The article below was published in BioCycle by Paul Brezovec in the November 2012 issue and features GMT’s Earth Flow In-Vessel Composting System.
Evaluating Composting for Contingency Bases
Technology is being evaluated to demonstrate a potentially viable supplement to waste incineration at Department of Defense bases that support operations of deployed units.
BioCycle November 2012, Vol. 53, No. 11, p. 20
To help address the solid waste management challenges at Department of Defense contingency bases overseas, the National Defense Center for Energy and Environment (NDCEE) is demonstrating an in-vessel composting technology at Joint Base Myer-Henderson Hall (JBM-HH) in Arlington, Virginia. Contingency bases are evolving military camps that support operations of deployed units and provide necessary support and services, moving as the war front moves. Mid-sized contingency bases, supporting 200 to 4,000 personnel, may generate 4 to 18 pounds/person/day of waste, approximately a fifth being compostable organics.
Standard means of disposal for most food waste and other biodegradable debris at contingency bases include burying and incineration. The buried waste produces organic gases and acidic leachate, both of which can be environmental and notable odor/nuisance problems. Incineration has high fuel requirements, especially for food and other moist organic wastes. Alternative waste management approaches are needed to safely and effectively reduce the volume of solid waste with a low energy footprint (versus incineration) and low labor requirement. Technical solutions at small to mid-size contingency bases need to be mobile, scalable, durable and easy to operate.
JBM-HH is hosting the demonstration of an in-vessel composting technology applicable to small to mid-size U.S. contingency bases as well as Army installations with space constraints. JBM-HH is home to the Army’s official ceremonial unit and security force in the Washington, D.C. metropolitan area, and includes horse stables. To advance the installation’s sustainability, JBM-HH is leveraging the in-vessel technology for composting horse manure, supplemented with dining facility (DFAC) kitchen and Officer’s Club food waste. Following active composting in the vessel, JBM-HH plans to cure and test the compost for area landscaping and soil amendment use throughout the Joint Base.
The NDCEE, operated by Concurrent Technologies Corporation, identified in-vessel systems with low energy demands to demonstrate a potentially viable supplement to waste incineration at contingency bases. The composter being demonstrated is Green Mountain Technology’s Earth Flow™. Organic feedstocks are loaded at the front end, and an inclined auger mixes and pushes the material through the vessel in a 14 to 21 day cycle. The insulated vessel retains the heat generated by the process while the greenhouse-like enclosure top captures radiant heat for increased efficiency. Odors are encapsulated inside the vessel and pulled through a biofilter.
Two essentially different mixes are being tested — one that includes horse manure and another (without horse manure) that represents the feedstock generated by contingency bases validated by solid waste characterization data from the theater. Initial feedstock testing helped to develop optimum composting recipes. The Solvita® test will be used during the intermediate phases of the composting process to measure the combination of carbon dioxide respiration and ammonia volatility and estimate the general condition and safety of the composted product. This information is necessary for determining if a contingency base could use the material for either erosion control or potential fill material when closing the site and returning it to the host nation. Data will be collected to analyze the cost/benefit of the composting system for contingency bases as well as for use at JBM-HH. The demonstration started July 2012.
Paul Brezovec is a Principal Process Engineer with Concurrent Technologies Corporation.