Biosolids and Carbon Footprint

Transcription

1 Biosolids and Carbon Footprint Patricia Scanlan Andrew Shaw, Steve Tarallo

2 The Buzz About Carbon Footprints International, national, and regional initiatives and drivers Page - 2

3 The Buzz Why are we inventorying GHG emissions and developing carbon footprints? GHG emissions vs. carbon footprint Means for auditing, measuring GHG emissions Global warming potential (GWP) Useful if carbon trading programs are implemented or carbon caps are imposed in the future Important component of a sustainability assessment Strategic planning and process selection Page - 3

4 International Initiatives and Drivers Kyoto Protocol (1997) By 2012, reduce GHG emissions to 5% below 1990 levels Reduction requirements vary by country Only 37 countries required to reduce emissions US targeted at 7% reduction US did NOT ratify Kyoto Expires in UN Climate Change Conference (Dec 2009) Page - 4

5 National Initiatives Conference of Mayors Climate Protection Agreement Includes 1,012 cities Meet or beat Kyoto Protocol targets (7% reduction by 2012) Local implementation Arizona cities include: Page - 5 Apache Junction Bisbee Buckeye Bullhead City Flagstaff Gilbert Goodyear Mesa Oro Valley Phoenix Tucson Winslow

6 National Initiatives - Legislation Page - 6

7 National Initiatives - Legislation American Clean Energy and Security Act of 2009 (ACES) (H.R. 2454) Reduce GHG emissions by 17% by 2020 Applies to emitters of 10,000 tonne/yr CO 2 e (for specific categories of emitters) Establishes federal GHG registry Includes Cap-and-Trade provisions Addresses barriers to carbon sequestration and capture Provides for trading, banking, borrowing credits and offsets Senate hearings this week Page - 7

8 National Initiatives - Rules USEPA 40 CFR Part 98 Mandatory reporting of GHG emissions for specific industries Triggered at 25,000 tonne/year CO 2 equiv Based on actual, direct emissions Does not include electricity purchase Biogenic emissions reported separately 30 mmbtu/hr comparison Page - 8

9 Regional Initiatives Northeast, midwest, and western initiatives Western Climate Initiative (WCI) Reduce GHG emissions to 15% below 2005 levels by 2020 (beginning in 2012). POTWs included starting Measured at point of emission Reporting begins at 10,000 tonne/yr CO2e Compliance at 25,000 tonne/yr CO2e Triggers based on stationary combustion emissions Includes reporting of emissions from biomass combustion Offsets limited to 49% of reductions WCI Partners Page - 9

10 Carbon footprint of biosolids management Options to reduce emissions Page - 10

11 What are the WW Treatment Carbon Footprint Boundaries? Treatment System Construction Operation Decommissioning Page - 11

12 Inventory Operational Boundaries Source: WRI/WBCSD Page - 12

13 Scope Definitions Scope 1 Direct process emissions Direct fugitive emissions Stationary combustion Vehicle fleet fuel combustion Scope 2 Purchased electricity Scope 3 (Optional) Contracted services Supply chain sources Waste disposal Employee travel Page - 13

14 Scope 1 Sources Wastewater treatment CO 2 CH 4 N 2 O Stationary combustion, vehicle use stationary combustion, fugitive emissions, vehicle use, lagoons stationary combustion, N/DN, vehicle use, incineration, plant effluent Page - 14

15 Scope 2 Purchased Electricity - egrid The Emissions & Generation Resource Integrated Database for 2007 (egrid2007) Technical Support Document AZNM: 1,316 lb/mwh National Average: 1,329 lb/mwh Page - 15

16 Scope 3 Sources Wastewater treatment Solids disposal/final use Contractor hauling (mobile combustion) Landfill gas production (w/ or w/o LFG collection system) Land application Fertilizer offset, carbon sequestration, N 2 O emissions Embodied carbon from supply chain Equipment Chemicals Consumables for maintenance Page - 16

17 Developing the Carbon Footprint for Biosolids Processes Build GHG emissions from ground up Identify evaluated processes Identify emissions associated with each process Use measurement or emission factors May be difficult to identify actual energy use associated with specific processes Remember impacts of sidestream treatment Page - 17

