{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/45148"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/45148","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"A Study of the Patterns, Stoichiometry, and Kinetics of Microbial BTX Degradation Under Denitrifying Conditions by an Activated Sludge Consortium Receiving a Mixed Waste","abstract":"The patterns, stoichiometry, and kinetics of microbial benzene, toluene, p-xylene, m-xylene, and o-xylene degradation by a denitrifying activated sludge consortium was investigated in a sequencing batch reactor (SBR) receiving a mixed waste. After six months of acclimation, toluene and m-xylene were routinely degraded to below detection. Both toluene and m-xylene could serve as sole carbon and energy sources. The removal of o-xylene was also possible; however, its transformation was dependent upon gratuitous metabolism during toluene degradation. Benzene and p-xylene were recalcitrant throughout the study. The first order decay coefficient (b) of the denitrifying biomass was determined to be 0.016 ± 0.006 h⁻¹ on a theoretical oxygen demand (thOD) basis. The true growth yields (Y) for the biogenic and toluene/m-xylene components of the mixed waste were determined to be 0.41 ± 0.02 and 0.35 ± 0.04 mg thOD biomass per mg thOD substrate, respectively. The Monod parameters, qmax and KS, for toluene ranged from 0.059 to 0.14 mg toluene/mg protein/h and 0.84 to 6.9 mg/L, respectively. For m-xylene, the qmax and KS parameters ranged from 0.034 to 0.041 mg m-xylene/mg protein/h and 0.28 to 3.7 mg/L, respectively. Some of the variation observed between kinetic experiments was attributed to the different accumulation levels of the denitrification intermediate nitrite (NO⁻) and the inhibitory effects of its conjugate acid, nitrous acid (HNO₂). Other evidence suggested that part of the variation was also due to a continuous acclimation and refinement towards higher affinity toluene- and m-xylene-degrading enzyme systems within the biomass.","abstract_html":"The patterns, stoichiometry, and kinetics of microbial benzene, toluene, p-xylene, m-xylene, and o-xylene degradation by a denitrifying activated sludge consortium was investigated in a sequencing batch reactor (SBR) receiving a mixed waste. After six months of acclimation, toluene and m-xylene were routinely degraded to below detection. Both toluene and m-xylene could serve as sole carbon and energy sources. The removal of o-xylene was also possible; however, its transformation was dependent upon gratuitous metabolism during toluene degradation. Benzene and p-xylene were recalcitrant throughout the study. The first order decay coefficient (b) of the denitrifying biomass was determined to be 0.016 ± 0.006 h⁻¹ on a theoretical oxygen demand (thOD) basis. The true growth yields (Y) for the biogenic and toluene/m-xylene components of the mixed waste were determined to be 0.41 ± 0.02 and 0.35 ± 0.04 mg thOD biomass per mg thOD substrate, respectively. The Monod parameters, qmax and KS, for toluene ranged from 0.059 to 0.14 mg toluene/mg protein/h and 0.84 to 6.9 mg/L, respectively. For m-xylene, the qmax and KS parameters ranged from 0.034 to 0.041 mg m-xylene/mg protein/h and 0.28 to 3.7 mg/L, respectively. Some of the variation observed between kinetic experiments was attributed to the different accumulation levels of the denitrification intermediate nitrite (NO⁻) and the inhibitory effects of its conjugate acid, nitrous acid (HNO₂). Other evidence suggested that part of the variation was also due to a continuous acclimation and refinement towards higher affinity toluene- and m-xylene-degrading enzyme systems within the biomass.","abstract_has_math":false,"creators":["Fettig, James Drew"],"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":["Love, Nancy G."],"committee_members":["Little, John C.","Novak, John T."],"year":1998,"date_issued":"1998-08-28","date_published":"1998-08-28","updated_at":"2026-07-22T22:19:59Z","subjects":["hydrocarbons","toluene","wastewater","anoxic","bacteria"],"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-101198-200558"],"render_values":[{"text":"etd-101198-200558","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/45148","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Love, Nancy G."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Little, John C.","Novak, John T."]