Silicate mediated simultaneous in-situ CO2 sequestration and nutrients removal in anaerobic digestion. (June 2019)

• Record Type: Journal Article
• Authors: Liu, He; Gong, Linlin; Zhang, Yan; Jiang, Qianqian; Cui, Minhua; Zhang, Jie; Fu, Bo; Liu, Hongbo
• Is Part Of: Bioresource technology. Volume 282(2019)
• Page Start: 125
• Page End: 132
• Publication Date: 2019-06
• Subjects: Anaerobic digestion -- Mineral carbonation -- CO2 sequestration -- Nutrients removal -- Silicates; 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.2019.03.004
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: In-situ CO2 capture and nutrients removal in AD was achieved with silicate addition. Equimolar Mg 2+ and Ca 2+ released from silicate is the key for the best removal. Directed precipitation of Mg 2+ and Ca 2+ to form MgNH4 PO4 and CaCO3 is the mechanism. Methane production was improved by 51.2% simultaneously with silicate addition. Abstract: This study investigated the reactions among CO3 2−, PO4 3−, NH4 +, Mg 2+, and Ca 2+, under different CO3 2− concentration and Mg 2+ /Ca 2+ ratio, and conducted sludge anaerobic digestion (AD) with silicate addition to achieve in-situ CO2 sequestration and nutrients removal. High CO3 2− concentration facilitated the formation of MgNH4 PO4, and Mg 2+ /Ca 2+ ratio of 1:1 achieved best CO3 2−, PO4 3−, and NH4 + removal in simulated anaerobic digestate. Supplementation of 40 g/L magnesium silicate combined with 20 g/L wollastonite decreased CO2 content in biogas from 28.2% to 19.0%, and removed PO4 3− and NH4 + by 61.8% and 21.2%, respectively, in AD. Simultaneous in-situ CO2 sequestration and nutrients removal was achieved by directed precipitation of PO4 3−, NH4 +, and CO2 with silicate released Mg 2+ and Ca 2+, to form MgNH4 PO4 and CaCO3 . Meanwhile, methane production was improved by 51.2% with silicate supplementation. This study provides an attractive measure for CO2 and nutrients removal as well as methane production enhancement of sludge AD.