Dewatering of Sewage Sludge |
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Authors: | John T Novak |
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Affiliation: | 1. Department of Civil &2. Environmental Engineering , Virginia Polytechnic Institute &3. State University , Blacksburg, Virginia, USA jtnov@vt.edu |
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Abstract: | Dewatering of sewage sludges is usually carried out using belt filter presses or centrifuges. The ability to remove water from sludges by mechanical dewatering is a property of both the sludge and the equipment used for dewatering. Newer high-solids centrifuges can remove more water than a belt press but require a higher chemical conditioning dose. The Gt value, the product of the mean velocity gradient and the shear time, has been found to be a useful parameter for characterizing the shear in mechanical dewatering equipment. Dewatering can be considered a two-step process, filtration followed by expression. The expression step is the most important of these and the benefits of various sludge processing techniques and conditioning chemical types remains a fruitful area of research. |
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Keywords: | Dewatering Cake solids Centrifuge Belt press Chemical Conditioning |
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