From waste to resource – reshaping perspectives on food waste

With support from a NYSERDA grant, North Country School and Camp Treetops has designed and constructed a game changing commercial compost system, turning what was once considered a greenhouse-gas causing waste product into a valuable soil amendment. The compact, 20-foot, continuous-flow drum composter turns all sources of food scraps (yes, even milk, meat, and a stray T-shirt or shoe) to nutrient-rich material in approximately 35 days. The drum is turned one to three times a day, tumbling the processed food scraps out of the other end of the drum– just like a giant stomach. All organic material is mixed with a carbon source for bulking. Zillions of bacteria do all of the hard work; it is our job to provide the right conditions. The stabilized organic material undergoes secondary decomposition in a pile, and the completed product is deposited on campus garden beds, starting the food cycle anew. Our system is designed to be inserted into a retrofitted 40-foot shipping container – at this point three other organizations have successfully done this – providing opportunities for a mobile system.    

We are pleased to offer this design and other support materials for free. Whether you want to purchase a composter, or are interested in building your own, we are happy to help you navigate the decisions that work best for you. Site tours are available upon request, and the design and operating manuals are free to download through our website.

Happy composting!

 


(CLICK ON ICON IN UPPER LEFT HAND CORNER OF FILE TO DOWNLOAD)


(CLICK ON ICON IN UPPER LEFT HAND CORNER OF FILE TO DOWNLOAD)

 

In-Vessel Composter Highlights

  • Units of this size on the open market range from $40,000-$140,000
  • We secured a New York State economic development grant to design a system that is much more affordable and can be containerized within a 40-foot shipping container
  • Funding was funneled through The New York Energy Research and Development Authority (NYSERDA)
  • Our hope is that this design will allow many more organizations like ours to divert food scraps from landfills and create a high value soil amendment
  • Our first year of operation we composted approximately 30,000 pounds of food scraps. (It appears that the unit could easily handle 40,000 pounds/year.)
  • All of our easily composted materials go to our pigs. All other food waste: meat scraps; egg shells; rinds; etc. go to the composter
  • Our in-vessel composter is designed with “off the shelf” components
  • The design that we came up with is four feet in diameter and 20 feet long
  • The drum itself is a polyethylene highway culvert
  • The drum is on an angle of 2.5 inches over 20 feet
  • We used a 3-phase 1.5 hp motor with a reduction gear making a rotation of about 1 rotation in 45 seconds
  • A single phase, or possibly a DC motor tied to a PV solar panel could work as long as the reduction gear is matched appropriately to the motor and drum weight
  • The materials cost is approximately $15,000 and a competent machine shop can easily produce the frame
  • The design will soon be posted on our website and available to the world.

 

Sustainability/Composting

  • Our hope is that others will use this design, improve upon it and find ways to reduce the material cost even more. We know that can be done
  • Retention time depends on the amount of material added
  • During our school program we are feeding approximately 150 people, three times per day and generating approximately 65 pounds of food scraps per day
  • Retention time for the food scraps/carbon bulking material is approximately 28 days
  • During our seven-week camp program our numbers double, to about 125 pounds of food scraps per day resulting in a retention time of approximately 25 days
  • We can and do easily accommodate up to 300 pounds per day on occasion
  • Design temperature is 130 °F – We are reaching temperatures of 110-150 °F continuously
  • Our end product after 30-40 days is stable, smells like compost that one would purchase at a hardware store, does not attract dogs, vermin or flies
  • While the material coming out of the drum can be used as top dressing, it still needs several weeks of additional time (in a static pile) in order to produce the most useful product, with more stabilized carbon compounds
  • We are currently using wood pellets (the same type of pellet used in pellet stoves) for our carbon bulking material. This past year we have also used wood chips and wood shavings with success.
  • The recipe of food scraps to carbon bulking agent depends on the carbon type and the type of food waste
  • Our composter is designed to stay full all of the time- the weight of food scraps and carbon bulking material when full is about 3,300 pounds
  • We are beginning to experiment with composting human urine, with the goal of demonstrating that this design is capable of handling all organics coming out of non-industrialized towns and villages all over the developing world
  • We are now collecting temperature data through a data logger, capturing those data every five minutes as the data logger travels down the drum
  • We have demonstrable data suggesting that this design has the ability to meet the US EPA guidelines for effectively composting biosolids

Since our composter became operational we have been contacted by organizations and individuals all over the country asking how they can replicate our success with food scrap composting

For more information contact:

John Culpepper, Director of Facilities and Sustainability, at 518.523.9329, or by email at: jculpepper@northcountryschool.org