Greenacres Commissions their New Earth Flow Composting System

Greenacres Commissions their New Earth Flow Composting System

Greenacres Foundation is an educational non-profit and biodynamic farm located on nearly 600 acres north of Cincinnati, Ohio.  The mission of the Greenacres Foundation is to encourage conservation and appreciation of nature by providing the public, particularly children, with opportunities to learn about agriculture and wildlife.  Greenacres operates a variety of educational programs for young people as well as hosting events and operating a farm store. 

Greenacres has a substantial equine/riding program and generates about 4 yards of manure and bedding on a daily basis.  Greenacres also generates chicken manure and bedding, plant trimmings from their greenhouse operations, lawn clippings and food scraps from visitors and staff.  Greenacres needed a better way to quickly turn these farm-generated wastes into a valuable compost product.

Green Mountain Technologies (GMT) recommended a Site-Built Earth Flow system for Green Acres. The Earth Flow system provides optimum conditions for hot, aerobic composting.  This dramatically reduces the time required for horse manure composting from 6-12 months to 10-14 days (additional curing time of 1-2 months is recommended after the primary in-vessel composting phase is complete).  A Site-Built system means that the composter is built inside of a locally-built vessel instead of a prefabricated steel vessel container. 

GMT recommended the Site-Built Earth Flow for several reasons:

  • Greenacres generates a larger amount of waste per day than can fit in a steel vessel system.  This Site-Built Earth Flow provides about twice the capacity as can be processed with GMT’s largest steel vessel Earth Flow.
  • A locally built vessel provides more design flexibility and aesthetic options and an ability to modify the vessel overtime.
  • A Site-Built Earth Flow makes it easy to drive into the compost bay with a skid steer/bucket loader and directly manage the compost/feedstocks.   This provides a lot of operational flexibility and control.

Greenacres selected a 40’ x 12’ Site-Built Earth Flow composting system for their composting program.  This system has a total capacity of about 71 yards and a daily input capacity of about 6 yards per day with a planned retention time of 14 days. Green Acres is planning on operating the Earth Flow in “batch mode”.  This means that they will plan to fill the system up with feedstocks once every 2 weeks and then process a single batch of compost over a 14-day period.  Greenacres’ plan is to use the compost they create to provide soil amendments for the entire farm.

GMT provided the design guidance to the client, architect and contractor. GMT installed the Earth Flow automated mixing and aeration technologies in January 2021.  Greenacres designed covered storage areas for feedstocks and curing compost.

Nathan Bundy is the Greenhouse Horticulturalist and the Compost Manager for Greenacres Farm.  Van Calvez from GMT spoke recently with Nathan as Greenacres prepares to begin Earth Flow composting operations in February 2021.

Nathan provided context for why composting is so important at Greenacres: “Two things that are core to our mission here at Greenacres are education and sustainable agriculture.  And compost really is one of the biggest keys to both of these goals.  Because we farm here with relatively few external inputs, quality compost is super important to our success. Compost is one of the biggest keys to sustainable agriculture. Compost does so much to promote the growth of plants, build soil structure, soil health and retain water.  “One of our core values is being green and so we want to do composting right.  We don’t want our composting piles to be detrimental to the environment.  The longer a pile of animal manure and bedding sits, the more it can be a source of water and air pollution.  So by speeding up and better managing our composting process, we can quickly get that material stabilized so that it can be beneficial to the environment.”

Nathan explained how he expects the Earth Flow will help them make a better compost product:  “One of our major goals with this system is to be able to create a consistent and reliable compost product, free of pathogens and weed seeds.  If you are composting on a pile on a ground, it is challenging and time consuming to get that type of quality and have confidence in your product.”

Nathan also explained how the Earth Flow benefits them from a process standpoint.  “The Earth Flow will help us take a lot of the labor out of the composting process. This helps me spend less time on a skid steer and more time in the fields and in the greenhouse, focused on growing food.  The Earth Flow helps us keep up with the waste we generate and quickly turn that waste into a usable soil amendment.”

Earth Flow will be an important part of their tours and educational offerings:  “We want to involve students in learning about composting.  We want the kids that come through here to see how their food scraps can become a high-quality compost that feeds people.”  The Earth Flow vessel will feature an elevated walkway and viewports to allow kids to be able to observe the composting process firsthand.   The Earth Flow is a major accomplishment for Greenacres that will help them meet their goals for community education and sustainability.  

Written by Van Calvez

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