This study provided a first of a kind demonstration of the decontamination of High Level Radioactive Waste from the Savannah River Site using a continuous precipitation/adsorption process. Testing used a composite sample obtained from a number of waste tanks at the Savannah River Site. Preliminary batch processing experiments determined the efficacy of continuous process to precipitate sodium, potassium and cesium tetraphenylborate. The tetraphenylborate effectively removes cesium from solution. Researchers were also able to use the results of the batch experiments in design and prediction of the operation of the continuous process. This demonstration used two continuous reactors in series. This paper details the results obtained from batch tests with simulant and continuous decontamination of actual High Level Waste from the Savannah River Site.