Remediation of Persistent Organic Pollutants Using a Novel Two-Phase Soil Washing Biosorption Process

Abstract

A two-phase soil washing biosorption process was developed for the remediation of p,p′-DDT-contaminated soil. The process involved desorption of contaminants from soil using dilute primary alcohols (40% 1-propanol) followed by contaminant removal from cosolvent solutions using fungal biosorption. Bench scale remediation studies were preformed to simulate ex situ (recycling experiment) or in situ (soil column study) treatment strategies. Both systems were effective at cleaning the soil to below Australian regulatory p,p′-DDT levels. After 50–80 hours of soil washing, over 93% of p,p′-DDT was removed from the soil(990 mg kg-1 to <65 mg kg-1) using either of these methods.p,p′-DDT was removed from the cosolvent phase by sorption onto the fungal biomass. This resulted in only low levels of p,p′-DDT remaining in the cosolvent solution(<1.5 mg l-1). The application of both treatment strategies resulted in the rapid clean up of p,p′-DDT-contaminated soil and the potential to recycle cosolvent solutions. The ability to recycle cosolvent solutions provides a mechanism for cost reductions of the remediation strategy.