1 Opportunities and Challenges in Composting Organic Waste Harold Keener Food, Agricultural and Biological Engineering OARDC/The Ohio State University Wooster, OH 44691 International Symposium on Organic Recycling Akita, Japan. October 5-7, 2004. ISOR2004 OSU/OARDC 2 Composting Process Water Vapor, CO 2 , Heat Microbes Oxygen Fresh Organic Material Stabilized Organic Residue 25-75 % less volume Science of Composting
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Keener ISOR2004 Japan 10-5-04 Composting2 · 1 Opportunities and Challenges in Composting Organic Waste Harold Keener Food, Agricultural and Biological Engineering OARDC/The Ohio
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Opportunities and Challenges in Composting Organic Waste
Harold KeenerFood, Agricultural and Biological Engineering
OARDC/The Ohio State UniversityWooster, OH 44691
International Symposium on Organic RecyclingAkita, Japan. October 5-7, 2004.
• Need to lower composting cost. More efficient operations. Static pile versus in-vessel.
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ISOR2004 OSU/OARDC 19
U.S. Livestock and Poultry Manure Production*
*Based on USDA statistics and estimated daily production per animal listed. Total amount far in excess of 1 billion t. Amount of manure collected and land applied or composted unknown.
Agricultural Waste Issues in USA• Land application has lowest cost (however,
concerns over pathogens, air, water quality. • Transportation of liquid manures beyond 10 km
can exceed value of nutrients in manure.• Some new housing/manure management
systems lend themselves to composting manure.• Need to lower composting cost. • Need to find value added markets for compost.
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ISOR2004 OSU/OARDC 21
Location in U.S. Affects Approaches to Composting Manures
South West U.S.
Dry Climate
No amendment needed
Very Large Operations
Midwest and North East
U.S.
Wet Climate
Need to add amendment?
Most < 700 cows
Need to use cover over compost in
winter.
ISOR2004 OSU/OARDC 22
Regulations in the U.S.• Process to further reduce pathogens (PFRP) - know
as US EPA 503 regulations. Enacted for biosolids.≥ 55 C for 3 days in-vessel≥ 55 C , 5 turns, 15 days for windrow
• 2003/2004 studies at OARDC/OSU looked at survival of pathogens in manure during liquid storage or composting.– E.coli survival (rough type), E.coli survival (smooth
Controlling Odor, Complying with Clean Air and Water Act
• Use biofilters, acid scrubbers on compost operations control odor, emissions.
• Manage feedstock C/N to reduce ammonia loss.• Managing airflow to control ammonia.• Manage runoff from compost site.• Developing new livestock facilities:
– Manure Belt/Composting Systems for poultry– High Rise Hog Facility
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ISOR2004 OSU/OARDC 29
Using a Biofilter to Manage Odors
50,000 t/y of raw 50,000 t/y of raw materials :materials :
Yard, agricultural, and Yard, agricultural, and food wastesfood wastes
BiofilterBiofilter on exhaust airon exhaust air
New Milford Farms, Inc./Nestlé USA, Inc.
ISOR2004 OSU/OARDC 30
Increasing C/N Reduces NH3 Losses
y = -0.0089x + 0.5712= 0.5872
0%
10%
20%
30%
40%
20 30 40 50 60 70Initial CN ratio
N loss (% of initial)
N-Losses during composting dairy manure(% lost of initial amount)
Intermittent Aeration Run 173-99 Swine/Sawdust Mixture
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0
VFA
Em
issi
ons
(mg)
A c e tic A c id
Pr o p io n ic A c id
Is o b u ty r ic A c id
B u ty r ic A c id
Is o v a le r ic A c id
V a le r ic A c id
Continuous Aeration Run 173-99 Swine/Sawdust Mixture
ISOR2004 OSU/OARDC 32
Rainfall Runoff From Compost Windrows
• Pad size – 20,000 sq. ft. concrete, 1-2 % slope• Woodchip filter, lower end • 3 cell wetland to treat runoff 25 year storm
OARDC Compost Pad
Environmental Studies
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ISOR2004 OSU/OARDC 33
Cumulative Runoff Volume Comparison Row 2
0
50
100
150
200
250
300
350
400
450
500
0 50 100 150 200
Time (minutes) from start of storm
Lite
rs
Day 1 start collectat 23.13 min
Day 15 start collectat 21.15 min
Day 29 start collectat 17.13 min
Start moisture 53.2%
Start moisture 67.3%
Start Moisture47.7%
Ammonia
0.00.20.40.60.81.01.21.41.61.82.0
0 100 200 300 400 500
Cumulative Runoff (liters)
Gra
ms
Cum
ulat
ive
Day 1
Day 15
Day 29
Rainfall Simulator
Collection of Runoff
Wilkinson et al, 2004
Environmental Studies
ISOR2004 OSU/OARDC 34
One million birds use system at DayLay Farms. Manure dries on belt from 70% to 50-55% moisture. Manure goes to compost building.
