Bond R.,Black and Veatch Corporation |
Owen C.,Tampa Bay Water Authority |
Teegarden R.,Orlando Utilities Commission |
Browning K.,Orlando Utilities Commission |
And 2 more authors.
Water Quality Technology Conference and Exposition 2010 | Year: 2010
A Water Research Foundation Tailored Collaboration project was conducted to evaluate zero liquid discharge (ZLD) desalination of brackish water. The technical approach involved treating desalination concentrate with a new electrodialysis process referred to as electrodialysis metathesis (EDM). EDM is a variation of electrodialysis that uses a unique configuration of ion exchange membranes to produce desalinated water and two highly soluble concentrate streams, one containing sodium, sulfate, and chloride ions and the other sodium, calcium, and chloride ions. This characteristic gives EDM a unique advantage in ZLD treatment because the solubilities of sodium sulfate, calcium chloride, and sodium chloride salts are much higher than those of the sparingly soluble salts such as calcium sulfate and calcium carbonate that limit recovery in RO systems. EDM recoveries of over 99 percent without membrane fouling were observed in pilot tests treating concentrate from RO, NF, and EDR membrane plants. Pilot data were used to compare treatment costs for ZLD with EDM with the costs for ZLD with thermal devices. It was concluded the EDM method has the potential to significantly reduce ZLD costs, particularly for brackish sources with TDS less than 5000 mg/L. 2010 © American Water Works Association WQTC Conference Proceedings. All Rights Reserved.