{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/38785"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/38785","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"The effect of a large anoxic mass fraction and concentrations of nitrate and nitrite in the primary anoxic zone on low f/m filament bulking in nutrient removal activated sludge systems","abstract":"Filamentous bulking occurs when filamentous organisms are present in excessive numbers and extend from floes into the bulk solution. They interfere with the compaction and settling of the activated sludge either by producing a very diffuse floe structure or by causing bridging between floes. This results in a sludge with poor settleability i.e., low settling velocity and low solids concentration in the return activated sludge (RAS). In severe cases overflow of the sludge with the effluent occurs. Bulking not only causes these problems in the activated sludge process, but it also causes poor dewaterability of the waste activated sludge. Clearly bulking not only adversely affects the efficiency of the secondary settling tank but also the efficiency of the sludge treatment units at the plant. While controlling or eliminating bulking at plants will certainly be beneficial for sludge handling, by far the most significant impact would be on the activated sludge process itself. It has been estimated that if the sludge settleability could be controlled at Diluted Sludge Volume Indices (DSVI) below 100 me/g, 50 to 100% more wastewater could be treated in existing plants leading to enormous savings (Ekama and Marais, 1986a). This single factor is the principal driving motive behind the research to establish the causes and control of filamentous bulking.","abstract_html":"Filamentous bulking occurs when filamentous organisms are present in excessive numbers and extend from floes into the bulk solution. They interfere with the compaction and settling of the activated sludge either by producing a very diffuse floe structure or by causing bridging between floes. This results in a sludge with poor settleability i.e., low settling velocity and low solids concentration in the return activated sludge (RAS). In severe cases overflow of the sludge with the effluent occurs. Bulking not only causes these problems in the activated sludge process, but it also causes poor dewaterability of the waste activated sludge. Clearly bulking not only adversely affects the efficiency of the secondary settling tank but also the efficiency of the sludge treatment units at the plant. While controlling or eliminating bulking at plants will certainly be beneficial for sludge handling, by far the most significant impact would be on the activated sludge process itself. It has been estimated that if the sludge settleability could be controlled at Diluted Sludge Volume Indices (DSVI) below 100 me/g, 50 to 100% more wastewater could be treated in existing plants leading to enormous savings (Ekama and Marais, 1986a). This single factor is the principal driving motive behind the research to establish the causes and control of filamentous bulking.","abstract_has_math":false,"creators":["Musvoto, Eustina V"],"institution":"Department of Civil Engineering","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Ekama, George"],"committee_chairs":[],"committee_members":[],"year":1992,"date_issued":"1992","date_published":"1992","updated_at":"2026-07-22T22:23:41Z","subjects":["Civil Engineering"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/38785","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Ekama, George"]},{"key":"dc:creator","label":"Author","values":["Musvoto, Eustina V"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-09-20T06:52:37Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-09-20T06:52:37Z"]},{"key":"dc:date.issued","label":"Date","values":["1992"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Civil Engineering"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters","MSc"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Civil Engineering"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/38785"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Filamentous bulking occurs when filamentous organisms are present in excessive numbers and extend from floes into the bulk solution. They interfere with the compaction and settling of the activated sludge either by producing a very diffuse floe structure or by causing bridging between floes. This results in a sludge with poor settleability i.e., low settling velocity and low solids concentration in the return activated sludge (RAS). In severe cases overflow of the sludge with the effluent occurs. Bulking not only causes these problems in the activated sludge process, but it also causes poor dewaterability of the waste activated sludge. Clearly bulking not only adversely affects the efficiency of the secondary settling tank but also the efficiency of the sludge treatment units at the plant. While controlling or eliminating bulking at plants will certainly be beneficial for sludge handling, by far the most significant impact would be on the activated sludge process itself. It has been estimated that if the sludge settleability could be controlled at Diluted Sludge Volume Indices (DSVI) below 100 me/g, 50 to 100% more wastewater could be treated in existing plants leading to enormous savings (Ekama and Marais, 1986a). This single factor is the principal driving motive behind the research to establish the causes and control of filamentous bulking."]},{"key":"dc:title","label":"Title","values":["The effect of a large anoxic mass fraction and concentrations of nitrate and nitrite in the primary anoxic zone on low f/m filament bulking in nutrient removal activated sludge systems"]}]}],"canonical_facts":{"dc:contributor.advisor":["Ekama, George"],"dc:creator":["Musvoto, Eustina V"],"dc:date.accessioned":["2023-09-20T06:52:37Z"],"dc:date.available":["2023-09-20T06:52:37Z"],"dc:date.issued":["1992"],"dc:description.abstract":["Filamentous bulking occurs when filamentous organisms are present in excessive numbers and extend from floes into the bulk solution. They interfere with the compaction and settling of the activated sludge either by producing a very diffuse floe structure or by causing bridging between floes. This results in a sludge with poor settleability i.e., low settling velocity and low solids concentration in the return activated sludge (RAS). In severe cases overflow of the sludge with the effluent occurs. Bulking not only causes these problems in the activated sludge process, but it also causes poor dewaterability of the waste activated sludge. Clearly bulking not only adversely affects the efficiency of the secondary settling tank but also the efficiency of the sludge treatment units at the plant. While controlling or eliminating bulking at plants will certainly be beneficial for sludge handling, by far the most significant impact would be on the activated sludge process itself. It has been estimated that if the sludge settleability could be controlled at Diluted Sludge Volume Indices (DSVI) below 100 me/g, 50 to 100% more wastewater could be treated in existing plants leading to enormous savings (Ekama and Marais, 1986a). This single factor is the principal driving motive behind the research to establish the causes and control of filamentous bulking."],"dc:identifier.uri":["http://hdl.handle.net/11427/38785"],"dc:publisher.department":["Department of Civil Engineering"],"dc:subject":["Civil Engineering"],"dc:title":["The effect of a large anoxic mass fraction and concentrations of nitrate and nitrite in the primary anoxic zone on low f/m filament bulking in nutrient removal activated sludge systems"],"dc:type":["Master Thesis"],"dc:type.qualificationlevel":["Masters","MSc"]},"updated_at":"2026-07-22T22:23:41Z"}