Is the continuous two-stage anaerobic digestion process well suited for all substrates?. (January 2016)

• Record Type: Journal Article
• Authors: Lindner, Jonas; Zielonka, Simon; Oechsner, Hans; Lemmer, Andreas
• Is Part Of: Bioresource technology. Volume 200(2016)
• Page Start: 470
• Page End: 476
• Publication Date: 2016-01
• Subjects: Anaerobic digestion -- Two-stage -- Methane yield -- Substrate -- pH-control; 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.2015.10.052
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Control of pH in primary fermentation by effluent refeeding from anaerobic filter. A decreasing of pH in primary fermentation leads to enhanced hydrogen production. Reduced degradation of fibre rich substrates at low pH in primary fermentation. No influence of the pH in primary fermentation on degradation of sugary substrates. Two-stage biogas systems are favorable only for easily degradable substrates. Abstract: Two-stage anaerobic digestion systems are often considered to be advantageous compared to one-stage processes. Although process conditions and fermenter setups are well examined, overall substrate degradation in these systems is controversially discussed. Therefore, the aim of this study was to investigate how substrates with different fibre and sugar contents (hay/straw, maize silage, sugar beet) influence the degradation rate and methane production. Intermediates and gas compositions, as well as methane yields and VS-degradation degrees were recorded. The sugar beet substrate lead to a higher pH-value drop 5.67 in the acidification reactor, which resulted in a six time higher hydrogen production in comparison to the hay/straw substrate (pH-value drop 5.34). As the achieved yields in the two-stage system showed a difference of 70.6% for the hay/straw substrate, and only 7.8% for the sugar beet substrate. Therefore two-stage systems seem to be only recommendable for digesting sugar rich substrates.