Silicate mediated simultaneous in-situ CO2 sequestration and nutrients removal in anaerobic digestion

He Liu; Linlin Gong; Yan Zhang; Qianqian Jiang; Minhua Cui; Jie Zhang; Bo Fu; Hongbo Liu

doi:10.1016/j.biortech.2019.03.004

Silicate mediated simultaneous in-situ CO₂ sequestration and nutrients removal in anaerobic digestion

Bioresour Technol. 2019 Jun:282:125-132. doi: 10.1016/j.biortech.2019.03.004. Epub 2019 Mar 1.

Authors

He Liu¹, Linlin Gong², Yan Zhang³, Qianqian Jiang², Minhua Cui¹, Jie Zhang², Bo Fu¹, Hongbo Liu¹

Affiliations

¹ School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou 215011, China.
² School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
³ School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou 215011, China. Electronic address: yanzhang@jiangnan.edu.cn.

PMID: 30852332
DOI: 10.1016/j.biortech.2019.03.004

Abstract

This study investigated the reactions among CO₃^2-, PO₄^3-, NH₄⁺, Mg²⁺, and Ca²⁺, under different CO₃^2- concentration and Mg²⁺/Ca²⁺ 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 MgNH₄PO₄, and Mg²⁺/Ca²⁺ 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 Mg²⁺ and Ca²⁺, to form MgNH₄PO₄ 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.

Keywords: Anaerobic digestion; CO(2) sequestration; Mineral carbonation; Nutrients removal; Silicates.

MeSH terms

Anaerobiosis
Biofuels / analysis
Bioreactors
Carbon Dioxide / metabolism*
Methane / metabolism
Nutrients*
Sewage
Silicates / chemistry*

Substances

Biofuels
Sewage
Silicates
Carbon Dioxide
Methane