Turning dairy farm waste into Magic Dirt
Magic Dirt may sound like the soil used by Jack to grow his beans, but it's actually an organic garden and potting mix developed as a sustainable alternative to peat moss. The sustainability factor comes from the product's production process, which involves the efficient conversion of manure into three valuable byproducts: biogas for electricity generation, a treated non-odorous liquid stream for crop fertilizer, and a clean, nutrient-rich biosolid that forms the main ingredient of Magic Dirt.
Not to be confused with the Australian rock band of the same name, Magic Dirt garnered the Bioproduct Innovation of the Year award from the inaugural Bioproducts World Showcase and Conference for its uniqueness in being a co-product of a renewable energy regeneration. In other words, the company is creating a product that’s good for the environment from another product that’s good for the environment.
Addressing the environmental issues caused by effluence from factory farm feedlots, Magic Dirt's production process starts with underground anaerobic digesters from Wisconsin-based DVO Inc. These use mesophilic digestion, with the waste staying in the digester for 21 days at 101° F (38° C) as it is broken down by bacteria in the absence of oxygen. Around 60 percent of the post-digester material is biogas in the form of methane, which can be used to produce electricity. Remove the liquid, and what’s left is sterile, odorless fiber with all the voluble solids rung out of it. Add in some other organic waste material, such as composted forest products, possibly wave a wand, and the result is chemical-free Magic Dirt.
According to Cenergy USA co-founders Bob Joblin and Ted Sniegocki, the small company behind Magic Dirt, DVO digesters provide the highest quality biosolids, with more than 99 percent of voluble solids removed. Residues from livestock medication and heavy metals are either removed or below state and federal limits. Other digesters still have voluble solids, pathogens and other active ingredients in their biosolids, as well as an odor. And for anyone tempted to use raw manure as fertilizer, the high nitrogen, ammonia and pH levels would likely burn the roots of plants and interfere with seed germination.
DVO has about 80 of its digesters in farms around the US, primarily at dairy farms. Joblin prefers to work with just dairy farms for consistency sake. “Dairy cows are fed the same formula, so it gives you a good idea of what you’re going to get,” he says. It also provides the dairy farmers with another revenue stream.
Joblin adds that Magic Dirt has three to five times more naturally occurring nutrients, such as nitrogen, phosphate and potassium, than similar products on the market. What it doesn’t have is peat moss, a common ingredient in garden mulch. Both are excellent at holding water, but peat moss is a seasonal crop, and 80 percent of the US supply is shipped in from Canada. It’s also a natural sink for CO2, but when harvested releases large amounts of methane into the atmosphere. Joblin says that forgoing peat moss for Magic Dirt offsets greenhouse gas emissions by 1 ton per cubic yard.
A recent study commissioned by the Innovation Center for U. S. Dairy, backs this up, claiming Magic Dirt "provides an environmental advantage in comparison to peat moss for all indicators examined... (R)eplacing peat moss with dairy digester fiber in the US market could avoid the release of greenhouse gases equivalent to 5,800,000 million metric tons of CO2-eq."
Cenergy USA previously won a U.S. Dairy sustainability award for a biomass to renewable energy project on a 4,700-cow dairy in Idaho. Using methane capture from dairy waste, the facility generates greater than 1.2 MW of electricity, enough to power 5,000 homes in the area 24/7. Joblin says the company will continue to mine this unique field of sustainability in ways no one has done before, and promises more digester-related horticulture products in the near future.
For now, home gardeners in Idaho and the Pacific Northwest will soon be able to buy the Magic Dirt premium potting soil at retailers such as Walmart, as well as at independent nurseries and garden centers.