News

Dungster LLC Supplies Solar Powered Composter to Central Park NYC

Fairview PA - Dungster LLC has supplied four 30-yard in-vessel composters for Central Park NYC, working in partnership with Big Reuse, an environmental nonprofit that supports New York City's composting initiatives.

Betsy Smith, President & CEO of the Central Park Conservancy, reported in a Central Park news release, "This partnership reflects our commitment to sustainable practices by allowing us to reuse organic material generated in the Park and return it to the landscape. Managing Central Park means thinking long-term about how we maintain and sustain this cherished landscape for future generations."

The picture shows the four units side-by-side.

Dungster in-vessel composters eliminate the need to turn compost piles. Oxygen is added by proprietary blowers and aeration systems. Dungster's Founder Tim Shuttleworth quips, "We turn the switch, not the pile," and adds, "Turning the piles almost never happens on the necessary schedule and it requires the expense of a diesel-powered machine and a skilled operator. Dungster does not burn diesel fuel to aerate; we use sunshine."

The Dungster in-vessel composter uses common dumpsters "as-is" without modification, so an idle dumpster is a free asset to put into immediate service. The filled unit in the foreground of the picture was an available existing 30-yard dumpster that was not in use at the park. Capturing this unit for this task saved more than $6,000 in expenses, and it is in keeping with the mantra of "Reduce. Reuse. Recycle." The second unit is being filled.

The white object on the left-hand side above the second unit is the Dungster LLC proprietary DC blower. The solar panel is mounted to a DungsterGard cover.

Another angle of the same scene shows the narrow gap between units.

Dungster supplies 115VAC powered units and 36VDC solar powered units. The four units at Central Park are all solar powered. Tim Shuttleworth, Founder of Dungster LLC, reports that solar powered units out-sell AC powered units, saying, "Many sites ideal for composting are remote sites where the only power is diesel powered equipment. To install AC power over open ground can be expensive. Some users on landfills want to avoid disturbing landfill cover, refusing to set utility poles, or dig trenches. This means solar power is the natural solution. And for a sustainable activity like composting, solar powering it is the natural approach."

The solar control system has a cellular gateway, which allows monitoring of the system from anywhere over the internet. Push alerts are possible. The vertical bars in the report are the solar gain while the horizontal lines are the system voltage. Note the stable voltage despite the variable solar gain.

A typical solar monitoring report showing solar gain and system voltage.

The four units for Central Park were designed to be positioned very tightly next to one another with only personnel access between the units. All filling and emptying is done through the dumpster's end door. This was accomplished by using a narrow gauge aeration design.

When the dumpster is empty, the aeration system is laid on the steel floor narrow enough that the Bobcat skid-steer tires straddle the aeration pipes. The Bobcat drives with a loaded bucket from the door end to the end opposite the door and empties the bucket, then backs out, repeating this until the unit is full. Once full, the blower and solar controls are switched to an adjustable on-off cycle. This cycling pulses oxygen into the organic mass. The temperature soon shoots up to 130F and even higher.

The adjustable on-off pulsing of air maintains the ideal oxygen level to support microbial life, but not too much to cool the pile. Even in the dead of winter, temperatures remain in the ideal range of 120 to 140F. These temperatures are important to eliminate invasive plant species and their seeds. These high temperatures meet Process to Further Reduce Pathogens standards, eliminating pathogens and unwanted seeds.

This allows the compost to be used in the park without worries about spreading invasive species.

The narrow gauge aeration is shown here with tall NYC buildings in the background. Devin Reistsma of Big Reuse is standing in one 30-yard Dungster.

The chart below shows a typical temperature profile over four weeks of thermophilic composting. The double line is the benchmark 131F, which is supposed to be maintained for a minimum of three days for in-vessel composting. In this typical case, the Dungster maintained 131F or higher for twice or three times the minimum. The peak temperature was 176F at the end of September 2024.

Typical temperature profile over four weeks of thermophilic composting.

In addition to the solar powered in-vessel composters, Dungster supplied the DungsterGard PE covers. These covers are modular, interlocking, and durable plastic covers made from recycled PE. Weighing only 43 pounds each, four are used to cover one 30-yard composter. These can be installed by one person, although two people make it an easier task. One cover has the solar panels attached.

This means when the cover is installed and secured, it provides a dual function of enclosing the in-vessel composter while charging the batteries during the daytime hours. From dusk to dawn, the batteries supply the necessary power for the aeration blowers overnight. The covers are secured with two ratchet straps. Padlocks can be applied to the straps to deter tampering and pests, which is helpful in a public park setting.

The Dungster aeration system is made of all corrosion-resistant construction of advanced polymers and stainless steel metal parts. The electrical control system is a marine-grade design intended for outdoor use in harsh environments.

The original Central Park release can be seen here.

For more information, reach out to:
info@DungsterComposting.com