The Effects of Organic Waste Diversion on Landfill Gas Generation from U.S. Landfills

Transcription

1

2 The Effects of Organic Waste Diversion on Landfill Gas Generation from U.S. Landfills Maryland Recycling Network 2016 Conference June 21, 2016 Alex Stege, SCS Engineers

3 Introduction Organic waste diversion Changes in organic MSW disposal Lower landfill gas generation Lower GHG (methane) emissions Reduced methane fuel supply for landfill gas to energy projects 2

4 Purpose of Study Document historic changes in organic MSW disposal Develop & model alternative future organic MSW disposal scenarios Evaluate effects of organics diversion on landfill gas generation 3

5 GHG Emissions from Waste Disposal Methane emissions from landfills = largest GHG source in waste sector Large GHG emissions reduction from: Diverting organic waste from disposal Collecting landfill gas and generating electricity 4

6 Types of Models (1) Lifecycle Analysis e.g. WARM Accounts for all emissions by material Full life-cycle benefits from diversion Time independent e.g. 100 years Good for long-range planning Not good for monitoring progress from baseline for specific sources (landfills) 5

7 Types of Models (2) Emissions Inventory e.g. LandGEM Emissions from a specific source over time No accounting outside of source 6

8 Estimating Landfill Methane Emissions Emissions and emissions avoidance estimates not precise Variations in landfill methane emissions Methane generation Methane recovery Methane oxidation 7

9 Landfill Gas Generation Models LandGEM LandGEM well known Adjusting key assumptions for site conditions poorly known Regulatory vs. non-regulatory models IPCC Offers calculations by material category Option for GHG emissions reporting Similar climate adjustment limitations as LandGEM 8

10 MSW Disposal/Diversion Data U.S. EPA (2015 for ) Composition of U.S. MSW generated, diverted, and disposed EREF (2015) 2013 U.S. MSW disposal was 50% higher than reported by EPA 9

11 U.S. Organic MSW Disposal (EPA data adjusted to EREF totals) Thousand Tons MSW Disposed 80,000 70,000 60,000 50,000 40,000 30,000 20,000 10, Paper Food Waste Yard Waste Wood Textiles Rubber, Leather, Diapers 10

12 % of Amount Generated U.S. Organic MSW Diversion %s (EPA data) 70% 60% 50% 40% 30% 20% 10% 0% 63% 60% 40% 16% 14% 5% Paper Food Waste Yard Waste Wood All other organics Total Organics 11

13 Declines in U.S. Organic Waste Disposal Year Million Mg MSW Disposed % Organics in MSW Million Mg Organic MSW Disposed % % % % % % %

14 Declining Methane Productivity of U.S. Waste Year Million Mg MSW Disposed Average MSW L 0 (m 3 /Mg) L 0 x Mg MSW Disposed (% decline since 1990) % % % % % % 13

15 Effects of Declines in U.S. MSW Organics 17% decrease in organic MSW disposed 26% decrease in methane productivity of MSW disposed Does not = 26% decline in LFG generation Delayed effect depends on decay rates and timing of disposal 14

16 Future MSW Disposal Scenarios Define for organic MSW categories Disposal = Generation x (1-% Diversion) Generation defined by trends Discounted future MSW generation in medium and high diversion scenarios Diversion scenarios 1. Baseline continue trends 2. Mid-range 2 x Baseline diversion % increases 3. High 4 x Baseline diversion % increases 15

17 % of Amount Generated Baseline U.S. Organic MSW Diversion Forecasts 80% 70% 60% 50% 40% 30% 20% 10% 0% 68% 62% 42% 24% 17% 15% 2% Paper Food Waste Yard Waste Wood All other organics Total Organics 16

18 Thousand Tons MSW Disposed 60,000 50,000 40,000 30,000 20,000 10,000 0 Baseline U.S. Organic MSW Disposal Forecasts Paper Food Waste Yard Waste Wood Textiles Rubber, Leather, Diapers 12% increase in organic MSW disposal:

19 % of Amount Generated U.S. Organic MSW Diversion: Mid-Range Scenario 80% 70% 60% 50% 40% 30% 20% 10% 0% Paper Food Waste Yard Waste Wood All other organics Total Organics 18

20 Thousand Tons Disposed U.S. Organic MSW Disposal: Mid-Range Diversion Scenario 60,000 50,000 40,000 30,000 20,000 10, Paper Food Waste Yard Waste Wood Textiles Rubber, Leather, Diapers 2% decrease in organic MSW disposal:

21 % of Amount Generated U.S. Organic MSW Diversion: High Scenario 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Paper Food Waste Yard Waste Wood All other organics Total Organics *Meets US EPA food waste diversion goal of 50% by

22 Thousand Tons Disposed U.S. Organic MSW Disposal: High Diversion Scenario 60,000 50,000 40,000 30,000 20,000 10, Paper Food Waste Yard Waste Wood Textiles Rubber, Leather, Diapers 30% decrease in organic MSW disposal:

23 LFG Flow at 50% Methane (scfm) LFG from U.S. MSW Disposed ,000,000 1,750,000 1,500,000 1,250,000 1,000, , Baseline LFG Generation Medium Diversion LFG Generation High Diversion LFG Generation 22

24 % Decrease from Baseline U.S. % Decreases from Baseline Mid-Range Diversion 15.0% 12.5% 10.0% 7.5% 5.0% Organic Tons Organic WIP LFG Generation 2.5% 0.0%

25 U.S. % Decreases from Baseline High Diversion 40% 35% % Decrease from Baseline 30% 25% 20% 15% 10% 5% Organic Tons Organic WIP LFG Generation 0%

26 CA Organic MSW Disposal: Baseline Tons Disposed 9,000,000 8,000,000 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 1,000, Paper Food Waste Yard Waste Textiles Wood, rubber, leather Composite organic 12% decrease in organic MSW disposal:

27 Tons Disposed CA Organic MSW Disposal: Mid-Range Diversion Scenario 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 1,000, Paper Food Waste Yard Waste Textiles Wood, rubber, leather Composite organic 43% decrease in organic MSW disposal:

28 Tons Disposed CA Organic MSW Disposal: High Diversion Scenario 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 1,000, Paper Food Waste Yard Waste Textiles Wood, rubber, leather Composite organic 71% decrease in organic MSW disposal:

29 LFG Flow at 50% Methane (scfm) LFG from CA MSW Disposed , , , ,000 80,000 60,000 40,000 20, Baseline LFG Generation Medium Diversion LFG Generation High Diversion LFG Generation 28

30 CA % Decreases from Baseline Mid-Range Diversion 40% 35% % Decrease from Baseline 30% 25% 20% 15% 10% 5% Organic Tons Organic WIP LFG Generation 0%

31 % Decrease from Baseline CA % Decreases from Baseline High Diversion 70% 60% 50% 40% 30% 20% Organic Tons Organic WIP LFG Generation 10% 0%

32 % Decrease from Baseline CA High Diversion: Dry vs. Wet Climate 35% 30% 25% 20% 15% 10% Dry Climate Wet Climate 5% 0%

33 Summary From , organics diversion increased by 1% and generation increased by 3%, causing a 2% disposal increase Continuing disposal trends LFG increases Aggressive increases in recycling would be required to cause LFG generation declines 32

34 For More Information Alex Stege, Senior Project Advisor SCS Engineers, Phoenix, AZ 33