Transcript Smaller-scale Manure Composting Strategies

Composting Systems: An
Overview
Michael Massey
Horse Manure Mgmt., Spring 2007
February 1, 2007
Composting Systems?
• Theory is nice, but how do you do it?
• Each system is site-specific
• Your system is “engineered” to fit
your situation
• Different types involve tradeoffs
between numerous factors such as
management requirements, cost, and
performance
Factors to Consider
•
•
•
•
•
•
•
•
Number of horses (amount of manure)
Bedding volume/type
Space limitations, equipment size
Local climate (rainy? Semi-arid like CO?)
Budget (initial and operating costs)
Labor and management requirements
Neighbors, odor issues, local regulations
Water quality (keep away from streams, etc.)
Common Ways to Compost
Dynamically Aerated Windrows
Source: www.columbiapa.net, used without
permission
Dynamic Composting
• Refer to fact sheet for
full instructions
• Used most often for
larger scale, but can be
done at any scale
• Monitor temperature,
turn when it cools off
• Turning aerates pile,
mixes compost
• Check moisture!
Add New Material to One End
Dynamic Composting Advantages
• Temperature and
moisture control
• Mixing of pile
ensures that all parts
are exposed to high
temperatures
• High temperatures
(140˚F+) can kill
pathogens, weed
seeds
What’s the Catch?
• Dynamic composting requires either
equipment (such as a compost turner,
front end loader, etc.) or a lot of sweat!
• Equipment is expensive to purchase and
maintain, and is not always properly sized
to be practical for smaller operations
• Fuel cost, labor time
Alternative Methods
• Static composting: no
turning, no giant
vehicles
• Vermicomposting: let
worms do (most of)
the work
Source (top): organic.tfrec.wsu.edu, used without permission
Types of Static Composting
• Passive aeration (PA): Air is drawn up into
the compost through “perforated pipes”
at the bottom of the pile
• Forced (“active”) aeration (FA): Air is
pumped in with a fan or blower
• Natural aeration (NA): There is no
method for delivery of air to the compost,
only diffusion from the surrounding air
Drawbacks
Source: Fernandes et al., 1994, used
without permission
• NA can only be used
at 50% or lower
moisture content
• FA costs more to
install and operate
than PA, can dry out
and cool the pile by
over-aeration
• PA has lower
temperatures than FA
and dynamic
(pathogen risk)
Passively Aerated Static
Compost
Source: organic.tfrec.wsu.edu, used without permission
Building a Static Pile
Source: organic.tfrec.wsu.edu, used without permission
How to Build a Static Pile
•
•
•
•
•
•
Porous bottom layer
Evenly spaced perforated pipes
Layers of manure, bedding, etc.
Mulch or finished compost layer on top
See details in extension publication 1.226
For active aeration, attach aeration pipe(s)
to fan or blower (hopefully with timer)
Shopping List for Passively
Aerated Static Composting
• 10 cm (4”) diameter perforated pipes
(PVC or metal) with 0.5-1” holes spaced
6-12” apart, 10’ long
• Screen to cover holes if facing upward
• Wood chips, finished compost, or peat to
make base layer and to cover outside of
pile
Commercial Forced Aeration
Systems
• Small forced aeration
systems available
from O2Compost
• Easier to purchase
than to design and
install on your own
• (I’m not endorsing
the product, I’m just
saying…)
Source (top): www.o2compost.com, (bottom):
organic.tfrec.wsu.edu, used without permission
Vermicomposting in Brief
• Worms (like Eisenia fetida)
are expensive to buy, but
reproduce
• Worm population
requires monitoring and
care (must cover, too)
• Can handle higher C/N
ratio (incl. bedding mix)
• Payoff: Vermicompost
can command a premium
price!
