In 2002, the Federal Reserve Bank broke ground on a four-story, 280,000-square-foot facility on the former Jefferson Davis Memorial Hospital site in Houston, scheduled for completion in 2005. A gasoline plume from an off-site City of Houston vehicle maintenance facility threatened to disrupt construction, as previously installed recovery systems were still in place.
Geosyntec's Scope of Services
SKA Consulting, L.P. (SKA) retained Geosyntec to evaluate the expected completion of the remediation using the existing vertical recovery wells. Projections indicated that the clean up objectives of the Texas Commission on Environmental Quality (TCEQ) for product recovery prior to the construction start deadline would not be met. Geosyntec then provided remediation system design and installation, and assisted in successful negotiations for concurrent remediation and construction to meet the overall construction deadlines for facility completion. The project was awarded in February 2003 and on-site remediation system construction was completed prior to the start of building construction on May 5, 2003.
Geosyntec used two horizontal multi-phase extraction wells totaling approximately 1,200 feet in length to replace part of an existing vertical well recovery system. Additionally, we replaced the multi-phase extraction and liquid and vapor treatment systems with higher capacity, more reliable systems. The remediation design also addressed subsurface soil heterogeneities, hydraulic gradient, and the need to integrate vapor and water extraction function from a horizontal well. The horizontal wells are unique in their configuration because each southern termination intersects a 30-inch vertical sump at a depth of 42 feet below ground surface to dewater beneath the bank building. The northern termination of each well was connected to an SVE header to extract vapor phase hydrocarbons.
The system recovered and treated more than 10 million gallons of water and 88,600 lbs. of hydrocarbons. Geosyntec also worked met the construction schedule constraints while working under heightened security due to post- 9/11 terrorist concerns for a Federal Facility. Geosyntec achieved TCEQ site closure for our client on January 20, 2006.