Dissertations / Theses: 'Denitrification rate'

1

Richens, Jared. "Evaluating the Impact of External Carbon Source in Laboratory-Based Denitrification Rate Experiments." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/6912.

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Limitations in the quality of transformation rates used with water quality models such as QUAL2K have led to the need to identify methods that can effectively and accurately determine these rates. During the early stages of method development of a Utah Department of Environmental Quality (Utah DEQ) funded project seeking to identify such methods, it was determined that under certain situations external carbon amendment may be required to successfully determine denitrification rates. The focus of this study was to evaluate the potential impacts that introducing external carbon sources may have on estimating the laboratory denitrification rates resulting from these methods. Ultimately it was shown that, carbon amendment does not negatively impact the comparability of laboratory-generated rates to those that could be measured using in-situ methods. Additionally, it was determined that the Substrate Chemical Product method discussed herein should be used along with a no carbon, glucose, and sodium acetate amended treatments. After analysis of the data, the highest rate should be used if differences caused by carbon amendment can be identified.

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2

Elmi, Abdirashid A. "Denitrification in sandy loam soil as influenced by water table depth and nitrogen fertilization rate." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0003/MQ44163.pdf.

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3

Kjellin, Johan. "Coupled Hydrological and Microbiological Processes Controlling Denitrification in Constructed Wetlands." Licentiate thesis, Stockholm : [Mark- och vattenteknik, Kungliga Tekniska högskolan], 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4370.

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Yatham, Venkata Krishna Reddy. "Study of Nitrogen Removal Rate and Trouble shooting of Pilot plant (ITEST)." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171806.

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This paper is about improving the efficiency of nitrogen and other organic nutrient removal from activated sewage treatment by adopting an innovative technology. The work is to study the changes in nitrogen removal in pilot-scale experiments with the ITEST unit. The report also describes the various sources contributing to the eutrophication of the sea and water, caused by an increase in nutrient levels in different water bodies. Ineffective treatment of sewage contributes to the eutrophication. In the Baltic regions the temperature will be zero (0) or less than zero degree-centigrade during winter season. It results in decreased or fall in temperatures of incoming water to wastewater treatment plants. The temperature is an important parameter for sewage/wastewater treatment processes. Bacteriological nitrification and denitrification is an effective process for removing nitrogen from wastewater. From various research works and articles, it can be found that 23 + / - 2 °C, is the optimum temperature for nitrification and denitrification processes. So, the main aim is to study the effect of maintaining the incoming wastewater temperature by use of heat exchangers on incoming water to an activated sludge process line in pilot plant scale. In the pilot plant there were two testing lines; one line with heating system and the second line without heating system. A temperature of 19 to 20 °C was maintained in the influent to testing line. The nitrogen removal rates were compared between the two lines during the test period of approximately more than 8 months. Other biological activities in the treatment process were also compared between the two lines.

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Ersan, Yusuf Cagatay. "The Effects Of Seed Sludge Type And Anoxic/aerobic Period Sequence On Aerobic Granulation And Cod, N Treatment Performance." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615330/index.pdf.

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The aim of this master thesis study was improvement of the required operational conditions for aerobic granulation in sequencing batch reactors (SBRs). In the first part of the study, membrane bioreactor sludge (MBS) and conventional activated sludge (CAS), were used to investigate the effect of suspended seed sludge type on granulation in SBRs. The MBS granules were found to be advantageous in terms of size, resistance to toxic effects, stability and recovery compared to CAS granules. During non-inhibitory conditions, sCOD removal efficiencies were 70±
13% and 67±
11% for MBS and CAS, and total nitrogen (TN) removal efficiencies were 38±
8% and 26±
8%, respectively. In the second part of the study, the effects of period sequence (anoxic-aerobic and aerobic-anoxic) on aerobic granulation from MBS, and sCOD, N removal efficiencies were investigated. Granules developed in anoxic-aerobic period sequence were more stable and larger (1.8-3.5 mm) than granules developed in aerobic-anoxic sequence. Under steady conditions, almost 95% sCOD, 90% Total Ammonia Nitrogen (TAN) and around 39-47 % of TN removal was achieved. Almost 100% denitrification in anoxic period was achieved in anoxic-aerobic period sequence and it was observed around 40% in aerobic-anoxic period sequence. The effects of influent sulfate (from 35.1 mg/L to 70.2 mg/L) on treatment efficiencies of aerobic granules were also investigated. The influent SO42- concentrations of 52.6 mg/L to 70.2 mg/L promoted sulfate reduction. The produced sulfide (0.24 mg/L to 0.62 mg/L) inhibited the ammonia-oxidizing bacteria (AOB) performance by 10 to 50%.

