Mycorrhizal Inoculated Biochar as an Active Filter of

Mycorrhizal Inoculated Biochar as an Active Filter of Dairy Wastewater Jacob Kelsey Master’s candidate Gund Institute for Ecological Economics and Ecological Design Rubenstein School for Environment & Natural Resources, University of Vermont Felix Wai Phd Student Rubenstein School for Environment & Natural Resources, University of Vermont

Objectives: • To conduct a greenhouse column experiment in order to quantify the ability of biochar and mycorrhizal fungi to uptake phosphorus from a pollutant sample, representative of dairy farm wastewater. • Results will be used to discern the efficacy of biochar, compared to other alternative substrates (i. e. steel slag), for incorporation into constructed wetlands.

Eutrophication and Phosphorus Pollution

• Across the United States, eutrophication of freshwater value lost costs approximately $2. 2 billion per year • Vermont Agency of Agriculture says 95% of small scale dairy farms (<200 cows) need to address nutrient leachate problems • Total costs for Vermont small scale dairy farmers = $30. 5 million • ~$38, 000/ small farm

Integrated Constructed Wetlands • Cleanse and manage water flow from farmyards • Integrate the wetland infrastructure into the farm landscape, enhancing its biodiversity and beauty

Integrated Constructed Wetland Benefits • Runoff and flood management • Relative low cost and simplicity of operation • Odor minimization • Aesthetically pleasing • Habitat and biodiversity enhancement

Integrated Constructed Wetland Limitations • Farm constructed wetlands have a relatively large land requirement • P uptake, compared to other nutrient treatment is often below desired levels, especially in colder climates http: //www. fairfieldcity. nsw. gov. au/upload/images/Smithfield. Wetland 3 May 2006. jpg

Alternative substrates for increasing P uptake/retention in constructed wetlands • Best candidates to date are mostly industrial by products • Of 57 materials tested for P adsorption, Electric Arc Furnace Steel Slag was found to be the most effective • Vanadium and other heavy metal leaching possible http: //www. uvm. edu/~cwrc/Slag%20 image. JPG http: //www. cascadesteel. com/Images/manufacturing_process/02 a. j pg

Biochar P uptake/retention • Physical-Chemical: – Extremely high surface area – Increased Cation Exchange Capacity – Increased Anion Exchange Capacity (Lehmann, et al. , 2007)

Biochar P uptake/retention, cont. • Biological: -Beneficial microbe refugia -Mycorrhizal Fungi proliferation -Increased mycorrhizal populations positively correlated with P uptake www. d. yimg. com/kq/groups

Biochar P uptake/retention, cont. www. d. yimg. com/kq/groups

Hypothesis: Mycorrhizal inoculated biochar mixed in a gravel substrate in a simulated planted constructed wetland will uptake more phosphorus than a control treatment of plants and gravel substrate alone.

Experimental Setup & Methods

Experimental Setup & Methods, cont. Treatment # 1 (control): • Gravel substrate • 20 non-mycorrhizal plants Treatment # 2: • Gravel substrate • 20 mycorrhizal inoculated plants Treatment # 3: • 50/50 gravel: biochar substrate • 20 non-mycorrhizal plants Treatment # 4: • 50/50 gravel: biochar substrate • 20 mycorrhizal inoculated plants

Experimental Setup & Methods, cont.

P Concentration Hypothesis Revisited Time • • # 1) control # 2) +mycorrhizae # 3) +biochar # 4) +biochar +mycorrhizae

Preliminary Data

Phosphate Price Increase

Future Research Greenhouse potted plant experiments to test nutrient saturated, microbe inoculated biochar as soil amendment

Future Research Field application of biochar in an active filtering bioswale in combination with an Integrated Constructed Wetland at a small dairy farm in Vermont

Acknowledgments: John Todd Paul Schaberg Brian Bibens Paul Stamets