Abstract |
The South Tacoma Channel, Well 12A site is in the City of Tacoma, Washington, and includes industrial, commercial and residential areas. Well 12A is one of 13 wells used by the City to meet peak summer and emergency water demands. Research into the past ownership and activities on these properties indicated that waste oil and solvent reclamation processes and paint and lacquer thinning manufacturing occurred on the site. As a result of these processes, both the underlying ground water aquifer and portions of the surficial soils show contamination with organic solvents. The selected remedial action includes: air stripping of the ground water (continue to operate the IRM); extract and treat the ground water at the source to remove volatile organics; drill and sample additional soil test borings during the design phase, remove an appropriate length of railroad track adjacent to the Time Oil property and excavate; perform additional undercutting; install the drain field piping in the excavated areas and cover with a permeable material; pave or place soil cover on the portions of the unpaved Time Oil parking lot; transport and dispose of all excavated, contaminated soils in a RCRA-permitted landfill; maintain institutional controls; monitor ground water and after two years of operation, evaluate the effectiveness of the ground water extraction and treatment system. Total capital cost for the selected remedial alternative is estimated to be $1,590,000, and O&M costs are estimated to be additional $50,000 per year. |