Leachate flush strategies for managing volatile fatty acids accumulation in leach-bed reactors. (May 2017)

• Record Type: Journal Article
• Authors: Riggio, S.; Torrijos, M.; Vives, G.; Esposito, G.; van Hullebusch, E.D.; Steyer, J.P.; Escudié, R.
• Is Part Of: Bioresource technology. Volume 232(2017)
• Page Start: 93
• Page End: 102
• Publication Date: 2017-05
• Subjects: Dry anaerobic digestion -- Leach-bed reactor -- Leachate management -- VFA extraction -- VFA consumption; 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.2017.01.060
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: The co-digestion of easily- and slowly-degradable substrates is assessed in LBRs. A strategy to manage leachate flush and optimize methane production is proposed. A high leachate flush-rate at the start-up enhances substrate degradation rates. After methanogenesis started, leachate flush-rate can be reduced. Mature LBR can be used to degrade external VFAs after the methane production peak. Abstract: In anaerobic leach-bed reactors (LBRs) co-digesting an easily- and a slowly-degradable substrate, the importance of the leachate flush both on extracting volatile fatty acids (VFAs) at the beginning of newly-started batches and on their consumption in mature reactors was tested. Regarding VFA extraction three leachate flush-rate conditions were studied: 0.5, 1 and 2 L kg −1 TS d −1 . Results showed that increasing the leachate flush-rate during the acidification phase is essential to increase degradation kinetics. After this initial phase, leachate injection is less important and the flush-rate could be reduced. The injection in mature reactors of leachate with an acetic acid concentration of 5 or 10 g L −1 showed that for an optimized VFA consumption in LBRs, VFAs should be provided straight after the methane production peak in order to profit from a higher methanogenic activity, and every 6–7 h to maintain a high biogas production rate.