Tuesday, January 6, 2015

Using Fungi to Destroy E. coli in Stormwater

For years, Paul Stamets, Dr. Marc Beutel and Katherine Brownson, separately and together, have been studying the ability of certain species of fungi to clean up polluted water.

Stamets’ base of operations is Fungi Perfecti, LLC, a mushroom farm, research and distribution center in Oregon which Stamets founded with Dusty Yao.

Dr. Beutel is an engineer and associate professor who teaches and conducts research in the Department of Civil and Environmental Engineering at Washington State University.

Katherine (Katie) Brownson is a Ph.D. candidate in ecology and integrative conservation at the University of Georgia.

One facet of their research is the capacity of Stropharia rugosoannulata (aka wine cap or garden giant mushroom) to destroy E. coli bacteria in water.  The research commenced after Stamets observed that one of his mushroom beds eliminated E. coli  in water draining from an animal pasture.

In 2012, Stamets secured a Small Business Innovative Research award from the Environmental Protection Agency to develop technology for the removal of bacteria from stormwater runoff.

“Termed mycofiltration, this approach uses the web-like tissue of mushroom-forming fungi to capture and degrade environmental pollutants before they can reach sensitive water bodies.”

The research sought “...to identify which fungal species and cultivation methods can filter pathogens from storm water while meeting the physical and temporal demands required for use in the field.”  The project was expected “...to confirm that fungal mycelium can remove E. coli from flowing water, and that mycofilters can be developed to meet design requirements to treat municipal storm water runoff.”

“As mycofiltration is low-cost, low-impact, and requires relatively little installation space, it may soon provide municipal storm water managers with the perfect tool to help them meet their legal obligations under the Clean Water Act.”

“...[T]he current status quo BMPs [Best Management Practices] and other proprietary filtrations systems often require large capital investments and have significant additional maintenance costs that may not be appropriate for dense urban areas or for small and/or remote water treatment systems.”

Conclusions from Phase I of the research were published in 2013.

“...[T]here are fungal species that are appropriate candidates for the concept of mycofiltration. Of eight fungal strains that were tested over the course of the research, one clearly demonstrated resilience to harsh environmental conditions and a second showed promising characteristics. These species may therefore be considered as technically feasible for stormwater treatment applications. The second notable conclusion is that the permeability of mycofiltration media was generally in the range of 0.07 to 0.10 cm/sec—roughly equivalent to medium grain sand, which confirms applicability for field-relevant hydraulic loading. Additionally, mycofilters demonstrated a significant ability to remove suspended E. coli from flowing water. The final conclusion is that, as with other stormwater BMPs, mycofiltration may be more effective against sediment-bound bacteria—in some cases approaching 100% E. coli removal."

"The conclusion from the Phase I research on this innovative product is that specific fungal strains are resilient enough and biologically active enough to be considered for stormwater treatment applications against a variety of targets including pathogens, but that more research is needed to clearly define treatment design and operating parameters."


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