The 600-kW Storms Hog Power plant at Storms Hog Farm near Bladenboro, NC has been operating at full capacity for the past 90 days, according to Renewable Energy Focus. North Carolina’s largest swine waste-to-energy system, Storms Hog Power says it is generating enough clean renewable electricity to the local utility to offset the electricity consumption of almost one-third of the homes in the area.
The concept for the waste-to-energy project evolved from a grant for four swine farm renewable energy pilot projects administered by the NC Department of Energy, applied for in May of 2010. AgPower Partners LLC (APP) teamed up with DVO, Inc. for its patented Two-Stage Mixed Plug FlowTM anaerobic digester and Martin Machinery/GenTec for its biogas engine/generator turn-key services.
Manure collected daily from the nearly 30,000 hogs — formerly treated in open-air lagoons and mixed with off-site agricultural wastes, which were previously either land-applied or destined for a landfill — is biologically decomposed in an oxygen-free, 1.2-million gallon reinforced concrete vessel. The bacteria in the digester metabolically break down the waste and generate biogas, while destroying nearly all of the pathogens and odor. The biogas is combusted in an engine/generator, sending enough clean renewable electricity to the local utility to offset the electricity consumption of nearly 300 (of roughly 1,000) average-size homes in the area.
“[APP co-founder Dr. Garth Boyd] and I put a great team together, but without the vision, conviction and financial commitment of [farm owner William R.] Storms and the hard work and dedication of his sons-in-law, we would not be standing here today witness to this revolution in the industry," said Jeff Smerko, managing principal of AgPower Partners. "Hopefully others will embrace this concept as proven, scalable, and economical.”
What is really amazing, Smerko noted, is what you don’t see or rather, smell.
"Spending the better part of the past two and a half years down here, I thought that I had just grown accustomed to it," he explained. "But that’s not it. The odor now is virtually gone.”
Anaerobic digestion is becoming a more commonly used technology among dairy farms, which put the proliferation of non-food offerings from their herds to use powering their operations. But according to Steve Dvorak, owner and founder of DVO, Inc, anaerobic digestion presents many benefits far beyond power generation.
"Our digesters reduce greenhouse gas emissions from stored and land-distributed farm wastes by roughly 90 percent," he explained. "Pathogens in farm waste, including e-coli and salmonella, are reduced so much that they are almost undetectable, and our new nutrient recovery technologies allow for the practical removal of additional phosphorus and ammonia nitrogen.”
Storms Hog Power says its anaerobic digester and renewable energy-generating system — along with an enhanced animal waste extraction and collection system that uses scrapers instead of flush water to remove manure from the houses — greatly reduces the negative environmental impacts of the current lagoon and spray field manure management systems, while profitably generating renewable energy and other valuable byproducts.
While factory farming in general has miles to go to become truly sustainable, anaerobic digestion is helping the industry make a dent in its waste. The technology is also making it possible to convert other unsavory types of waste into energy, with organizations ranging from retailers and food manufacturing plants to cities are now using the technology to give food waste a second life.