Manure Belt System with Composting for Poultry
New Technology
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ISOR2004 OSU/OARDC 35
New Technology
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
2.000
N-Balance Poultry Systems
Manure
NH3-N @LH
Egg
lb N
/bir
d-ye
ar
Belt/Composting Deep Pit
NH3-N
NH3-N
NH3 losses cut in half compared to conventional deep pit.
Composted material has 10-20% moisture, granular nature
Compost building and turning machines at DayLay Farms. Two buildings have 12 lanes and one has 6 lanes with one turning machine per 6 lanes.
ISOR2004 OSU/OARDC 36
High-RiseTM Hog Building
Inlet 1
Inlet 2
Outlet
New Technology
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ISOR2004 OSU/OARDC 37
Material being windrow composted.
New Technology
Manure moved out of building. Moisture of manure/drying bed material was 65% wb.
ISOR2004 OSU/OARDC 38
Static Pile Composting of Yard Trimmings (PTI, Seattle, Washington)
Compost Systems
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ISOR2004 OSU/OARDC 39
Static Pile Composting of Yard Trimmings(Price Barnes, Delaware, Ohio)
Compost Systems
ISOR2004 OSU/OARDC 40
Windrow after grinding 65 carcasses6-12 in
12 in12 in
15 ft
8ft
Schematic of composting windrow (intact carcass)
2-3' thermometer
Rule of Thumb:• 250'x250' pad will hold
five 15'x200' windrows• 1 windrow will hold ~100
finishing cattleClean sawdust cover
Soiled amendment or used compost
carcass
Grass filtration strips around the perimeterSoil
Lime base
Static Pile Composting of Dead Animalsas an Alternative to Rendering
John Kube, Elanco Animal Health, Greenfield, IN
Compost Systems
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ISOR2004 OSU/OARDC 41
Schematic of Turned Windrow Composting Dimensions: width 3-6m, height 1-3m
Compost Systems
ISOR2004 OSU/OARDC 42
Turned Windrow Composting of Dairy Manure & Sawdust.
(Sigrist Farms, Ohio)
Using a skid loader to turn manure. The farm has a
turning machine but seldom uses it.
Compost Systems
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ISOR2004 OSU/OARDC 43
Sigrist Farms finds screening is essential for marketing a quality
product. Market as a bagged product (about 18 kg per bag) as
Bull Country Compost.
Compost is stored under roof for curing, approximately 6 months. Material is then bagged for marketing.
Compost Systems
Sigrist Farms, Ohio
ISOR2004 OSU/OARDC 44
Turned Windrow Composting of Cattle Manure and Yard Trimmings(Dan Young Farm, Ohio)
Dan Young speaking to a group of farmers, agricultural specialists, university persons at August field day.
Compost turner and water are added to tank. Water addition is
often necessary early in the process if starting with materials
less than 60% moisture.
Compost Systems
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ISOR2004 OSU/OARDC 45
Fleece cover is used to shed rainfall from finished compost (important in wet climate) since finished compost has little activity to evaporate moisture. Cover will last over 5 years.
Product is marketed in mini bulk bags as well as
truckloads. Suburban customers enjoy mini bulk bags are delivered with no
mess in the driveway. Bags have a refundable deposit.
Compost SystemsDan Young Farm, Ohio.
