201: Compost and Landfill Issues Stephanie Young, CIWMB Sally - PowerPoint PPT Presentation

201: Compost and Landfill Issues Stephanie Young, CIWMB Sally Brown, Univ. of Washington Brenda Smyth, CIWMB Gary Liss, Gary Liss & Associates Webinar # 2 West Coast Webinars on Climate Change, Waste Prevention, Recovery, and Disposal July 16, 2008 1

Disclaimer This presentation is part of the U.S. EPA’s Climate Change Webinar Series. • This document does not constitute EPA policy. • Mention of trade names or commercial products does not constitute endorsement or recommendation for use. • Links to non-EPA web sites do not imply any official EPA endorsement of or a responsibility for the opinions, ideas, data, or products presented at those locations or guarantee the validity of the information provided. • Links to non-EPA servers are provided solely as a pointer to information that might be useful to EPA staff and the public. 2

Landfills and Climate Change • Overview of Science • Methods of Controlling Emissions • California’s Approach to Landfill Methane Stephanie Young, PE California Integrated Waste Management Board West Coast Webinar on Climate Change, Waste Prevention, Recovery & Disposal July 16, 2008 3

Why Landfills? • Landfills Produce Methane o Largest Source of Anthropogenic Methane Emissions in California (CEC 2002, http://www.energy.ca.gov/2005publications/CEC-500-2005-097) o Accounted for approximately 23% of the total U.S. anthropogenic methane emissions in 2006 (EPA 2008, http://epa.gov/climatechange/emissions/usinventoryreport.html) • Methane is a Greenhouse Gas o Methane absorbs terrestrial infrared radiation (heat) that would otherwise escape to space. o Methane is 21x more powerful at warming the atmosphere than CO 2 . o Chemical lifetime in the atmosphere is 12 years, as such, makes it a good candidate for mitigation efforts over the near term. 4

How Does A Landfill Produce Methane? • Complex Anaerobic Biological Process • Depends on Waste Quantity, Type, Moisture, Climate, and Age o Anaerobic Decomposition of Biogenic Waste (i.e. paper, food scraps, and yard trimmings) o Landfill Gas Composition o Methane (45 to 60%) o Carbon Dioxide (40 to 60%) o N 2 (2-5%), O 2 (0.1-1%), NH 3 (0.1-1%), Sulfides (0-1%), H 2 (0-0.2%), CO (0-0.2%) o Non-Methane Organic Compounds (NMOCs) 0.01-0.6%, other non-NMOC HAPs/TACs (e.g., Hg) 5

6 6 TYPICAL LANDFILL GAS GENERATION PATTERN

7 CH 4 Generated = CH 4 Emitted + CH 4 Oxidized + CH 4 Recovered/Flared Methane Pathways

Methane Recovered � Directly � Actual Landfill Gas Collection and Control System Data � Indirectly � Used to estimate potential methane recovery when designing systems � Models (i.e. LandGEM, IPCC, proprietary consultant models) and an assumed collection efficiency 8

Methane Oxidation � Directly � Stable Carbon Isotope Technique � More information http://jeq.scijournals.org/cgi/content/abstract/30/2/369 titled “Methane Oxidation in Two Swedish Landfill Covers Measured with Carbon-13 to Carbon-12 Isotope Ratios (Börjesson, Chanton and Svensson, 2001) � Indirectly � Using Case Studies 9

Methane Oxidation Source: Technologies and Management Practices for Reducing Greenhouse Gas Emissions from Landfills, CIWMB Publication 200-08-001, 2008 10

Methane Generated � Directly � Baro-pneumatic Method – developed by Hydro Geo Chem, Inc. � More information www.hgcinc.com/landfill.htm � Indirectly � Back calculation using actual recovery data and assumed collection efficiency � First-Order Decay Models � Basics � EPA’s Landfill Gas Emissions Model (LandGEM) � http://www.epa.gov/landfill/res/index.htm#5) � Intergovernmental Panel on Climate Change (IPCC) � http://www.ipcc-nggip.iges.or.jp/public/2006gl/vol5.html 11

Methane Emitted Dependent upon the following factors: � Total amount of municipal solid waste in the landfill � Characteristics of the landfill receiving waste � Composition of Waste In Place � Climate � Structure (liner and cover systems) � Amount of landfill gas that is recovered/controlled � Amount of methane oxidized in cover soils 12

Methane Emitted (con’t) � Directly � Many techniques � “Research Roadmap for Greenhouse Gas Inventory Methods,” California Energy Commission Publication CEC-500-2005-097 : Comparisons 13

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Source: Research Roadmap for Greenhouse Gas Inventory Methods, Publication CEC-500-2005-097, 2005, California Energy Commission 15

