AWWA WKICO66043

This powerpoint presentation begins by providing a brief overview of the occurrence of nitrate and perchlorate in California groundwater. Project objectives were to: evaluate nitrate treatment options for conversion from ISEPTM to Single Pass Ion Exchange at the Valley County Water District Arrow Lante Treatment Facility; and, provide a cost comparison of the identified nitrate treatment options. Nitrate treatment technologies for the Valley County included: Tailored single pass ion exchange (IX); existing ISEP™ units; and, various blending/extraction options. Capital and operation and maintenance (O&M) costs to remove perchlorate and nitrate are presented, along with cost comparison, and application to other utilities with both perchlorate and nitrate contamination. Conclusions were that: nitrate removal cannot be achieved with Single Pass IX; the resin is expected to become saturated within 24 hours; the use of regenerable ion exchange (e.g., ISEPTM) for nitrate removal is a proven technology and ISEPTM is already onsite; at Valley County, nitrate levels can be reduced to < 8 mg/L as N by treating 33% of the total flow through the ISEPTM; five extraction/blending scenarios were identified, more information is needed before any of the scenarios can be recommended; total costs are higher for nitrate treatment via ISEP than for blending due to the O&M costs (e.g., salt purchases); however, retention of one or both ISEP system was recommended to provide maximum flexibility for meeting the nitrate MCL; and, if desired, alternate extraction/blending options could be explored in conjunction with installing single pass IX and bypass piping for the ISEP. Includes tables, figures.