Anaerobic fluidized membrane bioreactors with low strength wastewater: A long-term study on the impact of conductive polyaniline modified fluidized biocarrier on biomethane production

Abstract

Polyaniline (PANI) is used as a coating material to create a conductive surface on polyvinylidene fluoride (PVDF) substrate. This was implemented as a biocarrier in an anaerobic fluidized membrane bioreactor (AFMBR) to treat low-strength wastewater consisting of glucose. The results of parallel operation using AFMBRs indicate that the fouling rate was invariably similar in both AFMBR 1 and AFMBR 2 throughout the operation of 400 days for uncoated and PANI coated PVDF pellet as substrate, respectively. The conductive coating in AFMBR 2 enhanced the electron transfer between organic matter and microbes. The AFMBR 2 with PANI-PVDF biocarrier exhibited a methane yield that was 62 % more per gram soluble chemical oxygen demand (SCOD) removed at 12 h HRT than its uncoated counterpart in AFMBR 1. The results of the surface analysis of the biocarrier indicated the enhanced biomass attachment on the conductive surface owing to the roughness (which is 1.6 times more) created by PANI coating over PVDF supporting material. The findings of our study indicate that the utilization of conductive polymeric-based biocarrier has the potential to significantly enhance the kinetics of AFMBR during the treatment of low-strength wastewater.