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 TemperatureControl 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

COMPOSTING TECHNOLOGIES

Windrow Composting

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)

Aerated Static Pile

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

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

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

In Vessel Options

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

COMPETITIVE ANALYSIS

Attributes Wind RowsAerated

Static Pile In Vessel Aerated BedInitial Cost 30,000$ 15,441$ 56,050$ 19,700$ Space Requirement High Medium Low MediumSmell High Low Low LowMaintenance Costs Low Medium High MediumWeekly Management High Medium Low MediumAnimal Carcasses No Yes No NoLength of Composting Time (typical) (Days) 60 28 21 21Curing Time 1-2 Months 1-2 Months 2 Months 2 MonthsEnvironmental Control Low Medium High Medium

Alternatives

COMPETITIVE ANALYSIS

Additive Weighting Chart Wind RowsWeighted

ValueAerated Static

Pile Weighted Value In VesselWeighted

Value Aerated BedWeighted

ValueInitial Cost 0.64 0.14 1.00 0.22 0.00 0.00 0.90 0.20Space Requirement 0.00 0.00 0.50 0.10 1.00 0.19 0.50 0.10Smell 0.00 0.00 1.00 0.00 1.00 0.00 1.00 0.00Maintenance Costs 1.00 0.14 0.50 0.07 0.00 0.00 0.50 0.07Weekly Management 0.00 0.00 0.50 0.01 1.00 0.03 0.50 0.01Animal Carcasses 0.00 0.00 1.00 0.11 0.00 0.11 0.00 0.00Length of Composting Time (typical) (Days) 0.00 0.00 0.82 0.14 1.00 0.17 1.00 0.17Curing Time (Days) 1.00 0.08 1.00 0.08 0.00 0.00 0.00 0.00Environmental Control 1.00 0.06 0.50 0.03 0.00 0.00 0.50 0.03

Sum 0.42 0.76 0.39 0.57

Weighted Alternatives

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

Site picture, labels how system sits on site

SYSTEM OPTIONS

Flooring Blower Mixer Control Screener

Steel Decking

One LargerBatch Manual Batch

Concrete Multiple PTO Automatic None

Asphalt None None

Gravel

COMPETITIVE ANALYSIS: FLOORING

Steel DeckingCost: Free, provided

ConcreteCost: $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

AsphaltCost: $2000

GravelCost: $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 BlowerCost: 3,000-5,000

MultipleCost: 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

ManualCost: None/Time

•Positives:•Cost•Less Power Requirements

•Negatives:•Increased Labor•Increased Composting Time•Limited Control

AutomaticCost: <$1,000

•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

Future Schedule

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)

REFERENCES

1. 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.

2. Haug, Roger T. 1993. The Practical Handbook of Compost Engineering. 2nd Edition. Lewis Publishers. Boca Raton, FL.

3. Recycled Organics Unit. 2007. Food Organics Processing Options for New South Wales. 2nd Edition. University of New South Wales. Sydney, Australia.

REFERENCES

4. Washington State University. October 2000. Compost Systems. Available at: http://organic.tfrec.wsu.edu/compost/ImagesWeb/CompSys.html#anchor21101. Accessed 20 October 2009.

5. Renewable Carbon Management, LLC. Available at: http://composter.com/. Accessed 20 October 2009.

6. Green mountain Technologies. In-Vessel Systems. Available at: http://www.compostingtechnology.com/. Accessed 20 October 2009.