We all know the saying, one man's trash is another man's treasure. The symbiotic relationship of this mantra also holds true on a much larger scale. Big Island Carbon (BIC), a Hawai'i Island startup that's turning discarded macadamia nut shells from local farms into high-grade granular activated carbon, is a prime example. And with the Big Island macadamia nut industry producing approximately 25,000 tons of shells each year that up until now, ended up in landfills at the cost of the farmer, there are literally mountains of shells ready to be repurposed.
In high demand worldwide, activated carbon is used in an array of products including improving cell phone and wind turbines performance, aiding in air and water purification, acting as catalyst support in pharmaceuticals, and even helping clean up some aspects of nuclear accidents. Traditionally made from coal and wood, activated carbon can be manufactured from any carbonaceous source, but macadamia nut shells naturally produce an exceptionally pure and hard carbon product.
Big Island Carbon CEO Rick Vidgen spent 11 years as president of MacFarms of Hawaii before BIC broke ground in Kawaihae in 2009. Fusing his extensive knowledge of the mac nut industry with a degree in industrial chemistry, Vidgen has found a new use for agricultural waste and is also extracting biofuel in the process, which is used to power the plant.
While promoting local sustainability, the U.S. Environmental Protection Agency (EPA) acknowledged BIC as a green company, issuing a clean air permit to allow installation of the company's power plant. Big Island Carbon's technical process produces a gas energy stream that will generate internal power with recovered energy.
"The EPA's issuance of our Clean Air Permit means two important things," explains Vidgen. "First, it means we can operate our plant the way it was designed to operate‹clean and green. And secondly, it supports the fact that we are fully capturing and reusing much of what would otherwise be burned in a flare stack by producing most of our power from the manufacturing process itself. This clean, green technology allows us to be environmentally prudent, lower our energy costs and importantly, contribute to our bottom line."
Currently, 20,000 tons of shells that Big Island Carbon purchased from local farmers await processing at the plant. That's enough to produce 1,500 tons of the final product granular activated carbon. Until now, farmers have paid $5 a ton to have their shells hauled to landfills, but with this load alone, BIC has saved the farmers about $100,000.
After years of laboratory and pilot plant research and testing, BIC has been manufacturing testing since February 2011 and all is going well. According to BIC, two major processes transform the shells into carbon. First, gas pyrolysis occurs in a char reactor, converting the shells into charcoal by heating in the absence of air. Used effectively for thousands of years to produce charcoal from wood, BIC's process is unique in that it occurs in a closed system operating in the absence of oxygen.
Char then passes to an activation kiln while the combustible gases from the char reactor are used internally to fuel a boiler used for steam generation or condensed into distillate oil for use as a biofuel for plant operation. It's here where the char is subjected to further heat and super-heated steam to complete the activation process.
Sharing an island home with an almost endless supply of macadamia nuts, Vidgen and company are hopeful for the future. "As an agriculturally-based industry Big Island Carbon is unrelated to tourism. The project provides positive cash flow to the macadamia industry making it exactly the type of industry that the island needs," says Vidgen. "Furthermore, jobs at Big Island Carbon are high-tech and high-paying. We hope other entrepreneurs will recognize there is opportunity in Hawai'i beyond tourism and that our innovation will breed innovation."