Fixation of pumping station contaminated soils

This paper reports the development, testing and implementation of a one-step solidification/stabilization process. This process was developed for the contaminated soils at gas pumping stations. These contaminated soils have PCBs, petroleum hydrocarbons, VOCs, including degreasers and BTXs, and heavy metals. Clayey sands were spiked and tested to develop data above the highest concentrations of contaminants at the gas pumping station. These tests established the performance of the resulting monolithic waste form. The contaminants were fixed in a pozzolanic binder with additives. The waste form was emplaced on-site in the water table without a liner or a cap. These contaminated soils were mixed in a high-shear continuous mixer and pumped into the on-site disposal trench in 300-ton lifts. In 30 foot x 40 foot cells, two lifts were formed in layers. This emplacement schedule allowed TCLP and physical testing results to be taken before the first lift was covered. The processing rates were between 30 to 45 tons/hour over an 8- to 10-hour day