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UI Compost System Design and Pilot. Green Machine. Project Goals. The purpose of this project is to design, develop, and implement a composting system for the University of Idaho by July 2010. This system will incorporate 100% of the food waste created by the university.
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UI Compost System Design and Pilot Green Machine
Project Goals • The purpose of this project is to design, develop, and implement a composting system for the University of Idaho by July 2010. • This system will incorporate 100% of the food waste created by the university. • It will also process any animal carcasses produced by Vandals Meats, the university dairy, beef or sheep units. • The design will be flexible and allow for the possible expansion of operation in size and capability. • Secondarily, the design will allow for the possibility of producing a commercialized product, and for research into composting and waste streams.
Needs • Compost 100% of University of Idaho Food Waste • Compost all Dairy, Beef, and Sheep Carcasses • Robust and Expandable • Low Cost • Low Daily Manual Operations • Instructional Use Material (Operations Manual)
Specifications- Waste Stream • Food Waste: Approx. 100 tons/year sorted • Daily Waste Volume: <900 lbs/day • Carcasses: • 6-7 Full Bovine Carcasses/year • 60 gallon drum slaughter offal/month • Dairy manure with bedding for mixing • Final Product: • Dairy Bedding, C:N Ratio near 30:1
Composting Process Overview 1. Separation and Sorting (occurs at facility) 2. Establish initial pile conditions for feedstock degradation, including pile structure, nutrient balance, oxygen %, and moisture % 3. Biodegradation and stabilization of the compost 4. Collection of air from process and treatment in biofilter (if required) 5. Finishing step to develop level of compost stability required and ensure sufficient degradation 6. Removes physical contaminants (glass, metal, plastics, etc.) and oversized materials (rocks, bulking agents) down to specified size
Process Control Parameters Nutrient Balance- C:N Control Pile Moisture % Control Pile Temperature Control Pile Oxygen % Overall Feedstock Ratio by weight (food waste: manure: wood chips) 1: .28 : .63 Total weight per day treated: 1700lbs weekdays
Mixer Benefits and Costs • Using a mixer prior to loading compost bays would provide smaller and more uniform particles, speeding the composting process and improving quality of product • Range for Mixer Costs $6221-$30000 • 140 cu. ft from Patz Corp. = $20000 • Carbon Steel Paddle Mixer 46 cu. ft from Hayes & Stolz $25000-$30000 • Used 36 cu. ft Carbon Steel Paddle Mixer from Aaron Equipment = $7000 • S-1with 5.4 cu. ft mixer from H.C. Davis Sons Manufacturing = $6221
Curing • Provides additional stabilization • Further degradation • Can proceed until desired C:N ratio is achieved as further biological activity will lower the ratio as CO2 is released • Only requirement is space
General Composting Technology Considerations • Capital and operational costs are related to processing capacity of the technology and its sophistication • Capital costs increase with technology • Operational costs decrease with technology • Area requirements decrease with technology • Process control capability increases with technology • Processing capacity increases with technology
Windrow Composting-Mechanically Turned • Aeration by natural/passive air movement with periodic turning to build porosity, release trapped gases and heat • Suited for larger waste volumes • Large area required • Equipment reqs: • Tractor/FEL • Windrow Turner • Tractor pulled • Self propelled
Windrow Composting- Mechanically Turned • Extensive labor required • No enclosure, ventilation • Typically 1 acre can handle 5000-7000 cy of composting material • Seasonal weather will affect pile size and process speed • 5-6 Weeks 1st phase
Windrow Composting-Mechanically Turned • Advantages • Turning processes mix and pulverize compost for uniform end product • May require less final screening • Disadvantages • Space limited • Weather considerations • Low process control • Odor Release • Labor intensive
Windrow Composting Cost Breakdown • Equipment Cost: • Tractor/Front End Loader: $50,000-$150,000 (dairy owns) • Windrow Turner: $30,000-200,000 (FEL could be used instead)
Windrow Composting-Aerated Static Pile • Mix of food waste, bulking agents, carcasses placed over perforated pipe on prepared base • Aeration positive or negative • Negative allows filtration for odor control • 3-5 Weeks 1st Phase
Windrow Composting-Aerated Static Pile • Advantages • More space efficient • Fewer, larger piles • Reduced temperature variation • Closer process control • Shorter composting time • Less labor • Disadvantages • Higher capital cost • Collection of final product difficult due to piping • Control System for blower regulation • Pile drying • Areas of Anaerobic activity caused by pile settling • Learning curve, trial and error by operators
Aerated Static Pile Cost Breakdown • Flooring • Concrete: $5,000-$7,000 • Blower • $3,000-$5,000 • Piping • 120 feet @ $10 per foot =$1,200 • Mixer • $6,000-$20,000 • Total Costs = $15,200-$33,200
