From apartment owners making their own bins, to industrial-scale operations utilizing worm farms the size of a football field, vermiposting — or composting with earthworms — is becoming increasingly mainstream. It is expensive to collect, haul and dispose of materials that worms can otherwise easily digest, and their waste or castings are a commercially valuable soil conditioner commonly referred to as the “black gold” of compost. Charlotte Douglas International Airport in Charlotte, North Carolina, is applying the benefits of earthworms on a grand scale by incorporating vermiposting into its new $1.1 million recycling facility.
Each day at Charlotte Douglas, 300 pounds of worms in an 8,000 square foot bin munch away on almost a ton of traveler’s waste. Before they make it to the worm bin, compostable items that people go through during a typical day at the airport – food scraps, paper waste, bathroom towels, and plant trimmings – are collected and loaded into a 1,600 square foot pre-composter with odor controls. The pre-composter breaks the materials down into manageable bits for the earthworms to digest and loads the mix into the vermipost system. The worms eat their way vertically toward the fresher food on top of the bin, while leaving their castings at the bottom for easy collection. Castings are free fertilizer for the facility’s 6,000 acres of land and vegetation and whatever worm waste is leftover can be packaged and sold.
Charlotte Douglas’ vermiposting system is designed to process two tons of waste a day which will be enough to keep up with eventual airport expansion. Ten new jobs have been created to manage the airport’s entire recycling and worm-composting center which will pay for itself in the next five years by saving the airport approximately $1 million in waste disposal costs.