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

Park, Hee Deung; Whang, Liang Ming; Reusser, Steve; Noguera, Daniel R.

doi:10.2175/106143006x99786

Cited by 14 publications

(13 citation statements)

References 5 publications

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“…A laboratory-scale SBR was originally inoculated with activated sludge obtained from the Nine Springs WWTP in Madison, WI, which uses a modified University of Cape Town (UCT) process designed to achieve biological P removal 8 and operates with high aeration rates. 9 Synthetic wastewater containing acetate as the sole carbon source was used for the feed, as described elsewhere. 10 The hydraulic retention time (HRT) and solids retention time (SRT) were 24 h and 80 days, respectively.…”

Section: Methodsmentioning

confidence: 99%

Genome-enabled insights into the ecophysiology of the comammox bacteriumCandidatusNitrospira nitrosa

Camejo

Domingo²,

McMahon

et al. 2017

Preprint

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The recently discovered comammox bacteria have the potential to completely oxidize ammonia to nitrate. These microorganisms are part of the Nitrospira genus and are present in a variety of environments, including Biological Nutrient Removal (BNR) systems. However, the physiological traits within and between comammox- and nitrite oxidizing bacteria (NOB)-like Nitrospira species have not been analyzed in these ecosystems. In this study, we identified Nitrospira strains dominating the nitrifying community of a sequencing batch reactor (SBR) performing BNR under micro-aerobic conditions. We recovered metagenomes-derived draft genomes from two Nitrospira strains: (1) Nitrospira sp. UW-LDO-01, a comammox-like organism classified as Candidatus Nitrospira nitrosa, and (2) Nitrospira sp. UW-LDO-02, a nitrite oxidizing strain belonging to the Nitrospira defluvii species. A comparative genomic analysis of these strains with other Nitrospira-like genomes identified genomic differences in Ca. Nitrospira nitrosa mainly attributed to each strains’ niche adaptation. Traits associated with energy metabolism also differentiate comammox from NOB-like genomes. We also identified several transcriptionally regulated adaptive traits, including stress tolerance, biofilm formation and micro-aerobic metabolism, which might explain survival of Nitrospira under multiple environmental conditions. Overall, our analysis expanded our understanding of the genetic functional features of Ca. Nitrospira nitrosa, and identified genomic traits that further illuminate the phylogenetic diversity and metabolic plasticity of the Nitrospira genus.

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Section: Methodsmentioning

confidence: 99%

Genome-enabled insights into the ecophysiology of the comammox bacteriumCandidatusNitrospira nitrosa

Camejo

Domingo²,

McMahon

et al. 2017

Preprint

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“…The Nine Springs WWTP has approximately a 10-day SRT and 11 h hydraulic retention time. In the aerobic stage, DO reaches concentrations greater than 2 mg/L (Park et al, 2006b). …”

Section: Aterial and Methodsmentioning

confidence: 99%

Ammonia-oxidizing microbial communities in reactors with efficient nitrification at low-dissolved oxygen

et al. 2015

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Ammonia-oxidizing microbial communities involved in ammonia oxidation under low dissolved oxygen (DO) conditions (<0.3 mg/L) were investigated using chemostat reactors. One lab-scale reactor (NS_LowDO) was seeded with sludge from a full-scale wastewater treatment plant (WWTP) not adapted to low-DO nitrification, while a second reactor (JP_LowDO) was seeded with sludge from a full-scale WWTP already achieving low-DO nitrifiaction. The experimental evidence from quantitative PCR, rDNA tag pyrosequencing, and fluorescence in situ hybridization (FISH) suggested that ammonia-oxidizing bacteria (AOB) in the Nitrosomonas genus were responsible for low-DO nitrification in the NS_LowDO reactor, whereas in the JP_LowDO reactor nitrification was not associated with any known ammonia-oxidizing prokaryote. Neither reactor had a significant population of ammonia-oxidizing archaea (AOA) or anaerobic ammonium oxidation (anammox) organisms. Organisms isolated from JP_LowDO were capable of autotrophic and heterotrophic ammonia utilization, albeit without stoichiometric accumulation of nitrite or nitrate. Based on the experimental evidence we propose that Pseudomonas, Xanthomonadaceae, Rhodococcus, and Sphingomonas are involved in nitrification under low-DO conditions.

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“…Nitrification and denitrification kinetics under aerated conditions are characterized. Park et al (2006) Explored the advantages of operating the aerobic zone of one train of a full-scale University of Capetown BNR plant at a reduced dissolved oxygen concentration (0.5 mg/L). Biological nitrogen removal was increased from 54 to 65%, up to the limit of the available carbon.…”

Section: Simultaneous Biological Nutrient Removal Operating Mechanismsmentioning

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

Cited by 14 publications

References 5 publications

Genome-enabled insights into the ecophysiology of the comammox bacteriumCandidatusNitrospira nitrosa

Genome-enabled insights into the ecophysiology of the comammox bacteriumCandidatusNitrospira nitrosa

Ammonia-oxidizing microbial communities in reactors with efficient nitrification at low-dissolved oxygen

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

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