?,EPA United States Environmental Protection Agency EPA/540/MR-93/514 June 1993 SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION Demonstration Bulletin Fungal Treatment Bulletin USEPA-RREL/USDA-FPL Technology Description: Fungal Treatment is a bioremedia- tion process utilizing white-rot fungi as a means of destroying organic contaminants in soils. The Fungal Treatment technology was developed jointly by the Forest Products Laboratory (FPL) of the U.S. Department of Agriculture's Forest Services in Madison, Wl, and the U.S. EPA Risk Reduction Engineering Laboratory's Biosystems Branch. The Fungal Treatment demonstration was conducted on the site of a former wood treating facility, the Brookhaven Wood Preserving (BWP) in Brookhaven, MS. The goal of this demonstration was to determine the use of Fungal Treatment to destroy pentachlorophenol (POP) and select poly- nuclear aromatic hydrocarbons (PAHs: creosote constituents) in contaminated soil. White-rot fungi are the major degraders of lignin, a polymeric component of wood which is resistant to biodegradation. Interest in these fungi for biotechnological applications has increased during the past decade, spurred by the ability of these organisms to degrade a wide variety of hazardous compounds (including POP and PAHs). The fungal treatment process involves inocula- tion of the contaminated soil with selected fungal strain(s) fol- lowed by addition of nutrients (if needed), irrigation, and aeration of the soil through tilling/cultivating to provide optimal fungal growth conditions. Inoculation is accomplished by physically mix- ing the soil and the inoculum. Mixing can be performed in solids mixing equipment, or in-situ by placing the inoculum on the contaminated soil and tilling until the two are thoroughly mixed. In the case of ex-situ mixing, the soil-inoculurn mix must then be spread over the ground. Land farming procedures such as irriga- tion, aeration and nutrient addition are then implemented periodi- cally to sustain the fungal activity within the soil matrix As a result of the fungal activity, the hazardous compounds are trans- formed and become irreversibly bound to soil organic matter, in which state they are not biologically active and thus do not present toxicity problems. The fungal treatment can take several weeks to several months to achieve the desired level of contami- nant reductions. Two species of white-rot fungi, Phanerochaete chrysosporium and Phanerochaete sordida, have exhibited the best growth po- tential in soil contaminated with wood preserving wastes. Studies conducted by the developer have indicated that lignin-degrading enzymes generated by these fungal species are capable of oxidizing and detoxifying some normally recalcitrant PAHs. In addition, these fungal species have been known to detoxify phenolic compounds (PCP is one of them) by methylation of the phenolic group. The methylated product is susceptible to further transformation by the fungi. Prior to treatment, a treatability study either in the field or in a laboratory is performed using representative contaminated soil. Based on the treatability data, the developer will determine: (1) the applicable fungal species, (2) the inoculum loading level, (3) length of treatment time, and (4) the need for nutrients or other soil supplements. Waste Applicability: This Fungal Treatment has been tested for treatment of soils contaminated with organic wood preserving compounds such as pentachlorophenol (PCP) and select poly- nuclear aromatic hydrocarbons (PAHs) found in creosote. Warm temperatures (greater than 80°F) and sufficient moisture (greater than 30%) in the target matrix are desirable for the optimal growth of the fungus and, thus, for the degradation of the con- taminants. Demonstration Results: Over a 20-wk period, from June 1992 through November 1992, the Fungal Treatment technology was tested under actual field conditions. The test matrix was produced from excavated wood preserving wastewater treatment sludges from unlined onsite surface impoundments. This soil-like material was screened to remove solid debris larger than three inches in size, and further mixed/diluted with clean soil to bring the PCP concentration down to an acceptable level for fungal growth and viability. This test soil was then used in the test and the two control plots as described below. On the BWP site a Test Plot and two Control Plots, A and B, were constructed. In Control Plot B, the test soil mix only was homogenized and placed as a 10-in. bed on top of a sand layer. In Control Plot A, the test soil mix was homogenized with the sterile (i.e., non-inoculated or non-fungal) spawn material at a 10:1 w/w ratio and placed as a 10-in. bed on a sand layer. In the Test Plot, the test soil mix was homogenized with the fungal inoculum at a 10:1 w/w ratio and placed as a 10-in. bed on a sand layer. The Test and the two Control Plots were rototilled/ cultivated about once a week over the duration of the study. Soil temperatures were recorded on a daily basis. Moisture content of the soil from each of the plots was determined on a weekly basis. If the moisture content in a plot dropped below the target level, it was irrigated with leachate collected from the same plot and/or with the municipal tap water. Soil samples from each of the plots were collected at the start of the study, and then at the end of the 5th, 9th, and 20th weeks of the study. Data from the Demonstration are undergoing final review. Some key initial findings are as follows: /-v-y U%) Printed on Recycled Paper ------- • Levels of POP and the target PAHs found in the underlying sand For Further Information: layer and the leachate from each of the plots were insignificant, indicating low leachability and loss of these contaminants due to EPA Project Manager: periodic irrigation of the soil and heavy rainfall. Kim Lisa Kreiton U.S. EPA • Levels of POP, the target PAHs, and dioxins in the active air Risk Reduction Engineering Laboratory samples collected during the soil tilling events were insignifi- 26 West Martin Luther King Drive cant, indicating a very low potential of air-borne contaminant Cincinnati, OH 45268 transport as a result of Fungal Treatment activities. (513) 569-7328 An Applications Analysis Report and a Technology Evaluation Developer: Report describing the complete Fungal Treatment SITE demon- EPA/Biosystems- John Glaser stration will be available in Summer of 1993. (513) 569-7568 _. . , „ USDA/FPL: Richard Lamar The developers collected data independently and will produce (608) 231 -9200 results via other publications. •U.S. Government Printing Office: 1983 — 750-071/80011 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati, OH 45268 Official Business Penalty for Private Use $300 EPA/540/MR-93/514 BULK RATE POSTAGES FEES PAID EPA PERMIT No. G-35 ------- |