nitrate reduction Articles
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Enhanced removal of nitrate from water using nZVI@MWCNTs composite: synthesis, kinetics and mechanism of reduction
Herein, multi-wall carbon nanotubes (MWCNTs) were used as the carrier of nano-zero valent iron (nZVI) particles to fabricate a composite known as nZVI@MWCNTs. The composite was then characterized and applied in the nitrate removal process in a batch system under anoxic conditions. The influential parameters such as pH, various concentrations of nitrate and composite were investigated within ...
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Evaluation of passive reduction of nitrate from greenhouse effluent by planted bioreactors
A number of pilot-scale gravel and wood-chip hybrid bioreactors planted with select species, together with unplanted units, were evaluated for their nutrient removal capabilities from the typical greenhouse effluent with high levels of nitrate and salts. Two levels of nutrient solution (high and low loading: HL/LL) were prepared to simulate the typical characteristics of the greenhouse ...
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Ochrobactrum anthropi used to control ammonium for nitrate removal by starch-stabilized nanoscale zero valent iron
In this study, the hydrogenotrophic denitrifying bacterium Ochrobactrum anthropi was added in to the process of nitrate removal by starch-stabilized nanoscale zero valent iron (nZVI) to minimize undesirable ammonium. The ammonium control performance and cooperative mechanism of this combined process were investigated, and batch experiments were conducted to discuss the effects of ...
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Electrochemical treatment of wastewater polluted by nitrate: selective reduction to N2 on Boron-Doped Diamond cathode
Electrochemical tests of nitrate reduction on Boron-Doped Diamond cathode are investigated through a Design of Experiments (DOE) method. The results show good reduction of nitrate into almost exclusively N2. In the studied domain, the best experimental conditions are high initial nitrate content, low acidic pH values and low working current densities. The application of DOE conclusions on an ...
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Elimination of nitrate in secondary effluent of wastewater treatment plants by Fe0 and Pd-Cu/diatomite
Because total nitrogen (TN), in which nitrate (NO3–) is dominant in the effluent of most wastewater treatment plants, cannot meet the requirement of Chinese wastewater discharge standard (<15 mg/L), NO3– elimination has attracted considerable attention. In this research, the novel diatomite-supported palladium-copper catalyst (Pd-Cu/diatomite) with zero-valent iron (Fe0) was tried to use ...
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Effect of passivated iron powder on final-product distribution in Fe-supported denitrification
An integrated nitrate treatment using passivated iron powder (PIP) and Alcaligenes eutrophus, which is a kind of hydrogenotrophic denitrifying bacteria, was conducted to investigate the effect of iron oxide coating on final-product distribution in hydrogenotrophic denitrification. Based on the results, the autotrophic denitrification supported by PIP could completely remove about 50 ...
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The effect of several parameters on catalytic denitrification of water by the use of H2 in the presence of O2 over metal supported catalysts
The present paper involves a detailed study of the selective catalytic reduction of nitrates in aqueous mediums by the use of H2 in the presence of O2 over monometallic and bimetallic supported catalysts. In this study, an attempt has been made to improve the denitrification efficiency (XNO3−, SN2) of several catalysts by regulating some experimental parameters that are involved in the ...
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Impact of precipitation on the treatment of real ion-exchange brine using the H2-based membrane biofilm reactor
The H2-based membrane biofilm reactor (MBfR) was used to remove nitrate and perchlorate from real ion-exchange brine at two different salinities (30- and 50-g/L NaCl). Base production from nitrate reduction to N2 gas caused the pH to increase, and this exacerbated precipitation of calcium and magnesium carbonates onto the MBfR fibers. The precipitates lowered the H2 flux to the biofilm and caused ...
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Use of biopolymers as solid substrates for denitrification
The conventional process to remove nitrate from water, the biological denitrification, uses the addition of dissolved organic carbon that has the potential risk to further deteriorate water quality. Thus, this work aimed to evaluate the specific denitrification activity of a mixed microbial culture and a pure culture of Pseudomonas stutzeri with solid substrates such as polycaprolactone (PCL), ...
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Evaluation of nitrate and perchlorate reduction using sulfur-based autotrophic and mixotrophic denitrifying processes
The biological reduction of nitrate and perchlorate was comparatively evaluated in autotrophic and mixotrophic bioreactors using elemental sulfur and/or methanol as the energy source. The mixotrophic reactor was supplemented with methanol at CH3OH/NO3−-N ratio of 1 or 1.4. The mixotrophic reactor completely reduced perchlorate in the feed up to 1,000 μg l−1. The autotrophic reactor also ...
