Design-Build Remediation

The Kenilworth former manufactured gas plant (MGP) site is located in a residential neighborhood in Kenilworth, Illinois. GEI served as Commonwealth Edison’s environmental consultant for investigation and remediation of the site.

GEI initially conducted a focused site investigation (FSI), which was completed in accordance with the Illinois Environmental Protection Agency (IEPA) Site Remediation Program (SRP). The objectives of the FSI were to:

• Determine the presence or absence of MGP residuals in the subsurface
• Identify and characterize any extant MGP structures
• Determine the site geology and hydrogeology
• Collect sufficient analytical data to determine the need for remedial actions
• Determine off-site background levels for inorganics and polycyclic aromatic hydrocarbons (PAHs)

Based on the FSI, GEI developed remediation objectives that were accepted by IEPA. GEI then prepared a Remedial Action Plan (RAP), as well as an Ambient Air Monitoring Work Plan for the site. The RAP called for dewatering of the contents of a 50-foot-diameter subsurface gasholder, and excavation and off-site disposal of the uppermost 4 feet of soil in certain areas of the site.

GEI completed the remedial design, including construction plans and specifications and bidding documents, executed the bidding process, and selected and procured the remediation contractor. During remedial construction, which was performed as a design-build project, GEI provided construction oversight and contract administration.

GEI performed real-time monitoring of volatile organic compounds (VOCs), benzene, and suspended particulates, and time-averaged monitoring of VOCs and PAHs.

Given the proximity of the site to residential areas and two schools, GEI was instrumental in the success of community relations programs that were conducted as part of the site investigation and remediation. GEI promptly addressed concerns expressed by the public throughout the remediation process.