Performance of submerged anaerobic membrane bioreactor for thermomechanical pulping wastewater treatment

A hollow fiber submerged anaerobic membrane bioreactor (SAnMBR) was operated for 160 days for thermo-mechanical pulping pressate treatment. A COD removal efficiency of 83 ± 4% was achieved under all tested conditions, although the residual COD in permeate increased slightly with an increase in influent COD. The biogas yield slightly decreased with a higher feed concentration. The EPS production increased with an increase in organic loading rate. Membrane performance was affected by both the influent COD concentration and biogas sparging rate. The fouling layer samples were characterized using various analytical tools. The results suggest that it is feasible and attractive to treat thermomechanical pulping wastewater by a hollow fiber SAnMBR. Cake layer formation was the dominant mechanism of membrane fouling. An increase in biogas sparging rate actively mitigated the accumulation and deposition of sludge on/in membrane module, thus favored the enhancement of membrane flux and an efficient long-term operation.