{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/42947"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/42947","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Comparative phosphorus removals using modified activated sludge processes","abstract":"The operation of three continuous flow units as modified activated sludge models using mean cell residence time as a principal operational parameter has led to the following conclusions: 1. Lower mean cell residence times result in higher phosphorus removal efficiencies in biological reactors. 2. Higher mean solids residence times result in higher phosphorus removal efficiencies in strictly chemical reactors. 3. Calcium-phosphate precipitation can occur in continuous flow reactors in a normal activated sludge pH range (7.5-8.5) given sufficient Ca++ concentrations. 4. Calcium-phosphate precipitation can occur in the activated sludge process without hindering COO removal efficiency. 5. The phosphorus sludge content only exceeded the one to two percent range in the biochemical and chemical units, where phosphorus precipitation was the predominate phosphorus removal mechanism. 6. The anaerobiosis and acid stripping procedure, as used in this investigation, is not effective in enhancing either a biological or chemical unit's ability to remove phosphorus.","abstract_html":"The operation of three continuous flow units as modified activated sludge models using mean cell residence time as a principal operational parameter has led to the following conclusions: 1. Lower mean cell residence times result in higher phosphorus removal efficiencies in biological reactors. 2. Higher mean solids residence times result in higher phosphorus removal efficiencies in strictly chemical reactors. 3. Calcium-phosphate precipitation can occur in continuous flow reactors in a normal activated sludge pH range (7.5-8.5) given sufficient Ca++ concentrations. 4. Calcium-phosphate precipitation can occur in the activated sludge process without hindering COO removal efficiency. 5. The phosphorus sludge content only exceeded the one to two percent range in the biochemical and chemical units, where phosphorus precipitation was the predominate phosphorus removal mechanism. 6. The anaerobiosis and acid stripping procedure, as used in this investigation, is not effective in enhancing either a biological or chemical unit's ability to remove phosphorus.","abstract_has_math":false,"creators":["Elliott, William Richard"],"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":["Sherrard, Joseph H."],"committee_members":["Randall, Clifford W.","Boardman, Gregory D."],"year":1977,"date_issued":"1977-10-05","date_published":"1977-10-05","updated_at":"2026-07-22T22:20:07Z","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-06082010-020432"],"render_values":[{"text":"etd-06082010-020432","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/42947","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Sherrard, Joseph H."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Randall, Clifford W.","Boardman, Gregory D."]},{"key":"dc:contributor.department","label":"Department","values":["Civil Engineering"]},{"key":"dc:creator","label":"Author","values":["Elliott, William Richard"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T21:37:17Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T21:37:17Z","2010-06-08"]},{"key":"dc:date.issued","label":"Date","values":["1977-10-05"]},{"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-06082010-020432"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/42947"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The operation of three continuous flow units as modified activated sludge models using mean cell residence time as a principal operational parameter has led to the following conclusions: 1. Lower mean cell residence times result in higher phosphorus removal efficiencies in biological reactors. 2. Higher mean solids residence times result in higher phosphorus removal efficiencies in strictly chemical reactors. 3. Calcium-phosphate precipitation can occur in continuous flow reactors in a normal activated sludge pH range (7.5-8.5) given sufficient Ca++ concentrations. 4. Calcium-phosphate precipitation can occur in the activated sludge process without hindering COO removal efficiency. 5. The phosphorus sludge content only exceeded the one to two percent range in the biochemical and chemical units, where phosphorus precipitation was the predominate phosphorus removal mechanism. 6. The anaerobiosis and acid stripping procedure, as used in this investigation, is not effective in enhancing either a biological or chemical unit's ability to remove phosphorus."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["BTD"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Comparative phosphorus removals using modified activated sludge processes"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Sherrard, Joseph H."],"dc:contributor.committeemember":["Randall, Clifford W.","Boardman, Gregory D."],"dc:contributor.department":["Civil Engineering"],"dc:creator":["Elliott, William Richard"],"dc:date.accessioned":["2014-03-14T21:37:17Z"],"dc:date.available":["2014-03-14T21:37:17Z","2010-06-08"],"dc:date.issued":["1977-10-05"],"dc:description.abstract":["The operation of three continuous flow units as modified activated sludge models using mean cell residence time as a principal operational parameter has led to the following conclusions: 1. Lower mean cell residence times result in higher phosphorus removal efficiencies in biological reactors. 2. Higher mean solids residence times result in higher phosphorus removal efficiencies in strictly chemical reactors. 3. Calcium-phosphate precipitation can occur in continuous flow reactors in a normal activated sludge pH range (7.5-8.5) given sufficient Ca++ concentrations. 4. Calcium-phosphate precipitation can occur in the activated sludge process without hindering COO removal efficiency. 5. The phosphorus sludge content only exceeded the one to two percent range in the biochemical and chemical units, where phosphorus precipitation was the predominate phosphorus removal mechanism. 6. The anaerobiosis and acid stripping procedure, as used in this investigation, is not effective in enhancing either a biological or chemical unit's ability to remove phosphorus."],"dc:description.degree":["Master of Science"],"dc:format.medium":["BTD"],"dc:format.mimetype":["application/pdf"],"dc:identifier.other":["etd-06082010-020432"],"dc:identifier.uri":["http://hdl.handle.net/10919/42947"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Comparative phosphorus removals using modified activated sludge processes"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Civil Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:07Z"}