Integrated anaerobic digestion and CO2 sequestration for energy recovery from waste activated sludge by calcium addition: Timing matters

Changkai Yin, Yanwen Shen, Xiaohu Dai, Nanwen Zhu, Haiping Yuan, Ziyang Lou and Rongxue Yuan

Energy, 2020, vol. 199, issue C

Abstract: Anaerobic digestion (AD) with in-situ biogas upgrading is a technology that integrates methane production and selective CO2 sequestration in a one-pot process. This study investigated the effect of Ca2+ addition timing on thermophilic AD of waste activated sludge (WAS). CaCl2 solution was added to the digester on day 0, 2, 4, 6 and 8 at concentration of 3000 mg∙L−1. Ca2+ addition on day 4, after which exponential methane production started, achieved the best AD performance with cumulative CH4 production, maximum CH4 potential and maximum CH4 production rate increased by 20.8%, 20.8% and 50.2%, respectively. This treatment also remarkably reduced free ammonia inhibition and enhanced Methanosarcina abundance in the digester. A substantial increase (up to 58.4%) in the gas-phase CH4 to CO2 molar ratio was observed in the Ca2+-supplemented digesters, demonstrating the effectiveness of Ca2+ addition for CO2 sequestration. The relative change in the CH4 to gross CO2 ratio indicated the promoted hydrogenotrophic methanogenesis, possibly as a pertinent microbial mechanism behind the improved methane production.

Keywords: Waste activated sludge; Anaerobic digestion; In-situ biogas upgrading; CO2 sequestration; Methanogenesis (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544220305284
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:199:y:2020:i:c:s0360544220305284

DOI: 10.1016/j.energy.2020.117421

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().