	About Perchlorate

	Recent Cases Involving Perchlorate

	Perchlorate News and Notes

	Related Links About Perchlorate and Treatment

	Contact Perchlorate News

Full-Scale ISEP(R) Groundwater Treatment Plant

La Puente, CA

Source:
Calgon Carbon Corporation, Pittsburgh, Pennsylvania, Project Summary Information, December 2000

Project Summary:
The following text was excerpted from Calgon Carbon Corporation, Pittsburgh, Pennsylvania, Project Summary Information, December 2000; July 11, 1999 Press Release, available at http://www.findarticles.com, and Wagner, Norman, and Charles Drewry, 2000. "Commercial Systems Treating both High and Low Strength Perchlorate Applications Utilizing Ion Exchange" in Perchlorate Treatment Technology Workshop, 5th Annual Joint Services Pollution Prevention & Hazardous Waste Management Conference & Exhibition, August 21-24, 2000, Henry B. Gonzalez Convention Center, San Antonio, Texas:

Calgon Carbon Corporation announced on July 11, 1999, that it had been awarded a contract from the La Puente Valley County Water District in Southern California to supply the first commercial ISEP® system to remove perchlorate and to provide a Rayox(R) Tower to destroy N-nitrosodimethylamine (NDMA) in water from three of its wells. The wells have been shut down since 1997, when the contaminants were first detected. The contract is valued at over $3.0 million. Partial funding for the project will be provided by grants from the Main San Gabriel Basin Watermaster, the San Gabriel Basin Water Quality Authority, and the Upper San Gabriel Valley Municipal Water District.

The ISEP system utilizes Calgon Carbon's patented continuous ion exchange contactor which removes the perchlorate from drinking water. The Rayox Tower employs Calgon Carbon's proprietary, medium-pressure, ultraviolet (UV) lamps to destroy NDMA on-site. The two systems will treat approximately 2,500 gallons of water per minute. The ISEP will reduce the concentration of perchlorate from 200 parts per billion (ppb) to less than 5 ppb, while the Rayox Tower will reduce the NDMA from 900 parts per trillion (ppt) to less than 5 ppt.

Perchlorate, which prevents proper functioning of the thyroid gland, is a component of rocket fuels, fireworks, and explosives. NDMA, a suspected carcinogen, is a by-product of liquid rocket fuel combustion and has been found as a by-product in the manufacture of rubber products and certain chemical intermediates. Improved analytical testing methods in recent years have permitted the detection of the contaminants in low concentrations in drinking water. Calgon Carbon has been utilizing its UV technology to treat NDMA since 1991. However, no method for removing perchlorate from drinking water had been demonstrated until the ISEP successfully removed perchlorate in trials at two separate sites in the Greater Los Angeles Area last year. The La Puente installation will be the world's first commercial application of the ISEP to remove perchlorate from drinking water. In addition to removing perchlorate and NDMA, the Calgon Carbon systems will also reduce nitrates and sulfates in the treated water.

This report presents the results for the on-site testing of Calgon Carbon Corporation's (CCC) ISEP and Rayox UV/Oxidation processes for treatment of drinking water containing perchlorate, NDMA and 1,4-dioxane. The testing plan was formulated to provide supporting data for a treatment permit from California Department of Health Services (DHS) for the La Puente Valley County Water District treatment plant at 1695 Puente Avenue in Baldwin Park, California. The on-site tests were performed in phases. First, the ISEP system was tested to determine optimal operating brine rates. Second, at the minimal safe brine-operating rate, the Rayox system was tested to evaluate treatment efficiency and performance. Finally, both systems were studied to observe the effects of lower flow rates. During all phases, water quality parameters were measured to ensure they met DHS requirements.

The objectives of this test were:

Assess the performance of the ISEP and Rayox UV/Oxidation processes under full operating conditions.
Determine the treatment requirements for perchlorate, nitrate, and sulfate removal in the ISEP process and the destruction of NDMA and 1,4-dioxane in the Rayox UV/Oxidation process.
Recommend final operating conditions to ensure treatment to specifications at all times under varying water quality conditions.