},{"key":"dc:contributor.department","label":"Department","values":["Civil Engineering"]},{"key":"dc:creator","label":"Author","values":["Fettig, James Drew"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T21:47:28Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T21:47:28Z","1999-02-11"]},{"key":"dc:date.issued","label":"Date","values":["1998-08-28"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"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":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["hydrocarbons","toluene","wastewater","anoxic","bacteria"]}]},{"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-101198-200558"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/45148"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The patterns, stoichiometry, and kinetics of microbial benzene, toluene, p-xylene, m-xylene, and o-xylene degradation by a denitrifying activated sludge consortium was investigated in a sequencing batch reactor (SBR) receiving a mixed waste. After six months of acclimation, toluene and m-xylene were routinely degraded to below detection. Both toluene and m-xylene could serve as sole carbon and energy sources. The removal of o-xylene was also possible; however, its transformation was dependent upon gratuitous metabolism during toluene degradation. Benzene and p-xylene were recalcitrant throughout the study. The first order decay coefficient (b) of the denitrifying biomass was determined to be 0.016 ± 0.006 h⁻¹ on a theoretical oxygen demand (thOD) basis. The true growth yields (Y) for the biogenic and toluene/m-xylene components of the mixed waste were determined to be 0.41 ± 0.02 and 0.35 ± 0.04 mg thOD biomass per mg thOD substrate, respectively. The Monod parameters, qmax and KS, for toluene ranged from 0.059 to 0.14 mg toluene/mg protein/h and 0.84 to 6.9 mg/L, respectively. For m-xylene, the qmax and KS parameters ranged from 0.034 to 0.041 mg m-xylene/mg protein/h and 0.28 to 3.7 mg/L, respectively. Some of the variation observed between kinetic experiments was attributed to the different accumulation levels of the denitrification intermediate nitrite (NO⁻) and the inhibitory effects of its conjugate acid, nitrous acid (HNO₂). Other evidence suggested that part of the variation was also due to a continuous acclimation and refinement towards higher affinity toluene- and m-xylene-degrading enzyme systems within the biomass."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["A Study of the Patterns, Stoichiometry, and Kinetics of Microbial BTX Degradation Under Denitrifying Conditions by an Activated Sludge Consortium Receiving a Mixed Waste"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Love, Nancy G."],"dc:contributor.committeemember":["Little, John C.","Novak, John T."],"dc:contributor.department":["Civil Engineering"],"dc:creator":["Fettig, James Drew"],"dc:date.accessioned":["2014-03-14T21:47:28Z"],"dc:date.available":["2014-03-14T21:47:28Z","1999-02-11"],"dc:date.issued":["1998-08-28"],"dc:description.abstract":["The patterns, stoichiometry, and kinetics of microbial benzene, toluene, p-xylene, m-xylene, and o-xylene degradation by a denitrifying activated sludge consortium was investigated in a sequencing batch reactor (SBR) receiving a mixed waste. After six months of acclimation, toluene and m-xylene were routinely degraded to below detection. Both toluene and m-xylene could serve as sole carbon and energy sources. The removal of o-xylene was also possible; however, its transformation was dependent upon gratuitous metabolism during toluene degradation. Benzene and p-xylene were recalcitrant throughout the study. The first order decay coefficient (b) of the denitrifying biomass was determined to be 0.016 ± 0.006 h⁻¹ on a theoretical oxygen demand (thOD) basis. The true growth yields (Y) for the biogenic and toluene/m-xylene components of the mixed waste were determined to be 0.41 ± 0.02 and 0.35 ± 0.04 mg thOD biomass per mg thOD substrate, respectively. The Monod parameters, qmax and KS, for toluene ranged from 0.059 to 0.14 mg toluene/mg protein/h and 0.84 to 6.9 mg/L, respectively. For m-xylene, the qmax and KS parameters ranged from 0.034 to 0.041 mg m-xylene/mg protein/h and 0.28 to 3.7 mg/L, respectively. Some of the variation observed between kinetic experiments was attributed to the different accumulation levels of the denitrification intermediate nitrite (NO⁻) and the inhibitory effects of its conjugate acid, nitrous acid (HNO₂). Other evidence suggested that part of the variation was also due to a continuous acclimation and refinement towards higher affinity toluene- and m-xylene-degrading enzyme systems within the biomass."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-101198-200558"],"dc:identifier.uri":["http://hdl.handle.net/10919/45148"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["hydrocarbons","toluene","wastewater","anoxic","bacteria"],"dc:title":["A Study of the Patterns, Stoichiometry, and Kinetics of Microbial BTX Degradation Under Denitrifying Conditions by an Activated Sludge Consortium Receiving a Mixed Waste"],"dc:type":["Thesis"],"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":"2026-07-22T22:19:59Z"}