A.47 Natural Gas Compressor Station, MS

A.47.1 Summary

Environment:	Freshwater
Scale:	Full
Contaminants of Concern:	PCBs
Final Remedy:	Creek flow diverted by pumping to nearby tributary to allow for dry excavation. Little to no dewatering of excavated material done. Typically dry enough to put into vehicles to transport to Emelle, AL.   In a few instances, fly ash or lime was mixed in to make the material dry enough for transport.

A.47.2 Site Description

Year: 1997

Contaminated sediment area: 2 mile stretch on the Little Conehoma Creek approximately, 15-25 ft wide.

Water Depth: Creek bed/flood plains

Target Volume:

51,432 yd³ of stream sediment

8,290 yd³ of floodplain soils.

Actual Volume Removed: 23,883 yd³ excavated

A.47.3 Remedial Objectives

1ppm PCB for Creek, 5ppm > for floodplain soils.

Sediment thickness: At one point, excavation to depths of 8-10 ft necessary to reach cleanup levels. Remainder were 0-8 ft.

Dredge depth: Avg. 1 ft, more near outfall.

A.47.4 Remedial Approach

Dry excavation (Caterpillar 320 and long stick excavator)

A.47.5 Monitoring

There were no suspension controls because dry excavation was used. Air monitoring was in effect.

All remediated areas were at or below 1 ppm. All goals were met.

A minimum of 2 ft of clean backfill was installed along the banks of section 26. Backfill was followed by seeding and application of mulch.

A.47.6 References

Major Contaminated Sediment Sites Database; Sept. 2004 as updated 2008. http://www.smwg.org/MCSS_Database/MCSS_Database_Docs.html.

Publication Date: August 2014