Enhanced Phosphorus Recovery as Vivianite from Anaerobically Digested Sewage Sludge with Magnetic Biochar Addition

Yuan Liu, Jie Jin, Jiawei Li, Ziwei Zou, Renchan Lei, Jintao Sun and Jinxia Xia
Additional contact information
Yuan Liu: MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
Jie Jin: MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
Jiawei Li: MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
Ziwei Zou: MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
Renchan Lei: MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
Jintao Sun: MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
Jinxia Xia: MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China

Sustainability, 2022, vol. 14, issue 14, 1-14

Abstract: Sustainable phosphorus (P) recovery from sewage sludge is crucial to reconciling the simultaneous shortage and excess of P. In this study, magnetic biochar (MBC) was synthesized and innovatively applied to enhance P recovery as vivianite. The effects of anaerobic digestion (AD) time, hydrothermal (HT) pretreatment temperature and MBC dose on vivianite formation were investigated using batch experiments and a modified sequential P extraction protocol. The P fractionation results showed that the concentration of pure vivianite-bound P (Fe(II)-P) reached a maximum on the 10th day of AD treatment, and then declined sharply due to vivianite oxidation and P limitation. HT pretreatment operated at relatively high temperatures (135 and 185 °C) reduced vivianite formation; this negative effect of HT pretreatment was partially compensated by MBC supplementation. The proportion of Fe(II)-P in the solid phase of sludge was substantially raised up to 57.1% from 8.3~17.4% with an increasing dose of MBC from 0 to 12.5 g/L, indicating that MBC had a markedly enhanced effect on vivianite formation; this could be attributed to the MBC-improved Fe(II) production, as evidenced by the elevated proportion of Fe(II) in Fe2p XPS spectra and the increased ratio of Fe(II)-P to oxidized vivianite-bound P (Fe(III)-P) in the sludge after MBC supplementation. MBC addition also decreased the proportion of water-extractable P by sorption and promoted organic P decomposition, which further facilitated vivianite production. These findings reveal a new strategy for enhancing P recovery from HT-pretreated AD sludge.

Keywords: vivianite; sewage sludge; P recovery; biochar; HT-AD (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/2071-1050/14/14/8690/pdf (application/pdf)
https://www.mdpi.com/2071-1050/14/14/8690/ (text/html)

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:gam:jsusta:v:14:y:2022:i:14:p:8690-:d:863725

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().