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Food Waste Diversion at Correctional Facilities Composting Technologies and Costs. Craig Coker Organics Recycling Coordinator DENR/ Div. Of Pollution Prevention & Environmental Assistance. Overview . Technology in Composting Materials Handling Biological Process Optimization
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Food Waste Diversion at Correctional FacilitiesComposting Technologies and Costs Craig Coker Organics Recycling Coordinator DENR/ Div. Of Pollution Prevention & Environmental Assistance
Overview • Technology in Composting • Materials Handling • Biological Process Optimization • Odor Control • Capital Cost • Increases with technology • Operational Costs • Decrease with technology • Footprint (Area Required) • Decreases with technology (usually)
Technology Classification • Low - Tech • Windrow • Mid - Tech • Aerated Static Pile • Aerated Compost Bins • High - Tech (In-Vessel) • Rotary Drum Composters • Box/Tunnel Composting Systems • Mechanical Compost Bins
Windrow Composting • Long, narrow piles agitated/turned regularly • Aeration by natural/passive air movement • Better suited to larger volumes • Composting Time: 3 - 6 Months
Windrow Composting, cont. • Equipment Needed • Grinder/Shredder • Tractor/FEL • Windrow Turner • tractor-pulled • self-propelled • Screener • Manual labor costs excessive without equipment
Windrow Composting, cont. • Footprint • One Acre Can Handle 4,000 - 7,000 CY Compost Mix • Costs • Site Prep -Site Specific • Asphalt/Concrete Pad ($12 - $27/square yard) • Equipment • Grinder/Shredder : $3,500 • Tractor/Front End Loader : $50K - $150K • Windrow Turner : $30K - $200K • Screeners : $50K - $180K
Aerated Compost Bins • Aeration Through Porous Floor Plates • Composting Time: 2 - 3 Weeks • Curing Time: 2 Months • Durable Materials of Construction • Equipment Needed: Front End Loader • Vector/Vermin Control Needed With Food Wastes • Capacities: 3 - 4 Days Food Waste + Bulking Agent Per Bin
Aerated Compost Bins At Caledonia • 12 Bins - Two Rows of 6 Bins • Construction Cost - $40,000 • Footprint - 50 SF per Bin • Capacity of Each Bin - 36 Barrels (35 - gal.) of Food Scraps • Blowers - 980 CFM • Aeration Plates - 2’ x 2’, $89 Each • Filling/Emptying - With Bobcat
Aerated Static Pile • Aeration Provided By Mechanical Blowers • Can Shorten Composting time to 3 - 5 Weeks (followed by 30 days curing)
Aerated Static Pile • Better Suited to Larger Volumes (landscape debris and food waste) • May Not Be Suited to Wastes That Need Mixing During Composting, Like Food Wastes • Difficult to Adjust Moisture Content During Composting If Needed • Odor Control Difficult With Positive Aeration • Less Land Area Than Windrows, Still Labor Intensive
Rotary Drum Composters • Rotation Mixes, Aerates Compost Mix • Second - Stage Curing/Composting Needed • Food Waste Grinding and Mixing With Bulking Agent Needed Prior to Feeding Drum • Recipe For Drum Composting Food Wastes: • 2 Parts Wood Chips • 1 Part Sawdust • 2 Parts Food Waste
Rotary Drum Composting at Brown Creek • Type 616 Greendrum Composter with Patz 9427 Chopper • Mounted on Tandem Axle Frame - moveable • Footprint - 200-300 SF • Daily Loading Rate - 2,000 - 5,000 Lbs/Day • Operating Capacity - 11 CY • Retention Time - 1 Week, Curing Time - 2 Months • Cost - Approx. $45,000
Auburn Correctional Facility, NY • Wright Environmental Model 1500 (Model 750 shown)
Auburn Correctional Composting • Capacity: 1500 lbs/day • Composting Time: 4 Weeks • Curing Time: 1 Month • Labor - 2 Inmates • Cost: $123,000 • Disposal Savings: $33,000 / yr. (4-yr. Payback) • Footprint: 50’ Long x 10’ Wide
Mechanical Compost Bins • Green Mountain Technologies “Earth Tub” • Modular Design, Batch Operation • Capacity: 200 lbs/day • Composting Time: 4 Weeks; Curing: 1 Month • Footprint: 1 Parking Space • Cost: $6,000 • Labor: 1 Operator
GMT “Earth Tub” Installations • UNC - Asheville (Spring, 1999) • Univ. of Georgia • Hyatt Regency, Chicago • Vermont DEC • Univ. of South Carolina • Connecticut DEP • Flushing Hospital, NY • Texas A&M University
For More Information: • Greendrum Rotary Drum Composter • Bob Broom, RKB Enterprises (888) 475-2368 • Wright Environmental Tunnel System • Paul Roth, Innovative Environmental Systems (757)890-1354 • Green Mountain Technologies Earth Tub • John DeRham, (802) 368-7291
Summary • Factors To Consider In Selecting Technology • Available Space • Available Labor (Inmate or Staff) • Vendor Previous Experience With Same Feedstocks • Control of Odors, Vermin, and Vectors • Life - Cycle Costs • Capital Costs And All O&M Costs Over Expected Life Of System • Low - Tech: Lower Capital; Higher Operating Costs • High - Tech: Higher Capital; Lower Operating Costs