonstrated considerable benefits for high quality effluent and energy recovery. Recent developments in the understanding of membrane biofilms in anaerobic membrane bioreactors (AnMBRs) indicate additional advantages to their known benefits as an emerging technology. In addition to high COD removal, increased biogas production, and lower energy costs, AnMBRs have been found to play a key role in the degradation of emerging contaminants. The present work aimed to determine the effect of combining different membrane biofilm development conditions in an AnMBR on effluent quality, trimethoprim removal, antibiotic resistance gene (ARG) proliferation, and effluent methane concentrations. Membrane biofilms were initially developed at target fluxes of 13, 7, and 3 L m⁻² h⁻¹, then operated at the same flux of 5 L m⁻² h⁻¹ for performance comparison. Improved effluent parameters were observed for the membrane on which the biofilm was initially developed at high TMP (7 psi). After reduction of flux, lower TMP was sustained for the same membrane while higher COD and trimethoprim removals were also observed. 16S rRNA gene-based analysis of membrane biofilm communities indicated a likely direct influence on the effluent quality. This study highlights a new approach for controlled membrane biofilm development and subsequent operation that can potentially promote better water quality and enhanced emerging contaminant removal.