Research on ‘high-pH precipitation treatment’ for RO concentrate minimization and salt recovery in a municipal groundwater desalination facility

Rioyo, Javier and Aravinthan, Vasantha and Bundschuh, Jochen and Lynch, Mark (2018) Research on ‘high-pH precipitation treatment’ for RO concentrate minimization and salt recovery in a municipal groundwater desalination facility. Desalination, 439 . pp. 168-178. ISSN 0011-9164

Abstract

This study evaluated ‘high-pH precipitation treatment’ of a reverse osmosis (RO) concentrate followed by secondary
RO treatment to increase overall water recovery in an existing inland desalination system. In contrast
with previous studies that used calcium dominated surface waters, this study dealt with magnesium dominated
groundwater. The high-pH process removed scale-forming precursors including magnesium, calcium, strontium,
barium and SiO2 from primary RO concentrate by precipitation and adsorption/enmeshment. Lime and soda ash
were determined to be the superior caustic agents when compared to sodium hydroxide for the high pH demineralization
process. Following ‘high-pH precipitation treatment’, pH readjustment and antiscalant addition,
the use of secondary RO enabled the overall water recovery to be increased from 80 to 97%. In addition, this
study evaluated CaCO3 and CaO recovery from the precipitated sludge through CO2 gas injection to selectively
dissolve magnesium.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Date Deposited: 26 Apr 2018 05:09
Last Modified: 16 May 2018 01:47
Uncontrolled Keywords: reverse osmosis in inland areas; brackish groundwater; RO concentrate minimization; zero liquid discharge
Fields of Research : 09 Engineering > 0907 Environmental Engineering > 090703 Environmental Technologies
Identification Number or DOI: 10.1016/j.desal.2018.04.020
URI: http://eprints.usq.edu.au/id/eprint/34052

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