{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/8305"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/8305","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Causes and control of low F/M bulking in long sludge age nutrient removal activated sludge systems","abstract":"A problem plaguing the greater proportion of nutrient removal activated sludge systems treating municipal sewage, is the prolific growth of :filamentous organisms (bulking), which inhibits the rate of sludge settling in the clarifier (secondary settling) stage of treatment and reduces plant throughput. To find the causes of :filament proliferation, a four-stage investigation was conducted: (1) A review of literature indicated that the promoted method for control of bulking in carbonaceous removal systems (the selector reactor) does not control bulking in nutrient removal systems. (2) From a laboratory-scale experimental programme it was concluded that low F /M filaments proliferate when sludge is subjected to alternating anoxic-aerobic conditions with nitrite present. (3) A review of the biochemistry of respiration led to the formulation of a biochemical model for facultative organism respiration, an important aspect of which is a series of mechanisms that give rise to inhibition of aerobic respiration following anoxic conditions. Inhibition of respiration was measured in activated sludge with aerobic batch test procedures. ( 4) Application of the biochemical model to filaments and floe-formers allowed the formulation of a biochemical/microbiological (bulking) model to describe the prolific growth of filamentous organisms. The model was tested and verified at laboratory-scale.","abstract_html":"A problem plaguing the greater proportion of nutrient removal activated sludge systems treating municipal sewage, is the prolific growth of :filamentous organisms (bulking), which inhibits the rate of sludge settling in the clarifier (secondary settling) stage of treatment and reduces plant throughput. To find the causes of :filament proliferation, a four-stage investigation was conducted: (1) A review of literature indicated that the promoted method for control of bulking in carbonaceous removal systems (the selector reactor) does not control bulking in nutrient removal systems. (2) From a laboratory-scale experimental programme it was concluded that low F /M filaments proliferate when sludge is subjected to alternating anoxic-aerobic conditions with nitrite present. (3) A review of the biochemistry of respiration led to the formulation of a biochemical model for facultative organism respiration, an important aspect of which is a series of mechanisms that give rise to inhibition of aerobic respiration following anoxic conditions. Inhibition of respiration was measured in activated sludge with aerobic batch test procedures. ( 4) Application of the biochemical model to filaments and floe-formers allowed the formulation of a biochemical/microbiological (bulking) model to describe the prolific growth of filamentous organisms. The model was tested and verified at laboratory-scale.","abstract_has_math":false,"creators":["Casey, Timothy Gervase"],"institution":"Department of Civil Engineering","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1993,"date_issued":"1993","date_published":"1993","updated_at":"2026-07-24T01:34:16Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/8305","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Casey, Timothy Gervase"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-10-11T11:57:41Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-10-11T11:57:41Z"]},{"key":"dc:date.issued","label":"Date","values":["1993"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Civil Engineering"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"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/11427/8305"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes bibliography."]},{"key":"dc:description.abstract","label":"Abstract","values":["A problem plaguing the greater proportion of nutrient removal activated sludge systems treating municipal sewage, is the prolific growth of :filamentous organisms (bulking), which inhibits the rate of sludge settling in the clarifier (secondary settling) stage of treatment and reduces plant throughput. To find the causes of :filament proliferation, a four-stage investigation was conducted: (1) A review of literature indicated that the promoted method for control of bulking in carbonaceous removal systems (the selector reactor) does not control bulking in nutrient removal systems. (2) From a laboratory-scale experimental programme it was concluded that low F /M filaments proliferate when sludge is subjected to alternating anoxic-aerobic conditions with nitrite present. (3) A review of the biochemistry of respiration led to the formulation of a biochemical model for facultative organism respiration, an important aspect of which is a series of mechanisms that give rise to inhibition of aerobic respiration following anoxic conditions. Inhibition of respiration was measured in activated sludge with aerobic batch test procedures. ( 4) Application of the biochemical model to filaments and floe-formers allowed the formulation of a biochemical/microbiological (bulking) model to describe the prolific growth of filamentous organisms. The model was tested and verified at laboratory-scale."]},{"key":"dc:title","label":"Title","values":["Causes and control of low F/M bulking in long sludge age nutrient removal activated sludge systems"]}]}],"canonical_facts":{"dc:creator":["Casey, Timothy Gervase"],"dc:date.accessioned":["2014-10-11T11:57:41Z"],"dc:date.available":["2014-10-11T11:57:41Z"],"dc:date.issued":["1993"],"dc:description":["Includes bibliography."],"dc:description.abstract":["A problem plaguing the greater proportion of nutrient removal activated sludge systems treating municipal sewage, is the prolific growth of :filamentous organisms (bulking), which inhibits the rate of sludge settling in the clarifier (secondary settling) stage of treatment and reduces plant throughput. To find the causes of :filament proliferation, a four-stage investigation was conducted: (1) A review of literature indicated that the promoted method for control of bulking in carbonaceous removal systems (the selector reactor) does not control bulking in nutrient removal systems. (2) From a laboratory-scale experimental programme it was concluded that low F /M filaments proliferate when sludge is subjected to alternating anoxic-aerobic conditions with nitrite present. (3) A review of the biochemistry of respiration led to the formulation of a biochemical model for facultative organism respiration, an important aspect of which is a series of mechanisms that give rise to inhibition of aerobic respiration following anoxic conditions. Inhibition of respiration was measured in activated sludge with aerobic batch test procedures. ( 4) Application of the biochemical model to filaments and floe-formers allowed the formulation of a biochemical/microbiological (bulking) model to describe the prolific growth of filamentous organisms. The model was tested and verified at laboratory-scale."],"dc:identifier.uri":["http://hdl.handle.net/11427/8305"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Civil Engineering"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["Causes and control of low F/M bulking in long sludge age nutrient removal activated sludge systems"],"dc:type":["Doctoral Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["PhD"]},"updated_at":"2026-07-24T01:34:16Z"}