Large Scale Operations
Presentation 8:
The Composting Toolkit
Funded by the Indiana
Department of
Environmental
Management Recycling
Grants Program
Developed by the Indiana
Rural Community
Assistance Program RCAP
Large Scale Operations
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This section will help you to implement the
composting techniques discussed in the earlier
section on aerobic composting
This section will help you identify the key
steps to a large scale operation
This section will help you identify appropriate
equipment and appropriately sized equipment
Important Questions
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What will you do with the finished product?
How much yard waste is available for you to
compost?
How much yard waste can you expect to divert?
Will you utilize only yard waste or also food waste
and/or biosolids?
Will it be cost effective?
What resources are currently available?
What type of program will you implement?
How are you going to finance the program?
Key Steps
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Collection
Particle size reduction
Initial material screening (Front-end)
Composting
Regular turning
Finished product screening (Back-end)
Sections Within This Chapter
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Composting Operations Equipment
Start-up Considerations
Ongoing Operations are covered in the next
chapter . . .
Composting Operation
Equipment
Equipment
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Many of the pieces of equipment discussed in the
“woody waste” management presentation are also
useful for composting operations
Size Reduction Equipment:
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Moving Materials / Turning Materials:
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Loader
Dedicated Turning Equipment:
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Chipping and/or Shredding Equipment
Windrow Turner
Sorting Equipment:
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Screens
Size Reduction Equipment
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Size reduction is one of the first critical steps
in the composting process.
An optimal particle size is 1 to 3 inches.
The key is maximizing surface area. Sufficient
surface area will give the microbes that
perform the composting a place to complete
their work.
Shredding Verses Chipping
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The two primary ways size reduction is
accomplished is shredding or chipping
Shredding:
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Shredders grind the waste by employing a hammer
mill to pound trees into shreds.
Chipping:
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Chippers use sharpened knives on a disc or a drum
to make dimensional chips
Shredding Verses Chipping
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The two primary ways size reduction is accomplished is shredding or
chipping
Shredding:
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The primary advantage of shredding is that is maximizes surface area which is
optimal for composting. Shredding equipment is also able to handle some
contamination from dirt and rocks.
The primary disadvantage of shredding is cost. The equipment to shred is
usually much larger than chipping equipment and is significantly more expense
to purchase and maintain.
Chipping:
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The primary advantage of chipping is that the equipment is smaller, multipurpose, faster, and less expensive.
The primary disadvantages to chipping is that the composting process will take
longer because the chips provide significantly less surface area than shredding
equipment. A chipper is unable to tolerate contamination from dirt and debris.
Chippers
Variations with Chippers
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Disc-style chippers are much more common than
drum-style chippers.
The disc-style is at this time the “industry standard”
However, at this time there are new developments
being made in the drum-style arena. Drums have
great promise because they are more compact, yet
they can have a larger-diameter opening for feeding
materials into the chipper.
Variations with Shredders:
Tub Grinders
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Tub grinders have long been the industry standard in
shredding equipment.
Tub grinders have an opening on the top. Materials
must be dropped in and rely on gravity to feed the
hammer mills.
The primary advantage of a tub grinder is it tends to
be faster than other shredders with woody wastes.
The primary disadvantage of tub grinders is they tend
to “throw-out” materials which is hazardous to
operators as much as within 300 feet of the machine.
Shredders: Tub Grinders
Variations on Shredders:
Horizontal Grinders
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Horizontal grinders pull in materials to be
processed via a conveyor belt of chain track
which feed materials to be shredded into the
hammer mill.
Horizontal grinders do not have the tub
grinders tendency to “throw-out” materials
Shredders: Horizontal Grinders
Size Matters
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To increase capacity and production, new grinders are getting
heavier, with bigger hammer mills. The largest models now
approximate the size and weight of a railroad freight car and
cost well over half a million dollars.
Smaller tub-grinders weigh around 80,000 pounds. Larger
tub-grinders weigh over 110,000 pounds. Horizontal grinders
often weigh approximately 100,000 pounds.
The lighter the machine, the more you will sacrifice longevity
The thickness of steel determines how soon the machine will
require welding to remain in one piece. Extra weight reduces
vibrations in turn reducing wear and tear.
Variations with Shredders:
Stump Grinders
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These are specialized machines designed
specifically to pulverize tree stumps in place
down to a specific depth.
