{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/9945"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/9945","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"External nitrification in biological nutrient removal activated sludge systems","abstract":"In conventional nitrification-denitrification biological excess phosphorous removal (NDBEPR) activated sludge systems, such as the UCT system for example, both nitrification and phosphorous uptake (P uptake) occur simultaneously in the, usually large, aerobic reactor. In the UCT system the nitrate load to the anoxic reactor is limited by the a-recycle (i.e. system constraint recycle from the aerobic to the anoxic reactor) and the internal aerobic nitrification performance. The latter process, is mediated by the nitrifiers having a slow growth rate of 0.45/d, governs the sludge age of the biological nutrient removal activated sludge (BNRAS) system and thus results in long (20 - 25 day) sludge ages and large aerobic mass fraction requirements to nitrify completely. However, if stable nitrification could be achieved outside the BNRAS external nitrification (EN) system then nitrification and the suspended solids sludge age become uncoupled allowing greater flexibility into the BNRAS system.","abstract_html":"In conventional nitrification-denitrification biological excess phosphorous removal (NDBEPR) activated sludge systems, such as the UCT system for example, both nitrification and phosphorous uptake (P uptake) occur simultaneously in the, usually large, aerobic reactor. In the UCT system the nitrate load to the anoxic reactor is limited by the a-recycle (i.e. system constraint recycle from the aerobic to the anoxic reactor) and the internal aerobic nitrification performance. The latter process, is mediated by the nitrifiers having a slow growth rate of 0.45/d, governs the sludge age of the biological nutrient removal activated sludge (BNRAS) system and thus results in long (20 - 25 day) sludge ages and large aerobic mass fraction requirements to nitrify completely. However, if stable nitrification could be achieved outside the BNRAS external nitrification (EN) system then nitrification and the suspended solids sludge age become uncoupled allowing greater flexibility into the BNRAS system.","abstract_has_math":false,"creators":["Moodley, Rajan"],"institution":"Department of Mechanical Engineering","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Ekama, George A","Wentzel, Mark C"],"committee_chairs":[],"committee_members":[],"year":1999,"date_issued":"1999","date_published":"1999","updated_at":"2026-07-22T22:22:51Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/9945","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Ekama, George A","Wentzel, Mark C"]},{"key":"dc:creator","label":"Author","values":["Moodley, Rajan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-12-10T08:13:10Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-12-10T08:13:10Z"]},{"key":"dc:date.issued","label":"Date","values":["1999"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Mechanical Engineering"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["MSc"]}]},{"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/11427/9945"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes bibliography."]},{"key":"dc:description.abstract","label":"Abstract","values":["In conventional nitrification-denitrification biological excess phosphorous removal (NDBEPR) activated sludge systems, such as the UCT system for example, both nitrification and phosphorous uptake (P uptake) occur simultaneously in the, usually large, aerobic reactor. In the UCT system the nitrate load to the anoxic reactor is limited by the a-recycle (i.e. system constraint recycle from the aerobic to the anoxic reactor) and the internal aerobic nitrification performance. The latter process, is mediated by the nitrifiers having a slow growth rate of 0.45/d, governs the sludge age of the biological nutrient removal activated sludge (BNRAS) system and thus results in long (20 - 25 day) sludge ages and large aerobic mass fraction requirements to nitrify completely. However, if stable nitrification could be achieved outside the BNRAS external nitrification (EN) system then nitrification and the suspended solids sludge age become uncoupled allowing greater flexibility into the BNRAS system."]},{"key":"dc:title","label":"Title","values":["External nitrification in biological nutrient removal activated sludge systems"]}]}],"canonical_facts":{"dc:contributor.advisor":["Ekama, George A","Wentzel, Mark C"],"dc:creator":["Moodley, Rajan"],"dc:date.accessioned":["2014-12-10T08:13:10Z"],"dc:date.available":["2014-12-10T08:13:10Z"],"dc:date.issued":["1999"],"dc:description":["Includes bibliography."],"dc:description.abstract":["In conventional nitrification-denitrification biological excess phosphorous removal (NDBEPR) activated sludge systems, such as the UCT system for example, both nitrification and phosphorous uptake (P uptake) occur simultaneously in the, usually large, aerobic reactor. In the UCT system the nitrate load to the anoxic reactor is limited by the a-recycle (i.e. system constraint recycle from the aerobic to the anoxic reactor) and the internal aerobic nitrification performance. The latter process, is mediated by the nitrifiers having a slow growth rate of 0.45/d, governs the sludge age of the biological nutrient removal activated sludge (BNRAS) system and thus results in long (20 - 25 day) sludge ages and large aerobic mass fraction requirements to nitrify completely. However, if stable nitrification could be achieved outside the BNRAS external nitrification (EN) system then nitrification and the suspended solids sludge age become uncoupled allowing greater flexibility into the BNRAS system."],"dc:identifier.uri":["http://hdl.handle.net/11427/9945"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Mechanical Engineering"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["External nitrification in biological nutrient removal activated sludge systems"],"dc:type":["Master Thesis"],"dc:type.qualificationlevel":["Masters"],"dc:type.qualificationname":["MSc"]},"updated_at":"2026-07-22T22:22:51Z"}