{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/52313"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/52313","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Bacterial extracellular polymers and flocculation of activated sludges","abstract":"The extracellular polymers produced by bacteria play an important role in bacterial aggregation or bacterial flocculation in secondary waste treatment. The mechanisms responsible for this floc formation are thought to be polymer induced adsorption and interparticle bridging among bacterial cells or between bacterial cells and inorganic colloids. The efficiency of the processes following flocculation in the treatment line such as sedimentation, sludge thickening, and sludge dewatering depends on the extent of this bacterial flocculation. In this research, sludge samples from under various substrate conditions were examined for type, molecular weight, physical characteristics„ and quantity of extracellular polymers so that the general characteristics of the various polymers could be established. An attempt was made to determine if a relationship exists between the state of bacterial aggregation and the polymer characteristics. This research also investigated the sludge physical properties. The effect of various parameters such as pH, divalent cation (mixture and concentration), and mixing (period and intensity) on dewatering properties were studied. A major goal of this study was to develop a flocculation model for activated sludge. This model could be used to determine if plants can increase the efficiency of waste treatment and sludge thickening and sludge dewatering processes.","abstract_html":"The extracellular polymers produced by bacteria play an important role in bacterial aggregation or bacterial flocculation in secondary waste treatment. The mechanisms responsible for this floc formation are thought to be polymer induced adsorption and interparticle bridging among bacterial cells or between bacterial cells and inorganic colloids. The efficiency of the processes following flocculation in the treatment line such as sedimentation, sludge thickening, and sludge dewatering depends on the extent of this bacterial flocculation. In this research, sludge samples from under various substrate conditions were examined for type, molecular weight, physical characteristics„ and quantity of extracellular polymers so that the general characteristics of the various polymers could be established. An attempt was made to determine if a relationship exists between the state of bacterial aggregation and the polymer characteristics. This research also investigated the sludge physical properties. The effect of various parameters such as pH, divalent cation (mixture and concentration), and mixing (period and intensity) on dewatering properties were studied. A major goal of this study was to develop a flocculation model for activated sludge. This model could be used to determine if plants can increase the efficiency of waste treatment and sludge thickening and sludge dewatering processes.","abstract_has_math":false,"creators":["Kajornatiyudh, Sittiporn"],"institution":"Virginia Polytechnic Institute and State University","degree_name":"Ph. D.","degree_level":"doctoral","degree_discipline":"Environmental Science and Engineering","degree_department":"Environmental Science and Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Novak, O.T."],"committee_members":["Randall, Clifford W.","Hoehn, Robert C.","Knocke, William R.","Benoit, Robert E."],"year":1986,"date_issued":"1986","date_published":"1986","updated_at":"2026-07-22T22:18:42Z","subjects":[],"languages":["en_US"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/52313","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Novak, O.T."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Randall, Clifford W.","Hoehn, Robert C.","Knocke, William R.","Benoit, Robert E."]},{"key":"dc:contributor.department","label":"Department","values":["Environmental Science and Engineering"]},{"key":"dc:creator","label":"Author","values":["Kajornatiyudh, Sittiporn"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-05-14T16:36:14Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-05-14T16:36:14Z"]},{"key":"dc:date.issued","label":"Date","values":["1986"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Environmental Science and Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D."]},{"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:language.iso","label":"Language (ISO)","values":["en_US"]},{"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.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/52313"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The extracellular polymers produced by bacteria play an important role in bacterial aggregation or bacterial flocculation in secondary waste treatment. The mechanisms responsible for this floc formation are thought to be polymer induced adsorption and interparticle bridging among bacterial cells or between bacterial cells and inorganic colloids. The efficiency of the processes following flocculation in the treatment line such as sedimentation, sludge thickening, and sludge dewatering depends on the extent of this bacterial flocculation. In this research, sludge samples from under various substrate conditions were examined for type, molecular weight, physical characteristics„ and quantity of extracellular polymers so that the general characteristics of the various polymers could be established. An attempt was made to determine if a relationship exists between the state of bacterial aggregation and the polymer characteristics. This research also investigated the sludge physical properties. The effect of various parameters such as pH, divalent cation (mixture and concentration), and mixing (period and intensity) on dewatering properties were studied. A major goal of this study was to develop a flocculation model for activated sludge. This model could be used to determine if plants can increase the efficiency of waste treatment and sludge thickening and sludge dewatering processes."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph. D."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Bacterial extracellular polymers and flocculation of activated sludges"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Novak, O.T."],"dc:contributor.committeemember":["Randall, Clifford W.","Hoehn, Robert C.","Knocke, William R.","Benoit, Robert E."],"dc:contributor.department":["Environmental Science and Engineering"],"dc:creator":["Kajornatiyudh, Sittiporn"],"dc:date.accessioned":["2015-05-14T16:36:14Z"],"dc:date.available":["2015-05-14T16:36:14Z"],"dc:date.issued":["1986"],"dc:description.abstract":["The extracellular polymers produced by bacteria play an important role in bacterial aggregation or bacterial flocculation in secondary waste treatment. The mechanisms responsible for this floc formation are thought to be polymer induced adsorption and interparticle bridging among bacterial cells or between bacterial cells and inorganic colloids. The efficiency of the processes following flocculation in the treatment line such as sedimentation, sludge thickening, and sludge dewatering depends on the extent of this bacterial flocculation. In this research, sludge samples from under various substrate conditions were examined for type, molecular weight, physical characteristics„ and quantity of extracellular polymers so that the general characteristics of the various polymers could be established. An attempt was made to determine if a relationship exists between the state of bacterial aggregation and the polymer characteristics. This research also investigated the sludge physical properties. The effect of various parameters such as pH, divalent cation (mixture and concentration), and mixing (period and intensity) on dewatering properties were studied. A major goal of this study was to develop a flocculation model for activated sludge. This model could be used to determine if plants can increase the efficiency of waste treatment and sludge thickening and sludge dewatering processes."],"dc:description.degree":["Ph. D."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/52313"],"dc:language.iso":["en_US"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Bacterial extracellular polymers and flocculation of activated sludges"],"dc:type":["Dissertation"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Environmental Science and Engineering"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Ph. D."],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:42Z"}