Sludge conditioning, thickening and dewatering optimization in a screw centrifuge decanter: Which means for which result?. (15th February 2021)

• Record Type: Journal Article
• Authors: Ginisty, P.; Mailler, R.; Rocher, V.
• Is Part Of: Journal of environmental management. Volume 280(2021)
• Publication Date: 2021-02-15
• Subjects: Sludge conditioning thickening dewatering centrifugation; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2020.111745
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Centrifuge are common machines used for sludge thickening and dewatering in wastewater treatment plant but performances and optimal setting parameters are often difficult to predict and optimize, owing to complex mechanisms occurring during separation and high shear stresses undergone by flocs. Laboratory tests are necessary to assess performances and to screen chemicals and dosage in order to decrease optimization time at full scale. They include volatile matters characterization, drainage and CST tests vs mixing time, basket spin tests with shearing, limit dryness determination. The ability of these tests, to assess sludge dehydration and/or to select polymer and dosage, is discussed and is compared with performances obtained in a screw centrifuge decanter at lab and full scale. Highlights: Floc characterization tests give useful trends to evaluate sludge dewaterability. They fail to produce realistic predictions for a screw centrifuge. Lab screw centrifuge is an additional means to provide more reliable data on flocs. Lab screw centrifuge allows to take into account the shearing action of the screw. A good correspondence is obtained with industrial machines for activated sludges.