ammonia concentration Articles
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Characteristics of N2O production and hydroxylamine variation in short-cut nitrification SBR process
In order to study the characteristics of nitrous oxide (N2O) production and hydroxylamine (NH2OH) variation under oxic conditions, concentrations of NH2OH and N2O were simultaneously monitored in a short-cut nitrification sequencing batch reactor (SBR) operated with different influent ammonia concentrations. In the short-cut nitrification process, N2O production was increased with the ...
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Nitrogen removal efficiency and microbial community analysis of ANAMMOX biofilter at ambient temperature
An upflow anaerobic biofilter (AF) was developed to investigate anaerobic ammonium-oxidizing (ANAMMOX) efficiency in treating low-strength wastewater at ambient temperature (15.3–23.2 °C). Denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization were used to investigate treatment effects on the microbial community. Stepwise decreases in influent ...
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Ammonia diffusion through Nalophan™ bags
The aim of the work is to verify the diffusion rate of ammonia through the Nalophan™ film that constitutes the sampling bag, considering storage times ranging from 1 to 26 h. The ammonia decay over time was evaluated using gas-chromatography for the quantification of ammonia concentration inside the bag. The research assesses the roles of both of ammonia and water concentration gradients ...
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Nitrogen removal from raw landfill leachate by an algae–bacteria consortium
A remediation system for the removal of nitrogen from landfill leachate by a mixed algae–bacteria culture was investigated. This system was designed to treat leachate with minimal inputs and maintenance requirements, and was operated as an open semi-batch reactor in an urban greenhouse. The results of this study showed a maximum nitrogen removal rate of 9.18 mg N/(L·day) and maximum biomass ...
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Factors affecting formation of disinfection by-products during chlorination of Cyclops
Effects of reaction time, chlorine dosages, pH, temperature and ammonia concentrations on the formation of disinfection by-products (DBPs), including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), chloral hydrate (CH), and chloropicrin (TCNM), were investigated during the chlorination of Cyclops metabolite solutions containing 4 mg/L (as total ...
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Nitrogen removal and recovery from human urine by struvite precipitation
In this study, struvite precipitation of human urine was experimentally studied on both synthetic and actual urine samples. One of the main conclusions of the study was that removal of the ions constituting struvite from the solution was not in proportion with the stoichiometry of the solid and excess magnesium and phosphate removals varied from 2.5% to 4.8% on a molar basis. Redissolution of the ...
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Influence of nitrite on the removal of Mn(II) using pilot-scale biofilters
Two pilot-scale biofilters were used to systematically investigate the influence of nitrite on biological Mn(II) removal. Gibbs free energy change (ΔG) of the redox reaction between MnO2 and NO2– was 122.28 kJ mol–1 in 298 K, suggesting that MnO2 could not react with NO2–. When nitrite in the influent was increased from 0.05 to 0.5 mg L–1, manganese oxides did not react with nitrite in ...
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Ammonia sanitisation of sewage sludge using urea
The aim of the study was to develop a simple, low-cost treatment for sewage sludge using urea as a sanitising agent. Sewage sludge was spiked with Enterococcus faecalis and Salmonella typhimurium, treated with 0.5, 1, 1.5 and 2% w/w urea at laboratory scale, and the viability was monitored during 4 months of storage at 4, 10 and 22 °C (only 0.5%). A linear relationship was ...
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Performance of an
in-situ rotating biological contactor in a recirculating aquaculture systemThe start-up and activation of a nitrifying rotating biological contactor (RBC) and its performance inside a culture tank of rainbow trout were studied. First, in a lab-scale operation, the system was fed with a synthetic medium containing a high ammonia concentration (567 mg NH4+-N L−1) and operated at a high hydraulic retention time (HRT) (6.5 days) to minimize the wash-out of the biomass and ...
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High dry solids digestion
Abstract Digestion of sewage sludge normally takes place at pH values between 7,0 and 7,5. Control methods of the process stability are based on practical experience such as the ratio of volatile fatty acids (VFA) and total alkalinity (TA). Thermal sludge disintegration for an enhanced digestion process allows a digester feed with higher dry solids concentrations. This is due to an opening of ...
