Brewery wastewater treatment using MBR coupled with nanofiltration or electrodialysis: biomass acclimation and treatment efficiency

Breweries release significant amounts of wastewater loaded with various organic and mineral materials. Prior studies of membrane bioreactor (MBR) wastewater treatment have been conducted with very little interest granted to the conditions of biomass acclimation. This study displays biomass behavior during brewery wastewater treatment by an aerobic MBR. In addition, nanofiltration and electrodialysis have been studied as potential post-treatment to decrease mineral concentrations and permit further water reuse for agriculture. An anoxic/aerobic laboratory MBR, associated with a flat sulfonated polyether membrane was used for synthetic brewery wastewater treatment. Biomass acclimation was performed using a feeding substrate. Organic concentrations in the MBR influent varied from 700 mg COD/L to 10,600 mg COD/L (COD: chemical oxygen demand) for 110 days. The results indicate a good acclimation to effluent with high salts and organic matter loads. Steady evolution of biomass concentration and activities was achieved after 90 days of operation. A reduction of COD of around 95% was obtained with MBR and up to 99% with nanofiltration post-treatment for the reconstructed brewery effluent with an organic loading rate of 7 g COD/L·d and a solid and hydraulic retention time of 30 days and 36 hours. A good reduction of the salt content was also recorded primarily with the nanofiltration and electrodialysis processes.