RICHLAND, Wash. – A new resin EM, the Richland Operations Office, and contractor CH2M HILL Plateau Remediation Company are using in contaminated groundwater treatment is expected to increase efficiency and reduce costs in the operation of pump-and-treat facilities along the Columbia River at the Hanford site.
The higher performance resin, SIR-700, is expected to reduce DOE’s estimated operation and maintenance costs over the lifetime of the 100-DX Groundwater Treatment Facility by approximately $20 million. In comparison to this expected cost savings, the construction cost for the treatment facility was $25 million. Lifecycle costs decrease through the resin’s increased capacity and longer design life, reducing future facility modification costs and allowing for expanded treatment of contaminated groundwater.
The ion exchange resin is loaded into a series of treatment tanks. As water flows through the tanks, the resin strips specific contaminants from the water.
Chromium contamination is in the groundwater near Hanford’s former processing reactors, where an anti-corrosion chemical was added to water for cooling the reactors in the Cold War. The form of chromium used for this task — hexavalent chromium — is being cleaned up because it is a toxic form of chromium, and can contaminate drinking water.
The new resin retains more than 15 times the amount of chromium than previous resins. As treatment systems are fitted with the new material, the increased capacity of the resin and the need for fewer resin loadings will reduce worker handling and lower lifecycle costs and energy use associated with shipping spent resin for treatment.
Using a resin skid designed to simulate the treatment vessels, CH2M HILL tested a series of resins that were previously demonstrated or reported to be capable of removing the hexavalent chromium. The performance of the single-use SIR-700 demonstrated high capacity in side-by-side testing.
The resin installed at 100-DX operated over one year without a single resin change, which costs about $10,000. Between 120 and 160 change-outs were avoided, saving approximately $1.2 to $1.6 million.
Based on the resin’s effectiveness, CH2M HILL engineers determined the number of operating vessels can be reduced while still achieving the desired capacity or treatment rate. This reduces the material needs at the current capacity but also makes available more vessels to increase the treatment capacity in the future.
The new resin has also been installed at the 100-HX Groundwater Treatment Facility and is currently being tested for 100K Area treatment facilities.