Project NameWashington Avenue Former MGP Remediation
LocationBelleville, Illinois

Project Summary

AMEREN contracted 06 ENV to provide project management, field resources, and equipment for the Excavation, Transportation and Disposal of Impacted Soils at the Former Manufactured Gas Plant in Belleville, Illinois.

O6 ENV completed the demolition and removal of Washington Avenue. The road was demolished, sized and disposed of at an approved landfill. Additionally, 12,000 cubic yards of soil impacted with coal tar from previous plant activities was also excavated during the remediation phase. The source of the coal tar contamination was discovered to have originated from the underground gas holder that remained in place from when the former manufactured gas plant was in operation. Due to the proximity of active public streets and utilities, the excavation work was performed inside of an Earth Retention System (ERS) consisting of driven steel sheet piling and tie backs.

The impacted soil was excavated with a pair of hydraulic excavators and loaded onto end dump trailers and transported under manifest for disposal at a Subtitle D landfill. The impacted soil was manifested as NON-RCRA Regulated Waste under 40 CFR Section 262.34(a) which provides a RCRA exemption for certain wastes generated from former manufactured gas plant activities.

Due to a high groundwater table, O6 ENV utilized a dewatering system to support deep excavation within the ERS. Approximately, 300,000 gallons of MGP-impacted groundwater was pumped and filtered through an onsite Wastewater Treatment Plant consisting of an oil water separator, solidification bag filters, carbon and resin vessels. The treated water was analyzed prior to release to the local POTW.

The excavations were backfilled using soil and virgin gravel from an off-site borrow source. The borrow material mater was transported by tandem trucks, placed in lifts by a dozer and compacted to specifications. Topsoil was placed to the match the original grade and the area was restored with seed and straw.