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OXYGEN TRANSFER STUDIES AT THE MADISON METROPOLITAN SEWERAGE DISTRICT FACILITIES
Citation:
Boyle, W. C., A. Craven, W. Danley, AND M. Rieth. OXYGEN TRANSFER STUDIES AT THE MADISON METROPOLITAN SEWERAGE DISTRICT FACILITIES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-94/096 (NTIS 94-200847), 1994.
Impact/Purpose:
Information.
Description:
Field studies at the Madison Metropolitan Sewerage District facilities were conducted over a 3-year period to obtain long-term data on the performance of fine pore aeration equipment in municipal wastewater. The studies were conducted on several basins in the East Plant containing ceramic domes installed in 1977 and two sets of first-pass basins in the West Plant with newly installed ceramic discs. The performance of the domes was excellent even after 10 years of service. This conclusion was based on measured oxygen transfer efficiencies by off-gas analysis, alpha calculations, and diffuser characterization. Reasons for excellent performance included routine maintenance of the diffusers and the use of high quality ceramic diffusers and hardware. There was evidence presented in this plant that operation at high SRTs (low F/M loadings), which produced complete nitrification, resulted in higher aSOTE values than operation at low SRTs. Studies on the impact of diffuser cleaning and hydraulic flow patterns on performance were also reported. The ceramic discs in the West Plant were monitored for 800 days. In this period of time, no perceptible decrease in diffuser performance was observed based on aSOTE measurements. The mean first-pass (aSOTE values over 800 days was about ll.S%. The mean-weighted aSOTE for all three passes ranged from 12.1 to 15.3%. The West Plant aeration system was operated at high SRT values in order to achieve complete nitrification. As seen in the East Plant, there was some evidence of improved aeration performance (aSOTE) with increased SRT. Brief evaluations of diffusers in these low loaded basins suggested that fouling was not a problem in this plant. This report was submitted in partial fulfillment of Cooperative Agreement No. CR812167 by the American society of civil Engineers under subcontract to the university of Wisconsin under the partial sponsorship of the U.S. Environmental Protection Agency. The work reported herein was conducted over the period of 1985-1987. Project summary may be ordered as EPA/600/S-94/001).