Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 40 for “"Nitrifiers"”.
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Comparing the responses of nitrifiers to differing ammonia loadings
Return active sludge from the Danville Sanitary plant (Danville, IL) was fed 10 mg NH3-N/L per cycle of separated swine manure to allow the biomass to adapt to a new influent in a sequencing batch reactor. The biomass was then separated into three reactors. A control reactor was exposed to 10 mg …
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Evaluation of seasonal impacts on nitrifiers and nitrification performance of a full-scale activated sludge system
Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology), Durban University of Technology, Durban, South Africa, 2016.
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Design of an integrated fixed-film activated sludge (IFAS) system for possible application at the Borcherds Quarry WWTW
… biological nutrient removal (BNR). Suspended nitrifiers only grow in the aerobic zone of the biological reactor but are subjected to anaerobic and anoxic conditions where no nitrifier growth takes place. To establish a nitrifier population that consistently produces low effluent ammonia …
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Variations in the Oxidative Rates of Nitrosomonas europaea in Coke-Plant Activated Sludge.
… of the population dynamics and physiology of the nitrifiers by developing a fast and accurate method for enumerating the nitrifiers. This will enable correlations to be made between the population densities and oxidation rates of the ammonia oxidizers.A fluorescent antibody (FAb) technique was …
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Nitrification and denitrification kinetics in the activated sludge process
… is affected in so far that growth of nitrifiers takes place in an aerobic environment, whereas death of nitrifiers takes place in both aerobic and anoxic environments. The existing empirical denitrification models (valid for constant flow and load conditions) could be deduced from the …
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Nitrification in premise plumbing and its effect on corrosion and water quality degradation
… concrete and iron materials encouraged growth of nitrifiers in certain oligotrophic waters, materials such as lead, PVC/plastic pipe, glass and surfaces of other materials were readily colonized by nitrifiers, and materials such as copper and brass were very toxic and relatively resistant to …
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Long-Term Lab Scale Studies of Simulated Reclaimed Water Distribution: Effects of Disinfectants, Biofiltration, Temperature and Rig Design
… dissolved oxygen, and caused elevated levels of nitrifiers and heterotrophic cell counts. A metagenomic taxonomic survey revealed high levels of gene markers of nitrifiers in the biofilm samples at 22°C for the chloraminated system. Non-metric multidimensional scaling analysis confirmed distinct …
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External nitrification in biological nutrient removal activated sludge systems
… The latter process, is mediated by the nitrifiers having a slow growth rate of 0.45/d, governs the sludge age of the biological nutrient removal activated sludge (BNRAS) system and thus results in long (20 - 25 day) sludge ages and large aerobic mass fraction requirements to nitrify …
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Characterizing Kinetic Shifts in Nitrifying, Denitrifying, and Phosphorus Removing Biomass Adapting to Low DO
… a method to characterize oxygen kinetics for nitrifiers, denitrifiers, and PAOs simultaneously is lacking. Here a method was developed to simultaneously measure the oxygen kinetics of nitrifiers, denitrifiers, and PAOs. This method, termed the SND and P-Uptake Oxygen Kinetics test, was able to …
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Comparing the Metcalf and Eddy and UCT steady state guidelines for sizing of biological nutrient removal activated sludge wastewater treatment plants
… using a fixed maximum specific growth rate of nitrifiers at 20oC (μAm20) at 0.90 g/(g.d), and after correcting for temperature, DO concentration in the aerobic reactor and assigning a safety factor (Sf = 1.5), the minimum sludge age for nitrification is slightly shorter than for the UCT …
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The biogeochemistry of marine nitrous oxide
… isotopic signatures of N2O produced by marine nitrifiers. This thesis shows that in addition to chemical controls on N2O production rates such as oxygen (O2) and nitrite (NO-2) concentrations, there are also biological controls such as nitrifier cell abundances and coastal phytoplankton blooms …
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The biogeochemistry of marine nitrous oxide
… isotopic signatures of N₂O produced by marine nitrifiers. This thesis shows that in addition to chemical controls on N₂O production rates such as oxygen (O₂) and nitrite (NO₂- ) concentrations, there are also biological controls such as nitrifier cell abundances and coastal phytoplankton blooms …
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Turnover and fluxes of carbon and nitrogen in a spruce forest under natural and extreme meteorological conditions
… than net ammonification, indicating that nitrifiers are more sensitive to drought stress than ammonifiers. The effect of soil frost strongly depended on soil freezing temperature. Only soil frost at temperature below -8°C led to short periods of additional DOC production in the organic …
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THE EFFECT OF BIOFILM CARRIER LENGTH ON NITRIFICATION IN MOVING BED BIOFILM REACTORS: AN EXAMINATION OF MIXING INTENSITY, SHOCK LOADINGS, AND PH CHANGES
… also conducted to assess inhibition effects on nitrifiers. Greater biomass was consistently measured on the longer media despite both media types having similar ammonia uptake during continuous operation. Lower G values consistently produced greater ammonia utilization in the short media biofilm …
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Geomicrobiology of nitrogen in a coastal aquifer : isotopic and molecular methods to examine nitrification and denitrification in groundwater
… methods to identify the populations of nitrifiers and denitrifiers, where they occur, and what levels of activity are present through the upper four meters of a coastal groundwater system. This work shows two different populations of putative ammonia-oxidizing archaea (AOA) based on the …
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Nitrification process in integrated fixed-film activated sludge (IFFAS) system
… and nitrite, in addition to the conventional nitrifiers found in the IFFAS system. Through the use of batch experiments, the different forms of nitrogen in the microbial nitrogen cycle (ammonia, nitrite, and nitrate) were measured over the course of the IFFAS reaction period, under aerated and …
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METHYLATED AMINE-UTILISING BACTERIA AND MICROBIAL NITROGEN CYCLING IN MOVILE CAVE
… bacteria. The roles of N2 fixers and nitrifiers were also investigated. Both bacterial and archaeal ammonia oxidisers were found to be active; however, sulfur oxidisers appeared to be the dominant autotrophs in Movile Cave.
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Mathematical modelling of integrated chemical, physical and biological treatment of wastewaters
… of pH on the maximum specific growth rates of nitrifiers was included.
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Geomicrobiology of nitrogen in a coastal aquifer : isotopic and molecular methods to examine nitrification and denitrification in groundwater
… methods to identify the populations of nitrifiers and denitrifiers, where they occur, and what levels of activity are present through the upper four meters of a coastal groundwater system. This work shows two different populations of putative ammonia-oxidizing archaea (AOA) based on the …
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The Potential for Eutrophication Mitigation from Aquaculture of the Native Oyster, Crassostrea virginica, in Chesapeake Bay: Quantitative Assessment of an Ecosystem Service
… by increasing the abundance of nitrifiers in sediments.
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