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FINE PORE DIFFUSER SYSTEM EVALUATION FOR THE GREEN BAY METROPOLITAN SEWERAGE DISTRICT
Citation:
Marx, J. J. FINE PORE DIFFUSER SYSTEM EVALUATION FOR THE GREEN BAY METROPOLITAN SEWERAGE DISTRICT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-94/093 (NTIS 94-200813), 1994.
Impact/Purpose:
Information.
Description:
The Green Bay Metropolitan Sewerage District retrofitted two quadrants of their activated sludge aeration system with ceramic and membrane fine pore diffusers to provide savings in energy usage compared to the sparged turbine aerators originally installed. Because significant diffuser fouling was expected, the two diffuser types were closely monitored over an 18-month period. The oxygen transfer efficiencies of the full-scale systems were measured using off-gas techniques. The effects of diffuser fouling and the effectiveness of cleaning procedures were evaluated in the laboratory using dynamic wet pressure and steady-state clean water oxygen transfer tests. Although fouling was significant on both types of diffusers, cost-effective cleaning procedures were developed. The ceramic disc diffusers provided better long-term performance than the membrane tube diffusers, which irreversibly lost oxygen transfer efficiency with time in use. Collectively, the fine pore diffuser systems provided a 30% savings in electrical power usage compared to the original sparged turbine aerators. This report was submitted in partial fulfillment of Cooperative Agreement No. CR812167 by the American Society of Civil Engineers under subcontract to Rusk Environment and Infrastructure, Inc. (formerly Donohue and Associates, Inc.) under the partial sponsorship of the U.S. Environmental Protection Agency. The work reported herein was conducted over the period of 1986-1987. Project summary may be ordered as EPA/600/S-94/001).