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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

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 re...

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Main Author: Musvoto, Eustina V
Other Authors: Ekama, George
Format: Thesis
Language:English
Published: Department of Civil Engineering 2023
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access_status_str Open Access
author Musvoto, Eustina V
author2 Ekama, George
author_browse Ekama, George
Musvoto, Eustina V
author_facet Ekama, George
Musvoto, Eustina V
author_sort Musvoto, Eustina V
collection Thesis
description 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.
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institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:47:37.468Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2023
publishDateRange 2023
publishDateSort 2023
publisher Department of Civil Engineering
publisherStr Department of Civil Engineering
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source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/38785 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 Musvoto, Eustina V Ekama, George Civil Engineering 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. 2023-09-20T06:52:37Z 2023-09-20T06:52:37Z 1992 2023-09-20T06:52:18Z Master Thesis Masters MSc http://hdl.handle.net/11427/38785 eng application/pdf Department of Civil Engineering Faculty of Engineering and the Built Environment
spellingShingle Civil Engineering
Musvoto, Eustina V
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
thesis_degree_str Master's
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
title_full 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
title_fullStr 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
title_full_unstemmed 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
title_short 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
title_sort 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
topic Civil Engineering
url http://hdl.handle.net/11427/38785
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