The role of residual quantities of suspended sludge on nitrogen removal efficiency in a deammonifying moving bed biofilm reactor

Leix, Carmen; Drewes, Jörg E.; Koch, Konrad

doi:10.1016/j.biortech.2016.07.134

Cited by 11 publications

(7 citation statements)

References 30 publications

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“…Both second stages were initially inoculated with concentrated sludge from a full-scale single-stage deammonification plant at the WWTP Ingolstadt, Germany. A high abundance of AOBs as well as AnAOBs has been detected for these biofilm carriers in our previous study [23], providing evidence for deammonification being the main underlying process. Due to the identical inoculation as well as a comparable startup and operation regime for both second stages, results from this predominant nitrogen removal process are also applicable to the reactor with suspended sludge.…”

Section: Methodssupporting

confidence: 67%

“…This is especially crucial for slow-growing AnAOBs [1]. Their predominant clustering in biofilms [23] is advantageous for their stable abundance in the system, while poor settling of the suspended sludge is often the reason for loss of biomass. Additionally, no settling phase is needed for biofilm carriers, elongating the reaction phase in the MBBR.…”

Section: Operational Assessmentmentioning

confidence: 99%

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Performance and N2O Formation of the Deammonification Process by Suspended Sludge and Biofilm Systems—A Pilot-Scale Study

Leix

Hartl

Zeh³

et al. 2016

Water

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Abstract:A two-stage deammonification pilot plant with two different second-stage reactors, namely a sequencing batch reactor (SBR) with suspended sludge and a moving bed biofilm reactor (MBBR) with biofilm carriers, was investigated over a 1.5-year period to compare reactor performances. Additionally, dissolved nitrous oxide (N 2 O) was measured to determine the reactors' N 2 O formation potential. Although the nitritation performance was moderate (NO 2 -N/NH 4 -N effluent ratio of 0.32 ± 0.15 in combination with SBR and 0.25 ± 0.14 with MBBR), nitrogen turnover and degradation rates exceeding 500 g N/(m 3 ·day) and 80%, respectively, were achieved in both second stages, yet requiring additional aeration. The SBR's average nitrogen removal was 19% higher than the MBBR's; however, the SBR's nitrite influent concentration was comparably elevated. Concerning N 2 O formation, the nitritation reactor exhibited the lowest N 2 O concentrations, while the buffer tank, interconnecting the first and second stages, exhibited the highest N 2 O concentrations of all reactors. Given these high concentrations, a transfer of N 2 O into the second stage was observed, where anoxic phases enabled N 2 O reduction. Frequent biomass removal and a decreased hydraulic retention time in the buffer tank would likely minimize N 2 O formation. For the second stage, enabling anoxic periods in the intermittent aeration cycles right after feeding to support N 2 O reduction and thus minimize the stripping effects or the implementation of a complete anoxic ammonium oxidation will mitigate N 2 O emissions.

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Section: Methodssupporting

confidence: 67%

Section: Operational Assessmentmentioning

confidence: 99%

Performance and N2O Formation of the Deammonification Process by Suspended Sludge and Biofilm Systems—A Pilot-Scale Study

Leix

Hartl

Zeh³

et al. 2016

Water

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“…3). Both are biological nutrient removal systems removing nitrogen by partial nitritation, followed by anammox (22)(23)(24). The biomass samples were from thick biofilm carriers for Kempten and large biomass granules from the swing-redox reactor.…”

Section: Discussionmentioning

confidence: 99%

“…Activated sludge samples from a WWTP in Garching, Germany, next to the Technical University of Munich (TUM), were collected from the denitrifying basin, which receives clarified nitraterich effluent from an upstream trickling filter (38). Biofilm carriers from the WWTP in Kempten, Germany, were collected from the deammonification basin (22). Biomass samples were also collected from two single-stage deammonification bioreactors, operating under alternating oxic/anoxic conditions (23).…”

Section: Methodsmentioning

confidence: 99%

Unexpected Diversity and High Abundance of Putative Nitric Oxide Dismutase (Nod) Genes in Contaminated Aquifers and Wastewater Treatment Systems

