BL Companies performed remedial investigation and action activities at this former Manufactured Gas Plant (MGP) facility located in Ashland, Pennsylvania. The site had been previously closed under Pennsylvania Act 2 using site-specific standards. The remaining Site impacts were assessed and an interim remedial action was performed to address soils impacted by non-aqueous phase liquids (NAPL).
A summary of the services performed during this project are as follows:
- Performed a desktop evaluation of prior reports to assess data gaps and the potential for sources areas and associated impacts to remain on the site following the prior remedial actions.
- Performed a pre-design evaluation using test pits, direct-push soil borings, and hollow-stem auger soil borings and gauging of existing monitoring wells to assess current subsurface and groundwater conditions. NAPL-impacted soils were identified in subsurface samples throughout much of the site and particularly proximal to the two belowgrade gas holder foundations that remained on the site. Also performed qualitative hydrogeologic evaluation to assess dewatering options for future remedial action activities.
- Performed a focused feasibility study to assess the appropriate remedial alternative for the site in terms of short-term and long-term effectiveness, cost, ability to implement, and proven effectiveness of the technology.
- Developed remedial action plans, bid documents, and specifications for soil remedial action. Coordinated the procurement process by issuing bid documents and specifications to prospective contractors, soliciting bids to perform the remedial action, evaluating bids, and assisting utility company with contractor selection and award.
- Decommissioned all existing recovery and monitoring wells and remediation system.
- Performed field oversight for the interim remedial action that included removing the two belowgrade gas holder foundations, a former building foundation, and the area of NAPL-impacted soils. Field oversight included performing perimeter air monitoring; coordinating excavation, demolition, and restoration activities; documenting field activities; and verifying adherence with bid specifications. A total of approximately 14,000 tons of impacted soil were properly transported and disposed at approved offsite facilities. An onsite treatment system was constructed to manage wastewater generated from dewatering activities. Approximately 295,000 gallons of impacted groundwater was discharged to the local wastewater treatment facility. The excavation approach was modified to account for heightened groundwater infiltration rates related to abnormal precipitation events experienced during the remediation.
- Coordinated work with utility company and local authorities, including obtaining an approval for discharge to the local wastewater treatment facility.
- Reviewed contractor invoices and change order requests to verify consistency with bid pricing and field observations.
- Developed an Interim Remedial Action Report to document the activities performed.