The cost of concentrate disposal has been reported to be the highest operational line item
(up to 70%) for inland brackish groundwater RO (BWRO) processes. Antiscalants are used to prevent precipitation on the RO membrane surface and improve recovery, but their range is limited. This research focused on a side-stream treatment to oxidize and inactivate the antiscalants with peroxone (hydrogen peroxide with ozone), and then encourage precipitation prior to a solid/liquid separation (microfiltration) step. The filtrate is then sent to a final RO membrane to increase the overall recovery of the system. The three waters tested were likely candidates for groundwater RO: Martin County, FL; Maricopa County, AZ; and Cameron County, TX. Florida and Arizona concentrates were synthetically prepared in the laboratory based on available water quality data. Texas concentrate samples were both synthetically prepared and obtained from an operating BWRO plant. Ozonation of antiscalants, in combination with a small increase in precipitation pH, was found to be ineffective at achieving sufficient calcium precipitation for two synthetic water recipes (representative of Maricopa County, Arizona and Martin County, Florida) and concentrate from an actual BWRO plant in Cameron County, TX. However the precipitation process at highly elevated pH and S values appears feasible and beneficial to current BWRO desalination operations. By implementing this method to the concentrate streams of existing BWRO plants, appreciable improvements to system recovery could be realized. Specific cost improvements will vary dramatically based on several key characteristics of the treatment process, including the existing concentrate
This presentation is available to AMTA Members only.
- Scott Hekman
- Freese and Nichols, Inc.
- AMTA Annual Meeting, San Diego, CA
- San Diego Biennial
- Concentrate Recovery, Reverse Osmosis, Brackish Groundwater