It is easier to pulverize a stump in the ground
than to pull it out and grind it.
This would more commonly be used in on-site
wood waste management than in composting
operations separate from where the woody
waste is generated.
Loaders
Loaders
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The front-end loader is the single most
important piece of equipment for large scale
composting facilities.
It may be the only piece of equipment needed
for operations for smaller communities.
The loader moves materials around the site and
can be used as the turning equipment for
windrows as well.
Windrow Turner
Windrow Turners
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Windrow turners are designed specifically to turn and
aerate compost in a windrow.
There are both self-propelled models and models that
require a tractor to pull them.
The advantage of windrow turners is they thoroughly
turn and mix materials and do so more quickly than
front end loaders can.
This superior mixing produces a superior compost
product.
Their primary disadvantage is the added cost of
purchasing an additional piece of equipment for a
composting operation.
Screens
Screens
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Plastic, cloth, wire mesh, deck (flat), disc,
grizzly, orbital, star, and trommel screen. The
many varieties of screens.
Screening
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Large scale composting facilities will nearly always
employ some form of screening.
If your facility plans to SELL finished compost a
screen is essential. When paying for the finished
compost, people demand a quality of finished product
that simply can’t be obtained without screening.
If a community has strong controls on the front end of
their process such as strong litter control, strong
compliance on not allowing plastic bags, then the
community may be able to get by without a screen if
the end product is given away.
Screening
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Removal of contamination
Proper sizing of starting and finished product
Material passing through a screen is generally
referred to as “undersize”
Material that remains on the screen surface is
generally referred to as “oversize”
Cost Effectiveness of
Windrow Composting
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That equipment looks expensive! I thought
you said this was cost effective!
First, compare these to the costs of landfill
equipment or MRF equipment.
Second, select equipment appropriate to your
size operation.
Third, form partnerships!
Form Partnerships
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Bartholomew County SWMD contracts with a
private contractor who provides tub grinder
services. The District pays an hourly rate for the
equipment. The contractor maintains the
equipment and Bartholomew is simply one of
many clients for the contractor.
Northeast Indiana SWMD owns a tub grinder and
uses it at five composting sites over a four county
area.
Start-up Considerations
Start-up Considerations
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Facility Location
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Facility Type
Site Characteristics
Customer Access
Collection Options
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Drop-off
Curbside
Out-of-system Users
Operational Considerations
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Hours of Operation
Staffing
Equipment
Site Requirements
Fee Schedule
Program Budget
Site Layout
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Office
Drop-off Area
Chipping/Shredding Area
Mulch / Woody Waste Storage Area
Composting Area
Screening Area
Equipment Service and Storage Area
Operation Plan and Procedures
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Composting Registration
Site and Traffic Plan
Administrative Procedures
Safety Procedures
Materials Processing Procedures
Testing Requirements
Maintenance Procedures
Marketing Plan
Example Site Layout
Compost Facility Registration
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Compost facilities that process more than
2,000 pounds of vegetative matter during a
year are required to register with IDEM.
Registered facilities must then submit an
annual report to IDEM in regard to the volume
of materials processed in the previous year.
Registration is valid for five years and may be
renewed.
Compost Facility Registration
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The registration must include the following components:
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A registered Indiana compost facility may not:
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A legal description of the site
A topographic map of the site
A description of the composting facility and who it will serve
An estimate of the yearly volume to be processed
Be located within 200 feet of a potable water supply
Be located within 200 feet of a existing residential structure
Be located within a 10-year floodplain
A registered Indiana composting facility must:
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Keep compost five feet from the water table
Manage leachate and runoff generated by the compost site
Control dust, odor, and noise
White Papers
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Don’t reinvent the wheel (or the compost pile in this
case)
Composting tool-kit white paper topics include:
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Facility Siting Guidelines
“How to” for Navigating Compost Facility Registration
Process
Start-up and operation logistics recommendations
Guidelines for identifying appropriately sized equipment
QUESTIONS?
Thank You!
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Additional Questions, Comments, or You
Think You Have A Potential Pilot Community
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Please Feel Free to Contact Me:
Mark W. Davis
Technical Assistance Provider
Rural Community Assistance Program
Office: 1-800-382-9895
Wireless: (812) 320-0720
E-mail: mdavis@incap.org