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Arenas CB, González R, González J, Cara J, Papaharalabos G, Gómez X, Martínez EJ. Assessment of electrooxidation as pre- and post-treatments for improving anaerobic digestion and stabilisation of waste activated sludge. J Environ Manage 2021; 288:112365. [PMID: 33765574 DOI: 10.1016/j.jenvman.2021.112365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 07/24/2020] [Accepted: 03/11/2021] [Indexed: 05/16/2023]
Abstract
This study evaluates the effects of electro-oxidation as a means for enhancing sludge stabilisation. Boron-doped diamond electrodes were used to treat waste activated sludge and digestate under different operating parameters (current density, conductivity, pH, and time). Electro-oxidation runs affected the solubilisation of organic matter, which seemed to improve anaerobic digestion and dewaterability characteristics. Among the tested parameters, pre-treating sludge via electro-oxidation under alkaline conditions (Treatment T5) resulted in the highest increase in soluble organic material compared to that in the control, with total organic carbon (TOC) and soluble chemical oxygen demand (COD) values of 2753 and 7819 mg L-1, respectively (control TOC and COD values were 385 and 1073 mg L-1). This pretreatment also achieved a high hydrolysis rate (higher concentration in volatile fatty acids) with a concomitant increase in methane yield (approximately 18%). On the other hand, the application of electro-oxidation as a post-treatment for improving digestate dewaterability resulted in noticeable changes in the release of water during drying due to protein and aliphatic matrix modification of the sample.
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Affiliation(s)
- Cristian B Arenas
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Ruben González
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Judith González
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Jorge Cara
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - George Papaharalabos
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Xiomar Gómez
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - E Judith Martínez
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain.
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González-Arias J, Gil MV, Fernández RÁ, Martínez EJ, Fernández C, Papaharalabos G, Gómez X. Integrating anaerobic digestion and pyrolysis for treating digestates derived from sewage sludge and fat wastes. Environ Sci Pollut Res Int 2020; 27:32603-32614. [PMID: 32514914 DOI: 10.1007/s11356-020-09461-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
The coupling of biological and thermal technologies allows for the complete conversion of wastes into energy and biochar eliminating the problem of sludge disposal. The valorisation of fatty residues as co-substrate in a mesophilic digester of a wastewater treatment plant was studied considering an integrated approach of co-digestion and pyrolysis. Four digested samples obtained from co-digestion of sewage sludge and butcher's fat waste were studied by thermogravimetric analysis. The activation energy corresponding to the sludge pyrolysis was calculated by a non-isothermal kinetic. Arrhenius activation energy was lower for the pyrolysis of a digested grease sample (92 kJ mol-1 obtained by OFW and 86 kJ mol-1 obtained by Vyazovkin) than for the pyrolysis of sewage sludge and its blends (164-190 kJ mol-1 obtained by OFW and 162-190 kJ mol-1 obtained by Vyazovkin). The analysis of the integrated approach of anaerobic co-digestion and pyrolysis of digestates demonstrated that the addition of 3% (w/v) of fat to the feeding sludge results in a 25% increase in the electricity obtained from biogas (if a combined heat and power unit is considered for biogas valorisation) and increasing the fat content to 15% allows for covering all thermal needs for drying of digestate and more than doubles (2.4 times) the electricity production when the scenario of digestion and pyrolysis is contemplated.
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Affiliation(s)
- Judith González-Arias
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, León, Spain
| | - María Victoria Gil
- Instituto Nacional del Carbón, INCAR-CSIC, Francisco Pintado Fe 26, 33011, Oviedo, Spain
| | - Ramón Ángel Fernández
- Department of Mechanical, Computer Science and Aerospace Engineering, School of Industrial Engineering and Computer Science, University of León, Campus Vegazana, 24009, León, Spain
| | - Elia Judith Martínez
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, León, Spain
| | - Camino Fernández
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, León, Spain
| | - George Papaharalabos
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, León, Spain
| | - Xiomar Gómez
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, León, Spain.
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Ieropoulos IA, Ledezma P, Stinchcombe A, Papaharalabos G, Melhuish C, Greenman J. Waste to real energy: the first MFC powered mobile phone. Phys Chem Chem Phys 2014; 15:15312-6. [PMID: 23939246 DOI: 10.1039/c3cp52889h] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This communication reports for the first time the charging of a commercially available mobile phone, using Microbial Fuel Cells (MFCs) fed with real neat urine. The membrane-less MFCs were made out of ceramic material and employed plain carbon based electrodes.
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Affiliation(s)
- Ioannis A Ieropoulos
- Bristol Robotics Laboratory, Faculty of Environment & Technology, University of the West of England, BS16 1QY, Bristol, UK.
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