If you ride down Railroad Street in the City of Menasha, you might not notice a small patch of land chock-full of trees along the road. But this piece of urban greenery didn’t always look this way. The location was once the site of an industrial chemical company and a drum refinishing operation, and over time contaminants leached into the surrounding soils and groundwater leaving the site an urban brownfield.
Blighted sites like this are often abandoned and left for the municipalities to clean up. OMNNI Associates was hired by the Wisconsin Department of Natural Resources (WDNR) to investigate the site, identify the contaminants and recommend a remedial solution to clean up the site for future development. Part of the remedial solution included using Phytoremediation.
What is Phytoremediation?
Phytoremediation uses plants to enhance natural attenuation of contaminated sites. There are a number of processes that fall under the term Phytoremediation. The EPA provides a good overview on Phytoremediation here.
Soils that are contaminated with Volatile Organic Compounds (VOCs), or heavy metals, are often cleaned up by excavating the soil and placing it in a landfill, which can be a very costly solution. Phytoremediation is a “green” technology that involves the use of plants to assist in the cleanup of contaminants. Under the right conditions, Phytoremediation can be a very cost-effective remediation solution.
“Phytoremediation doesn’t work at every contaminated site,” explains Brian Wayner, OMNNI’s Environmental Project Manager. “There are many factors to assess, such as the type of contamination, the level and depth of contamination and the timeframe for cleanup. It’s best used when the contamination is found at shallow depths (the length of the plant’s root system). It’s also a process that can take time to clean up a site, sometimes decades. However, if site conditions and property use allow, Phytoremediation can be significantly cheaper than some remedial options and it can be less disruptive to the environment.”
A Collaborative Effort
The site in Menasha proved to be an ideal candidate for evaluating if Phytoremediation could reduce the contaminant concentrations to a point that would allow natural attenuation to complete the site restoration. As additional site data became available, it was apparent that there were four primary conditions that were going to influence the remedial options evaluation. These conditions were:
- The contamination existed in all three soil strata found on the site (clay, hardpan and bedrock) each often requiring different remedial approaches.
- The concentrations of contaminants in both the soil and groundwater indicated that product remained on the site.
- Sample analysis for hazardous soils based on characteristic of toxicity indicated a significant amount of soil would be classified as hazardous material.
- The majority (63%) of the contaminant mass appears to be contained in the clay soils.
Based on discussions between the WDNR, Winnebago County, City of Menasha and OMNNI, the focus of the remedial option review was centered on addressing the most contaminated soils in the source area north of the former building. Several options to treat these contaminated soils were evaluated. Phytoremediation appeared to be the most cost-effective option, and since there was no immediate plan for reuse of the property, cleanup requirements were not under a short timeline.
Brian worked closely with Winnebago County, the City of Menasha and a forestry consultant to apply for and receive an urban forestry grant from the WDNR for the project. With the grant money, he was able to plant additional Hybrid Poplar, Cottonwood and Aspen trees across the site. The University of Wisconsin-Madison’s Department of Entomology, also supported the project by donating 100 Aspen trees to study the effectiveness of using a native species for Phytoremediation projects. The grant money was also used towards a public awareness campaign to educate the community about the process.
“We will be monitoring this site for quite some time,” notes Brian. “Initial testing results indicate that the process is working; however, we will need to keep up the monitoring, replacing damaged trees if needed, and assessing the reduction in contaminants.”
As a member of the project team, Brian was honored with the 2009 Innovations in Urban Forestry Award from the Wisconsin Urban Forestry Council. The award recognizes the innovative use of trees to assist in the cleanup of contaminated soil and groundwater at a contaminated brownfield property. The Wisconsin Urban Forestry Council presents annual awards to outstanding individuals, organizations, communities and tribes that further urban forestry in Wisconsin.
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If your community has a brownfield that might benefit from Phytoremediation, contact Brian at email.
There are also many state and federal grant programs available to fund your environmental projects. It’s just a matter of finding the right one for you. Brian has a highly successful track record of identifying funding options, determining eligibility and providing grant writing and administration. He has secured grants and other sources of funding for numerous projects ranging from remediating Brownfield sites to managing stormwater runoff.