Abstract
A hybrid process combining reverse osmosis and electrodialysis has been shown to be effective in recovering 97-98% of brackish water as product water with chloride levels of 200 mg/L or less. Potential for scaling on the brine side of the electrodialysis unit was prevented by acidification, operating the electrodialysis in a reversal mode (EDR), and a side loop crystallizer which prevented buildup of scaling components. Settlers, inline microfiltration, and side-loop ultrafiltration kept suspended solids from returning to the EDR unit. This process was demonstrated in a series of more than eighty batch experiments of 1.5 to 1.8 m3 of RO concentrate of raw brackish groundwater from the Negev Highland, Israel. Each batch could be processed within a single day. The feed-water was concentrated from 0.3% to over 10% TDS super-concentrate while producing the water that could be recycled to the RO permeate. This super-concentrate from the EDR unit was further concentrated in a wind powered WAIV unit that brought final brine TDS to N30%, and showed promise as a method to recover mineral byproducts such as magnesium salt. Initial economic estimates show that this hybrid process is competitive with conventional RO and other enhanced recovery processes for inland desalination requiring use of evaporation ponds.
Original language | English |
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Pages (from-to) | 321-330 |
Number of pages | 10 |
Journal | Desalination |
Volume | 261 |
Issue number | 3 |
DOIs | |
State | Published - 1 Jan 2010 |
Keywords
- BWRO
- EDR
- Inland desalination
- Near ZLD
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- General Materials Science
- Water Science and Technology
- Mechanical Engineering