Arrowhead Contracting, Inc.

Scope Of Work

Under a multi-year ID/IQ Environmental Services Contract, Arrowhead was awarded a competitive Task Order by USACE Omaha District for completion of remedial services which will result in a Remedy Complete status at a former nuclear missile silo located in Northeastern Colorado. The property was operated by the US Air Force as an Atlas Missile site between 1960 and 1965, during this time operational use of TCE resulted in contamination of a shallow aquifer. The property consists of approximately 27 acres, is privately owned and is currently operated as a light industrial manufacturing facility. The remedy proposed by Arrowhead was a multi-phased approach comprising in-situ chemical oxidation (ISCO) treatment (sodium permanganate as the selected oxidant) in the areas of highest TCE contamination and groundwater extraction, liquid phase granular carbon treatment, and re-injection in areas containing low levels of TCE. This approach provided two distinct advantages, the highest concentrations of TCE were directly treated by ISCO treatment while groundwater extraction produced increased hydraulic gradients decreasing the travel time necessary for oxidant to migrate through the saturated interval. Arrowhead was responsible for a wide range of tasks as part of this contract including: development of site-specific project plans (QAPP, SAP, HASP, Work Plans), completion of aquifer testing, data gap sampling, bench and pilot scale studies, community meetings, development of the Proposed Plan, preparation of the Decision Document, quarterly groundwater sampling, and construction of a full scale ISCO injection and groundwater extraction system. Arrowhead completed data collection and pilot testing to determine hydrologic parameters such as hydraulic conductivity, porosity and transmissivity (as collected in aquifer pump tests), and geochemical characteristics of the aquifer including the natural oxidant demand (NOD).