Pathogens in Vermicomposting
• Pathogenic bacteria, etc. may not all be
destroyed when they pass through a
worm’s digestive tract
• Static composting of the material for one
week before adding worms has been
found to destroy pathogens, weed seeds,
etc. more effectively due to heat
• Worms naturally move in when it cools
If you want to try worms…
There are a lot of great resources on
vermicomposting, one of which is CSU
extension publication number 1.224,
“Vermicomposting Horse Manure”.
You Can Use Bins, Too…
• Bins can be used with
any method, with
some modifications
• Must have adequate
bin space to hold the
expected amount of
manure
• Advantages: easy to
cover if needed,
aesthetics
So Which is “Best”?
• Depends on your situation!
• Lowest management requirement: static
composting (esp. passively aerated)
• Best pathogen and weed seed destruction:
dynamic windrows
• Premium price: vermicomposting
• Compromise: actively aerated static
compost (don’t overdo it!)
Keep in Mind…
• The right composting system for you will
depend on how much space, manure and
bedding you have, your goals, budget, how
much time you want to spend managing it
• Climate affects design and management (wet
areas: cover to prevent water logging, dry areas:
add water, prevent evaporation)
• Composting can save you money, and keeps
your manure out of the landfill! Choosing the
right system for your situation is important
Further Reading
Bansal, S. and Kapoor, K.K. 2000. Vermicomposting of Crop Residues and Cattle Dung with Eisenia foetida.
Bioresource Technology 73, 95-98.
Barrington, S., D. Choiniere, M. Trigui, and W. Knight. 2003. Compost Convective Airflow Under Passive Aeration.
Bioresource Technology 86, 259-266.
Card, A.B. J.V. Anderson, and J.G. Davis. 2002. 1.224, Vermicomposting Horse Manure. Colorado State University
Cooperative Extension.
Card, A.B. and J.G. Davis. 2002. 1.225, Composting Horse Manure in Dynamic Windrows. Colorado State University
Cooperative Extension.
Card, A.B. and J.G. Davis. 2002. 1.226, Composting Horse Manure in Static Windrows: Passively Aerated Windrow
Method. Colorado State University Cooperative Extension.
Contreras-Ramos, S.M., E.M. Escamilla-Silva, and L. Dendooven. 2005. Vermicomposting of Biosolids with Cow
Manure and Oat Straw. Biol. Fertil. Soils 41, 190-198.
Davis, J.G. and A.M. Swinker. 1996. 1.219, Horse Manure Management. Colorado State University Cooperative Extension.
Fernandes, L., W. Zhan, N.K. Patni, and P.Y. Jui. 1994. Temperature Distribution and Variation in Passively Aerated
Static Compost Piles. Transactions of the ASAE 48, 257-263.
Larney, F.J., L.J. Yanke, J.J. Miller, and T.A. McAllister. 2003. Fate of Coliform Bacteria in Composted Beef Cattle
Feedlot Manure. Journal of Environmental Quality 32, 1508-1515.
Larney, F.J., A.F. Olson, A.A. Carcamo, and C. Chang. 2000. Physical Changes During Active and Passive Composting
of Beef Feedlot Manure in Winter and Summer. Bioresource Technology 75, 139-148.
Lynch, N.J. and R.S. Cherry. 1996. Design of Passively Aerated Compost Piles: Vertical Air Velocities Between the
Pipes. Biotechnol. Prog. 12, 624-629.
Mitchell, A. 1997. Production of Eisenia Fetida and Vermicompost from Feed-Lot Cattle Manure. Soil Bioogy and
Biochemistry 29, 763-766.
Mote, C.R., B.L. Emerton, J.S. Allison, H.H. Dowlen, and S.P. Oliver. 1988. Survival of Coliform Bacteria in Static
Compost Piles of Dairy Waste Solids Intended for Freestall Bedding. Journal of Dairy Science 71, 1676-1681.
O2Compost forced aeration compost systems. http://www.o2compost.com (accessed Dec 2006).
Sartaj, M., L. Fernandes and N.K. Patni. 1997. Performance of Forced, Passive, and Natural Aeration Methods for
Composting Manure Slurries. Transactions of the ASAE 40, 457-463.