ISOR2004 OSU/OARDC 46
Forced Aerated Windrow Compost Systems
Perforated pipes distribute air in compost. Hole spacing is a function of length, pipe diameter and depth of compost. Maximumlength is 22-30 m. Air can be pushed or pulled through the pile.
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ISOR2004 OSU/OARDC 47
Aerated Static Pile for Composting Biosolids and Woodchips.
(Columbus, Ohio, 1994)
Compost Systems
Elwell et al., 1994
Wedge-shaped approach with air pushed through the pile.
ISOR2004 OSU/OARDC 48
Aerated Static Pile for Composting Biosolids and Woodchips
(Columbus, Ohio, 2004)
Compost Systems
Biofilter
J. Hoff, 2004
Wedge shaped approach with air pulled through the pile then pushed through a biofilter.
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ISOR2004 OSU/OARDC 49
“Ag Bag” used for yard and food waste in California.
Operators claim it is effective in a dryer climate.
Compost Systems
Aerated static pile for composting biosolids/ woodchips in “Ag Bag”did not prove effective in Ohio’s high humidity climate.
ISOR2004 OSU/OARDC 50
Aerated Turned Windrows. (DayLay Farms, Ohio)
Compost Systems
Unamended poultry manure is composted in the first 45 m of the windrow and turned 18 times during the 54-day process.
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ISOR2004 OSU/OARDC 51
In-Vessel Forced Aeration System(Paygro, Ohio)
Compost Systems
Composting of cattle manure and food and yard wastes is completed in 21-28 days.
ISOR2004 OSU/OARDC 52
In-Vessel Composting(Akron, Ohio)
Compost Systems
Biosolids, sawdust, woodchips and yard waste are composted in an aerated system with turning in 21-28 days.
Study on mixture of paper mill sludge (PS) and broiler litter (BL) with C/N = 32. Gaussian function used to describe relationship.
Optimization of the Process
ISOR2004 OSU/OARDC 62
Airflow Requirements Control Temperature
Q o Mo khcHAO HAI
e ka
( ) ( )[ ]
θ βρ
θθ= −−
−⎡
⎣⎢⎤
⎦⎥−1
Optimization of the Process
For this equation, decomposition rate, compost equilibrium, heat of decomposition, air density, enthalpy of air (temperature, moisture), and compost maturity are the identified factors.
Keener, et al., 2002d
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ISOR2004 OSU/OARDC 63
1 m3/ (kgco day) = 22.3 cfm/ (tonco)
Airflow Requirements Control Temperature
Case Study
ISOR2004 OSU/OARDC 64
Systems Optimization
Refer to references in paper:Keener, H.M. 2004. Opportunities and Challenges in Composting Organic Waste. ISOR2004 Conference Proceedings. Akita
a) Compost maturity, i.e. reduction in organic matter, must be specified when calculating system efficiency as system cost increases significantly for higher levels of maturity.
b) Optimum C/N for composting two or more products depends on decomposition rate as a function of C/N and bulk densities of materials.
c) Optimum moisture varies with material. For example: dairy/sawdust vs biosolids/woodchips/recycle
65% vs 55%.
ISOR2004 OSU/OARDC 66
Observations from Field and Computer Studies (continued)
d) An ash/inert free moisture should be used to formulate mixes with high ash or inert content.
e) Facilities fixed cost can be minimized by: 1) minimizing bulking agent; 2) minimizing the number of aisles and alleys at the
f) Using two-stage composting reduces cost, eg. 14-28 days stage 1 & stage 2 composting/curing.
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ISOR2004 OSU/OARDC 67
Observations from Field and Computer Studies
g) Composting rate is maximum from 55-60 oCtemperature and follows a Gaussian curve.
h) Selecting fan size to compost initially at temperatures 5-10 oC above the optimum, although slowing the process initially, can be a cost effective approach to minimize fan size, and power consumption, while minimally delaying maturity.
ISOR2004 OSU/OARDC 68
Observations from Field and Computer Studies
i) Sharing fans across windrows of different maturities reduces fixed and operating costs.
j) Water loss per unit dry matter loss is approximately 2/3 of the theoretical value for continuous aeration.
k) The highest rates of sustained water loss occur using continuous aeration.
