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An innovative depth filtration technology, which involves the use of a synthetic fiber porous material instead of conventional granular material, has been evaluated as an advanced treatment step for domestic wastewater. The filter medium has two unusual properties; (1) the medium is highly porous and (2) the medium is compressible. These two uncommon properties of the new filter medium are unique and potentially offer significant advantages over existing filtration technologies employing incompressible solid filter mediums. Unlike conventional filters, it is possible to optimize the performance of the compressible medium filter (CMF) by adjusting the medium properties (i.e., collector size, porosity, and depth) to respond to the variations in the influent quality. The CMF has also been designated as the “Fuzzy Filter” because of the appearance of the material.

The CMF is effective for the filtration of secondary effluent. The performance of the CMF, in terms of removal efficiency and headloss development across the entire medium depth, was shown to be highly dependent on the degree of the medium compression. Greater influent turbidity values can be handled at filtration rates between 205 and 1230 L/m2•min, as the degree of the medium compression is increased. For filtration rates between 410 and 1230 L/m2•min and a bed compression value of 30 percent, the effluent turbidity will be equal to or lower than 2 NTU for influent turbidity values of up to approximately 8 NTU (without chemical addition). The headloss across the entire filter medium increases significantly as the medium compression ratio is increased. Typically, the minimum compression ratio that results in the maximum or the required degree of particle removal is selected to prevent excessive headloss development across the filter bed. The effects of the major filtration parameters including medium compression ratio, influent particle size distribution (PSD), and the flow rate on the effluent quality were not studied in detail for the CMF prior to this investigation. The results of the experiments conducted to understand the effects of these filtration parameters on the removal performance of the CMF are presented in this paper.

Document Type: Research Article


Publication date: January 1, 2005

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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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