The area designated as Operable Unit 5 (OU-5) is located north of TNT Manufacturing Line 10, and includes Pond 13 and the former Wet Wells and Wastewater Pump Station. During the manufacture of TNT, the pump station and wet wells were part of the process wastewater handling system at the TNT manufacturing facility. The pump station was used to divert red and yellow water from the TNT manufacturing lines to their respective discharge points (the Red and Yellow Water Reservoirs, respectively). Two large wet wells constructed of earthen materials, with approximate diameters of 75 feet, were used for emergency storage of wastewater during pump station maintenance and overflow when inflow of wastewater exceeded the capacity of the pump station.
Ponds 12 and 13 were created to provide a habitat for wildlife after WVOW was declared as surplus in December 1945. As part of this closure, the wastewater pump station was removed.
The Pond 13/Wet Wells Area was identified as a potential area of concern in 1981 when a red water seep was identified at the edge of Pond 13. The analytical results revealed that nitroaromatics were present in the seep water. In 1982, the USEPA installed four monitoring wells, collected soil and groundwater samples in the vicinity of the seep, and analyzed the samples for nitroaromatics. Nitroaromatic contamination was found in soils and groundwater at the location of the former pumping station. Due to potential fish contamination, Pond 13 was closed to fishing in the 1980's.
In 1988 the U.S. Army Corps of Engineers (USACE) was originally required to cap the Wet Well area and treat groundwater in this area. The Wet Well Area would have been covered with two feet of soil and the groundwater treated by a carbon absorption system before entering Pond 13. However, a better, cheaper alternative was sought.
It was discovered that nitroaromatic contamination was confined to one small, subsurface area. This source fed contamination into the groundwater, although at low levels. Instead of capping the entire area, it was decided to remove this “hot spot” of nitroaromatic-contaminated material.
Rather than disposing of the soil in a landfill, the Corps researched bioremediation of nitroaromatic compounds. Different types of bioremediation have been used at Department of Defense and other sites for several kinds of contaminants, including nitroaromatics and fuel. Windrow composting was selected by the USACE Huntington District based on its success in treating nitroaromatics compounds such as TNT and DNT.
From late 2003 to November 2004 nearly 1,400 cubic yards of nitroaromatic-contaminated soil were excavated from the OU-5 Wet Well Area treated through windrow composting. The treated soil was placed within the TNT Manufacturing Area in areas selected by WV Division of Natural Resources personnel for habitat enhancement. It is estimated that nearly $650,000.00 was saved on this project by using bioremediation techniques instead of the original plan of capping and monitoring. Two new extraction wells were installed in this area to pump and treat groundwater, and began operation in December 2005. The groundwater in this area will be treated and monitored to evaluate the effectiveness of the removal action.