Soil washing or flushing has been shown to be an effective method for removing heavy metals from metal-contaminated soils at Superfund sites. Sandy soils can often be washed with water to mobilize metal ions in an aqueous phase, but for clay soils or soils which contain insoluble metal compounds, e.g., lead sulfate, other additives such as chelating agents (EDTA) are used to effect transfer of metal ions to the aqueous phase. EDTA, however, complexes with innocuous metal ions (calcium, magnesium, iron), and EDTA-heavy metal complexes are difficult to remove from the aqueous phase. Bio-Recovery Systems has developed a proprietary process to circumvent these difficulties using a chelating agent (MLA) which has little or no affinity for innocuous metal ions and which has a higher affinity for many toxic metal ions than does EDTA. Furthermore, the heavy metal-MLA complexes can be removed from the aqueous phase by sorption on AlgaSORB TM resins, a proprietary biomass developed by Bio-Recovery. Thus, the use of MLA as a soil washing agent and the use of AIgaSORB TM will be tested to recover the MLA metal ion complexes in order to ascertain if this approach will yield a more cost effective treatment for metal-contaminated soils at Superfund sites than current methods.Since simple water washes have been effective for mobilization of metals in sandy soils, solutions resulting from simple water washing will he treated with AlgaSORB TM to determine metal removal efficiency.
