RT info:eu-repo/semantics/article T1 Photosynthetic biogas upgrading to bio-methane: Boosting nutrient recovery via biomass productivity control A1 Toledo Cervantes, Alma A1 Serejo, Mayara L. A1 Blanco, Saúl A1 Pérez Fernández, Rebeca A1 Lebrero Fernández, Raquel A1 Muñoz Torre, Raúl K1 Biogás K1 Aguas residuales AB A pilot high rate algal pond (HRAP) interconnected to an external CO2–H2S absorption column via settled broth recirculation was used to simultaneously treat a synthetic digestate and to upgrade biogas to a bio-methane with sufficient quality to be injected into natural gas grids. An innovative HRAP operational strategy with biomass recirculation based on the control of algal-bacterial biomass productivity (2.2, 4.4 and 7.5 g m− 2 d− 1) via settled biomass wastage was evaluated in order to enhance nutrient recovery from digestate at a constant hydraulic retention time. The influence of the recycling liquid to biogas (L/G) ratio on the quality of the upgraded biogas was assessed. The bio-methane composition under a L/G ratio of 1 (0.4 ± 0.1% CO2, 0.03 ± 0.04% O2, 2.4 ± 0.2% N2 and 97.2 ± 0.2% CH4) complied with the technical specifications of most European bio-methane legislations regardless of the biomass productivity established. The HRAP operational strategy applied allowed increasing the N and P recovery from 19 and 22% to 83 and 100%, respectively, when the biomass productivity was increased from 2.2 to 7.5 g m− 2 d− 1. Finally, the dynamics of microalgae and bacteria population structure were characterized by morphological identification and Denaturing Gradient Gel Electrophoresis analysis. PB Elsevier YR 2016 FD 2016 LK http://uvadoc.uva.es/handle/10324/23454 UL http://uvadoc.uva.es/handle/10324/23454 LA eng NO Algal Research, 2016, Volume 17, pg.46–52 NO Producción Científica DS UVaDOC RD 19-abr-2024