Wastewater DU Sludge Stabilization and Disposal

The scope of work included the initial characterization of accumulated radioactive wastewater sludge in five above ground storage tanks which historically received process waste water from a depleted uranium manufacturing operations for more than 25 years. Initial historic site assessment information from two tanks indicated the sludge might become pyrophoric if allowed to dry out. This waste required stabilization prior to shipment offsite for direct disposal. The DDES team pumped 6,500 gallon of radioactive wastewater through a five micron filter to assure high activity sludge was not entrained in the liquids.

Our project team designed a pilot study to stabilize this sludge and demonstrate compliance with the receiving disposal facility’s waste acceptance criteria (WAC). The pilot study was scaled up to full size production and 125 cubic feet of sludge solidified without incident. We assembled the waste profile and received approval from the disposal site to ship the stabilized waste for direct disposal within two weeks.

The DDES team removed the radioactive sludge from the two tanks and decommissioned the Tank House. We stabilized the sludge and performed QA/QC testing to verify the full-scale process was equivalent to the bench-scale results. ISOCs assays were used on the solidified materials to assign total activity in picoCuries/gram (pCi/g). The project was completed without incident and the radioactive wastes were shipped for disposal at a permitted facility in Idaho.