Story

Project: Former Agricultural Site Florida, USA

Confidential Client

Summary

In November 2004, Adventus conducted a 2,600-ton in situ pilot-scale technology validation project using Adventus’ patented DARAMEND technology to remove organochlorine pesticides from impacted soils at a former agricultural site in Florida. The treatment area consisted of two treatment plots identified as North and South, each containing a 1-foot layer of soil with elevated concentrations of dieldrin.

The remedial goal was met in a 2-3 week period and subsequent field monitoring showed that soil dieldrin concentrations decreased by 67% in that period at a total project cost of approximately $12.50/yd3.

The Challenge

Results from the site characterization sampling indicated an average initial soil dieldrin concentration of 45.9 µg/kg in the treatment plots. The remedial objective was to treat the dieldrin to below 15 µg/kg.

The Solution

Two sequential Daramend treatments consisting of sequential anoxic and oxic conditions were applied. These conditions were generated through the application of DARAMEND amendments (0.5 % by weight), which were applied to the soil surface and incorporated to a depth of 1 foot with a tractor-driven deep rotary tiller or disc (Figure 1). After amendment incorporation, water was applied to bring the soil moisture content up to 90% of the soil water- holding capacity (Figure 2). These steps were repeated for the second treatment cycle. Each cycle consisted of an eight day anoxic phase, followed by a two day oxic phase.

Figure 1: In-place application of DARAMEND

Figure 2: Irrigation to meet optimal soil moisture amendment.

The Result

The soil dieldrin decreased from an average of 45.9 µg/kg to 15.1 µg/kg in two treatment cycles, which comprises a removal rate of 67% (Figure 3). A third treatment cycle was able to reduce the concentration by 85 to 90%. Figure 3: Rapid, Cost-Efficient and Effective DARAMEND Bioremediation of dieldrin-impacted soil.

The Time Line and Cost

The remedial objective was reached within a 2-3 week period at a total project cost of approximately $12.50/yd3.