Wood Chips Colonized by "Wild" Fungi for Stormwater Petroleum Reduction
Over 3 years
Petroleum generated hydrocarbons are present in stormwater runoff at most transportation facilities, and reducing their levels is a common requirement in National Pollutant Discharge Elimination System (NPDES) permits. Many best management practices (BMPs) reduce export of these pollutants through actions such as "settling out" of hydrocarbons but fail to actively eliminate the hydrocarbons. One technique that has demonstrated actual breakdown of petroleum hydrocarbons is mycoremediation. Mycoremediation is a form of bioremediation that utilizes fungi for various treatment objectives. Numerous studies have demonstrated the potential of using fungi to treat PAHs, gasoline, diesel and heavy oil. Generally, mycoremediation requires extensive preparation of a substrate (e.g., straw or wood chips) for the fungal food source and habitat, and seeding with select fungal species. However, mycoremediation with waste wood chips, colonized by naturally occurring "wild" fungi, may offer petroleum remediation benefits without the standard preparation and seeding practices. The methods fungi employ to breakdown petroleum hydrocarbons are not completely known. Most of the research points to the mechanisms for breaking down lignin, which contains complex carbon and hydrogen bonds that share some similarities with petroleum hydrocarbons. However, few studies have examined the potential of decomposing wood chips colonized by wild local fungi for remediating petroleum. In most ecosystems fungi are the principal decomposers of wood and specifically the predominant decomposers of lignin. Considering that any decomposing wood chip pile is experiencing breakdown of lignin, it seems plausible these breakdown mechanisms may apply to the carbon-hydrogen bonds referenced in petroleum mycoremediation literature. Even if wood chips colonized by wild fungi remediate fewer hydrocarbons than standard mycoremediation practices, which often target high levels of petroleum contamination such as oil spills, they may remediate the generally lower levels of petroleum found in transportation facility stormwater runoff. Utilizing wood chips colonized by wild fungi would be significantly more cost effective and feasible than standard mycoremediation and many other BMP practices. The objectives of the research are to: 1. Test and establish the petroleum hydrocarbon reduction efficacy of wood chips colonized by naturally occurring wild fungi for treating transportation facilities runoff. 2. Develop guidance on the use, limitations, design, and implementation of wild colonized wood chips in treating petroleum hydrocarbons in stormwater. Achieving the project's objectives involves the following tasks: Task 1: Conduct a survey and synthesis of existing literature related to establishing practical mycoremediation procedures for treating hydrocarbons with wood chips, as well as monitoring for potential negative impacts from the wood chips. Task 2: Design and implement testing of wild fungi colonized wood chips. Task 3: Develop guidance on the use of wood chips colonized by wild fungi for treating petroleum hydrocarbons in stormwater runoff at transportation facilities.
Petroleum and petroleum by-products, particularly PAHs, are major contributors to toxicity of highway runoff. A greater focus on those pollutants from resource and regulatory agencies can be expected in the near future. Effective and inexpensive techniques for removing this class of pollutants are needed. At the same time, the accumulation of petroleum and petroleum by-products in BMP filter media complicate the disposal of the media when its effectiveness wanes. By developing a BMP that is effective at both trapping and decomposing petroleum hydrocarbons in stormwater, both issues can be addressed. Additionally, the low cost and feasibility of using waste wood chips allows for broad scale implementation of this petroleum treatment in much of the nation. Any location where robust decomposition of wood chip occurs should be appropriate to accomplish levels of petroleum remediation.
Washington State Dept. of Transportation
June 1, 2017
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