Effect of sparging rate on permeate quality in a submerged anaerobic membrane bioreactor (SAMBR) treating leachate from the organic fraction of municipal solid waste (OFMSW)

• High-strength wastewater was treated in an anaerobic membrane bioreactor.
• More than 90% COD can be removed at 5 days HRT.
• Reducing the sparging rate to 2 LPM caused the bulk COD to increase.
• The permeate COD remain constant when the sparging rate was reduced to 2 LPM.
• The permeate COD increased when the sparging rate was changed to 10 LPM.

This paper focuses on the treatment of leachate from the organic fraction of municipal solid waste (OFMSW) in a submerged anaerobic membrane bioreactor (SAMBR). Operation of the SAMBR for this type of high strength wastewater was shown to be feasible at 5 days hydraulic retention time (HRT), 10 L min−1 (LPM) biogas sparging rate and membrane fluxes in the range of 3–7 L m−2 hr−1 (LMH). Under these conditions, more than 90% COD removal was achieved during 4 months of operation without chemical cleaning the membrane. When the sparging rate was reduced to 2 LPM, the transmembrane pressure increased dramatically and the bulk soluble COD concentration increased due to a thicker fouling layer, while permeate soluble COD remained constant. Permeate soluble COD concentration increased by 20% when the sparging rate increased to 10 LPM.