18 Carbon Footprint of Thickening and Dewatering None Scope 1 Scope 2 Purchased electricity Scope 3 (Optional) Polymer use Equipment manufacture and construction Transportation for staff Page - 18

19 Carbon Footprint of Aerobic Digestion Scope 1 N 2 O emissions Scope 2 Purchased electricity Scope 3 (Optional) Polymer use Equipment manufacture and construction Transportation for staff Page - 19

20 Carbon Footprint of Anaerobic Digestion Scope 1 Natural gas use Fugitive CH 4 emissions Flare combustion or cogeneration emissions (N 2 O and CH 4 ) Scope 2 Purchased electricity Electricity offset (shown as reduction in purchased electricity) Scope 3 (Optional) Chemicals for biogas cleaning Offsets for biogas use outside the fence Equipment manufacture and construction Transportation for staff Page - 20

21 Carbon Footprint of Thermal Processes Scope 1 Combustion emissions (incinerators N 2 O) Natural gas use (incineration/heat drying) Scope 2 Purchased electricity Electricity offset from power generation (shown as reduction in purchased electricity) Scope 3 (Optional) Equipment manufacture and construction Transportation for staff Page - 21

22 Carbon Footprint for Final Use Options Scope 1 Utility-owned hauling Scope 2 Purchased electricity Scope 3 (Optional) Contracted hauling Landfill emissions Land application N 2 O emissions Chemical use (alkaline stabilization) Offsets for energy use outside the fence Offsets for fertilizer replacement Offsets for carbon sequestration Page - 22

23 Reducing Carbon Footprint First, determine your objectives Scope 1 and 2 only? For reporting reasons or total system sustainability decisions? Drying Beds Choose technologies with lower energy requirements Minimize options that require aeration Consider impact of thickening and dewatering Heat drying and incineration have high energy requirements Solar drying has low energy requirements Page - 23

24 What Portion of Total is Purchased Energy? Fugitive Em issions 2% Polym er 4% Stationary 0% Mobile 2% Centrifuge Dewatering 21,000 tonne/yr CO2e Scope 1 and Scope 2 Mobile Purchased Elec. Stationary Polymer Fugitive Emissions Purchased Elec. 92% Converting to BFP dewatering reduces GHG by 11% Page - 24

25 What is the Impact of Technology Choice on GHG? GHG Emissions By Emissions Source 40,000 Tonne/year 35,000 30,000 25,000 20,000 15,000 10,000 5,000 Fugitive Emissions Incineration Polymer Stationary Purchased Elec. Mobile 0 Cent. BFP Cent w / ER BFP w /ER Drying Incineration Page - 25

26 Environmental Product Declarations (EPD) Consider Impacts of Equipment Choice EPD describes the environmental impact of producing and using a product based on verified Life Cycle Assessments (LCA) in accordance with ISO Good Example: Flygt Pumps CO2e kg per kw of Pumping Power Used over 5yr Life Climate Declaration is a simplified EPD just for green-house gases, expressed as CO 2 -equivalents for a product's life cycle. Production Use Total Tools where customers can compare different products' environmental performance. Page - 26

27 Reducing Carbon Footprint (continued) Maximize use of energy recovery Use biogas for power generation, process or building heating/cooling Consider biogas augmentation processes Co-digestion with FOG WAS pretreatment (OpenCEL, Crown Biogest, thermal hydrolysis) Page - 27

28 Reducing Carbon Footprint Scope 3 In general, final use options using land application have the lowest GHG emissions Landfill disposal has high GHG emission Landfill gas systems may not capture methane generated by biosolids (3-5 year delay) Page - 28

29 Putting Biosolids in Perspective Western Australia (42 mgd / 62 dtpd) SBR treatment Rotary screw thickeners Anaerobic digestion Centrifuge dewatering 1.3 tonne/tonne total 29% 71% Page - 29 Co-generation Co-generation decreased total by 1.1 tonne/tonne (46%) Plant Total Solids Treatment