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ISOR2004 OSU/OARDC 69
Observations from Field and Computer Studies
l) Ammonia loss is proportional to airflow in the initial phase of composting.
m) VOCs disappear rapidly after start of aerobic process (if pH not inhibiting).
ISOR2004 OSU/OARDC 70
Using Compost for Growing Plants
Harry A. J. Hoitink
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ISOR2004 OSU/OARDC 71
Examples of Compost Examples of Compost PhytotoxicityPhytotoxicity ProblemsProblems
1.1. Fermentation acids, etc. in immature high C/N Fermentation acids, etc. in immature high C/N materials (materials (egeg. Sour bark, sweet or sour smell). . Sour bark, sweet or sour smell).
Satisfactory if soil is Below 2Satisfactory if soil is Below 2 0.15 to 0.500.15 to 0.50high in organic matter,high in organic matter,but too low if soil isbut too low if soil islow in organic matter.low in organic matter.
Satisfactory range forSatisfactory range for 3 to 43 to 4 0.50 to 1.800.50 to 1.80established plants, butestablished plants, butupper range may be tooupper range may be toohigh for some seedlings.high for some seedlings.
Slightly higher thanSlightly higher than 4 to 84 to 8 1.80 to 2.251.80 to 2.25desirable. desirable.
Compost Utilization
ISOR2004 OSU/OARDC 76
Organic matter must be decomposed Organic matter must be decomposed
-- RecolonizationRecolonization by microbes after peak heatingby microbes after peak heating
-- Chemical and physical factorsChemical and physical factors
Compost Utilization
ISOR2004 OSU/OARDC 82
Each temperature zone in a compost pile has its own characteristic microflora. During curing, high temperature microorganisms are replaced by lower temperature soil microorganisms, some of which control Phytophthoraand Pythium root rots.
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ISOR2004 OSU/OARDC 83Spring et al., 1980, Phytopathology 70:1209-1212
Peat mix Compost Mix
This Phytophthora root rot bioassay helped prove that natural suppression in compost mixes is effective.
Compost Utilization
ISOR2004 OSU/OARDC 84
Natural lysis (destruction) ofPhytophthora sporangia in a composted bark potting mix
20 uM
Compost Utilization
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ISOR2004 OSU/OARDC 85
NATURAL SUPPRESSIONBlending materials for disease suppressive potting mix.
Silica Sand/Expanded Shale 5 - 10%
Aged Pine Bark 60 - 65%
Fibrous Sphagnum Peat 15%
Composted Biosolids 8 - 12%
Compost Utilization
ISOR2004 OSU/OARDC 86
Suppressive potting mix used to control root diseases in potted poinsettia plants.
HAJ Hoitink
New Uses for Compost.
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ISOR2004 OSU/OARDC 87
Seven-yr-old Taxus crop transplanted at 1-1.5 yr intervals to sustain natural suppression of root rot. Fungicides are not used in spite of its extreme susceptibilty to Phytophthora root rot!!!!
20 gal pots
Compost Utilization
ISOR2004 OSU/OARDC 88
Pot–in-pot systems allow naturalsuppression to be used to produce root disease free trees.
Compost Utilization
45
ISOR2004 OSU/OARDC 89
Rhododendrons in naturally suppressive compost amended mix
ISOR2004 OSU/OARDC 90
Rhizoctonia web blight in a mix suppressive
to Phytophthora root rot
What about other diseases?Compost Utilization
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ISOR2004 OSU/OARDC 91
Why was Why was RhizoctoniaRhizoctonia not suppressed in the not suppressed in the mix that controlled Phytophthora?mix that controlled Phytophthora?
•• RhizoctoniaRhizoctonia isis a very common pathogen in soil a very common pathogen in soil that produces large 1that produces large 1--2 mm diameter structures. 2 mm diameter structures.
•• Such large pathogens are not suppressed by Such large pathogens are not suppressed by bacteria that commonly colonize composts and bacteria that commonly colonize composts and control control PhytophthoraPhytophthora..
•• Specific Specific biocontrolbiocontrol agents that naturally agents that naturally suppress suppress RhizoctoniaRhizoctonia do not consistently do not consistently colonize composts after peak heating! colonize composts after peak heating!