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Thunberg, Andreas. "Energieffektivisering av luftningssteget på Käppalaverket, Lidingö." Thesis, Uppsala University, Department of Earth Sciences, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88824.

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This master thesis in energy optimization was made during the autumn of 2006 at Käppala wastewater treatment plant in Lidingö, Stockholm. A preceding thesis, where all electricity consumption was mapped, showed that the aeration in the biological treatment is the single largest consumer in the plant, and it is therefore of interest to reduce this cost. The oxygen control strategy used at Käppala WWTP is working well from a nutrient removal point of view, but not from an economic one. The last aerobic zones have a very low oxygen consumption during low loading periods which give rise to enhanced dissolved oxygen concentrations with excessive costs and reduced denitrification as a result. But also during periods of normal loading unnecessary high oxygen concentration are sometimes given.

By modifying the aeration control strategy three full-scale experiments have been made, with the intention to reduce the air consumption. The experiments were carried out during week 37-50 in the autumn of 2006 and showed that savings could be made.

The regular oxygen control at Käppala WWTP controls the oxygen level in the aerobic compartment with two DO-setpoints; one in the first aerobic zone and one in the last. The zones in between are controlled by an airflow fractionation depending on the oxygen level in the first and last zone. In the first strategy to be evaluated, all four zones in the aerated part were individually controlled with its own setpoint. Two different setpoint combinations were tested. By using the fact that the efficiency in the oxygen transfer rate was higher at low airflows, savings of approximately 16 % were achieved. In the second strategy tested, an ammonia-feedback control combined with a DO-feedback controlled the DO-set point in the first aerobic zone. This strategy adjusted the DO- set points to the loading variations, and this gave a decreased airflow of approximately 9 %. Finally the two strategies were combined. All zones were then controlled individually with DO-set points set by an ammonium-feedback and a DO-feedback. The strategy gave savings in the airflow of approximately 18 %. In all three trials the aerated zones were more efficiently used, and the estimated savings are 550 000 SEK/year, and with a preserved nutrient removal efficiency.

Under hösten 2006 har ett examensarbete om energieffektivisering på Käppalaverket på Lidingö utförts. Ett föregående examensarbete där all elenergiförbrukning kartlades visade att blåsmaskinerna i biosteget står för den enskilt största förbrukningen i verket och det är därför av intresse att minska denna kostnad. Syrestyrningsstrategin som används på Käppalaverket fungerar mycket bra ur reningssynpunkt, men är inte optimal ur energisynpunkt. Dels luftas de första aeroba zonerna för mycket vid låg belastning vilket ger upphov till kraftigt förhöjda syrekoncentrationer i de sista aeroba zonerna med höga luftningskostnader och risk för försämrad denitrifikation, men även under normal belastning har det visat sig att onödigt höga syrekoncentrationer ibland ges.

Tre fullskaliga optimeringsförsök har utförts, med syfte att minska luftförbrukningen med bibehållen reningsgrad. Försöken pågick från vecka 37 till 50 hösten 2006, och visade att det finns möjlighet att spara energi genom att modifiera syrestyrningsstrategin.

