Simultaneous biogas upgrading and centrate treatment in an outdoors pilot scale high rate algal pond. (May 2017)

• Record Type: Journal Article
• Authors: Posadas, Esther; Marín, David; Blanco, Saúl; Lebrero, Raquel; Muñoz, Raúl
• Is Part Of: Bioresource technology. Volume 232(2017)
• Page Start: 133
• Page End: 141
• Publication Date: 2017-05
• Subjects: Algal-bacterial symbiosis -- Biogas upgrading -- Biomethane -- Microalgae -- Outdoors conditions -- Wastewater treatment; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2017.01.071
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Effective outdoors biogas upgrading and digestate treatment achieved at pilot scale. CO2 removal (50–95%) was highly influenced by the alkalinity of the culture broth. 100% H2 S removal was recorded regardless of the operational conditions. Maximum CH4 concentration of 94% was achieved at L/G ratios of 1 and 2. Effluent minimization supported high C, N, P and S recoveries as algal biomass. 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 -H2 S 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 H2 S removal was achieved regardless of the operational conditions. A maximum CH4 concentration of 94% with a limited O2 and N2 stripping 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 15 g m −2 d −1 and 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.