DARAMENDÔ Bioremediation Technology
GRACE DEARBORN INC.
(DARAMENDÔ Bioremediation Technology)
TECHNOLOGY DESCRIPTION:
The GRACE Dearborn Inc., organic amendment-enhanced bioremediation technology (DARAMENDÔ) is designed to degrade many organic contaminants, including pentachloro-phenol (PCP), polynuclear aromatic hydro-carbons (PAH), and petroleum hydrocarbons in industrial soils and sediments. The technology has been applied both in situ and ex situ. In either case, soil may be treated in lifts up to 2 feet deep using available mixing equipment.
The technology treats batches of soil using DARAMENDÔ soil amendments. These amend-ments are introduced using conventional agricultural equipment (see photograph below), followed by regular tilling and irrigation. DARAMENDÔ soil amendments are solid-phase products prepared from natural organic materials to have soil-specific particle size distribution, nutrient content, and nutrient release kinetics. Soil amendments sharply increase the ability of the soil matrix to supply water and nutrients to the microorganisms that degrade the hazardous compounds. The amendments can also transiently bind contaminants, reducing the acute toxicity of the soil aqueous phase. This reduction allows microorganisms to survive in soils containing very high concentrations of toxic compounds.
DARAMENDÔ treatment involves the following three fundamental steps:
· The treatment area is prepared. For the ex situ application, a treatment cell to contain free water is constructed. In situ application requires the treatment area to be cleared and ripped, to reduce soil compaction.
· The soil is pretreated. This includes removing debris larger than 10 inches, such as metal or rocks, that may damage the tilling equipment. Sediments under-going treatment must be dewatered.
· The DARAMENDÔ soil amendment is incorporated, usually at 1 percent to 5 percent by weight, followed by regular tilling and irrigating.
Soil is tilled with a rotary tiller to reduce varia-tion in soil properties and contaminant concen-trations. Tilling also incorporates the required soil amendments and helps deliver oxygen to contaminant-degrading microorganisms.
An irrigation system is used to maintain soil moisture in the desired range. Leachate or surface runoff caused by heavy precipitation is collected and reapplied to the soil as needed.
Equipment needed to implement this technology includes a rotary tiller, irrigation equipment, and excavation and screening equipment. Depending on site-specific factors such as contaminant type and initial concentration, and project schedule and climate, a waterproof cover may be constructed over the treatment area.
WASTE APPLICABILITY:
The DARAMENDÔ technology can treat soils and sediments with a wide range of organic con-taminants. The technology has proven effective on soils with total PAH concentrations of up to 20,000 milligrams per kilogram (mg/kg), total petroleum hydrocarbon contamination up to 6,300 mg/kg, and PCP concentrations up to 680 mg/kg. Results are often attained within a year; however, environmental and site-specific conditions may decrease or increase this treatment time.
Bench- and pilot-scale investigations have demonstrated the technology's applicability to PAH-contaminated sediment. A patented cyclic DARAMENDÔ technology has been demonstra-ted to remediate soils containing chlorinated pesticides and nitroaromatics. Principle target markets are wood industries, manufactured gas, petroleum hydrocarbon and pesticide manufacturers.
STATUS:
This technology was accepted into the SITE Demonstration Program in spring 1993. The ex situ application of the technology was demon-strated from fall 1993 to summer 1994 at the Domtar Wood Preserving facility in Trenton, Ontario, Canada. Detailed demonstration results will be available in late 1995.
The demonstration was one component of a 5,000-ton remediation project underway at the site. Internal analyses of treated soil indicated significant reductions in the concentrations of both PAHs and chlorinated phenols.
DEMONSTRATION RESULTS:
In the ex situ demonstration area, the DARAMENDÔ technology achieved the follow-ing overall reductions: PAHs, 94 percent (1,710 mg/kg to 98 mg/kg); chlorophenols, 96 percent (352 mg/kg to 13.6 mg/kg); and total petroleum hydrocarbons (TPH), 87 percent. These reductions were achieved in 254 days of treatment, including days when no activity occurred because of low soil temperatures. The control area showed a reduction of 41 percent in PAH concentrations; no reduction was seen in the concentration of either chlorinated phenols or TPH during the treatment time. Results from the toxicity analysis (earthworm mortality and seed germination) showed that the toxicity was eliminated or greatly reduced in the treated soil.
FOR FURTHER INFORMATION:
EPA PROJECT MANAGER:
Teri Richardson
U.S. EPA
National Risk Management Research
Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7949
Fax: 513-569-7620
TECHNOLOGY DEVELOPER CONTACTS:
Alan Seech or Igor Marvan
GRACE Dearborn Inc.
3451 Erindale Station Road
Mississauga, Ontario, Canada
L5A 3T5
905-279-2222, ext. 390
Fax: 905-279-0020