Search results for "TRIF"
showing 10 items of 1419 documents
Nitrous oxide from integrated fixed-film activated sludge membrane bioreactor: Assessing the influence of operational variables
2017
The influence of the main operational variables on N2O emissions from an Integrated Fixed Film Activated Sludge University of Cape Town membrane Bioreactor pilot plant was studied. Nine operational cycles (total duration: 340 days) were investigated by varying the value of the mixed liquor sludge retention time (SRT) (Cycles 1â3), the feeding ratio between carbon and nitrogen (C/N) (Cycles 4â6) and simultaneously the hydraulic retention time (HRT) and the SRT (Cycles 7â9). Results show a huge variability of the N2O concentration in liquid and off-gas samples (ranged from 10â1μg N2O-N Lâ1to 103μg N2O-N Lâ1). The maximum N2O concentration (1228 μg N2O-N Lâ1) in the off-gas sa…
Greenhouse gas emissions from membrane bioreactors: analysis of a two-year survey on different MBR configurations
2018
Abstract This study aimed at evaluating the nitrous oxide (N2O) emissions from membrane bioreactors (MBRs) for wastewater treatment. The study investigated the N2O emissions considering multiple influential factors over a two-year period: (i) different MBR based process configurations; (ii) wastewater composition (municipal or industrial); (iii) operational conditions (i.e. sludge retention time, carbon-to-nitrogen ratio, C/N, hydraulic retention time); (iv) membrane modules. Among the overall analysed configurations, the highest N2O emission occurred from the aerated reactors. The treatment of industrial wastewater, contaminated with salt and hydrocarbons, provided the highest N2O emission…
Biological nitrate removal from wastewater of a metal-finishing industry
2006
An upflow packed bed reactor at laboratory scale has been operated for a continuous period of 5 months to investigate the technical feasibility of biological nitrate removal applied to the effluent of the coagulation-sedimentation wastewater of a metal-finishing industry. The reactor was fed with industrial wastewater in a five-fold dilution to reproduce the global spill in the factory (20/80, industrial wastewater/domestic wastewater) with a concentration of nitrate between 141 and 210 gNO(3)-N/m(3). Methanol was added as a carbon source for denitrification. Inlet flow rate was progressively increased from 9 to 40 L/day (nitrogen input load from 45 to 250 gNO(3)-N/(m(3)h)). The highest obs…
Biological groundwater denitrification systems: Lab-scale trials aimed at nitrous oxide production and emission assessment
2018
Bio-trenches are a sustainable option for treating nitrate contamination in groundwater. However, a possible side effect of this technology is the production of nitrous oxide, a greenhouse gas that can be found both dissolved in the liquid effluent as well as emitted as off gas. The aim of this study was to analyze NO3 − removal and N2O production in lab-scale column trials. The column contained olive nut as organic carbon media. The experimental study was divided into three phases (I, II and III) each characterized by different inlet NO3 − concentrations (30, 50, 75 mg NO3-N L−1 respectively). Sampling ports deployed along the length of the column allowed to observe the denitrification pro…
Low cost-sensors as a real alternative to on-line nitrogen analysers in continuous systems.
2009
This paper is focused on the evaluation of the applicability of low-cost sensors (pH and ORP) versus nutrient analysers for controlling biological nitrogen removal in WWTPs. A nutrient removal pilot plant located in Carraixet WWTP (Valencia, Spain) that is equipped with a significant number of nutrient analysers and low-cost sensors was used. The relations between reliable, cheap on-line sensors such as pH and ORP (located in anaerobic, anoxic and aerobic zones) and the nitrification/denitrification processes are provided. The nitrification process can be evaluated by measuring the pH difference between the first and last aerobic zones. The denitrification process can be evaluated by measur…
Treatment of a submerged anaerobic membrane bioreactor (SAnMBR) effluent by an activated sludge system: the role of sulphide and thiosulphate in the …
2014
This work studies the use of a well-known and spread activated sludge system (UCT configuration) to treat the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) treating domestic waste-water. Ammonia, phosphate, dissolved methane and sulphide concentrations in the SAnMBR effluent were around 55 mg NH4-N L-1, 7 mg PO4-P L-1, 30 mg non-methane biodegradable COD L-1, and 105 mg S2- L-1 respectively. The results showed a nitrification inhibition caused by the presence of sulphur compounds at any of the solids retention time (SRT) studied (15,20 and 25 days). This inhibition could be overcome increasing the hydraulic retention time (HRT) from 13 to 26 h. Among the sulphur compounds, …
Biological nitrogen removal from municipal landfill leachate: low-cost nitrification in biofilters and laboratory scale in-situ denitrification.
2002
The slow leaching of nitrogen from solid waste in landfills, resulting in high concentrations of ammonia in the landfill leachate, may last for several decades. The removal of nitrogen from leachate is desirable as nitrogen can trigger eutrophication in lakes and rivers. In the present study, a low-cost nitrification-denitrification process was developed to reduce nitrogen load especially in leachates from small landfills. Nitrification was studied in laboratory and on-site pilot aerobic biofilters with waste materials as filter media (crushed brick in upflow filters and bulking agent of compost in a downflow filter) while denitrification was studied in a laboratory anoxic/anaerobic column …
Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.
2006
Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10–20 °C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 °C. Removal of total chemical oxygen demand (CODt) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperatu…
Greenhouse gases from sequential batch membrane bioreactors: A pilot plant case study
2016
Abstract The paper reports the results of nitrous oxide (N 2 O) emissions from aerobic and anoxic tank of a Sequential Batch Membrane Bioreactor (SB-MBR) pilot plant. The influence of salinity variation on N 2 O emission was analyzed by gradually increasing the inlet salt concentration from 0 to 10 g NaCl L −1 . The observed results showed that the N 2 O concentration of the gaseous samples was strongly influenced by the salt concentration. This result was likely related to a worsening of the nitrification activity due to the effect of salinity on autotrophic bacteria. Dissolved oxygen concentration and salinity were found to be the key factors affecting N 2 O concentration in the gaseous s…
Nitrification of anaerobically pretreated municipal landfill leachate at low temperature
2000
Abstract Nitrification of anaerobically pretreated municipal landfill leachate (270–1000 mg COD l −1 , 53–270 mg NH 4 –N l −1 ) was studied in laboratory-scale activated sludge reactors without (AS) and with (ASC) the addition of plastic carrier material. The reactors were run at 10°C (149 d), 7°C (21 d) and 5°C (16 d). With a loading rate of 0.027 g NH 4 –N g MLVSS −1 d −1 and a hydraulic retention time of ca. 3 d, at 10°C, complete nitrification was obtained in both reactors. At 7°C, and in loading rate of 0.023 g NH 4 –N g MLVSS −1 d −1 , both reactors appeared to be overloaded and ammonium removal was only ca. 93%. At 5°C, with a lower loading rate of 0.010 g NH 4 –N g MLVSS −1 d −1 …