Horizontal Well Remediation System and Subslab Depressurized System

A new terminal building was constructed over an area affected by historical jet fuel release. To protect the building from potential migration of vapors from the release and to remediate soil and groundwater, GEI completed a Pilot Test and prepared plans and specifications for a Horizontal Well Remediation System (HWRS) and a Subslab Depressurization System (SDS), at Bradley International Airport in Connecticut.

Pilot-scale testing was conducted to evaluate potential remediation technologies, including bioslurping, bioventing, soil vapor extraction and air-sparging. The pilot testing was performed following protocol developed by the Air Force Center for Environmental Excellence. The selected remediation technology was a HWRS that consisted of two horizontal air sparge (AS) wells and two horizontal soil vapor extraction (SVE) wells. A conventional vertical AS and SVE system was discounted because of construction of the new terminal building. The total length of each blind well is about 750 feet with screened intervals of approximately 200 to 300 feet. A general air permit for the HWRS was approved by the CT DEP.

To prevent potential jet fuel vapors from migrating into the terminal, a subslab depressurization system (SDS) was designed. The system consisted of eight loops of Schedule 40 PVC perforated pipe totaling 200 feet for each loop. The loops were manifolded into a header and connected to an exhaust fan on the roof where any vapors will be discharged into the ambient air. No air discharge permits will be required for the system.

GEI also completed plans and specifications for the SDS and the HWRS and sent out to bid. Contractor submittals were reviewed and estimated costs were developed for the systems that were used by our client for comparison to contractor estimates.

GEI was on site as the owner’s representative overseeing construction/installation of the SDS, HWRS, and treatment building.