title: Simultaneous biogas upgrading and centrate treatment in an outdoors pilot scale high rate algal pond.
abstract: The bioconversion of biogas to biomethane coupled to centrate treatment was evaluated in an outdoors pilot scale high rate algal pond interconnected to an external CO2-H2S absorption column (AC) via settled broth recirculation. CO2-removal efficiencies ranged from 50 to 95% depending on the alkalinity of the cultivation broth and environmental conditions, while a complete H2S removal was achieved regardless of the operational conditions. A maximum CH4concentration of 94% with a limited O2and N2stripping was recorded in the upgraded biogas at recycling liquid/biogas ratios in the AC of 1 and 2. Process operation at a constant biomass productivity of 15gm-2d-1and the minimization of effluent generation supported high carbon and nutrient recoveries in the harvested biomass (C=66±8%, N=54±18%, P≈100% and S=16±3%). Finally, a low diversity in the structure of the microalgae population was promoted by the environmental and operational conditions imposed.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Posadas
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain; Universidad Pedagógica Nacional Francisco Morazán, Boulevard Centroamérica, Tegucigalpa, Honduras.
authors.forename: David
authors.initials: D
authors.lastname: Marín
authors.affiliation: Department of Biodiversity and Environmental Management, University of León, 24071 León, Spain.
authors.forename: Saúl
authors.initials: S
authors.lastname: Blanco
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Lebrero
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain. Electronic address: mutora@iq.uva.es.
authors.forename: Raúl
authors.initials: R
authors.lastname: Muñoz
mesh_terms: D056804:Biofuels / Q000032:analysis*; D018533:Biomass; D002244:Carbon / Q000032:analysis; D002245:Carbon Dioxide / Q000032:analysis; D004777:Environment; D058086:Microalgae / Q000378:metabolism*; D010865:Pilot Projects; D061005:Ponds; D013696:Temperature; D013997:Time Factors; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: D056804:Biofuels; D002245:Carbon Dioxide; D002244:Carbon
keywords: Algal-bacterial symbiosis; Biogas upgrading; Biomethane; Microalgae; Outdoors conditions; Wastewater treatment