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Nitrate reductase activity: A solution to nitrate problems tested in free and Immobilized algal cells in presence of heavy metals
Every organism has different potential to accumulate NO3- from the environment. Nitrate reduction processes are perhaps most significant in maintaining water quality by alteration of nitrate to nitrite. A comparative study between the nitrate reductase NR activity of green and blue green algae in presence of heavy metals is being conducted to present a situation where nitrate reductase process ...
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Donor-dependent extent of uranium reduction for bioremediation of contaminated sediment microcosms
Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of ...
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Nitrogen patterns in subsurface waters of the Yzeron stream: effect of combined sewer overflows and subsurface–surface water mixing
Urbanization subjects streams to increased nitrogen loads. Therefore studying nitrogen forms at the interface between urban stream and groundwater is important for water resource management. In this study we report results on water δ18O and nitrogen forms in subsurface waters of a stream (Yzeron, France). The sites studied were located upstream and downstream of combined sewer overflows ...
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Planktonic and biofilm grown nitrogen cycling bacteria exhibit different susceptibilities to copper nanoparticles
Proper characterization of nanoparticle (NP) interactions with environmentally relevant bacteria under representative conditions is necessary to enable their sustainable manufacture, use, and disposal. Previous nanotoxicology research based on planktonic growth does not adequately explore biofilms, which serve as the predominant mode of bacterial growth in natural and engineered environments. ...
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Catalytic reduction of nitrate in secondary effluent of wastewater treatment plants by Fe0 and Pd–Cu/γ–Al2O3
Total nitrogen, in which NO3− is dominant in the effluent of most wastewater treatment plants, cannot meet the requirements of the Chinese wastewater discharge standard (<15 mg/L), making nitrate (NO3−) elimination attract considerable attention. In this study, reductant iron (Fe0) and γ–Al2O3 supported palladium–copper bimetallic catalysts (Pd–Cu/γ–Al2O3) were innovatively used for the ...
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City of Green, Kansas Nitrate Reduction - Case study
In September 2012, AdEdge Water Technologies, LLC participated and was awarded a Contract managed by BG Consultants for the equipment pre-selection of a nitrate removal treatment system for the City of Green, Kansas. The scope of the contract included the design, manufacture, and startup of the treatment system. The City of Green is a small community of approximately 125 residents located in ...
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Sizing mitigation wetlands in agricultural watersheds
In this study, we investigated use of microcosms to supplement field studies for establishing the size of wetlands required to mitigate nitrate pollution in agricultural watersheds. Wetlands investigated in this study were located in San Joaquin Valley (California, USA) and demonstrated mean nitrate-nitrogen mass removal efficiencies ranging between 10 and 34%. Mean areal nitrate removal ...
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Reduction of concentrated nitrate by using in situ synthesized zero-valent copper
Although zero-valent iron represents a promising approach for reduction of nitrate (NO3−) in water, its application in concentrated nitrate is limited by surface passivation. In this study, an alternative approach using in situ synthesized zero-valent copper (Cu0) produced by borohydride (NaBH4) was investigated. Complete reduction was observed within 55 min by reacting 677 mg-N/L of NO3− ...
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The heterotrophic-combined-with-autotrophic denitrification process: performance and interaction mechanisms
In this work, the interaction mechanisms between an autotrophic denitrification (AD) and heterotrophic denitrification (HD) process in a heterotrophic-autotrophic denitrification (HAD) system were investigated, and the performance of the HAD system under different S/Ac− molar ratios was also evaluated. The results demonstrated that the heterotrophic-combined-with-autotrophic ...
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Effect of precursor type on the reduction of concentrated nitrate using zero-valent copper and sodium borohydride
In this study, we demonstrated that the choice of precursor has a strong effect on the reduction of nitrate (NO3−) using zero-valent copper (Cu0) synthesized by sodium borohydride (NaBH4). Different precursors: CuSO4, CuO, Cu2O, Cu powder, and Cu mesh were used to reduce NO3− at 677 mg-N/L under the reducing conditions of NaBH4. Compared with the prehydrolyzed samples, those prepared without ...
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