$1 million in cost savings
Our team was able to narrow the target area, allowing for more localized treatment and saving significant expense.
Client
U.S. EPA
Location
Tacoma, Washington
Practices
Tackling one of the most difficult remediation projects in the United States
Nearly a half-century of industrial manufacturing and waste oil recycling left behind harmful chemicals in the groundwater near Commencement Bay and the Port of Tacoma. When traces of TCE were found in a water well, it joined the list of Superfund sites, and years of remediation efforts followed with mixed results. Conventional methods successfully removed some of the chemicals, but the process was slow. U.S. EPA and CDM Smith introduced a new strategy with three additional treatment technologies, made possible by CDM Smith's research efforts. They paired the new aggressive triple-treatment approach with a contaminant mass-discharge reduction goal, using a mix of integrated technologies to maximize synergy and overall treatment performance.
A 97% reduction in TCE mass discharge
Even with an ambitious goal of 90% reduction, the team exceeded it by an incredible margin.
3D modeling of the contaminated site
Modeling pinpointed a discrete zone of DNAPL-impacted aquifer responsible for over 96% of contaminant discharge.
Returning the site to the state of Washington
Bringing the site in line with EPA goals cleared the path to turnover of the site.
The Well 12A project team achieved the record of decision goals and made more progress in reducing the contaminant impacts to the drinking water aquifer than the previous 30 years of treatment.
This project represents a significant investment in the restoration of the aquifer to its beneficial use as a drinking water source for the City of Tacoma. Post-remediation sampling and evaluations have demonstrated that the project lowered contaminant mass discharge well below acceptable levels and that residual contaminants will attenuate to below MCLs prior to reaching Well 12A. Additionally, the project has set a precedent for the continued use of mass discharge as a measure of success. Incorporating mass discharge into a project record of decision can lead to more efficient treatment combinations and ultimately a more cost-effective and streamlined remediation process.
Deployment and results
Client
U.S. EPA
Location
Tacoma, Washington