Top: Dungsters’ roll-off dumpsters equipped with aeration piping are used to compost horse manure and bedding on a farm near Erie, Pennsylvania. Photo by Craig Coker

In 2018, inventor Tim Shuttleworth was frustrated by algal blooms in his on-farm pond near Erie, Pennsylvania. “My next door neighbor had an equine boarding facility, and for a long time, the manure was removed by a local nursery,” he explains. “When that arrangement ended, the manure just piled up and the nutrients from the manure were running into my pond.” Shuttleworth and his neighbor researched different ideas for manure management and concluded that in-vessel composting would be best as it offered protection from rainfall-induced runoff. But none of the options explored were affordable. “It dawned on me that roll-off dumpsters were a good host for an aerated in-vessel composting system,” he adds. “I had many years of experience in the recycling industry and dumpsters are reliable, available, affordable, and they are only made in certain sizes, so designing the aeration system became easier.”

Pipe on grade nylon pull straps are attached to the back of the piping (foreground above). Pulling on the straps helps to compress the PVC piping when removing it, preventing the connectors (center) from pulling apart. Photo by Tim Shuttleworth

Shuttleworth patented his idea (U.S. Patent 11,111,188, Sept. 7, 2021) and started Dungster, which offers 10-, 20-, 30- and 40-cubic yard capacities. Aeration kits are available for each size. Tarps can be attached to keep off rainfall. The company has about a dozen installations handling animal manures and one handling food wastes. The single-phase blower is mounted against the back wall of the dumpster (solar-powered blowers are also available). His aeration system design includes a feature where the “pipe-on-grade” nylon pull straps are attached to the back of the piping. “When you pull on the straps to remove the piping, you’re compressing the PVC piping,” notes Shuttleworth. “PVC is stronger in compression than it is in tension, so the connectors don’t want to pull apart. Think of it as pulling a piece of uncooked spaghetti out of a box of noodles.”

The Dungster can be filled manually or with a tractor or loader and emptied using the same equipment. Alternatively, a roll-off truck can pick it up at an angle and the contents will fall out through the open door at one end. Retention time in the Dungster is roughly 30 days, followed by about 30 days of curing. The units are available for purchase or for rent.

—Craig Coker