title: Sludge electrooxidation as pre-treatment for anaerobic digestion.
abstract: Anaerobic digestion of wastewater sludge is the preferred method for sludge treatment as it produces energy in the form of biogas as well as a stabilised product that may be land applied. Different pre-treatments have been proposed to solubilise organic matter and increase biogas production. Sludge electrooxidation with boron-doped diamond electrodes was used as pre-treatment for waste activated sludge (WAS) and its effect on physicochemical properties and biomethane potential (BMP) was evaluated. WAS with 2 and 3% total solids (TS) achieved 2.1 and 2.8% solubilisation, respectively, with higher solids requiring more energy. After pre-treatment, biodegradable chemical oxygen demand values were close to the maximum theoretical BMP, which makes sludge suitable for energy production. Anaerobic digestion reduced volatile solids (VS) by more than 30% in pre-treated sludge with a food to microorganism ratio of 0.15 g VSfedg-1VSbiomass. Volatile fatty acids were lower than those for sludge without pre-treatment. Best pre-treatment conditions were 3% TS and 28.6 mA cm-2.
authors.affiliation: Instituto de Ingeniería, UNAM, P.O. Box 70-186, México, D.F. 04510, Mexico E-mail: jbarriosp@iingen.unam.mx.
authors.forename: J A
authors.initials: JA
authors.lastname: Barrios
authors.affiliation: Instituto de Ingeniería, UNAM, P.O. Box 70-186, México, D.F. 04510, Mexico E-mail: jbarriosp@iingen.unam.mx.
authors.forename: U
authors.initials: U
authors.lastname: Duran
authors.affiliation: Instituto de Ingeniería, UNAM, P.O. Box 70-186, México, D.F. 04510, Mexico E-mail: jbarriosp@iingen.unam.mx.
authors.forename: A
authors.initials: A
authors.lastname: Cano
authors.affiliation: Instituto de Ingeniería, UNAM, P.O. Box 70-186, México, D.F. 04510, Mexico E-mail: jbarriosp@iingen.unam.mx.
authors.forename: M
authors.initials: M
authors.lastname: Cisneros-Ortiz
authors.affiliation: Instituto de Ingeniería, UNAM, P.O. Box 70-186, México, D.F. 04510, Mexico E-mail: jbarriosp@iingen.unam.mx.
authors.forename: S
authors.initials: S
authors.lastname: Hernández
mesh_terms: D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000254:growth & development / Q000378:metabolism; D056804:Biofuels / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D055664:Electrochemical Techniques / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000032:analysis; D008697:Methane / Q000096:biosynthesis; D010084:Oxidation-Reduction; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D056804:Biofuels; D005232:Fatty Acids, Volatile; D012722:Sewage; D008697:Methane