{"id":{"repo_id":"manitoba","oai_identifier":"oai:mspace.lib.umanitoba.ca:1993/1462"},"canonical_url":"https://search.dev.ndltd.org/etd/manitoba/oai:mspace.lib.umanitoba.ca:1993/1462","repository":{"repo_id":"manitoba","name":"University of Manitoba","base_url":"https://mspace.lib.umanitoba.ca/oai/request"},"display":{"title":"Volatile fatty acid production during thermophilic aerobic digestion pre-treatment","abstract":"This study was initiated to demonstrate the application of thermophilic aerobic digestion pre-treatment as a method of producing volatile fatty acids (VFA) for potential use as a denitrification carbon source. In order to achieve this goal, volatile fatty acid production and nitrogen release were examined under two oxygenation states with detention times ranging from 6 to 24 hours at 55$\\sp\\circ$C. The semi-continuous laboratory scale reactors, with 3 L operating volumes, were fed primary solids obtained from the City of Winnipeg's North End Water Pollution Control Centre. VFAs accumulated under all oxygen-deprived conditions (O$\\sb2$ flow rate: 0.025 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$330 mV to $-$390 mV) and the production rate increased with increasing retention time from 0.029 mg HAc/mg VS$\\cdot$d at 6 hours to 0.057 mg HAc/mg VS$\\cdot$d at 24 hours. VFAs were consumed under the oxygen-satisfied condition (O$\\sb2$ flow rate: 0.14 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$10 mV to $-$225 mV). The VFA specific production rate did not appear to vary with the influent solids concentration. Acetic acid constituted the largest fraction of VFAs in both the oxygen-satisfied and oxygen-deprived experiments and ranged from 59.6% to 64.3%. The oxygen-satisfied condition exhibited much higher propionic acid concentrations (average of 30.3%) than did the oxygen-deprived conditions (average of 17.2%). Ammonia nitrogen accumulated under all conditions studied, but more so with a decreasing oxygen supply and increasing retention time. Under the oxygen-deprived condition, the 6 hour SRT/HRT exhibited the lowest ammonia nitrogen increase of 41.6% while the 24 hour SRT/HRT exhibited the highest at 142.8%. The soluble organic carbon to ammonia ratio increased with a decreasing oxygen supply and detention time. Returning the VFA-rich supernatant to the plant influent would increase the overall chemical oxygen demand to ammonia ratio and aid in the denitrification process.","abstract_html":"This study was initiated to demonstrate the application of thermophilic aerobic digestion pre-treatment as a method of producing volatile fatty acids (VFA) for potential use as a denitrification carbon source. In order to achieve this goal, volatile fatty acid production and nitrogen release were examined under two oxygenation states with detention times ranging from 6 to 24 hours at 55$\\sp\\circ$C. The semi-continuous laboratory scale reactors, with 3 L operating volumes, were fed primary solids obtained from the City of Winnipeg's North End Water Pollution Control Centre. VFAs accumulated under all oxygen-deprived conditions (O$\\sb2$ flow rate: 0.025 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$330 mV to $-$390 mV) and the production rate increased with increasing retention time from 0.029 mg HAc/mg VS$\\cdot$d at 6 hours to 0.057 mg HAc/mg VS$\\cdot$d at 24 hours. VFAs were consumed under the oxygen-satisfied condition (O$\\sb2$ flow rate: 0.14 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$10 mV to $-$225 mV). The VFA specific production rate did not appear to vary with the influent solids concentration. Acetic acid constituted the largest fraction of VFAs in both the oxygen-satisfied and oxygen-deprived experiments and ranged from 59.6% to 64.3%. The oxygen-satisfied condition exhibited much higher propionic acid concentrations (average of 30.3%) than did the oxygen-deprived conditions (average of 17.2%). Ammonia nitrogen accumulated under all conditions studied, but more so with a decreasing oxygen supply and increasing retention time. Under the oxygen-deprived condition, the 6 hour SRT/HRT exhibited the lowest ammonia nitrogen increase of 41.6% while the 24 hour SRT/HRT exhibited the highest at 142.8%. The soluble organic carbon to ammonia ratio increased with a decreasing oxygen supply and detention time. Returning the VFA-rich supernatant to the plant influent would increase the overall chemical oxygen demand to ammonia ratio and aid in the denitrification process.","abstract_has_math":true,"creators":["McIntosh, Karen Bonnie"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1998,"date_issued":"1998-09-01T00:00:00Z","date_published":"1998-09-01T00:00:00Z","updated_at":"2026-07-24T03:02:03Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1993/1462","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["McIntosh, Karen Bonnie"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2007-05-17T12:37:18Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2007-05-17T12:37:18Z"]},{"key":"dc:date.issued","label":"Date","values":["1998-09-01T00:00:00Z"]},{"key":"dc:type","label":"Dc