Aerated Bins • Aeration in covered or uncovered bays through porous floor plates or perforated pipes • Size of bays can be changed • Large number of bays may be needed for continuous processing • Compost 3-4 weeks • Equipment • Front end loader • Blowers
Aerated Bins • Advantages • Easy in-and-out rotational system • Compact • Rectangular piles in bins for simple loading, unloading • Disadvantages • Expensive construction • Anaerobic areas can develop
Aerated Bins Cost Breakdown • Flooring • Concrete: $5,000-$7,000 • Elevated Flooring • $4,500 • Blower • $3,000-$5,000 • Piping • 120 feet @ $10 per foot =$1,200 • Mixer • $6,000-$20,000 • Total Costs = $19,700-$37,700
In-Vessel Systems • Varied technology for volume of waste stream • Often modular systems, more containers or “boxes” can be added to expand systems • Careful process monitoring and control possible • Mixing occurs with fixed augers or agitated beds • Aeration forced • Systems insulated to retain heat • Employ leachate capture and management (moisture recycle)
In-Vessel Systems • Advantages • Close process control • Low labor, highly automated • Disadvantages • Require extensive screening/shredding before process begins • Very expensive • Loading and Screening equipment cost • Still require curing • Not recommended for mortalities composting
B W Organics • We make the following proposal for your food, manure, and wood shavings up to 4 cubic yards per day. To make an excellent bedding for dairy cows. • One Model 405 B W Organics composter, portable, w/1/3 hp drive unit $ 39,400.00 • One Model 910 U-trough screw loading conveyor $ 3,450.00 • One Model 101 mixer $ 8,950.00 • One Single phase electrical control panel $ 650.00 • Total equipment package fob Sulphur Springs, Texas $ 52,550.00 • Delivery and installation to Idaho $ 3,500.00 • Total $ 56,050.00 • Note: Customer to furnish single phase service to the control panel • Note: We would suggest some type roof structure cover approx. 20 ft by 40 ft to protect system and waste materials from rain, snow, and bitter north wind. • Note: Terms: 50% down with order, balance upon delivery
GREEN MOUNTAIN TECHNOLOGIES- EARTH TUB • Earth Tub System package for University capacity would cost about $38,000 • Would consist of 3 separate units
BIOSYSTEM SOLUTIONS • $300-350K • Includes: Grinder (Mixer), Biochamber, Computers to automate • Pros: Possible partnership, Shared PR, Research center to reduce cost- $150-175K • Not all up front • Cons: Doesn’t include site costs
Recommended System • Choice: Aerated Static Pile/Bin • Initial Costs are the most manageable • System will incorporate both food waste • and animal carcasses • Smaller foot print • Expandable
Competitive Analysis: Flooring Steel Decking Cost: Free, provided Concrete Cost: $5,000-7,000 • Positives: • Affordable • Easy to install • Can be installed without • outside help • Negatives: • Possible Drainage Issues • Life Span • Flexible • Positives: • Long Life Span • Ridged construction • Pipe/Drainage Control • Aesthetics • Negatives: • Cost • Labor Intensive
Competitive Analysis: Flooring Asphalt Cost: $2000 Gravel Cost: $500-750 • Positives: • Long Life Span • Pipe/Drainage Control • Negatives: • Cost • Flexible • Positives: • Inexpensive • Negatives: • Shorter life span • Sorting Problems • Possible Drainage Problems
Competitive Analysis: Blower One Blower Cost: 3,000-5,000 Multiple Cost: 3,000-5,000 • Positives: • Fewer Moving Parts • Simpler Filter Design • Negatives: • Cost • If it breaks down, • the whole operation stops • Positives: • Simpler Control Scheme • Energy Saving • Easy to Expand • Negatives: • Control Difficulty • Increase Housing Cost • Complication of Filter
Competitive Analysis: Control Manual Cost: None/Time Automatic Cost: <$1,000 • Positives: • Cost • Less Power Requirements • Negatives: • Increased Labor • Increased Composting Time • Limited Control • Positives: • Less Management • Faster Compost Time • Negatives: • Cost • Increase Operator Knowledge
Recommended Components • Surface: Asphalt • Cost: $2000 • Blower: Single • Cost: $5,000 • Control System: Automatic • Cost: $1,000 • Walls: Eco-Blocks • Cost: Free; $35 a block • Piping: Industrial Grade PVC • Cost: $10/foot • Mixer (Used) • Cost: $6,221 • Total: $15,421
Finalize Conceptual Design (Dec. 4) Interim design report (Dec. 11) Testing (January) C/N ratio Moisture Content Density Material Acquisition (February) Build conceptual design (March) Testing components of design (April) Future Schedule
References • Leege, Philip B. and Thompson, Wayne H.1997. Test Methods for the Examination of Composting and Compost. 1st Edition. Bethesda, MD. The US Composting Council. • Haug, Roger T. 1993. The Practical Handbook of Compost Engineering. 2nd Edition. Lewis Publishers. Boca Raton, FL. • Recycled Organics Unit. 2007. Food Organics Processing Options for New South Wales. 2nd Edition. University of New South Wales. Sydney, Australia.
References • Washington State University. October 2000. Compost Systems. Available at: http://organic.tfrec.wsu.edu/compost/ImagesWeb/CompSys.html#anchor21101. Accessed 20 October 2009. • Renewable Carbon Management, LLC. Available at: http://composter.com/. Accessed 20 October 2009. • Green mountain Technologies. In-Vessel Systems. Available at: http://www.compostingtechnology.com/. Accessed 20 October 2009.