Aerated Anoxic Oxidation-Denitrification Process

Albertson, Orris E.; Coughenour, Jim

doi:10.1061/(asce)0733-9372(1995)121:10(720)

Cited by 12 publications

(7 citation statements)

References 3 publications

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“…a Generally, acetic and propionic acid. Reference Observation Albertson and Coughenour (1995) and Albertson and Stensel (1994) The anoxic zone of an MLE process in one 115 000-m 3 /d train of the 91st Avenue WRRF in Phoenix, Arizona, was aerated to allow both nitrification and denitrification to occur there and to enhance total nitrogen removal. Complete denitrification in the aerated anoxic zone was observed.…”

Section: Simultaneous Biological Nutrient Removal Observationsmentioning

confidence: 99%

Simultaneous Biological Nutrient Removal: A State‐of‐the‐Art Review

Daigger¹,

Littleton

2014

Water Environment Research

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Simultaneous biological nutrient removal (SBNR) is the occurrence of biological nutrient removal (BNR) in systems that do not possess defined anaerobic and/or anoxic zones. A review of the relevant literature demonstrates that two mechanisms are primarily responsible for SBNR: (1) the bioreactor macro-environment and (2) the floc microenvironment. Complex hydraulic flow patterns exist in full-scale bioreactors that can result in the cycling of mixed liquor through the different environments needed for BNR. Diffusion resistance further allows oxygen-sufficient and oxygen-deficient zones to develop in activated sludge flocs if the external dissolved oxygen concentration is properly controlled. The diffusion of substrates between these zones allows BNR to occur. Long-term acclimation to the unique environmental conditions occurring in these systems results in the selection of microorganisms well adapted to the low dissolved oxygen concentrations occurring in them. The experience base for the design and operation of SBNR systems is expanding, thereby allowing their more widespread application, especially coupled with conventional mathematical modeling approaches. Computational fluid dynamics is an evolving tool to assist with the design and optimization of SBNR.

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Section: Simultaneous Biological Nutrient Removal Observationsmentioning

confidence: 99%

Simultaneous Biological Nutrient Removal: A State‐of‐the‐Art Review

Daigger¹,

Littleton

2014

Water Environment Research

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“…The DO concentration is a major environmental factor controlling nitrification and denitrification rates, and therefore, traditional nutrient removal treatment plants include separate anoxic and aerobic zones. Although significant nitrification is not expected at DO below 0.3 mg/L (Stenstrom and Poduska, 1980), treatment processes that promote simultaneous nitrification/denitrification can achieve up to 80% of the total nitrification under conditions involving minimal aeration (aerated-anoxic process) with no detectable DO levels (Albertson and Coughenour, 1995). Nitrification at low DO conditions contradicts the general paradigm that the DO concentration should be maintained above 1.5 mg/L for efficient nitrification (Wanner, 1997).…”

Section: Introductionmentioning

confidence: 99%

Molecular analysis of ammonia-oxidizing bacterial populations in aerated-anoxic Orbal processes

Park

Regan

Noguera

2002

Water Science and Technology

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Aerated-anoxic processes operate under the principle that small additions of oxygen to an anoxic reactor induce simultaneous nitrification and denitrification. In these systems, ammonia oxidation in the anoxic zone can easily account for 30-50% of the total nitrification in the reactor, even though the dissolve oxygen concentration is usually below detection limit. To investigate whether the nitrification efficiency in aerated-anoxic processes was due to the presence of specialized ammonia-oxidizing bacteria (AOB), an analysis of the AOB population in an aerated-anoxic Orbal process and a conventional nitrogen removal process was carried out using phylogenetic analyses based on the ammonia monooxygenase A (amoA) gene. Terminal restriction fragment length polymorphism (TRFLP) analyses revealed that Nitrosospira-like organisms were one of the major contributors to ammonia oxidation in a full-scale aerated-anoxic Orbal reactor. However, the relative populations of Nitrosospira-like and Nitrosomonas-like AOB were not constant and appeared to have seasonal variability. Cloning and sequence comparison of amoA gene fragments demonstrated that most of the AOB in the aerated-anoxic Orbal process belonged to the Nitrosospira sp. and Nitrosomonas oligotropha lineages. The abundance of Nitrosospira-like organisms in aerated-anoxic reactors is significant, since this group of AOB has not been usually associated with nitrification in wastewater treatment plants.

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“…The retrofitted plant had a modest increase in total nitrogen removal (from 54 to 65%) and a slight deterioration in effluent ammonium levels, although the latter were likely caused by the increased flow into the retrofitted plant rather than the reduction in DO. The gains in total nitrogen removal were low compared to removals reported for extended aeration systems that rely on simultaneous nitrification and denitrification in aerated‐anoxic zones ( Albertson and Coughenour, 1995 ; Applegate et al, 1980 ; Bertanza, 1997 ; Park et al, 2002 ; Smith, 1996 ). The study also demonstrated that including an aerated‐anoxic section in a UCT process without nitrate recycle does not negatively effect phosphorus removal.…”

Section: Resultsmentioning

confidence: 82%

Taking Advantage of Aerated‐Anoxic Operation in a Full‐Scale University of Cape Town Process

Park

Whang

Reusser

et al. 2006

Water Environment Research

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To evaluate the potential benefits or limitations of aerated‐anoxic operation in high‐rate biological nutrient removal processes, we conducted a full‐scale experiment in a University of Cape Town (UCT)‐type wastewater treatment plant by reducing oxygen supply and increasing flowrates within one treatment train so that aerated‐anoxic conditions (i.e., zones that receive oxygen but maintain dissolved oxygen concentrations below 0.5 mg/L) could be implemented in a section of the aerated zone. With this retrofitted configuration, total nitrogen removal increased from 54 to 65%, but was limited by the organic carbon available for denitrification. Furthermore, the significant reduction in dissolved oxygen concentrations in the aerated zone did not negatively affect enhanced biological phosphorus removal, demonstrating that the implementation of an aerated‐anoxic zone within a UCT‐type reactor can contribute to a reduction in operational costs and a slight improvement in total nitrogen removal, without compromising the extent of phosphorus removal.

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Aerated Anoxic Oxidation-Denitrification Process

Cited by 12 publications

References 3 publications

Simultaneous Biological Nutrient Removal: A State‐of‐the‐Art Review

Simultaneous Biological Nutrient Removal: A State‐of‐the‐Art Review

Molecular analysis of ammonia-oxidizing bacterial populations in aerated-anoxic Orbal processes

Taking Advantage of Aerated‐Anoxic Operation in a Full‐Scale University of Cape Town Process

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