title: Evaluation of the simultaneous biogas upgrading and treatment of centrates in a high-rate algal pond through C, N and P mass balances.
abstract: The simultaneous capture of CO2 from biogas and removal of carbon and nutrients from diluted centrates in a 180 L high-rate algal pond (HRAP) interconnected to a 2.5 L absorption column were evaluated using a C, N and P mass balance approach. The experimental set-up was operated indoors at 75 μE/m(2)·s for 24 h/d at 20 days of hydraulic retention time for 2 months of steady state, and supported a C-CO2 removal in the absorption column of 55 ± 6%. Carbon fixation into biomass only accounted for 9 ± 2% of the total C input, which explains the low biomass productivity recorded in the HRAP. In this context, the low impinging light intensity along with the high turbulence in the culture broth entailed a C stripping as CO2 of 49 ± 5% of the total carbon input. Nitrification was the main NH4(+) removal mechanism and accounted for 47 ± 2% of the inlet N-NH4(+), while N removal as biomass represented 14 ± 2% of the total nitrogen input. A luxury P uptake was recorded, which resulted in a P-PO4(-3) biomass content over structural requirements (2.5 ± 0.1%). Phosphorus assimilation corresponded to a 77 ± 2% of the inlet dissolved P-PO4(-3) removed.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011, Valladolid, Spain E-mail: mutora@iq.uva.es.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Alcántara
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011, Valladolid, Spain E-mail: mutora@iq.uva.es.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: García-Encina
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011, Valladolid, Spain E-mail: 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*; D007700:Kinetics; D058086:Microalgae / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D061005:Ponds / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
chemical_list: D056804:Biofuels; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen