| 1. |
- Modin, Oskar, 1980, et al.
(författare)
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Redistribution of wastewater alkalinity with a microbial fuel cell to support nitrification of reject water
- 2011
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 45:8, s. 2691-2699
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Tidskriftsartikel (refereegranskat)abstract
- In wastewater treatment plants, the reject water from the sludge treatment processes typically contains high ammonium concentrations, which constitute a significant internal nitrogen load in the plant. Often, a separate nitrification reactor is used to treat the reject water before it is fed back into the plant. The nitrification reaction consumes alkalinity, which has to be replenished by dosing e.g. NaOH or Ca(OH)(2). In this study, we investigated the use of a two-compartment microbial fuel cell (MFC) to redistribute alkalinity from influent wastewater to support nitrification of reject water. In an MFC, alkalinity is consumed in the anode compartment and produced in the cathode compartment. We use this phenomenon and the fact that the influent wastewater flow is many times larger than the reject water flow to transfer alkalinity from the influent wastewater to the reject water. In a laboratory-scale system, ammonium oxidation of synthetic reject water passed through the cathode chamber of an MFC, increased from 73.8 +/- 8.9 mgN/L under open-circuit conditions to 160.1 +/- 4.8 mgN/L when a current of 1.96 +/- 0.37 mA (15.1 mA/L total MFC liquid volume) was flowing through the MFC. These results demonstrated the positive effect of an MFC on ammonium oxidation of alkalinity-limited reject water.
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| 2. |
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| 3. |
- Hai, F.I., et al.
(författare)
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Pesticide removal by a mixed culture of bacteria and white-rot fungi
- 2012
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Ingår i: Journal of the Taiwan Institute of Chemical Engineers. - : Elsevier BV. - 1876-1070. ; 43:3, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- Combining activated sludge cultures with microbes harboring specific degradation pathways could constitute a relevant process for the removal of toxic and recalcitrant organic substances from wastewater. Enhanced removal of three widely used recalcitrant pesticides from their liquid mixture was demonstrated by implementing a non-acclimated mixed culture of bacteria and white-rot fungus. During an incubation period of 14 days, the mixed fungus-bacteria culture achieved 47, 98, and 62% removal of aldicarb, atrazine and alachlor from the liquid phase, respectively. This compared favorably to batches containing only non-acclimated fungus or previously published removal rates with non-acclimated bacterial cultures. Biosorption along with biodegradation was responsible for the removal of the pesticides from the liquid phase. Potential application modes of the studied biodegradation process were also discussed.
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| 4. |
- Modin, Oskar, 1980, et al.
(författare)
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Development and testing of bioelectrochemical reactors converting wastewater organics into hydrogen peroxide
- 2012
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 66:4, s. 831-836
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Tidskriftsartikel (refereegranskat)abstract
- In a bioelectrochemical system, the energy content in dissolved organic matter can be used to power the production of hydrogen peroxide (H2O2), which is a potentially useful chemical at wastewater treatment plants. H2O2 can be produced by the cathodic reduction of oxygen. We investigated four types of gas-diffusion electrodes (GDEs) for this purpose. A GDE made of carbon nanoparticles bound with 30% polytetrafluoroethylene (PTFE) (wt./wt.C) to a carbon fiber paper performed best and catalyzed H2O2 production from oxygen in air with a coulombic efficiency of 95.1%. We coupled the GDE to biological anodes in two bioelectrochemical reactors. When the anodes were fed with synthetic wastewater containing acetate they generated a current of up to similar to 0.4 mA/mL total anode compartment volume. H2O2 concentrations of similar to 0.2 and similar to 0.5% could be produced in 5 mL catholyte in 9 and 21 h, respectively. When the anodes were fed with real wastewater, the generated current was similar to 0.1 mA/mL and only 84 mg/L of H2O2 was produced.
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| 5. |
- Modin, Oskar, 1980, et al.
(författare)
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Production of high concentrations of H2O2 in a bioelectrochemical reactor fed with real municipal wastewater
- 2013
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Ingår i: Environmental Technology (United Kingdom). - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 34:19, s. 2737-2742
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Tidskriftsartikel (refereegranskat)abstract
- Bioelectrochemical systems can be used to energy-efficiently produce hydrogen peroxide (H2O2) from wastewater. Organic compounds in the wastewater are oxidized by microorganisms using the anode as electron acceptor. H2O2 is produced by reduction of oxygen on the cathode. In this study, we demonstrate for the first time production of high concentrations of H2O2 production from real municipal wastewater. A concentration of 2.26g/L H2O2 was produced in 9h at 8.3kWh/kgH(2)O(2). This concentration could poTENTially be useful for membrane cleaning at membrane bioreactor wastewater treatment plants. With an acetate-containing nutrient medium as anode feed, a H2O2 concentration of 9.67g/L was produced in 21h at an energy cost of 3.0kWh/kgH(2)O(2). The bioelectrochemical reactor used in this study suffered from a high internal resistance, most likely caused by calcium carbonate deposits on the cathode-facing side of the cation exchange membrane separating the anode and cathode compartments.
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