2024-03-29T07:07:13Zhttps://uvadoc.uva.es/oai/requestoai:uvadoc.uva.es:10324/535962022-05-30T20:51:41Zcom_10324_1173com_10324_931com_10324_894col_10324_1371
Photosynthetic upgrading of biogas from anaerobic digestion of mixed sludge in an outdoors algal-bacterial photobioreactor at pilot scale
Méndez, Lara
García, Dimas
Pérez, Enrique
Blanco, Saúl
Muñoz Torre, Raúl
Producción Científica
Anaerobic digestion can biotransform the biodegradable fraction of sewage sludge into biogas, while the symbiotic action of algal-bacterial consortia can remove both the CO2 and H2S from biogas and nutrients from digestate. A 100 L anaerobic digester operated at 20 days of retention time coupled with a 180 L high-rate algal pond (HRAP) engineered to upgrade the biogas and treat the liquid fraction of the pilot digester was optimized along four operational stages: (I) operation with a greenhouse during winter; (II) operation without greenhouse; (III) process supplementation with NaHCO3; (IV) process supplementation with Na2CO3. The biogas produced was composed of 63.7 ± 2.9% CH4, 33.7 ± 1.9% CO2, 0.5 ± 0.3% O2 and 1.6 ± 1.1% N2. An average methane productivity of 324.7 ± 75.8 mL CH4 g VSin−1 and total COD removals of 48 ± 20% were recorded in the digester. The CH4 concentration in the biomethane gradually decreased to 87.6 ± 2.0% and 85.1 ± 1.3% at the end of stage I and II, respectively, attributed to the loss of inorganic carbon in the HRAP. The supplementation of NaHCO3 and Na2CO3 mediated an increase in the CH4 content to 90.4 ± 1.5 and 91.2 ± 0.7% in stages III and IV, respectively. Steady state CO2 removals of 90% and 88% in stages I and II, and 95.7 and 97.6% in stages III and IV, respectively, were recorded. A constant biomass productivity of 22 g m−2 d−1, set by daily harvesting 26.5 g dry algal-bacterial biomass from the bottom of the settler, was maintained concomitantly with a complete removal of the N and P supplied via centrate.
2022-05-30
2022-05-30
2022
info:eu-repo/semantics/article
Journal of Water Process Engineering, 2022, vol. 48, 102891
2214-7144
https://uvadoc.uva.es/handle/10324/53596
10.1016/j.jwpe.2022.102891
eng
https://www.sciencedirect.com/science/article/pii/S221471442200335X?via%3Dihub
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
© 2022 The Authors
Attribution-NonCommercial-NoDerivatives 4.0 Internacional
Elsevier