Modelling Phenol Degradation Under Saline Conditions by AnMBR Biomass

Abstract

This study is part of a project titled: “Phenolic compounds degradation in AnMBR under mesophilic and thermophilic operation: BioXtreme-following up”.
Phenol is a toxic contaminant found widely in industrial effluents. It is toxic to humans and animals even at very low concentrations. Anaerobic digestion uses phenol as a carbon source and then to degrade it to non-toxic products for lower costs. Industrial effluents are also likely to have high concentrations of salinity which causes inhibition at high concentrations. Anaerobic membrane bioreactors are an attractive method as it enables biomass retention for biomass. The aim of this study is to understand the effect of Na+ concentration in a batch phenol degradation by phenol adapted mesophilic AnMBR biomass. NaCl concentration ranging from 0-90 g/L were tested on adapted AnMBR biomass. COD, phenol degradation, particle size distribution and methane production of adapted AnMBR biomass were analysed. The results from the batch test were used to model kinetic parameters. The biomass was acclimatized to 30 g/L of NaCl in AnMBR. Phenol removal of 98% was observed at 30 g/LNaCl and it decreased further with elevated salinity. Similarly, biogas production was also highest for 30g/L NaCl and decreased further with higher NaCl concentration. The highest value for SMA of 0.10 ± 0 gCOD-CH4.gVSS-1 d -1 was observed for 30g/L. However, the data did not indicate a specific trend with increasing salinity and showed high variability. The data showed poor fit to both Haldane and Monod growth model as these models were used for substrate inhibition. Modelling with modified Gompertz equation also failed to yield any conclusive results.