Methane Emitted (con’t) � Directly � Flux Chambers � More Information: M. 1986. Measurement of Gaseous Emissions Rates from Land Surfaces using an Emission Isolation Flux Chamber, User's Guide, EPA Users Guide, (EPA 600/8-86/008) � Optical Remote Sensing/Radial Plume Mapping � More information: http://www.clu- in.org/conf/tio/ors_022207/prez/ORS_RPMppt-Thorneloebw.pdf 16

Direct Measurement Techniques Opposite RPM Detectors Wellhead Penetration Radial Flux Chambers Flux Chamber Radial Plume Climate Station Mapping (RPM) Scissor Lift Mirror RPM Detectors 17

Flux Chamber Source: M. 1986. Measurement of Gaseous Emissions Rates from Land Surfaces using an Emission Isolation Flux Chamber, User's Guide, EPA Users Guide, (EPA 600/8-86/008) 18

Methane Emitted (con’t) � Indirectly � Models (i.e. LandGEM, IPCC, proprietary consultant models) � 75% collection efficiency or other default efficiency • Capture efficiency is controversial and a key measure of performance in reducing emissions. • Estimated based on modeled gas generation and measured gas that is flared or recovered . • Default capture efficiencies based on USEPA are 75% (with control) and 10% for natural oxidation. Actual capture may be higher or lower. • Active projects to reduce uncertainty (CEC Study). 19

Methods of Controlling Landfill Emissions � Divert Organics � Compost � Anaerobic Digestion � Segregation of Organic Waste into Dedicated Cells � Increase Gas Collection/Recovery � Early Installation of a System � Landfill Gas System Well Field Design Using horizontal collectors; tighter well spacing; leachate collection system hook-up � � Landfill Gas System Operation & Maintenance Redundant blower systems; barometric control � � Enhanced Monitoring: Migration and Surface Emissions � Landfill Operational Practices Bioreactor Landfills; fill sequence planning; LFG Master Planning � � Increase Oxidation � Cover Systems, including Biocovers 20

California’s Approach to Landfill Methane Landfill Methane Capture Strategy 1. Install new methane control systems at landfills currently without control systems. ARB Landfill Methane Control Measure (AB32) � 2. Maximize landfill methane capture efficiencies by optimizing landfill design, operation, and closure/postclosure practices. CIWMB Technologies and Management Options Guidance Document � (http://www.ciwmb.ca.gov/Publications/default.asp?pubid=1268) CIWMB Long-term Performance of Biocovers on Landfills to Mitigate Methane � Research on Methane Emissions � California Energy Commissions Study: “Improved Methods for Landfill Methane � Emissions in California” Waste Management’s Radial Plume Mapping Research � Los Angeles County Technique for Determining Collection Efficiency � 21

California’s Approach to Landfill Methane Landfill Methane Capture Strategy (con’t) 3. Increase recovery of landfill gas for use as a biomass renewable energy source to replace energy from nonrenewable fossil fuel sources. CIWMB and ARB LFG to LNG Grant Projects � CEC Projects under PIER Renewables Program � CPUC: AB1969 and Waste Technology Grants � 22

Questions? Stephanie Young, P.E. Waste Management Engineer California Integrated Waste Management Board 1001 I Street, 10 th Floor Sacramento, CA 95814 PH (916) 341-6357 FAX (916) 319-7543 EMAIL syoung@ciwmb.ca.gov 23

Climate Change and Organics: Compost Issues Sally Brown Slb@u.washington.edu University of Washington Brenda Smyth CIWMB 24

Behavior of organics • Under anaerobic conditions – Uncontrolled- landfill – Controlled - anaerobic digestion • Under aerobic conditions – Composting • In a soil system- use of compost 25

What life is like in a sanitary landfill Uncontrolled anaerobic conditions • Pretty hot- always summertime (LeFebvre et al., 2000) 26

Hard to breath, and a little damp (160-310 g H 2 O kg) (LeFebvre et al., 2000; Bäumler and Kögel-Knabner, 2008) 27

Perfect conditions for decomposition for CERTAIN feedstocks No Yes Food scraps are high in H 2 O and nutrients Paper is too dry and too high in carbon 28

When you have anaerobic decomposition • Fixed carbon will transform to CH 4 (23 x) and CO 2 (0 x) • Organic nitrogen has the potential to form N 2 O (296 x) during de- nitrification reactions [transformation of nitrate to nitrogen gas] 29

When you remove highly putrescible materials from landfills- GHG credits • Chicago Climate Exchange methane avoidance protocol = Θ (1-f) GWP CH4 (1-OX)16/12 F*DOC f *MCF* ∑ y x=1 ∑ Wj,x*DOCj*e -kj(y-x) *( 1-e-kj ) Two key components of this equation • F= methane collection efficiency of landfill • K = first order decay constant for specific waste types 30

f = gas collection efficiency • EPA default = 75% over life of landfill • IPCC = 40-50% over life Landfill closure • Actual ? Gas collection CH 4 Collection efficiency 31