Compost Quality Best Management Practices Athena Lee Bradley
What is Compost? Value-added product: converts waste material to easy-to-handle, useful product. Soil-like material, rich in organic matter & organisms. It is not: mulch, fertilizer, manure, peat moss, topsoil.
Advantages to Composting Typically can be done with existing farm equipment and available farm land. Improves manure handling. Reduces volume. Reduces moisture content. Reduces odor. Reduces fly & parasite problems. More uniform & easier to handle or spread. Produces a value-added product. Opportunity for tipping fees.
Benefits of Compost on Soil Improves Physical Properties: Increases water retention; improves soil aeration and structural stability; resistance to water and wind erosion; root penetration; soil temperature stabilization. Enhances Chemical Properties: Increases macro- and micronutrient content; availability of beneficial minerals; ph stability; converts nutrients to a more stable form, reducing fertilizer requirements. Improves Biological Properties: Increases the activity of beneficial micro-organisms; promotes root development; can increase agricultural crop yields; suppresses certain plant diseases; acts as biofilter, bonding heavy metals.
Major Factors Affecting Compost Demand and Sales Compost quality. Product consistency. Product availability (meeting demand). Economics of transportation & distance to markets. Economics & challenges associated with compost application. Industry standards and specifications.
Compost Markets Erosion Control/Reclamation Agricultural applications Topsoil Nurseries/Silviculture Sod production Turf grass Public Works Construction sites Landfill cover Marginal soils Biofiltering Direct marketing Retail sales Landscapers and Lawn Care Companies Golf Courses Greenhouses Rainwater filters
General Character of Compost Products CHARACTERISTIC Nutrients (N) Particle Size Maturity Salts Contamination Price PRODUCT Mulch/Erosion control Low Large Mod. Mod. None Mod. Soil amendment field, turf soil, sod, landscape beds Mod.- high Mod. Lowmod. Mod. high Low Mod. - high Topdress turf and field soils Mod.- high Small Mod. Mod. Mod.- high Mod. Soil amendment organic agriculture High Mod. Mod.- high Low- Mod. Mod.- high Mod. Rynk, SUNY Cobleskill
General Character of Compost Products (2) CHARACTERISTIC Nutrients (N) Particle Size Maturity Salts Contamination Price PRODUCT Potting soil Low Smallmod. High Very low None High Topsoil, manufactured soil Low- mod. Smallmod. Low Mod.- high Low Lowmod. Land reclamation Low- mod. Smalllarge Low Lowmod. Mod.- high Low Landfill cover Low- mod. Smalllarge Low Low- Mod. Mod.- high Low Rynk, SUNY Cobleskill
Higher Price Retail Markets Garden Centers Sports Turf Landscapers Grounds Crews Value Markets Wholesale Nurseries* Organic Agriculture* Floriculture & Greenhouses* Volume Markets Topsoil Blenders Erosion Control Residential & Commercial Turf Road Construction & Maintenance Sod Farms Land Reclamation Agriculture Silviculture Landfill Cover Greater Volume Rynk, SUNY Cobleskill
Best Management Practices (BMPs) Produce desired quality compost in shortest time possible with: Minimum odors. Minimum environmental impacts. Minimum process-related problems.
Elements of Composting Aeration Oxygen concentrations - 10-14+%. Carbon to Nitrogen (C:N) Ratio 20:1-60:1 (preferred 30:1-50:1) Moisture -- 40 to 65 percent (preferred 50 60%) like a damp sponge. Optimum ph range - 5.5 to 8 (preferred 6.5 8.0) Temperature 120 and 160 F. 131 F for 15 days to kill weed seeds & parasites.
Elements of Composting, cont. Bulk density < 1000 lbs. per cubic yard Particle size (diameter in mm) 3-13 (preferred depends on end market) Porosity, structure, texture - particle size, shape & consistency influence aeration. Adjust with bulking agents raw materials. Compost recipe. Grinding or mixing.
Compost System Recycled Organics University, www.recycledorganics.com
The Process Decomposers: bacteria, fungi, actinomycetes. Heat is released by microorganisms during the aerobic metabolism of an organic substrate (e.g. glucose). Temperature influences microbial population. Initial stage: Mesophilic bacteria As the temperature rises, mesophilic organisms begin to die off and thermophilic organisms begin to thrive.
The Recipe Know the compost process. What s the primary ingredient what must be managed? What feedstock(s) do you have readily available? What are the characteristics of the primary ingredient? Nutrient content, C:N ratio, moisture content, bulk density, ph, potential for odors.
The Recipe, cont. What are the complementary or secondary ingredients available? What are the characteristics of these? How can they be mixed together to properly compost with the primary ingredient. Balance C:N ratio, moisture, bulk density, etc. Observation, feel of compost, temperature, trial and error. Calculations.
Feedstock Considerations Is the feedstock difficult to handle? Does it fit into your recipe Will it blend with other materials at the site? Is the texture right? Proper moisture? Color? Is the particle size right? Does it need grinding? Color Is it relatively free of contaminants? What s the pathogen potential? Is it generated regularly in volumes your site can handle? Are the generators willing to pay a tip fee.
Matching Feedstocks and Compost Products PRODUCT Good Not So Good Mulch/Erosion control Soil amendment field, turf soil, sod, landscape beds Topdress turf and field soils Soil amendment organic agriculture Land reclamation/landfill Bark, wood, lumber, green organics, brush Green organics, manure, biosolids, food, mushroom Manure, grass, leaves, food, screened biosolids & green organics Manure, green organics w/o pesticides Contaminated green organics, MSW Manure, biosolids mushroom (?) Wood, MSW w/o processing Wood, unscreened green organics, MSW Biosolids, MSW, grass w/ pesticides Clean, nutrient & OM rich Rynk, SUNY Cobleskill
Quality Assurance Know & meet the quality requirements for your end market. Observe, monitor, sample, analyze, test. Track and keep accurate compost records. Feedstock sources, problems Materials, lot numbers, problems Turning frequency Temperature Train your staff.
Controlling Odors Cover piles/windrows layer of finished compost Direct process air through a biofilter to remove odors. Vessel containing mature compost. Suction-type aeration system In-vessel systems or an aerated static pile.
Aeration Turned windrows Front loader. Windrow turner. Modified turners. Forced air system. Aerated static pile. In-vessel system. Aerated Static Pile (ROI)
Static or Aerated Pile
Shed System
Small-Scale Aeration System
Windrows
Contained Systems Agitated Bed Rotating Drum
In-Vessel Systems
When is it Product? Types of raw materials. Compost recipe. Temperature. Moisture levels & consistency. Frequency of aeration. End market specifics: Screened? Bagged?
Contact Information Athena Lee Bradley, Project Manager 139 Main Street, Suite 401 Brattleboro, Vermont 05301 athena@nerc.org Tel: 802-254-3636, Fax: 802-254-5870 www.nerc.org