The physical treatment step of the soil washing process produces significant reductions in the lead concentrations in the soil composite samples. However, the treatment technique results only in recovery of the larger particulate lead fractions within the soil matrix. Therefore, this remediation process must be used in conjunction with another technique in order to recover small particulate and ionic lead fractions to reach cleanup standards. Parsons ES recommends that the technology be combined with other appropriate technologies in order to test the viability of density treatment with other remedial technologies.

Phytoremediation, electrokinetics, and stabilization are three possible remedial technologies suitable for implementation following density treatment. Phytoremediation, the use of plants and plant processes to remove or degrade hazardous materials present in the soil or groundwater, is particularly adept at removing ionic forms of metals from soils. This technology may be performed in-situ or in raised beds over an extended period of time. As with the SWMU O-1 soils, electrokinetics may not offer a cost effective result for the highly buffered soils, yet the soil washing technique offers a unique way to potentially mobilize metal contaminants by varying wash water amendments. The wash water may be augmented with a basic leaching agent, surfactant, pH adjustment, or chelating agent to help remove contaminants. Stabilization does not remove contaminants; however, it reduces the potential exposure of a leachable lead by locking contaminants in a solidified matrix.

One stabilization technology suggested by Brice mixes contaminated soils with an emulsion to create a RCRA-exempt paving product that may be used without restriction for the installation of paving projects. However, to date, TNRCC has not accepted this treatment method for use as road paving. All these technologies, phytoremediation, electrokinetics, or stabilization, could be employed following density treatment to remediate the smaller particulate and ionic lead found in the soils.

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