A closer look at the bacteriology of nitrification

Hagopian, Daniel S.; Riley, John G.

doi:10.1016/s0144-8609(98)00032-6

Cited by 211 publications

(126 citation statements)

References 101 publications

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“…The observed variation of nitrification with depth supports the fact that the process is partly light inhibited (Fig. 5b) and this is in agreement with what we know about the distribution of nitrification in the ocean (Hagopian and Riley, 1998;Ward, 2008). High nitrification rates are usually reported near the bottom of the euphotic layer where organic matter is still abundant and light is much reduced, allowing the nitrifiers to compete with phytoplankton for the ammonium produced by remineralization (Lipschultz et al, 1991;Ward, 2008).…”

Section: Upper-ocean N Cycling: High F Ratios and Nitrification Ratessupporting

confidence: 87%

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

et al. 2015

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Abstract. Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO − 3 and NH + 4 ), and nitrification rates were measured at eight stations in austral spring 2011 (October-November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m −2 d −1 and up to 0.31 d −1 respectively) compared to the HNLC reference site (12 mmol C m −2 d −1 and 0.06 d −1 respectively). Primary production was mainly sustained by nitrate uptake, with f ratios (corresponding to NO − 3 -uptake / (NO − 3 -uptake + NH + 4 -uptake)) lying at the upper end of the observations for the Southern Ocean (up to 0.9). We report high rates of nitrification (up to ∼ 3 µmol N L −1 d −1 , with ∼ 90 % of them < 1 µmol N L −1 d −1 ) typically occurring below the euphotic zone, as classically observed in the global ocean. The specificity of the studied area is that at most of the stations, the euphotic layer was shallower than the mixed layer, implying that nitrifiers can efficiently compete with phytoplankton for the ammonium produced by remineralization at low-light intensities. Nitrate produced by nitrification in the mixed layer below the euphotic zone is easily supplied to the euphotic zone waters above, and nitrification sustained 70 ± 30 % of the nitrate uptake in the productive area above the Kerguelen Plateau. This complicates estimations of new production as potentially exportable production. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration.

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Section: Upper-ocean N Cycling: High F Ratios and Nitrification Ratessupporting

confidence: 87%

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

et al. 2015

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“…For example, salmon absorbs only around 58% of feed protein. Thus around 25% of nitrogen in feed is emitted through gill and with excrements (Hagopian, Riley, 1998).…”

Section: Nitrogen In Ras Wastementioning

confidence: 99%

Waste and Its Characterization in Closed Recirculating Aquaculture Systems – A Review

Mongirdas¹,

Žibienė

Žibas

2017

Journal of Water Security

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Abstract. Just like every economic activity, aquaculture has a particular effect on environment, which manifests itself due to waste through declining quality of subterranean water and eutrophication of surrounding surface water. Less than half of the feed in aquaculture is digested and assimilated, the rest ending up as waste either solid or dissolved and the nutrients phosphorus (P) and nitrogen (N) that are derived from fish excretion, faeces, and uneaten feed. The advantage of recirculating aquaculture systems (RAS) is that their wastewater discharges are 10-100 times lower and pollutant concentration respectively 10-100 times higher and can reach the level of pollution of household waste. This makes the pollution much easier to control. Additionally, striving to ensure and improve the stability and longevity of RAS, additional technological solutions, warranting the reduction of the amount of used water, waste concentration increase and their secondary utilization as bio stock are added. This article presents the research information from the engineering perspective, summarizing RAS design sensitive data concerning aquacultural waste components excreted in RAS.

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“…Essa tendência se deve, provavelmente, à diminuição da eficiência da atividade microbiana ocasionada pelo desligamento dos microrganismos do meio-suporte, devido à maior turbulência no meio líquido observada no reator quando em maiores concentrações de oxigenação. Segundo HAGOPIAN & RILEY (1998), a imobilização da biomassa favorece a eficiência do processo, pois possibilita situações que permitem melhor desempenho dos microrganismos.…”

Section: Resultsunclassified

Influência de nitrogênio amoniacal e vazão de ar no processo de nitrificação, etapa de tratamento de efluente de abatedouro de peixe

et al. 2010

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RESUMO: O efluente proveniente de abatedouro de peixes possui alto teor de nitrogênio, um dos principais causadores de eutrofização nos corpos d'água. Sua remoção pode ser feita em duas etapas separadas: nitrificação e desnitrificação. Este experimento teve como objetivo testar a influência da vazão de ar (valores de 1 a 3 L min -1 ) e a concentração de nitrogênio amoniacal (de 40 a 100 mg L -1 ) no processo de nitrificação. Foi utilizado um reator em batelada sequencial com biomassa imobilizada, com volume útil de 2,5 L, operado conforme delineamento composto central rotacional, em que as variáveis-resposta analisadas foram percentagem de conversão de nitrogênio amoniacal a nitrato e percentagem de acúmulo de nitrito. Os resultados mostraram, com intervalo de confiança de 95%, que o aumento dos dois fatores diminuiu significativamente a percentagem de conversão de nitrogênio amoniacal a nitrato. Já a percentagem de acúmulo de nitrito aumentou significativamente quando houve aumento da concentração de nitrogênio amoniacal, não sendo influenciada significativamente pela vazão de ar. Durante o experimento, a melhor condição de operação encontrada para o equilíbrio das reações foi com concentração de nitrogênio amoniacal de 70 mg L -1 e com vazão de ar de 2 L min -1 . PALAVRAS-CHAVE:efluente anaeróbio, remoção de nitrogênio, nitrificação. AMMONIA NITROGEN AND AIR FLOW INFLUENCE ON NITRIFICATION PROCESS, PART OF THE TREATMENT FOR FISH SLAUGHTERHOUSE EFLUENT ABSTRACT:The fish slaughterhouse effluent presents high levels of nitrogen, one of the major causes of eutrophication in water bodies. Nitrogen removal can be accomplished in two separate stages: Nitrification and Denitrification. This experiment aimed to test the influence of air flow (values between 1 and 3 L min -1 ) and ammonia nitrogen concentration (between 40 and 100 mg L -1 ) in the nitrification process. A 2.5 L volume sequencing batch reactor with immobilized biomass was operated as central rotational composed design, where the evaluated results were conversion of ammonia nitrogen to nitrate in percentage and nitrite accumulation in percentage. The results with confidence interval of 95% showed that the increase of both variables resulted in the significant reduction of the percentage of nitrogen conversion to nitrate. The nitrite accumulation percentage significantly increased with the ammonia nitrogen increase, although it was not observed significant influence of air flow. During the experiment the best condition found for the equilibrium of the reactions was 70 mg L -1 of ammonia nitrogen and air flow of 2 L min -1 .

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A closer look at the bacteriology of nitrification

Cited by 211 publications

References 101 publications

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

Waste and Its Characterization in Closed Recirculating Aquaculture Systems – A Review

Influência de nitrogênio amoniacal e vazão de ar no processo de nitrificação, etapa de tratamento de efluente de abatedouro de peixe

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