Evaluation Of FWENC Process For Treatment Of MVST Sludges, Supernates, And Surrogates

Barton, JW

Oak Ridge National Laboratory

关键词: Evaporators;    Leaching;    Storage;    Nitrates;    Sludges;   

DOI  :  10.2172/885867
RP-ID  :  ORNL/TM-2003/30
RP-ID  :  DE-AC05-00OR22725
RP-ID  :  885867

美国|英语

来源: UNT Digital Library

【 摘 要 】

In 1998, the Foster Wheeler Environmental Corporation (FWENC) was awarded an 11-year contract to treat transuranic waste at the Oak Ridge National Laboratory, including Melton Valley Storage Tank (MVST) waste. Their baseline tank waste process consists of: (1) Separating the supernate from the sludge, (2) Washing the sludge with water and adding this wash water to the supernate, (3) Stabilizing the supernate/wash water or the washed sludge with additives if either are projected to fail Resource Conservation Recovery Act (RCRA) Toxic Characteristics Leaching Protocol (TCLP) criteria, and (4) Stabilizing both the washed sludge and supernate/wash water by vacuum evaporation. An ''Optimum'' treatment procedure consisted of adding a specified quantity of two stabilizers--ThioRed{reg_sign} and ET Soil Polymer{reg_sign}--and an ''Alternate'' treatment simply increased the amount of ThioRed{reg_sign} added. This report presents the results of a study funded by the Tanks Focus Area (TFA) to provide Oak Ridge Operations (ORO) with independent laboratory data on the performance of the baseline process for treating the sludges, including washing the sludge and treating the wash water (although supernates were not included in the wash water tests). Two surrogate and seven actual tank wastes were used in this evaluation. Surrogate work, as well as the initial work with actual tank sludge, was based on an existing sludge sample from Bethel Valley Evaporator Storage Tank (BVEST) W23. One surrogate was required to be based on a surrogate previously developed to mimic the weighted average chemical composition of the MVST-BVEST using a simple mix of reagent grade chemicals and water, called the ''Quick and Dirty'' surrogate (QnD). The composition of this surrogate was adjusted toward the measured composition of W23 samples. The other surrogate was prepared to be more representative of the W23 sludge sample by precipitation of a nitrate solution at high pH, separating the solution from the solids, measuring the composition of the wet solids, and adding reagent grade chemicals to closely mimic the measured composition of the W23 sample.