Septic Systems

Since initial efforts to control the discharge of liquids from process operations was completed in 1995, additional emphasis has been placed on further reducing the amount of liquid discharged to the soil within the 200 Areas. The remaining discharges within the 200 Areas are primarily from sanitary sewer systems. Continuing liquid waste disposal practices have the potential to leach contaminants from the vadose zone into the groundwater and/or simply increase the volume of contaminated groundwater.

Within the Central Plateau, the ongoing uranium pump-and-treat operations have the potential to be adversely affected by continuing sanitary sewer discharges. The septic system that may adversely affect the pump-and-treat operations is 2607-W5. This discharge location is approximately 100 feet (30.5 meters) from the 216-U-1 and 216-U-2 cribs. The 216-U-1 and 216-U-2 cribs are a major source of technetium-99 and uranium in the vadose zone that could be leached from the soil by the adjacent septic discharges. The volumes from this particular system are relatively small, but the size of the pump-and-treat operation is only 50 gallons (190 liters) per minute, so the volume of recharge needed to impact the existing remedy may be much smaller.

The performance management plan specifies that discharge to this system will be eliminated by September 2004. Other systems will be evaluated and any further actions will be identified by September 2004.