Pump and Treat System at Commencement Bay, South Tacoma Channel (Well 12A), Phase 2, Tacoma, Washington

Site Name:

Commencement Bay South Tacoma Channel Superfund Site


Tacoma, Washington

Period of

Status: Ongoing
Report covers - 1988 to 2/94


Full-scale cleanup
(interim results)


Not Available

Groundwater Extraction followed by Granular Activated Carbon (GAC) - 7 groundwater extraction wells with a 500 gpm design flow rate - Designed to have drawn-down sufficient to create a cone of depression and to reduce further migration of contaminants out of the source area - 2 liquid-phase GAC containers operated in parallel - Treated water discharged to a storm drain system - Soil vapor extraction used in a related application to remove volatile contaminants from the soil matrix

Cleanup Authority:
CERCLA; Local Requirements - ROD Date: 3/85

SIC Code:
2851 (Paints, Varnishes,
Lacquers, Enamels,
and Allied Products)
Point of Contact:
Kevin Rochlin
Remedial Project Manager
U.S. EPA Region 10
Seattle, Washington

Chlorinated Aliphatics - trans-1,2-Dichloroethene (DCE), 1,1,2,2-Tetrachloroethane (PCA), 1,1,2,2-Tetrachloroethane (PCE), Trichloroethene (TCE) - PCA contamination plume measured at levels greater than 10,000 g/L; PCA at 10.7 g/L; TCE at 80.7 g/L to 2,000 g/L to 13 g/L and a separate liquid phase of contamination was suspected in both the soil and groundwater. In addition, chlorinated hydrocarbons were detected in a City of Tacoma production well (Well 12A) in 1981. The site was placed on the National Priorities List (NPL) and a Record of Decision was signed in 1985.

A groundwater extraction system using granular activated carbon (GAC) for treatment of extracted groundwater was installed and began operating at the site in 1988. This system includes 7 groundwater extraction wells and a 500 gpm design flow rate, and was designed to have a draw-down sufficient to create a cone of depression and to reduce further migration of contaminants out of the source area. Treated water is discharged into a storm drain system. The groundwater remediation was ongoing at the time of this report.

As of February 1994, approximately 282,000,000 gallons of groundwater had been extracted, and an estimated 10,631 pounds of VOCs removed by the GAC. Specific VOCs in the GAC system influent ranged from 13 g/L, and, in the effluent, from <1 g/L. The contract amount for total capital cost was identified as $1,343,701, as of July, 1988.

Also view/download http://cluin.org/download/remed/rse/well_12a.pdf