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Novel application of oxygen‐transferring membranes to improve anaerobic wastewater treatment
Author(s) -
Kappell Anthony S.,
Semmens Michael J.,
Novak Paige J.,
LaPara Timothy M.
Publication year - 2005
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20219
Subject(s) - bioreactor , aeration , chemical oxygen demand , effluent , wastewater , membrane bioreactor , pulp and paper industry , anaerobic exercise , chemistry , sewage treatment , pollutant , environmental engineering , environmental science , biology , physiology , organic chemistry , engineering
Anaerobic biological wastewater treatment has numerous advantages over conventional aerobic processes; anaerobic biotechnologies, however, still have a reputation for low‐quality effluents and operational instabilities. In this study, anaerobic bioreactors were augmented with an oxygen‐transferring membrane to improve treatment performance. Two anaerobic bioreactors were fed a synthetic high‐strength wastewater (chemical oxygen demand, or COD, of 11,000 mg l −1 ) and concurrently operated until biomass concentrations and effluent quality stabilized. Membrane aeration was then initiated in one of these bioreactors, leading to substantially improved COD removal efficiency (>95%) compared to the unaerated control bioreactor (∼65%). The membrane‐augmented anaerobic bioreactor required substantially less base addition to maintain circumneutral pH and exhibited 75% lower volatile fatty acid concentrations compared to the unaerated control bioreactor. The membrane‐aerated bioreactor, however, failed to improve nitrogenous removal efficiency and produced 80% less biogas than the control bioreactor. A third membrane‐augmented anaerobic bioreactor was operated to investigate the impact of start‐up procedure on nitrogenous pollutant removal. In this bioreactor, excellent COD (>90%) and nitrogenous (>95%) pollutant removal efficiencies were observed at an intermediate COD concentration (5,500 mg l −1 ). Once the organic content of the influent wastewater was increased to full strength (COD = 11,000 mg l −1 ), however, nitrogenous pollutant removal stopped. This research demonstrates that partial aeration of anaerobic bioreactors using oxygen‐transferring membranes is a novel approach to improve treatment performance. Additional research, however, is needed to optimize membrane surface area versus the organic loading rate to achieve the desired effluent quality. © 2005 Wiley Periodicals, Inc.