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High dry solids digestion
ABSTRACTDigestion of sewage sludge normally takes place at pH values between 7,0 and 7,5. Control methods of the process stability are based on practical experience such as the ratio of volatile fatty acids (VFA) and total alkalinity (TA). Thermal sludge disintegration for an enhanced digestion process allows a digester feed with higher dry solids concentrations. This is due to an opening of cell ...
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Dinitrogen oxide (N2O) emission in the treatment of urban wastewater via nitrite: influence of liquid kinetic rates
N2O emission was studied in a continuous process via nitrite for real urban wastewater treatment. The relationship between the gaseous forms and the liquid kinetic rates of nitritation and denitritation was investigated. N2O mass load and global nitrogen mass balance were quantified. The emission factor of the N2O (gN2Oemitted/kg mixed liquor volatile suspended solids [MLVSS]/d) was ...
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Mathematical models and bacterial communities for ammonia toxicity in mesophilic anaerobes not acclimated to high concentrations of ammonia
In this study, we evaluated ammonia toxicity in mesophilic anaerobic digestion at various pH values and total ammonia nitrogen (TAN) concentrations. We performed anaerobic toxicity assays (ATAs) to evaluate the toxicity effects of TAN and pH on mesophilic anaerobic digestion. Modeling based on the results of the ATAs indicated that the specific methanogenic activity (SMA) decreased by 30% at ...
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Cold weather ammonia reduction in municipal/industrial treatment plant case study
Problem During cold weather this municipal wastewater treatment plant with a high percentage of industrial flow from food processing and electronics manufacturing suffered from high ammonia loadings. As temperatures dropped the plant lost nitrification. The objective of this full-scale product application program was to reestablish ammonia oxidation and reduce ammonia-nitrogen in the lagoon ...
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Short-term effect of ammonia concentration and salinity on activity of ammonia oxidizing bacteria
A continuously aerated SHARON (single reactor high activity ammonia removal over nitrite) system has been operated to achieve partial nitritation. Two sets of batch experiments were carried out to study the effect of ammonia concentration and salinity on the activity of ammonia-oxidizing bacteria (AOB). Activity of AOB raised as free ammonia concentration was increased reaching its maximum value ...
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Exploration of rapid start-up of the CANON process from activated sludge inoculum in a sequencing biofilm batch reactor (SBBR)
In this study, a laboratory-scale sequencing biofilm batch reactor (SBBR) was employed to explore a fast start-up of completely autotrophic nitrogen removal over nitrite (CANON) process. Partial nitrification was achieved by controlling free ammonia concentration and operating at above 30 °C; then the reactor was immediately operated with alternating periods of aerobiosis and anaerobiosis to ...
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Electrochemically-assisted ammonia recovery from wastewater using a floating electrode
This work presents and explores a novel methodology for the removal and recovery of ammonia from wastewater based upon two mechanisms: electrochemical oxidation and a previously unreported electrochemically-assisted surface transfer mechanism. Recovery of ammonia is enabled by placing a porous cathodic electrode at the wastewater-air interface. In this configuration, the cathode creates local ...
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Effect of seed particle size and ammonia concentration on the growth of ZnO nanowire arrays and their photoconversion efficiency
ZnO nanowire arrays were synthesised for dye-sensitised solar cell applications using the chemical bath deposition technique. To study the effect of the particle size in the seed layer on the growth and resultant photoconversion efficiency, we prepared various seeded FTO substrates by repeating the seed layer sol-gel coating process. It was found that changing the number of coating process ...
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Electrochemical oxidation of landfill leachates at pilot scale: evaluation of energy needs
Two of the main drawbacks to be overcome before full scale implementation of boron-doped diamond electro-oxidation were addressed in this work; its energy consumption and hazard of formation of chlorinated organics. This was framed within a study in which the technical and economic feasibility of BDD electro-oxidation of landfill leachate was evaluated at pilot scale. On one hand, its technical ...
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Poultry processing - Ammonia removal case study
Background: A poultry plant in the South of England processes up to 100,000 birds per week. The company operates an Activated Sludge plant followed by a Rotating Biological Contactor the whole system being required to produce effluent ammonia of 20 mg/l. Whilst the treatment plant was able to reach this standard when it was first installed, the success of the company meant that more and more ...
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