Den reguljära syreregleringen i Käppalaverket styr syrehalten i den aeroba bassängen mot två syrebörvärden; ett i den första luftade zonen och ett i den sista. Luftflödet till de mellanliggande zonerna styrs av luftflödesandelar beroende på syrehalten i dessa två zoner. Den första strategin som utvärderades styrde istället samtliga zoner individuellt med egna börvärden, där två olika strukturer på de satta börvärdena användes. Genom att utnyttja en högre effektivitet i syreöverföringshastigheten vid låga luftflöden uppnåddes luftflödesbesparingar på ca 16 % i första försöket.

I den andra strategin styrdes syrebörvärdet i den första luftade zonen med hjälp av två återkopplingar, en från utgående ammoniumhalt och en från syrehalten i den sista luftade zonen.

Tack vare att strategin anpassade syrebörvärdena efter belastningen av syretärande ämnen erhölls luftflödesbesparingar på ca 9 %. Slutligen kombinerades de två strategierna; samtliga zoner styrdes individuellt med börvärden satta av en ammonium-återkoppling och en syre-återkoppling. Strategin medförde luftflödesbesparingar på ca 18 %. I samtliga försök utnyttjades de luftade zonerna bättre, och besparingspotentialen uträknad från 2005 års elpriser blev som mest 550 000 SEK/år, detta med en bibehållen reningsgrad.

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7

Bamber, Kevin William. "Nitrogen Cycling from Fall Applications of Biosolids to Winter Small Grains." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/71870.

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Environmental concerns about winter nitrogen (N) leaching loss limit the amount of biosolids applied to winter small grains in Virginia. Ten field studies were established 2012-2014 in Virginia to determine the agronomic and environmental feasibility of fall biosolids applications to soft red winter wheat (Triticum aestivum L.). Eight studies were located in the Coastal Plain physiographic province and two in the Ridge and Valley physiographic province. The effects of eight biosolids and urea N treatments on 1) biomass production at Zadoks growth stage (GS) 25-30, 2) soil inorganic N at GS 25-30, 3) soil mineralizable N at GS 25-30,4) N use efficiency (NUE) at GS 58, 5) grain yield, 6) end-of-season soil inorganic N, and 7) estimated N recovery were studied. Anaerobically digested (AD) and lime stabilized (LS) biosolids were fall applied at estimated plant available N (PAN) rates of 100 kg N ha-1 and 50 kg N ha-1. The 50 kg N ha-1 biosolids treatments were supplemented with 50 kg N ha-1 as urea in spring. Urea N was split applied at 0, 50, 100 and 150 kg N ha-1, with 1/3 applied in fall and 2/3 in spring. Biomass at GS 25-30 increased with urea N rate and biosolids always resulted in equal or greater biomass than urea. Soil mineralizable N at GS 25-30 rarely responded to fall urea or biosolids N rate, regardless of biosolids type. Biosolids and urea applied at the agronomic N rate resulted in equal grain yield and estimated N recovery in soils where N leaching loss risk was low, regardless of biosolids type or application strategy. Lime stabilized biosolids and biosolids/urea split N application increased grain yield and estimated N recovery in soils with high or moderate N leaching loss risk. Therefore, AD and LS biosolids can be fall-applied to winter wheat at the full agronomic N rate in soils with low N leaching loss risk, while LS biosolids could be applied to winter wheat at the full agronomic N rate in soils with moderate or high N leaching loss risk.
Master of Science

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8

Watkins, Natalie Lisa. "The ability of nitrification inhibitors to decrease denitrification rates in dairy farm soils." The University of Waikato, 2007. http://hdl.handle.net/10289/2518.

