Wood Chips Colonized by "Wild" Fungi for Stormwater Petroleum Reduction
Over 3 years
Research Idea Scope
Research Idea Scope: Background: Petroleum hydrocarbon pollutants 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. Mycoremediation with waste wood chips, colonized by “wild” local fungi, may offer an affordable, low maintenance, and nationally applicable technique for reducing these petroleum hydrocarbons. Mycoremediation is a form of bioremediation that utilizes fungi for various treatment objectives. Numerous studies have demonstrated the potential of using specific species of fungi (i.e., Pleurotus ostreatus) to break down and remove petroleum hydrocarbons from water (Sing 2006; Zitte et al. 2012). The methods these fungi employ to breakdown petroleum are not completely known, but much 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 (Stamets 2005). 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 wild fungi colonized wood chips remediate less petroleum 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 facilities stormwater. Research Objective and Primary Tasks: Determine if wood chips, naturally decomposing and colonized by wild local fungi, remediate levels of petroleum hydrocarbons typically found in transportation facilities stormwater. Monitoring will compare the petroleum remediation potential of different types of wood chip piles over time, as they are colonized by local fungi. These different piles will include: • Wood chips without competing strains of fungi (fresh or sterilized). • Wood chips at an advanced stage of decomposition. • Wood chips that have been inoculated per standard mycoremediation practices, for comparison. Staff will monitor between 7 to 11 wood chip piles, depending on available resources. Size, height, and shape of the piles will be determined by reviews of existing mycoremediation literature and tailored to local conditions, facility size, and influent petroleum concentrations. Staff will collect a minimum 12 influent and 12 effluent paired stormwater samples from each pile over three years. Monitoring for three years allows time for colonization and for observing changes in the decomposing wood piles. A greater number of samples and a longer monitoring period may be generated, if necessary, to meet statistical robustness. If possible, molecular analysis may be performed on the piles to speciate present fungi and other organisms. Staff will employ adaptive design and management to meet the study goals.
Urgency and Payoff
Urgency: The project is based on developing a new, affordable remediation technique, and is not tied to any specific deadline. Potential Benefits: • Provides a new tool for transportation agencies to meet regulatory requirements. • Applies to all regions where decomposition of wood chips occurs. • Utilizes an often waste resource for treatment goals. • Requires little, if any, maintenance apart from initial application of wood chips. • Extremely cost effective if waste wood chips are used.
Brandon Slone Washington State Dept. of Transportation 360-628-6103