Ogden Gas Co. / Investigation, Remediation and Monitoring

Client: PacifiCorp
Location: Ogden, Utah

The Ogden Gas Company operated a manufactured gas plant in downtown Ogden from 1889 to 1929. The plant retorted coal to produce “town gas” used for lighting street lamps and buildings. Under Utah’s Voluntary Cleanup Program (VCP), SAGE researched historic maps, aerial photos and company documents to focus our soil and groundwater sampling efforts on areas most likely to have been impacted by plant operations. We then conducted a phased site investigation and identified coal tar, benzene, and cyanide contamination due to coal gasification residues.

We prepared the remediation plan, and provided technical oversight and construction management of remedial activities. Remediation included the excavation and disposal of over 30,000 tons of soil/debris. Because the excavation extended beneath the groundwater table, a bentonite slurry wall groundwater cutoff system was installed to facilitate excavation dewatering. SAGE permitted and operated an activated carbon system that was used to treat 250,000 gallons of contaminated groundwater.

Emissions from the excavation were of great concern during the remediation process. SAGE developed both personal and perimeter air monitoring plans and implemented a daily air monitoring program that continued for five months. Engineering controls were implemented when contaminant concentrations in ambient air exceeded perimeter action levels.

With VCP oversight, SAGE developed a post-remediation ground water monitoring plan that included the installation of 12 new monitoring wells and initial quarterly monitoring.