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Increasing pressure is being placed on the dairy industry to reduce nitrogen losses from soil. Nitrification inhibitors are a management strategy that could be implemented on dairy farms to help reduce losses of nitrogen. Nitrification inhibitors work by temporarily inhibiting the microbial conversion of soil ammonium to nitrate. Past trials have indicated that nitrification inhibitors can increase grass production and decrease nitrate leaching; however, little is known about the long-term effects on other soil nitrogen processes such as denitrification. Denitrification rates in soils can be limited by the availability of substrate (carbon and nitrate) and by insufficient anaerobic microsites. The objective of this thesis was to establish whether the nitrification inhibitor, dicyandiamide (DCD), could decrease denitrification rates in dairy farm soils by limiting nitrate availability. A field trial was established at Dexcel's research farm near Hamilton, New Zealand on a Typic Orthic Allophanic Soil. Twenty replicated field plots were established in a paddock, ten plots acted as controls and ten plots had DCD applied to the soil once a month at a rate of 30 kg ha-1 yr-1. Denitrification rates were measured using the acetylene inhibition technique on intact soil cores. Ammonium and nitrate concentration, soil carbon availability, denitrifying enzyme activity and soil pH were measured from soil samples collected monthly. Two further field experiments and one laboratory experiment were undertaken. The distribution of denitrifying enzyme activity with soil depth was measured to ensure that the depth to which denitrification was sampled (15 cm) in the field experiment was sufficient. DCD degradation in the field during 20 days was measured to establish how long the effects of DCD might last. A laboratory study investigated whether DCD would decrease denitrifying enzyme activity in soil, when soil conditions were optimized for denitrification. More than 80% of the denitrifying enzyme activity occurred in the top 15 cm of the soil profile, indicating that the depth to which samples were collected was sufficient. There was no significant decrease in denitrification rates in the field experiment when DCD was added. Nitrification was partially inhibited as shown by a significant increase in soil ammonium (+14%) and a significant decline in soil nitrate (-17%) in the DCD-amended soils compared to the control soils. However, the decline in soil nitrate was not great enough for nitrate to limit denitrification. Nitrate concentrations were consistently greater than 5 mg NO3- kg-1 soil (the proposed threshold for declines in denitrification). The laboratory study supported the field study with DCD having no effect on denitrifying enzyme activity and nitrate concentrations remaining above 5 mg NO3- kg-1 soil. So while DCD reduced nitrification rates and the formation of nitrate, denitrification rates were not limited by nitrate availability. DCD was completely degraded in the soil 19 days after DCD application, with a half-life of 2.9 days, which may be a reason for the minor inhibition of nitrification. Denitrifying enzyme activity, carbon availability and soil pH were all unaffected by the application of DCD.

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9

Olsson, Camilla. "Nitrous Oxide in Himmerfjärden: Seasonal Variability in Production Rates and Fluxes." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-119634.

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10

Machado, Ana Margarida Pinto Henrique. "" Influence of Marsh Flora on Denitrification Rates and the Abundance and Community Structure of Denitrifying "." Dissertação, Instituto de Ciências Biomédicas Abel Salazar, 2010. http://hdl.handle.net/10216/57201.

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11

Machado, Ana Margarida Pinto Henrique. "" Influence of Marsh Flora on Denitrification Rates and the Abundance and Community Structure of Denitrifying "." Master's thesis, Instituto de Ciências Biomédicas Abel Salazar, 2010. http://hdl.handle.net/10216/57201.

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12

Wilson, Greg J. "Combining field measurement of nitrate removal rates and a flow model to predict nitrate removal in the Walker River riparian zone." abstract and full text PDF (free order & download UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1460789.

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13

Deemer, Bridget Read. "Thermal stratification impacts microbial nitrogen removal and nitrous oxide production in a small eutrophic reservoir an in-situ approach to quantifying hypolimnetic process rates /." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/B_Deemer_042310.pdf.

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Thesis (M.S. in environmental science)--Washington State University, May 2010.
Title from PDF title page (viewed on July 21, 2010). "School of Earth and Environmental Science." Includes bibliographical references (p. 23-28).

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Isaksson, Linnea. "Measurement of nitrogen transformation rates in Baltic Sea sediment : Measurements of denitrification and anammox using the 15N tracer method." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-90581.

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15

Wild, Lisa Maria [Verfasser], Florian [Akademischer Betreuer] Einsiedl, Gunnar [Gutachter] Nützmann, Florian [Gutachter] Einsiedl, and Karl [Gutachter] Auerswald. "Assessing denitrification in groundwater using environmental isotopes, oxygen reduction rates and Monte Carlo simulations / Lisa Maria Wild ; Gutachter: Gunnar Nützmann, Florian Einsiedl, Karl Auerswald ; Betreuer: Florian Einsiedl." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1210163462/34.

