Performance of anaerobic membrane bioreactor during digestion and thickening of aerobic membrane bioreactor excess sludge

• Published in: Bioresource technology Vol. 218; pp. 476 - 479
• Main Authors: Hafuka, Akira, Mimura, Kazuhisa, Ding, Qing, Yamamura, Hiroshi, Satoh, Hisashi, Watanabe, Yoshimasa
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2016
• Subjects: Anaerobic digestion; Anaerobiosis; Biofuels; Biological Oxygen Demand Analysis; Bioreactors; Biotechnology - methods; Excess sludge; Filtration; Gases; Hydrolysis; Membrane filtration; Membranes, Artificial; Microfiltration; Sewage - chemistry; Tubular PTFE membrane module; Microfiltration; Excess sludge; Tubular PTFE membrane module; Anaerobic digestion; Membrane filtration
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.06.124

•Anaerobic membrane bioreactor was applied to the treatment of excess sludge.•Sludge was thickened and digested without membrane cleaning for 90days.•A high COD removal efficiency of 98% was achieved. In this study, we evaluated the performance of an anaerobic membrane bioreactor in terms of digestion and thickening of excess sludge from an aerobic membrane bioreactor. A digestion reactor equipped with an external polytetrafluoroethylene tubular microfiltration membrane module was operated in semi-batch mode. Solids were concentrated by repeated membrane filtration and sludge feeding, and their concentration reached 25,400mg/L after 92d. A high chemical oxygen demand (COD) removal efficiency, i.e., 98%, was achieved during operation. A hydraulic retention time of 34d and a pulse organic loading rate of 2200mg-COD/(L-reactor) gave a biogas production rate and biogas yield of 1.33L/(reactor d) and 0.08L/g-CODinput, respectively. The external membrane unit worked well without membrane cleaning for 90d. The transmembrane pressure reached 25kPa and the filtration flux decreased by 80% because of membrane fouling after operation for 90d.