{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/45743"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/45743","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Effect of mixing intensity on polymer conditioning of sludges","abstract":"Conditioning studies were conducted on several water and wastewater sludges using polymers to determine the effect of high-intensity mixing on floc formation and breakup. Mechanisms acting in particle coagulation were also investigated. A rapid mixing apparatus was used in conditioning the sludge to simulate the high velocity gradients encountered in most dewatering equipment. Anionic and cationic polymers of varying molecular weights and an inorganic coagulant were chosen as the conditioning agents. Dewatering rates were measured by the capillary suction time (CST) apparatus. The effect of rapid mixing on the polymer efficiency was evaluated by premixing the polymer, using the same mixing apparatus, prior to applying it to condition the sludge. Data analyses revealed the great impact the primary floc breakup has on the sludge dewatering rate, although this was shown to be dependent on the nature of the sludge particles. Some minor changes were imparted to the polymer chains by intense mixing but there was no evidence that particle polymer bonds were fractured. The mechanisms of coagulation were observed to be related to sludge type. Overall, successful conditioning of sludges by polymers requires a proper determination of the sludge characteristics, a correct choice of polymer type and dose, and a knowledge of the mixing intensities.","abstract_html":"Conditioning studies were conducted on several water and wastewater sludges using polymers to determine the effect of high-intensity mixing on floc formation and breakup. Mechanisms acting in particle coagulation were also investigated. A rapid mixing apparatus was used in conditioning the sludge to simulate the high velocity gradients encountered in most dewatering equipment. Anionic and cationic polymers of varying molecular weights and an inorganic coagulant were chosen as the conditioning agents. Dewatering rates were measured by the capillary suction time (CST) apparatus. The effect of rapid mixing on the polymer efficiency was evaluated by premixing the polymer, using the same mixing apparatus, prior to applying it to condition the sludge. Data analyses revealed the great impact the primary floc breakup has on the sludge dewatering rate, although this was shown to be dependent on the nature of the sludge particles. Some minor changes were imparted to the polymer chains by intense mixing but there was no evidence that particle polymer bonds were fractured. The mechanisms of coagulation were observed to be related to sludge type. Overall, successful conditioning of sludges by polymers requires a proper determination of the sludge characteristics, a correct choice of polymer type and dose, and a knowledge of the mixing intensities.","abstract_has_math":false,"creators":["Bandak, Nazih"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Civil Engineering","degree_department":"Civil Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Novak, John T."],"committee_members":["Randall, Clifford W.","Knocke, William R."],"year":1986,"date_issued":"1986-07-05","date_published":"1986-07-05","updated_at":"2026-07-22T22:19:54Z","subjects":[],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-11152013-040418"],"render_values":[{"text":"etd-11152013-040418","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/45743","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Novak, John T."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Randall, Clifford W.","Knocke, William R."]},{"key":"dc:contributor.department","label":"Department","values":["Civil Engineering"]},{"key":"dc:creator","label":"Author","values":["Bandak, Nazih"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T21:49:47Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T21:49:47Z","2013-11-15"]},{"key":"dc:date.issued","label":"Date","values":["1986-07-05"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Civil Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-11152013-040418"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/45743"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Conditioning studies were conducted on several water and wastewater sludges using polymers to determine the effect of high-intensity mixing on floc formation and breakup. 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