Description
Joliet Army Ammunition Plant (JAAP) Wilmington, Illinois, USA
Project Bioremediation of Soil Containing Organic Explosives
Summary: DARAMEND® bioremediation effectively reduced
the concentrations of TNT, DNT and Tetryl during two separate pilot-scale
demonstrations on contaminated soil from the JAAP. DARAMENDR
bioremediation was also effectively applied during a full-scale (3,000
ton) demonstration of the technology at the same site on TNT impacted
soil.
The Challenge: The challenge for each of the pilots
and the full-scale demonstration differed. The first pilot-scale
demonstration was conducted by Plexus Environmental, under contract from
the US Army Environmental Center (AEC). In this case, DARAMEND
bioremediation was one of five technologies evaluated for their
effectiveness on TNT and Tetryl contaminated soils. The hypothetical
remedial goals for TNT and tetryl were 150 mg/kg and 20 mg/kg,
respectively.
The second pilot-scale demonstration was conducted on soils
contaminated with TNT, Tetryl and DNT. During this demonstration the
technology was applied using a windrow application, rather than a
land-farm application as had been used in the first pilot, this
demonstration compared DARAMEND technology with composting. For the
purposes of this demonstration the remedial goals for tetryl, TNT,
2,4-DNT, and 2,6-DNT were established at 14 mg/kg, 15 mg/kg, 8 mg/kg, and
8 mg/kg, respectively.
The third demonstration aimed to prove that DARAMEND could be
effectively applied at large-scale using windrow application.
The Solution: The first pilot-scale demonstration was
conducted by an independent third party (Plexus Environmental) under
contract from the US AEC with the intent of evaluating five potentially
innovative biological treatment technologies for use on organic explosive
compounds. The official report evaluating DARAMEND and the other four
technologies is available through the US AEC web page.
During this demonstration two 10-ton bioremediation cells were
constructed by Plexus Environmental, and DARAMEND bioremediation was
applied according to protocols provided by Adventus. One treatment cell
contained TNT impacted soil, and the other contained tetryl impacted soil.
The entire demonstration was scheduled to last 120 days, regardless of the
analytical results; therefore twelve, 10-day treatment cycles were applied
to each soil.
Each cycle consisted of the application of 1% (w/w) DARAMEND organic
amendments and 0.1% (w/w) powdered zero valent iron. Following amendment
application the moisture content was increased to about 80% of the soil
water holding capacity. During the second pilot-scale demonstration,
DARAMEND was applied to two 150-ton windrows. In this case, six 7-day
treatment cycles were applied to soils impacted with Tetryl, TNT and DNT.
A K-W windrow turner was used to incorporate amendments and aerate the
soil when necessary. Again, each cycle involved the application of
DARAMEND organic amendments (1%(w/w)), powdered iron (0.1%(w/w)), and
moisture (up to 80% of soil WHC).
The third demonstration, applied at full-scale, was primarily intended
to demonstrate the applicability of this technology, using windrows at
full-scale. In this case, two windrows containing approximately 1,500 tons
of TNT impacted soil were treated using DARAMEND bioremediation. Three
treatment cycles similar to those described above, were applied to these
windrows.
The Result: Interestingly, the conclusions drawn by
Plexus during the AEC biotechnology comparison indicated that
DARAMEND bioremediation was the only technology evaluated
capable of reaching the remedial goals for tetryl impacted soil, and was
forecast to be the cheapest for TNT impacted soils.
TNT concentrations were reduced from an initial value of about 5,900
mg/kg to less than 150 mg/kg after 48 days of treatment. The concentration
decreased to 114 mg/kg through the end of the demonstration. The
concentration of tetryl was reduced from about 6,000 mg/kg to less than 20
mg/kg after only 36 days of treatment. The concentration remained under 20
mg/kg for the remainder of the demonstration.
Results from the second pilot demonstration were also favorable,
although initial concentrations were not as high. Tetryl, TNT, and DNT
concentrations were reduced from 314 mg/kg, 122 mg/kg, and 62 mg/kg, to
8.3 mg/kg, 2.1 mg/kg, and 2.1 mg/kg, respectively, after six treatment
cycles (50 days).
During the full-scale demonstration DARAMEND bioremediation was
successfully applied to two 1,500 ton windrows. Unfortunately the initial
concentration of TNT in these soils was so low that it was well below the
remedial standard and we were not able to demonstrate effective treatment.
Nevertheless we did demonstrate that DARAMEND bioremediation could be
effectively applied at full-scale using windrow protocols.
The Cost: Cost estimates generated from the AEC
demonstration were extrapolated directly from 10-ton pilots and do not
reflect accurately the actual full-scale costs; nevertheless,
DARAMEND was determined to be the most cost effective
technology evaluated for both TNT and tetryl impacted soils.
Based on the second pilot demonstration full-scale treatment costs were
estimated at approximately $45 to $75/ton depending on the initial
contaminant concentrations.
The cost to apply DARAMEND at full-scale during the third
demonstration was approximately $45/ton.
The Timeline: As discussed above the first
demonstration lasted for 120 days, although the hypothetical remedial
goals established for the demonstration were attained after 48 days for
TNT impacted soils, and 36 days for tetryl impacted soils. During the
second demonstration remedial goals for tetryl, TNT, 2,4-DNT, and 2,6-DNT
were achieved following 14 days of treatment (2 cycles). For obvious
reasons a timeline for the full-scale demonstration is irrelevant.
Companies On This Project
ADVENTUS GROUP