Promoting anaerobic digestion by algae-based hydrochars in a continuous reactor. (December 2020)

• Record Type: Journal Article
• Authors: Wang, Fengbo; Wang, Jing; Li, Zelong; Zan, Shuaijun; Du, Miaomiao
• Is Part Of: Bioresource technology. Volume 318(2020)
• Publication Date: 2020-12
• Subjects: Microalgae -- Macroalgae -- Hydrochar -- Anaerobic digestion -- Organic loading rate; 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.2020.124201
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Effect of algae-based hydrochars on continuous anaerobic digestion was evaluated. The hydrochars added reactors performed well under organic loading rate increase. Both microalgae-based and macroalgae-based hydrochars improved methane production. Hydrochars enhanced sludge granulation and Methanothrix to benefit potential DIET. Abstract: The microalgae and macroalgae-based hydrochars produced by hydrothermal carbonization were mainly used as biofuels, however, their application in anaerobic digestion (AD) was little known. This study investigated the effects of microalgae Chlorella -based hydrochar (HC-C) and macroalgae Laminaria -based hydrochar (HC-L) on a continuous AD reactor under different organic loading rates (OLR). The AD process stability of hydrochars supplemented reactors were performed well under the increase of OLR from 2.6 to 6.5 g COD/L/d, and HC-C and HC-L addition could significantly enhance the daily methane yield by 36.0% and 31.4%, respectively. Interestingly, the possible mechanisms of HC-C and HC-L on the enhanced AD were similar, namely increasing sludge granulation, promoting the Methanothrix relative abundance and key enzyme activities, and further facilitating potential direct interspecies electron transfer between methanogens and organic-degrading bacteria. This study provided an implication on the potential application of algae-based hydrochars in wastewater treatment and energy recovery.