Zhu

Bradford

Huang

et al. 2017

Appl Environ Microbiol

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It has recently been suggested that oxygenic dismutation of NO into N 2 and O 2 may occur in the anaerobic methanotrophic "Candidatus Methylomirabilis oxyfera" and the alkane-oxidizing gammaproteobacterium HdN1. It may represent a new pathway in microbial nitrogen cycling catalyzed by a putative NO dismutase (Nod). The formed O 2 enables microbes to employ aerobic catabolic pathways in anoxic habitats, suggesting an ecophysiological niche space of substantial appeal for bioremediation and water treatment. However, it is still unknown whether this physiology is limited to "Ca. Methylomirabilis oxyfera" and HdN1 and whether it can be coupled to the oxidation of electron donors other than alkanes. Here, we report insights into an unexpected diversity and remarkable abundance of nod genes in natural and engineered water systems. Phylogenetically diverse nod genes were recovered from a range of contaminated aquifers and N-removing wastewater treatment systems. Together with nod genes from "Ca. Methylomirabilis oxyfera" and HdN1, the novel environmental nod sequences formed no fewer than 6 well-supported phylogenetic clusters, clearly distinct from canonical NO reductase (quinoldependent NO reductase [qNor] and cytochrome c-dependent NO reductase [cNor]) genes. The abundance of nod genes in the investigated samples ranged from 1.6 ϫ 10 7 to 5.2 ϫ 10 10 copies · g Ϫ1 (wet weight) of sediment or sludge biomass, accounting for up to 10% of total bacterial 16S rRNA gene counts. In essence, NO dismutation could be a much more widespread physiology than currently perceived. Understanding the controls of this emergent microbial capacity could offer new routes for nitrogen elimination or pollutant remediation in natural and engineered water systems.IMPORTANCE NO dismutation into N 2 and O 2 is a novel process catalyzed by putative NO dismutase (Nod). To date, only two bacteria, the anaerobic methaneoxidizing bacterium "Ca. Methylomirabilis oxyfera" and the alkane-oxidizing gammaproteobacterium HdN1, are known to harbor nod genes. In this study, we report efficient molecular tools that can detect and quantify a wide diversity of nod genes in environmental samples. A surprisingly high diversity and abundance of nod genes were found in contaminated aquifers as well as wastewater treatment systems. This evidence indicates that NO dismutation may be a much more widespread physiology in natural and man-made environments than currently perceived. The molecular tools presented here will facilitate further studies on these enigmatic microbes in the future.KEYWORDS nitric oxide (NO) dismutation, NO dismutase, oxygenic denitrification,

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“…This indicates that the activity of AOB plays a more important role than the biomass of AOB. An improvement in A E1 dissolved oxygen concentration allowed AOB activity to recover (Leix et al, 2016;Masic et al, 2010), but it enhanced NOB activity, which could be obtained from the activity ratio of AOB/NOB at phase III and phase V (Figure 4e,f). The difference between AOB and NOB activity decreased as dissolved oxygen concentration increased, and the percentage of NO À 2 -N in NO À x -N in the A E1 effluent decreased by 14.8% and 22.0% from phase II to III, and IV to V, respectively.…”

Section: Resultsmentioning

confidence: 93%

Shortcut Biological Nitrogen Removal from Coal Gasification Wastewater in Three‐Stage MBBRs

Han

2018

Water Environment Research

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A lab-scale aerobic-anoxic-aerobic (A E1 -A N -A E2 ) MBBR system was tested for the removal of COD, NH þ 4 -N, SCN -, phenols, and nitrogen from coal gasification wastewater, using a shortcut biological nitrogen removal process. Dissolved oxygen concentration in A E1 was maintained at 1.0 to 2.0 mg/L to ensure stable NO À 2 -N accumulation. Adding methanol wastewater to A N guaranteed denitrification efficiency. A E2 ensured high removal rates of NH þ 4 -N, SCN -, and phenols. The effects of influent pollutant concentration and hydraulic retention time (HRT) on nitrogen removal were studied. Improving the dissolved oxygen concentration in A E1 eliminated the negative effect of increased organic loading on nitrification, but it affected the stability of nitrosation. Shortening the HRT had negative effects on the performance of the system and performance recovered after it was extended. The average total nitrogen removal rate was 82.6% with a COD methanol /NO À x -N ratio of 3.5. Biomass and activity of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were measured to understand the evolution of nitrification. Water Environ. Res., 90, 1977Res., 90, (2018.

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The role of residual quantities of suspended sludge on nitrogen removal efficiency in a deammonifying moving bed biofilm reactor

Cited by 11 publications

References 30 publications

Performance and N2O Formation of the Deammonification Process by Suspended Sludge and Biofilm Systems—A Pilot-Scale Study

Performance and N2O Formation of the Deammonification Process by Suspended Sludge and Biofilm Systems—A Pilot-Scale Study

Unexpected Diversity and High Abundance of Putative Nitric Oxide Dismutase (Nod) Genes in Contaminated Aquifers and Wastewater Treatment Systems

Shortcut Biological Nitrogen Removal from Coal Gasification Wastewater in Three‐Stage MBBRs

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