Process Results for the Integrated Near-Tank Treatment System Pilot Demonstration

Abstract

The Near-Tank Treatment System (NTTS) is a supplementary waste treatment technology for Hanford tank waste being investigated as part of the Department of Energy Office of Environmental Management's Advanced Remediation Technologies (ART) Program to reduce the number of high-level waste (HLW) canisters that must be processed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The NTTS combines four basic unit operations into one integrated processing plant: caustic leaching, cross-flow filtration, ion exchange, and electrochemical recovery of sodium. Each unit operation has been studied and tested at the bench scale and was combined into a pilot-scale unit for further development.

The performance of the Continuous Sludge Leaching (CSL), Near Tank Cesium Removal (NTCR), and NTTS was evaluated by examining the process and analytical data. Overall, the NTTS integrated CSL and NTCR achieved an operational steady state that performed the waste treatment operations for which it was intended. The integrated system was stable and well-controlled, requiring very little manual intervention, and resulted in a product stream which is suitable for downstream sodium recycle, immobilization, and disposal.

Keywords:

• boehmite
• continuous sludge leaching
• cross-flow filtration
• high-level waste
• ion exchange
• near tank cesium removal
• waste treatment plant

Notes

^(a)TSS = total suspended solids.