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WAS Thickening Using Ultra-filtration Membranes – Preliminary Results at Oxford Water Pollution Control Plant

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The Oxford Water Pollution Control Plant (WPCP) was retrofitted to an MBR process in 2008. The conventional activated sludge process was converted to MBR process by adding membrane cassettes within the existing rectangular secondary clarifiers. Sludge co-settling/thickening was eliminated in favour of separated primary solids thickening within the primary clarifiers and using membranes for waste activated sludge (WAS) thickening. The subject of this paper was to compare the original design of the WAS thickener as specified versus actual operating performance for the year following start-up (June 2008 to June 2009). Generally speaking, the key differences observed between specified design and initial performance in the first 8 months following start-up (ie June 2008 to Feb 2009) include: 1) higher operating TMP than expected, 2) greater alarm frequency than expected, 3) lower thickened sludge concentration than expected, 4) higher chemical cleaning frequencies and usage than expected. Subsequent process optimizations made to adjust flux rates in the latter 4 month period (March-June 2009) have proven successful with respect to lowering operating TMP, reducing alarm frequencies, and increasing thickened sludge concentrations near specified levels.

Keywords: MBR; WAS; WAS thickener; membrane bioreactor; waste activated sludge

Document Type: Research Article


Publication date: 2009-01-01

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  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

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