COMPONENTS FOR SUCCESSFUL COMPOST FACILITY OPERATIONSSCAP Biosolids Committee Meeting
August 2, 2012
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AGENDA
• Facility Siting Considerations• Composting Technologies• Permitting• Regulatory Compliance• Process Control• Compost Quality
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FACILITY SITING CONSIDERATIONS
• Location, Location, Location!– Regulations– Nearby Compost Market– Sensitive Receptors
• Public Education/Politics– Education Begins Early– Keep it Simple– Remember the Benefits
• Diversion• Soil Enhancement• Erosion Control
– Don’t ignore the public/politics
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COMPOSTING TECHNOLOGY
• Windrow• Negative Aerated Static Pile with
Biofiltration• In-vessel
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COMPOSTING TECHNOLOGY: Negative Aerated Static Pile Composting
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COMPOSTING TECHNOLOGY: Negative Aerated Static Pile Composting
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PERMITTING
• Local Conditional Use Permit• CEQA• CA Solid Waste Facility Permit
– Report of Compost Site Information– Odor Impact Minimization Plan
• Regional Water Quality Control Board• Local Air District Permit• U.S. EPA Registration
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REGULATORY
• Inbound Materials Monitoring– Biosolids– Carbon Feedstocks
• Process Water Management• Ground Water Monitoring• Special Occurrences• Source Testing
• Compost Sampling – C.C.R. Title 14, Chapter 3.1, Article 7
• Metals Concentrations (max)• Pathogen Reduction (PFRP) • Sampling Requirements
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PROCESS CONTROL PARAMETERS
• Control Points– Feedstock Handling– Mix Ratios– Moisture– Aeration Rates– Temperature/PFRP
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THE COMPOSTING PROCESS
Feedstocks
Microorganisms
Oxygen
Water
Compost
CO2Water
Odors?
Heat
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COMPOST FACILITY FEEDSTOCK-PROCESS-MARKET
Identify and quantify
Feedstocks
Analyze Markets
Develop and adjust recipes
Collect or receive feedstocks
Process:Grind, Mix, Compost,
Cure, Screen, etc.
Market and distribute
AssessCompost Facility
Start here or
here
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THE KEY PROCESS VARIABLES for Control of the Composting Process
1. Initial feedstock mix
2. Pile moisture
3. Pile aeration
4. Pile shape and size
5. Pile temperature
6. Composting retention time
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FEEDSTOCKS: YOUR RAW MATERIAL
• Chemical Composition– Organic Matter, Nutrients, Degradability
• Physical Characteristics– Moisture, Bulk density, Heterogeneity
• Other– Contamination, Cost, Availability, Regulations
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FEEDSTOCK SUMMARY
• Each feedstock has certain attributes• The RECIPE is how feedstocks are combined• Composting system designed for feedstocks• Regulations are always partly based on feedstock
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OTHER CONSIDERATIONS
• Health & Safety• Initial Mix Ratios• Moisture• Aeration• Temperature• Time• Curing/Maturity• Testing
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SUMMARY: Key Initial Parameters for Composting
Condition Reasonable range Preferred range Moisture % 40 — 65 50 — 60 C:N 20:1 — 60:1 25:1 — 40:1 Oxygen % Greater than 5 Greater than 10 Temperature oF oC
113 — 160 45 -- 71
120 — 150 49 -- 66
pH 5.5 — 9.0 6.5 — 8.0 Particle size 1/8 to 2 inches
.3-5 cm Depends on feedstocks
and use for compost
Porosity: Bulk density lbs/ yd3
(kg/l)
Free Air Space %
Less than 1200
(.7) 40-60
800-1000 (.45-.6) 50-60