Conditioning for shear in sludge dewatering

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dc.contributor.authorBuckley, Margaret M.en
dc.contributor.committeechairNovak, John T.en
dc.contributor.committeememberKnocke, William R.en
dc.contributor.committeememberRandall, Clifford W.en
dc.contributor.departmentEnvironmental Engineeringen
dc.date.accessioned2014-03-14T21:44:39Zen
dc.date.adate2009-09-05en
dc.date.available2014-03-14T21:44:39Zen
dc.date.issued1994-04-10en
dc.date.rdate2009-09-05en
dc.date.sdate2009-09-05en
dc.description.abstractThe purpose of this study was to determine how chemical conditioning agents and mechanical dewatering devices affect sludge dewatering with respect to shear. Bench scale experiments were performed to determine the effect of shear and mole charge on polymer dose requirements using anaerobically digested sludge. Lime, ferric chloride, and polymer were used to condition anaerobically digested sludge to evaluate the influence of these conditioning agents, separately and in combination, on shear resistance. Dewatering studies were performed using a plate and frame press, a centrifuge, and a screw press to determine the amount of shear within each device and to develop a means of estimating polymer dose for each device. It was determined that increased molecular charge of polymer decreased chemical dose requirements and improved shear resistance. Both lime and ferric chloride improved sludge dewatering rates but only ferric chloride conditioned against shear. Ferric chloride addition prior to polymer conditioning improved sludge shear resistance, improved the dewatering rate (CST), and decreased the required polymer dose. The dewatering study using the plate and frame press verified that polymer dose could be estimated using CST values and a Gt value of approximately 30,000. Also, ferric chloride in combination with polymer improved filtrate quality, increased the cake solids concentration, and increased the filtrate volume throughput of sludge conditioned with lower polymer doses than if polymer alone was used. The dewatering study using a high speed centrifuge found that polymer dose could be estimated using CST values at a Gt between 10,000 and 20,000 or by use of the wedge zone simulator. The dewatering study of the screw press found that CST values and the wedge zone simulator under predicted polymer dose. This was thought to be the result of shear in the feed system prior to dewatering.en
dc.description.degreeMaster of Scienceen
dc.format.extentx, 78 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-09052009-040620en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09052009-040620/en
dc.identifier.urihttp://hdl.handle.net/10919/44579en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1994.B835.pdfen
dc.relation.isformatofOCLC# 30609721en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1994.B835en
dc.subject.lcshSewage sludge -- Conditioningen
dc.subject.lcshSewage sludge -- Dryingen
dc.subject.lcshShear (Mechanics)en
dc.titleConditioning for shear in sludge dewateringen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineEnvironmental Planningen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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