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Elshikh, Ahmed Fahmy Mahoud Aly, and 和平. "Effects Of Probiotics Isolated From Commercial Denitrification Product And Penaeus Monodon Colon On Denitrification Activities And Survival Rate Of Litopenaeus Vannamei." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/92207853154471814930.

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碩士
國立高雄海洋科技大學
海洋生物技術研究所
100
Litopenaeus vannamei, Pacific white shrimp, is one of the most intensively cultivated shrimps in the world. It is the most important commercially penaeid shrimp in Taiwan. Nitrite is one of the most important factors in pond water affecting shrimp’s survival and health. This study aimed to find how heterotrophic denitrification bacteria decompose nitrite in water and enhanc white shrimps survival rate at wide ranges of salinities and temperatures. Our results demonstrated that A5 and T bacteria are able to reduce nitrite up to 95% at different salinities up to 45g/L. A5 and T exhibited high activities in reducing NO2- at different temperatures, except at 15°C. A5 and T also could reduce NO2- at different salt sources, NaCl and sea salt. In white shrimps fed with A5, the mortality decreased around 60%. With the addition of Glucose shrimp food, A5 could reduce NO2- in cultured pond water in an dose-dependent manner. This result partially supported the farmer’s practical experience. Our results suggest that A5 might be usefule as a probiotic to enhance shrimp survival and degrade nitrite in pond water. In the future, we will carry on field test to investigate the denitrification mechanism(s) which are regulated by sugar and other factors in pond water.

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17

Hollingham, Melisa. "Effect of organic carbon substrates on denitrification rates in sediment." Thesis, 2013. http://hdl.handle.net/10012/8217.

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Nitrate (NO3-) is a ubiquitous groundwater contaminant in agricultural and wastewater discharge areas. The prediction of microbial mediated NO3- removal in subsurface environments requires an understanding of the rates at which electron donors are utilized by denitrifying microbes. This study focuses specifically on the following organic carbon compounds as electron donors: glucose, acetate, adenine, cysteine and fulvic acid. Six triplicate series of flow through reactors (FTRs) containing 35 cm3 of natural, organic-poor sediment were supplied for 10 weeks with solutions containing nitrate and the individual carbon compounds, along with a no-carbon added control. The organic carbon compounds were selected to yield a range of different types of organic carbon (sugars, amino acids etc.) as well as a range of Gibbs Free Energy (???G) values when their oxidation is coupled to denitrification. The initial flow rate of the FTRs was 1 ml h-1. Once steady NO3- concentrations were reached in the outflow, the flow rate was increased to 2 ml h-1 and, subsequently, 4 ml h-1. Potential denitrification rates (RD) measured for the different carbon substrates spanned a range of 0 to 114 nmol cm-3 h-1. Fulvic acid did not induce denitrification, while acetate yielded the highest rate. The outflow solutions for FTRs supplied with adenine and cysteine contained ammonia and sulfate, respectively. These results are consistent with the molecular structure of adenine, which contains an amine group, and of cysteine, containing an amine and thiol group. The results show that the addition of C-substrates to the sediment promotes denitrification, and the rate at which it occurs are dependant on which C-substrate is provided. RD results were used to determine if the denitrification rates imposed by the different carbon substrates could be predicted using theoretical approaches such as ???GR or the nominal oxidation state of carbon (NOSC). However, predictions determined by thermodynamics alone were not significantly correlated with the observed trends in denitrification rates.

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18

Eschenbach, Wolfram. "Determination of the denitrification capacity of unconsolidated rock aquifers using 15N tracer experiments at groundwater monitoring wells - development of a new method to assess actual and future denitrification in aquifers." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0023-994C-3.

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Dissertations / Theses on the topic 'Denitrification rate'

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