The results of the testing have shown that:

Perchlorate can be removed to non-detect (ND) levels at full flow conditions at a waste brine rate of 0.85%.
Sulfate removal to ND levels and nitrate removal to < 1.0 mg/l is also obtained at the 0.85% waste brine rate.
Volatile organics were completely removed by the existing treatment plant air stripers installed upstream of the CCC processes.
Due to the longer path length of the Rayox tower, the electrical energy per order (EE/O) for the Rayox UV/Oxidation process obtained in this test was less than 0.4, which is lower than the design EE/O of 1.8.
1,4-dioxane influent levels were non-detect during the test period so no treatment data was obtained for this compound. Based on previous experience and a list of treatment efficiencies in Section 7.2, the expected EE/O should be 1.3. Therefore, 1,4-dioxane levels up to 4 ppb would be treated to below 0.5 ppb with 8 lamps operating at a peroxide level of 3 ppm.
Operation of 8 lamps total in both Rayox towers at an average power consumption of 20 kVA per lamp was sufficient to reduce the NDMA to < 2 ppt in the treated water.

Based on a review of the data obtained during the testing, the following recommendations are made for ongoing operation of the treatment plant at full-scale flow conditions under varying water quality conditions that will ensure removal of the contaminants to specified levels.

The minimum waste brine rate to remove perchlorate to ND was 0.8%. For long term operation of the ISEP a waste brine rate of 0.90% based on a flow set point of 2,500 gpm is recommended. The actual waste brine rate at a well flow rate of 2,300 gpm would be 0.97% at this setting. This setting would be capable of treating perchlorate levels in the feed up to 100 ug/l at the typical nitrate and sulfate levels obtained during the testing.
NDMA removal to < 2 ppt was obtained when operating 8 lamps at the well flow rate of 2,300 gpm. Operating with 12 lamps at an average power consumption of 20 kVA per lamp is recommended to achieve treatment of NDMA to < 2 ppt over the duration of the operating life of the lamps.
Hydrogen peroxide should be added at the rate of 2 to 3 ppm to ensure removal of 1,4-dioxane should it be detected in the raw water.

The maximum treatment capacity of the system is estimated to be in excess of 600 ug/l for perchlorate and 3,000 ppt for NDMA. Increasing the brine use rate in the ISEP and operating additional lamps in the Rayox towers can realize these treatment conditions. Significantly higher levels of perchlorate could be treated by making modifications to the brine addition equipment to increase the brine flow rate above the current design. Periodic sampling of the well and the treated water should be done to make adjustments in the operating conditions as required to meet the specifications for the treatment plant.

The La Puente Valley County Water District CCC ISEP System was commissioned in February 2000, and as of August 2000, operates 19 hours per day to control the perchlorate plume. The ISEP system was accepted by the California Department of Health Services for perchlorate and nitrate drinking water applications. An emergency use permit was approved, and the operating permit is currently under review by California Department of Health Services -- Metropolitan District. As of March 31, 2000, the actual capital costs associated with the system were $4,070,041. The engineering and permits for the California Department of Health Services testing were $882,608, for a total of $4,952,649. The actual operating costs for the system totaled $227.66/AF, including wells, air strippers, booster, ISEP, brine disposal, Rayox, peroxide, and maintenance and labor.

Additional Info Source:
"SBIR Success at Marshall", in Aerospace Technology Innovation, Vol. 7, No. 4, July/August 1999, Small Business/SBIR, available at http://nctn.hq.nasa.gov/innovation/Innovation74/sbir.htm

< Back

About Perchlorate | Recent Cases Involving Perchlorate | Perchlorate News and Notes | Related Links About Perchlorate and Treatment | Contact Perchlorate News
Ground-Water Remediation Technologies Analysis Center ©2001 GWRTAC

The Perchlorate News Web Site is brought to you by:
Calgon Carbon Corporation, 400 Calgon Carbon Drive, Pittsburgh, PA 15205. Phone: (412) 787-6700, 1-800-422-7266

Use of this site signifies your acceptance of Calgon Carbon Corporation's Website Terms and Conditions and Privacy Policy.
© 2003 Calgon Carbon Corporation. All Rights Reserved.