North Portland Road PPA Implementation

Ash Creek has assisted North Portland Road, LLC with implementation of several remediation and site management activities conducted under a DEQ Prospective Purchaser Agreement (PPA).  The North Portland Road Site is approximately 1,000 feet from the Columbia Slough and had a direct stormwater connection from this unpaved site to the slough.  Chlorinated solvents are present in the subsurface at the North edge of the property.  The PPA addressed possible sediment contamination in the slough through the DEQ’s Columbia Slough “buy out” program (one of the first parties to be a part of this program).  Ash Creek was retained to manage and complete the following PPA scope of work items:

• Source area groundwater assessment and design of an enhanced bioremediation solvent source treatment.  Ash Creek implemented an enhanced bioremediation program, consisting of emulsified oil injections to facilitate reductive dechlorination of the chlorinated solvent source. 
• Construction of a stormwater treatment swale to infiltrate all groundwater on the site, eliminating all stormwater discharges from the site.  Approximately 2,400 cubic yards of mildly contaminated soil were generated during the swale project.  Since the soil did not contain leachable concentrations of any constituents, the soils were incorporated into an on-site grading project as part of the cleanup action that placed the soil with a gravel cover to expand the trailer parking area.
• Completing a soil vapor evaluation that addresses outdoor air quality and vapor intrusion from the chlorinated solvent source.

The project required underground injection control (UIC) permitting for the injections, City commercial building permits for the swale construction and the soil grading projects, and a Land Use Compatibility Statement for the soil grading project.  Project completion, with an NFA determination, is expected in spring 2011.