|Thorough mixing and blending of materials does not occur.||Thorough mixing and blending occurs enabling interaction of carbon and nitrogen
|Aeration||Airflow can form channels leaving anaerobic areas.||All materials turned have access to oxygen while passing over drum.|
positive pressure is used to vent heat, it may be difficult to meet
temp requirements near the pipes.
|All materials in row have access to required thermophilic cycle for pathogen and weed seed destruction.|
|Watering||Added to windrow perimeter. Not consistent throughout.||Each particle is watered for equal moisturization throughout the row.|
|Odors||Biofilters are frequently utilized to manage odors.||Odors in windrows should disappear after 2-3 days.|
|Typically defines quality in terms of the absence of pathogens.||Defines quality in terms of what it does for the soil and plant. Complete laboratory comparisons are encouraged.|
|Profitability||Such facilities are often government operated, as private entities have
difficulty profiting. Compost is often given away. Income is driven
by tipping fees.
|Compost is often sold at from two to four times the cost per ton to produce. Income from compost sales can be a significant profit stream because of the product quality.|
& Annual Costs
|Capital costs for an enclosed facility processing approximately 5,000 tonsper year of wood and yard waste is approximately 2 million to 5 million dollars. Capital costs, not including land, will be decreased by building costs ($75 sq. ft.) in an open facility. Annual operating costs range from $10 to $70 per ton. Aeration pipes may require disposal or recycling.*||Capital costs for an enclosed facility with similar tonnage would be in the $400,000 range. Open air facility would be significantly less.|