ISOR2004 OSU/OARDC 92
Suppression of Suppression of RhizoctoniaRhizoctonia
More than 80% of 300 different compost-amended potting mixes tested failed to suppress Rhizoctonia damping-off because specific biocontrol agents failed to colonize the compost naturally!!
The solution is to inoculate potting mixes during formulation with biocontrol agents (egTrichoderma spp.) that destroy Rhizoctonia.
•• Less than 2% of all types and batches of Less than 2% of all types and batches of composts tested naturally induced ISR. composts tested naturally induced ISR.
•• Specific Specific BacillusBacillus strains and strains and TrichodermaTrichodermaisolates are the most ISRisolates are the most ISR--active active microorganisms in composts.microorganisms in composts.
Krause et al, 2003, Phytopathology 93:1292-1300.
ISOR2004 OSU/OARDC 94Zhang et al., 1998, Phytopath. 88:450-455
Compost-Induced Systemic Resistance (ISR)
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ISOR2004 OSU/OARDC 95
Horst et al., 2003 Phytopathology 93: S37
ISOR2004 OSU/OARDC 96
•• ISR induced by T382 is more effective in ISR induced by T382 is more effective in compostcompost--amended than in peat potting amended than in peat potting mixes. mixes.
•• The same has been reported for control of The same has been reported for control of FusariumFusarium crown rot of tomato and for crown rot of tomato and for PhytophthoraPhytophthora blight of cucumber.blight of cucumber.
•Pharand et al, 2002, Phytopathol. 92:424-438•Khan et al, 2004, Plant Dis. In Press.
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ISOR2004 OSU/OARDC 97
Can ISR be scaled up commercially??Can ISR be scaled up commercially??
Examples:Examples:•• Phytophthora blight on RhododendronPhytophthora blight on Rhododendron
•• Leaf spot on RhododendronLeaf spot on Rhododendron
•• BotryosphaeriaBotryosphaeria on on M. M. pennsylvanicapennsylvanica
•• FusariumFusarium wilt of Cyclamenwilt of Cyclamen
•• Anthracnose of Anthracnose of EuonymousEuonymous
•• All plants treated 5x with All plants treated 5x with AlietteAliette and 3x with and 3x with Subdue from May 15Subdue from May 15-- Sept. 15Sept. 15
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ISOR2004 OSU/OARDC 99
T382 Control T382
ISOR2004 OSU/OARDC 100
Control T382
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ISOR2004 OSU/OARDC 101
p=0.002p= 0.05
1.31.15.16.3T382 b4.44.211.816.9Control
Std.Dev.MeanStd.Dev.MeanTreatment
Plants Killed (%)Dieback (%)Disease Severity a
Suppression of Phytophthora Dieback on Suppression of Phytophthora Dieback on Rhododendron Rhododendron cvcv English English RoseumRoseum induced by induced by
•• ISRISR--active microorganisms must be active microorganisms must be introduced into composts for consistent introduced into composts for consistent efficacy.efficacy.
•• Substrate matters! Substrate matters! PyrolyzedPyrolyzed or very old or very old composts do not support ISR!composts do not support ISR!
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ISOR2004 OSU/OARDC 103
Example of Pyrolyzed or very old composts which would not support ISR!
ISOR2004 OSU/OARDC 104
Overall ConclusionsOverall Conclusions•• Compost stability, nitrogen status and the presence of Compost stability, nitrogen status and the presence of
phytotoxicphytotoxic compounds are important indicators of compounds are important indicators of compost quality for valuecompost quality for value--added markets.added markets.
•• The highest value markets require quality composts and The highest value markets require quality composts and expert knowledge of potting mix formulations and expert knowledge of potting mix formulations and production technology to produce diseases suppressive production technology to produce diseases suppressive mixes.mixes.–– Biological control of root diseases with composts by Biological control of root diseases with composts by
natural suppression is practiced widely. natural suppression is practiced widely. –– Specific suppression requires inoculation.Specific suppression requires inoculation.–– Some foliar diseases controllable by ISRSome foliar diseases controllable by ISR--active active
composts. composts. –– ISR still is a novel field of science.ISR still is a novel field of science.