Date post: | 16-Dec-2014 |
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And Greenhouse Gases
CO2
CH4
N2OOrganic Waste Management
Compost Pile1 ton Carbon => 3.6 Tons CO2
Carbon-rich organics
Soil-enriching compost
Incineration
CO2
H2O
CO
C
N2O
Anaerobic Decomposition
Carbon/Water to CO2Carbon/Water to CH4
Sequestered Carbon
Palo Alto Composting & CO2
• 21,000 tons/yr (60% water)• 8,400 tons dry, 50% Carbon
• Methane production is negligible • 15,120 tons of CO2
• Biogenic CO2, not counted in “footprint”
• Transportation Concerns: – 1,100 tons additional if trucked to Sunnyvale
then Gilroy– Anthropogenic, counted in “footprint”– Traffic impact; Roadway maintenance
• Carbon Credit prices vary, but center around $20 / metric ton
• Added to costs of trucks, fuel, drivers, & acceptance fees.
What’s 1,100 Tons Worth?
$22,000 / year
1,100 tons = + 0.15%
Landfilled Compostables
tons
tons
tons
Compostables are 29% of Palo Alto’s “black bin” waste.
22,737 Tons of
Modern Landfill Design
Palo Alto Food and Green Waste in Landfill
– 15,934 tons wet (60% water) – 2,692 tons of Carbon (40% of dry is carbon) – 1,346 tons Carbon released in 1st year
• 50% into CO2: 2,424 tons CO2
• 50% into CH4: 50,880 tons CO2 Equivalent
– 1,346 tons Carbon remaining
Palo Alto Landfilled Compostables, after Cap
• 1,346 tons Carbon from food/green waste carryforward• 2,457 tons Carbon from other compostables (based on 45%
carbon in dry weight)
• Total: 3,803 tons carbon• 70% decomposes (2662 tons carbon)
– 85% captured and combusted to CO2
• 8,146 tons of CO2
– 15% escapes capture• 719 tons CO2
• 15,099 tons CO2 Equivalent (methane)
Total GHG Emissions from Landfilled Compostables
• For one year’s waste: – 79,262 tons CO2 Equivalent !
• If diverted and composted:– 18,534 tons CO2
• Full diversion would reduce PA Carbon Footprint by 60,728 tons of CO2e! – 2.7 tons CO2e per ton food/yard waste
• (carbon credit value $54)
Single Family vs MF/C
• Greenwaste Palo Alto Target:– 9000 tons– (comm/mf)– $70/ton +/-
• 13,700 tons still going to landfill– 37,000 tons CO2e
Organics GHG Reduction
• Part of the Zero Waste Plan
• Execution of plan is what matters
• What we do matters more than where
• Attention, Measurement, Reporting, Evaluation, & Improvement
Organics GHG Reduction
#1
Move Aggressively on MF/Commercial Food Waste Collection! (& 3500 tons of leaves & grass)
(‘000s tons CO2e reduction)
Organics GHG Reduction
#2
Implement Residential Food Waste Collection!
(‘000s tons CO2e reduction)
C
Organics GHG Reduction
#3Transform to BioChar/Bioenergy!
• All green bin contents = minus 7,000 tons CO2e
• 50% blackbin compostables = - 4500 tons CO2e
• Wastewater sludge = - 6,000 tons CO2e
CO2
CO2
Organics Management
PassiveCriteria:• lowest cost disposal
• diversion mandates
ActiveCriteria:• Resource recovery• GHG minimization• Long-term cost
?
Organics Management Passive Active
Palo AltoOperation
Multi-cityPartnership
Contracted
Location &Technology
Organics Management
Control
Economiesof Scale
City-Owned
Multi-City
Contracted
Multi-tech Organics Approach
Composting
Digestion
Soils Restoration
Sequestration
Green Energy
Green Bins
Wastewater
Black BinsPyrolysis
Location Possibilities
• Expansion of WWTF• Industrial sites in
Palo Alto• Industrial sites
elsewhere• Energy/GHG
Efficiency tradeoff: – Large scale
operations vs – Local operations
GHGs in Perspective
• Compost just a small piece of the opportunity
• What more important than where.
• Audit, execute, and improve.
• Regional partnership (we are not alone)