Michael Bryan-Brown

Michael Bryan-Brown

Michael Bryan-Brown

Speaker | Green Mountain Technologies

Bainbridge Island, WA | (206) 842-5471 | mbb@compostingtechnology.com

USCC Member

Mr. Bryan-Brown earned his degree in Environmental Engineering from Tufts University in 1989. He has 28 years of experience in the fields of composting, biosolids management and wastewater treatment plant design. He is president and founder of Green Mountain Technologies and holds 4 patents related to aerated composting systems. He has developed systems for a wide range of composting applications from the Earth Tub on-site composter to facilities processing up to 200,000 tons per year. In addition to his work with Green Mountain Technologies, he has worked as consultant to the City of New York Department of Sanitation and EPA to investigate on-site composting systems for food waste. As consulting engineer to the City of New York Department of Environmental Protection, he was contracted for the assessment of odor impacts from 8 proposed biosolids composting facilities.

Presentation Title: Improving Energy Efficiency for Aerated Composting Systems

Session: New Learnings on Composting Technological Deployment

Time: Wednesday, January 30, 11:00 AM – 12:30 PM

Presentation Summary: One of the advantages of aerated pile composting systems(ASP)is the reduction in energy consumption required for turning and handling. However, delivering pressurized air for the purpose of cooling compost requires a significant amount of energy. Large ASP systems can have multiple blowers of 100 hp or more running continuously and power bills can exceed $10,000 per month. Additional blowers for bio filters and building ventilation can add to the overall power consumption. All this energy consumption diminishes the benefits of green house gas reductions typically associated with composting.

Several strategies have been employed by the author and others to reduce the energy demand and improve efficiencies. The most common strategy is variable frequency drives (VFD) coupled with system sensor feedback to deliver only the amount of air required. Also, programming controllers to reduce energy consumption during peak demand charges helps lower bills and minimize impacts on the grid. Some facilities have employed landfill gas to run the blowers using direct drive CNG motors while others have used duct misters to lower the air temperature and improve cooling.

Operationally sites have utilized a courser grind to maximize porosity while reducing diesel consumption by the grinder. Pile height is another factor that influences the power required for cooling cost due to pressure losses when higher piles compact and loose porosity. The author will provide energy data from several operating facilities and make a comparison of energy inputs vs composting time to offer the most efficient design.