Synergy of phosphate recovery from sludge-incinerated ash and coagulant production by desalinated brine

Journal article (2023)

Authors

Xiangyang Wang Beijing University of Civil Engineering & Architecture
Chen Shi Beijing University of Civil Engineering & Architecture
Xiaodi Hao Beijing University of Civil Engineering & Architecture
Mark C.M. van Loosdrecht Beijing University of Civil Engineering & Architecture, BT/Environmental Biotechnology - AS
Yuanyuan Wu Beijing University of Civil Engineering & Architecture
Research Group
BT/Environmental Biotechnology (AS) (TU Delft)
Copyright: © 2023 Xiangyang Wang, Chen Shi, Xiaodi Hao, Mark C.M. van Loosdrecht, Yuanyuan Wu
DOI
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https://doi.org/10.1016/j.watres.2023.119658
Waste activated sludge (WAS) Phosphorus recovery Ash Coagulants Incineration Metals’ recovery
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Published Date

2023

Language

English

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Faculty

Applied Sciences

Department

BT/Biotechnologie

Research Group

BT/Environmental Biotechnology

Abstract

Wet-chemical approach is widely applied for phosphate recovery from incinerated ash of waste activated sludge (WAS), along with metals removed/recovered. The high contents of both aluminum (Al) and iron (Fe) in WAS-incinerated ash should be suitable for producing coagulants with some waste anions like Cl− and SO42− With acid (HCl) leaching and metals’ removing, approximately 88 wt% of phosphorus (P) in the ash could be recovered as hydroxylapatite (HAP: Ca5(PO4)3OH); Fe3+ in the acidic leachate could be selectively removed/recovered by extraction with an organic solvent of tributyl phosphate (TBP), and thus a FeCl3-based coagulant could be synthesized by stripping the raffinate with the original brine (containing abundant Cl− and SO42−). Furthermore, a liquid poly-aluminum chloride (PAC)-based coagulant could also be synthesized with Al3+ removed from the ash and the brine, which behaved almost the same in the coagulation performance as a commercial coagulant on both phosphate and turbidity removals. Both P-recovery from the ash and coagulant production associated with the brine would enlarge the markets of both ‘blue’ phosphate and ‘green’ coagulants.