Transcript Results of the Modesto Compost Emissions Study

Compost Air Emissions
Association of Compost Producers
Dec. 2, 2010
This Presentation
1. CalRecycle commitment to composting
2. Past CalRecycle emissions studies
3. Current CalRecycle emissions studies
4. Compost and climate change
5. Title 1, Title 5 and fugitive emissions
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The Hierarchy
CA Public Resources Code Section 40051
State and local government SHALL
promote the following waste
management practices in order of
priority:
(1) Source reduction.
(2) Recycling and composting.
(3) Environmentally safe transformation and
environmentally safe land disposal…
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Massive investment
Private
Private
Public
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CIWMB Strategic Directive 6.1
Reduce organics sent to the landfill by 50% by
2020
Compostable
organics
Everything
else
Materials
still going to
California
landfills
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CalRecycle proactive efforts
• 20 years of support for composting
• Fund basic research on compost
use and compost emissions
• Work with stakeholders to
determine reasonable best
management practices
• Work with other regulators to
foster efficient, effective
rulemaking
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Studying Compost Emissions
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2002 CIWMB Study
Tierra Verde Industries, Irvine, CA
 High C:N windrow (67:1) emitted 63% less
VOC than low C:N ratio windrow (22:1)
 Turned windrows emitted more VOC than
static windrows, but matured faster
 Ammonia not a concern in green waste
compost operations
2006 CIWMB Study
City of Modesto Compost Facility
 Measure life-cycle (60 days) VOC
emissions for greenwaste and food
waste windrows
 Test efficacy of two potential emissionsreducing practices (BMPs)
– Additives: one feeds microbes; other forms
crust on windrow (Cost: $1.50 per ton)
– Pseudo-biofilter: Cover “active” windrows with a
layer of finished compost (60 cents per ton)
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Windrows
as seen
from above
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Putting on the
“pseudobiofilter”
compost cap
Modesto study conclusions
 70-80% of VOCs emitted during first two
weeks of composting
 70-85% of VOC emissions vent through top
of windrows as opposed to middle or sides
 “Pseudo-biofilter” compost cap reduced VOC
emissions up to 75% for first two weeks.
 Additives reduced VOC emissions 42% for
first week; 14% for first two weeks.
 Greenwaste emissions factor @ 1 lb/ton
 15% food waste roughly doubled emissions
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Wide range of
greenwaste emissions factors
Zamora Greenwaste
Grover (some food?)
Jepson Greenwaste
SJV - Draft EF
South Coast Avg.
Modesto Greenwaste
0
12
5
10
15
20
Pounds of VOC per ton feedstock
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Food waste likely to
increase emissions?
Modesto 15% Food
Jepson - Micropor 45-day
Jepson - Micropor 30-day
Grover (some food?)
Jepson - Compostex
Jepson - Ag Bag
Zamora - Grape Pomace
0
13
10
20
30
40
50
60
Pounds of VOC per ton feedstock
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2009-10 CalRecycle-led study
4 Locations in the San Joaquin Valley
 Not all VOCs make ozone; reactivity
strongly impacts ozone formation
 Focus on types of VOC and ozone
formation, instead of how much total VOC
 Compost emissions mostly alcohols, very
weak ozone formation in all samples
 3-week old windrows slightly more potent
than young windrows
 Compost cap made of “overs” reduces
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ozone formation
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Overall reactivity
very low
More Reactive VOCs
Less Reactive VOCs
100%
6.4%
4.1%
9.8%
90%
80%
70%
60%
50%
93.6%
40%
95.9%
90.2%
30%
20%
10%
0%
Tipping Pile
3-6 day windrow
2-3 week windrow
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6
Comparative reactivity of
different VOC sources
Low Range
High Range
5
4
3
2
1
0
17Compost
Overs
Compost
Windrows
Dairy Cow
Manure
Dairy Cow
Silage
Light Duty
Vehicles
Urban VOC
Mix
Pinene
isomers
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Compost & Climate change
 Organics in landfills release methane
 Methane (CH4): GHG Factor 21
 Synthetic N fertilizers used in farming
made from fossil fuels, release N2O
 Compost piles also release methane and
probably release N2O
 Nitrous oxide (N20): GHG Factor 296
 ARB analysis shows very slight GHG
benefit for composting
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CalRecycle GHG Study
 $450,000 contract with UC Davis
 Study plan finalized November, 2010
 Will study CH4 & N2O from piles
 Are there ways to reduce GHG
emissions?
 Will study impacts of compost use in
ag lands, both alone and in
conjunction with synthetic N use
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Increasing compost use…
…may
decrease use of less sustainable methods.
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The Backstory
 Very low thresholds in bad-air
basins for federal “major source”
polluter status
 San Joaquin Valley APCD saying
all new compost facilities will go
through Title 1 New Source Review
 Will composters be subject to Title
5 permitting too?
What is Title I?
 Authorized by federal Clean Air Act
 Known as “New Source Review”
 Applies to new or modified facility with an
increase in 2 lbs. per day of pollutants
 Requires facility to adopt “best available
control technology” (BACT)
 Even after BACT, facilities must purchase
offsets for all emissions over threshold
 VOC offsets run up to $40,000 per ton in
23 SJV; many owned by oil companies
What is Title V?
 Federal permit program, authorized by
Clean Air Act, implemented by local air
pollution control districts
 Monitoring, record-keeping and reporting
requirements
 Fees to apply for, review & revise permit,
and also for annual renewal
 USEPA can inspect, issue fines
 Opportunities for public input
Title V Permits are the same permits used
for oil refineries, chemical factories, etc.
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Fugitive emissions?
 Fugitive emissions cannot “reasonably”
be passed through a “stack, chimney,
vent or functionally equivalent opening”
 Fugitive emissions generally do NOT
count toward a facility’sTitle I or Title V
emissions threshold
 USEPA guidance, but no case law
 CalRecycle position: compost pile
emissions ARE fugitive.
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[email protected]
916-341-6523
http://www.calrecycle.ca.gov/Organics/Air/default.htm
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