Type","values":["master thesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1993/1462"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This study was initiated to demonstrate the application of thermophilic aerobic digestion pre-treatment as a method of producing volatile fatty acids (VFA) for potential use as a denitrification carbon source. In order to achieve this goal, volatile fatty acid production and nitrogen release were examined under two oxygenation states with detention times ranging from 6 to 24 hours at 55$\\sp\\circ$C. The semi-continuous laboratory scale reactors, with 3 L operating volumes, were fed primary solids obtained from the City of Winnipeg's North End Water Pollution Control Centre. VFAs accumulated under all oxygen-deprived conditions (O$\\sb2$ flow rate: 0.025 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$330 mV to $-$390 mV) and the production rate increased with increasing retention time from 0.029 mg HAc/mg VS$\\cdot$d at 6 hours to 0.057 mg HAc/mg VS$\\cdot$d at 24 hours. VFAs were consumed under the oxygen-satisfied condition (O$\\sb2$ flow rate: 0.14 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$10 mV to $-$225 mV). The VFA specific production rate did not appear to vary with the influent solids concentration. Acetic acid constituted the largest fraction of VFAs in both the oxygen-satisfied and oxygen-deprived experiments and ranged from 59.6% to 64.3%. The oxygen-satisfied condition exhibited much higher propionic acid concentrations (average of 30.3%) than did the oxygen-deprived conditions (average of 17.2%). Ammonia nitrogen accumulated under all conditions studied, but more so with a decreasing oxygen supply and increasing retention time. Under the oxygen-deprived condition, the 6 hour SRT/HRT exhibited the lowest ammonia nitrogen increase of 41.6% while the 24 hour SRT/HRT exhibited the highest at 142.8%. The soluble organic carbon to ammonia ratio increased with a decreasing oxygen supply and detention time. Returning the VFA-rich supernatant to the plant influent would increase the overall chemical oxygen demand to ammonia ratio and aid in the denitrification process."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf","text/plain"]},{"key":"dc:title","label":"Title","values":["Volatile fatty acid production during thermophilic aerobic digestion pre-treatment"]}]}],"canonical_facts":{"dc:creator":["McIntosh, Karen Bonnie"],"dc:date.accessioned":["2007-05-17T12:37:18Z"],"dc:date.available":["2007-05-17T12:37:18Z"],"dc:date.issued":["1998-09-01T00:00:00Z"],"dc:description.abstract":["This study was initiated to demonstrate the application of thermophilic aerobic digestion pre-treatment as a method of producing volatile fatty acids (VFA) for potential use as a denitrification carbon source. In order to achieve this goal, volatile fatty acid production and nitrogen release were examined under two oxygenation states with detention times ranging from 6 to 24 hours at 55$\\sp\\circ$C. The semi-continuous laboratory scale reactors, with 3 L operating volumes, were fed primary solids obtained from the City of Winnipeg's North End Water Pollution Control Centre. VFAs accumulated under all oxygen-deprived conditions (O$\\sb2$ flow rate: 0.025 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$330 mV to $-$390 mV) and the production rate increased with increasing retention time from 0.029 mg HAc/mg VS$\\cdot$d at 6 hours to 0.057 mg HAc/mg VS$\\cdot$d at 24 hours. VFAs were consumed under the oxygen-satisfied condition (O$\\sb2$ flow rate: 0.14 $\\rm m\\sp3/m\\sp3\\cdot h;$ ORP: $-$10 mV to $-$225 mV). The VFA specific production rate did not appear to vary with the influent solids concentration. Acetic acid constituted the largest fraction of VFAs in both the oxygen-satisfied and oxygen-deprived experiments and ranged from 59.6% to 64.3%. The oxygen-satisfied condition exhibited much higher propionic acid concentrations (average of 30.3%) than did the oxygen-deprived conditions (average of 17.2%). Ammonia nitrogen accumulated under all conditions studied, but more so with a decreasing oxygen supply and increasing retention time. Under the oxygen-deprived condition, the 6 hour SRT/HRT exhibited the lowest ammonia nitrogen increase of 41.6% while the 24 hour SRT/HRT exhibited the highest at 142.8%. The soluble organic carbon to ammonia ratio increased with a decreasing oxygen supply and detention time. Returning the VFA-rich supernatant to the plant influent would increase the overall chemical oxygen demand to ammonia ratio and aid in the denitrification process."],"dc:format.mimetype":["application/pdf","text/plain"],"dc:identifier.uri":["http://hdl.handle.net/1993/1462"],"dc:language.iso":["eng"],"dc:title":["Volatile fatty acid production during thermophilic aerobic digestion pre-treatment"],"dc:type":["master thesis"]},"updated_at":"2026-07-24T03:02:03Z"}