Checking In on the Chino Concentrate Reduction Facility

The Chino II Desalter (Chino II) began operation in 2006 to expand the capacity of the groundwater treatment system with a combined ion exchange (IX) and reverse osmosis (RO) treatment capacity of 10 million gallons per day (MGD). High salinity concentrate from the Chino II Desalter is disposed of through the Inland Empire Brine Line (IEBL). The IEBL allows transport of saline waste out of the watershed for disposal to the Pacific Ocean through the Orange County Sanitation District water reclamation facilities and ocean outfall. A 10.5-MGD expansion of the Chino II RO capacity has been constructed in 2011; however, due in part to the high cost of concentrate disposal, the CDA has decided to construct and operate a concentrate reduction facility in lieu of purchasing additional capacity in IEBL. RO recovery is typically limited by precipitation of sparingly soluble salts on the surface of the membranes. With the current mineral content of the groundwater treated at the Chino II RO facilities, the primary RO recovery is 83.5%. The remaining 16.5% is discharged into the IEBL as RO concentrate. The concentrate reduction strategy for the Chino II Concentrate Reduction Facility (CRF) involves the use of chemical softening to remove the limiting foulants (specifically, calcium and silica) from the primary RO concentrate. Softened water is then passed through granular media filters to provide particulate removal upstream of a secondary RO (SRO) process. Treated water (SRO permeate) will be blended with the primary RO permeate, and SRO concentrate will be disposed of into the IEBL. Using this approach, total water recovery from the RO system at Chino II Desalter will be increased from 83.5% to as high as 95%, substantially reducing the volume of concentrate disposed into the IEBL while increasing permeate production. This paper will discuss the design philosophy of the Chino II Concentrate Reduction Facility, the selection of appropriate treatment technologies to meet the challenges of scaling constituents in the concentrate stream, the projected beneficial use of the process residuals, and the current status of construction.

This presentation is available to AMTA Members only.