Full Description

Castaic Lake Water Agency was faced with a dilemma: how to support the increasing waterneeds of a growing population in the Santa Clarita Valley with three to five wells in the area shutdown due to the presence of perchlorate. Carollo Engineers was hired to design a treatmentprogram for the removal of perchlorate from Saugus Aquifer. Several unknowns challenged theproject including an uncertainty in a regulatory MCL for perchlorate, lack of brine line in the area,and low chloride limits in LACSD sewer lines. One of the selected alternatives was throw-awayion exchange. Selection criteria included cost, minimal formation of wastes and full-scaledemonstration of the processes. Bench-scale testing of the ion-exchange resins was conductedover a period of 3 months. Single-use ion exchange resins performed well to remove perchloratebelow the detection level. The adsorption cycles of two of the resins lasted more than 70,000bed volumes before perchlorate was detected in the effluent of the columns (approximately200,000- 550,000 gal/cu-ft resin). No NDMA was formed as a result of post-chlorination with freeand combined chlorine, or as a result of prechlorination with free chlorine. The metals measuredin the spent results were well below the TTLC and STLC limits, despite the long run times. Ionexchangeis therefore a feasible technology for treatment perchlorate in the Santa Clarita Valley. Includes tables, figures.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 5File Size: 1 file , 330 KB