Commercial, Farm and Municipality Composting
Composting is the accelerated biological decomposition of organic matter under managed aerobic conditions resulting in a stabilized product that can be used as a soil additive, fertilizer, growth media or other beneficial use (compost).
Composting is the second most preferred method of materials management in EPA’s Waste Management Hierarchy.
Different types of composting
Aerated Static Pile - Process in which decomposing organic material is placed in piles over an air supply system that can be used to supply oxygen and control temperature for the purpose of producing compost. Piles must be insulated to assure that all parts of the decomposing material reach and maintain temperatures at or above 55°C for a minimum of 3 days.
Turned Windrow - Process in which decomposing organic materials are placed in long piles for the purpose of producing compost. The piles are periodically turned or agitated to assure all parts of the decomposing material reach the desired stability.
In-vessel - Process in which decomposing organic material is enclosed in a drum, silo, bin, tunnel, or other container for the purpose of producing compost; and in which temperature, moisture and air-borne emissions are controlled, vectors are excluded and nuisance and odor generation minimized.
Benefits of Composting
There are a number of benefits to compost that not everyone is aware of. Some examples are listed below:
- Organic waste in landfills generates methane, a potent greenhouse gas. By composting wasted food and other organics, methane emissions are significantly reduced.
- Compost reduces and in some cases eliminates the need for chemical fertilizers.
- Compost promotes higher yields of agricultural crops.
- Compost can help aid reforestation, wetlands restoration, and habitat revitalization efforts by improving contaminated, compacted, and marginal soils.
- Compost can be used to remediate soils contaminated by hazardous waste in a cost effective manner.
- Compost can capture and destroy 99.6 percent of industrial volatile organic chemicals (VOCs) in contaminated air.
- Compost can provide cost savings over conventional soil, water and air pollution remediation technologies, where applicable.
- All composting requires four basic ingredients:
- Browns - This includes materials such as dead leaves, branches, and twigs.
- Greens - This includes materials such as grass clippings, vegetable waste, fruit scraps, and coffee grounds.
- Water – Composting organisms need a moist environment.
- Air – Air circulation in the pile will allow the composting organisms the oxygen they need to live and keep the pile from producing a foul odor.
- Initial Parameters for Composting (preferred ranges)
- Moisture: 50-60%
- Carbon to Nitrogen: 25:1-40-1
- Oxygen: Greater than 10%
- Temperature: 120-150°F (49-60°C)
- pH: 6.5-8.0
- Particle Size: the preferred range depends on feedstocks and use of compost, but a reasonable range is 1/8-2 inches
- Bulk Density: 800-1000 lbs/yd3
- Free Air Space: 50-60%
Compost vs. Mulch
- Mulch IS NOT Compost
|Organic in nature||Organic or inorganic in nature|
|Processed to reduce pathogens||Not processed to reduce pathogens|
|The process often requires a Solid Waste Permit||The process does not require a Solid Waste Permit|
|“Earthy” smell (usually)||“Woodsy” smell (usually)|
|Final C:N ratio should be less than 20:1||No ideal C:N ratio, but usually carbon-rich if organic|
|Applied at 2" or less depth or can be incorporated into soil||Applied at least 2-3" deep and not incorporated into soil|
|Can be used as mulch||May turn into a carbon-rich compost-like product if organic|
The Department offers grants for organics management for municipalities and non-profit organizations. Information will be linked here when available.
Other Relevant Information
Cornell University’s Compost Page - good information for large scale and farm composting (including mortality composting)
US Composting Council: Compost Sampling Videos and Reference Guide
Best Management Practices (BMPs) for Incorporating Food Residuals into Existing Yard Waste Composting Operations
A Practical Safety Manual for the Composting and Mulching Industry
TN Department of Agriculture on Mortality Management
Register your site at findacomposter.com