1. SCS ENGINEERS 1 LANDFILL GAS ASPECTS OF BIOREACTOR LANDFILLS ASTSWMO STATE SOLID WASTE MANAGERS CONFERENCE SALT LAKE CITY, UTAH JULY 23, 2003 Patrick S. Sullivan, R.E.A., C.P.P SCS Engineers

2. SCS ENGINEERS 2 OUTLINE OF PRESENTATION Landfill Gas (LFG) Generation Rates LFG-Related Emissions and Odor Energy Recovery Potential Maximum Achievable Control Technology (MACT) Standard LFG System Design/Operational Issues

3. SCS ENGINEERS 3 LFG MODELING REFRESHER EPA’s LFG generation model (LANDGEM) Annual waste input (“M i ” value) = Mg Age of waste (“T i ” value) = yr Methane generation potential (“L o ” value) = m 3 /Mg Refuse decay constant (“k” value) = yr -1 Equation: Q m = 2 k L o M i (e -kti )

4. SCS ENGINEERS 4 GENERAL LFG MODELING INPUTS LANDGEM developed for “dry” sites M i and T i are site-specific L o = 100 to 170 m 3 /Mg k = 0.02 to 0.05 yr -1 (conventional); rainfall dependent k = 0.1 to 0.25 yr -1 (bioreactor); derived from limited lab and pilot scale studies

5. SCS ENGINEERS 5 COMPARATIVE STUDY INPUTS Conventional Landfill: 25 million tons, 25 years of life Bioreactor: 30% density increase Conventional Landfill: k = 0.05 (wet climate) Bioreactor: k = 0.12 (average)

6. SCS ENGINEERS 6 STUDY INPUTS (cont.) No adjustments made to L o (= 100 m 3 /Mg) Issue of “ultimate” L o and “effective” L o Site modeled over 100 years of operational and post-closure life

7. SCS ENGINEERS 7 STUDY INPUTS (cont.) NMOC Concentration = 595 ppmv (AP-42) 75% Collection Efficiency for LFG Collection and Control System (GCCS) NOx = 0.06 lb/ MM BTU (BACT) 98% Destruction Efficiency for NMOC

8. SCS ENGINEERS 8 STUDY INPUTS (cont.) Conventional Landfill: GCCS Installed (Year 8) and Turned Off (Year 75) per the NSPS Bioreactor: GCCS Installed Early (Year 2) per MACT Bioreactor: GCCS Turned Off 10 Years Sooner (Year 65)

9. SCS ENGINEERS 9 MODELING RESULTS LFG FlowConventionalBioreactor Maximum LFG (scfm) 636210,631 LFG Flow in Year 2 (scfm) 6501265 LFG Flow in Year 8 (scfm) 26336358

10. SCS ENGINEERS 10 MODELING RESULTS (cont.) LFG FlowConventionalBioreactor LFG Flow in Year 65 (scfm) 90599 LFG Flow in Year 75 (scfm) 54943 LFG Flow – 25 yr. (scfm) ~4500~7500

11. SCS ENGINEERS 11 MODELING RESULTS (cont.) PollutantConventionalBioreactor Maximum NMOC (tpy) 108124 Maximum NOx (tpy) 5084 Maximum CO 2 (Mg/yr) 496,253829,202

12. SCS ENGINEERS 12 MODELING RESULTS (cont.) PollutantConventionalBioreactor Total NMOC (tons/100 yr.) 31213283 Total NOx (tons/100 yr.) 16072199 Total CO 2 (Mg/100 yr.) 15.9 MM21.8 MM

13. SCS ENGINEERS 13 MODELING RESULTS (cont.) Energy ValueConventionalBioreactor Maximum Heat (MM BTU/hr) 191319 Maximum Power (MW) 1930 25-Year Average Power (MW) 1220

14. SCS ENGINEERS 14 DATA SUMMARY Bioreactor will generate more LFG and produce more LFG-related emissions LFG will be generated sooner and have higher peak rate LFG generation will remain near peak for longer period of time LFG generation will decline faster after landfill closure

15. SCS ENGINEERS 15 DATA SUMMARY (cont.) Bioreactor will collect over 37% more methane and produce 37% more energy LFG generation profile more conducive to energy recovery Bioreactor will reduce greenhouse gas (GHG) emissions Bioreactor will slightly increase organic compound emissions from LFG

16. SCS ENGINEERS 16 DATA SUMMARY (cont.) Bioreactor will slightly increase sulfur compound emissions from LFG Bioreactor will increase combustion by-product emissions

17. SCS ENGINEERS 17

18. SCS ENGINEERS 18 EMISSIONS ISSUES Increases in organic chemical emissions (NMOCs, VOCs, and toxic organics) –Ozone non-attainment areas (VOCs) –Health risk issues (toxics) –Much larger peak emissions –Increase is very small over life of landfill

19. SCS ENGINEERS 19 EMISSIONS ISSUES (cont.) Increases in sulfur compound emissions –Hydrogen sulfide, mercaptans, etc. –Commonly caused by C&D waste and sludge –Odor issues –Much larger peak emissions –Increase is very small over life of landfill –Bigger problem if sludge if used for moisture

20. SCS ENGINEERS 20 EMISSIONS ISSUES (cont.) Increases in combustion by-product emissions (NOx, CO, PM10, and SOx) –Non-attainment area issues –Odor/nuisance issues –Much larger peak emissions –Increase is moderate over life of landfill –Technology improvements might offset increases

21. SCS ENGINEERS 21 EMISSIONS ISSUES (cont.) GCCS must be installed earlier by regulation and necessity GCCS must be sized properly to handle increased LFG generation Additional cost of sizing equipment for peak year GCCS must be designed to combat increased liquids content of waste

22. SCS ENGINEERS 22 EMISSIONS BENEFITS Significant Reductions in GHG Emissions through Methane Recovery (23x CO 2 ) Better Scenario for Energy Recovery Less Years of GCCS Operation in Total Less Years of GCCS Operation After Landfill Closure

23. SCS ENGINEERS 23 LANDFILL MACT STANDARD Promulgated on January 16, 2003 Supplement to the NSPS Affects NSPS Landfills Required to Install GCCS Also Affects Bioreactor Landfills

24. SCS ENGINEERS 24 NSPS REFRESHER Affects Landfills that Accepted Waste After November 1987 Design Capacity Limit: 2.5 million m 3 or 2.5 million Mg GCCS Required After Exceeding 50 Mg/year NMOC Must Operate GCCS for Minimum 15 Years

25. SCS ENGINEERS 25 NSPS REFRESHER (cont.) Minimum Control Device Temperature 98% Destruction Efficiency for NMOCs Surface Emissions Less than 500 ppmv

26. SCS ENGINEERS 26 NSPS REFRESHER (cont.) Wellhead Standards to Prevent Landfill Fires –Oxygen or Nitrogen Limit –Temperature Limit –Wells under vacuum Various Monitoring, Reporting, and Recordkeeping Requirements

27. SCS ENGINEERS 27 MACT STANDARD (cont.) MACT Contents –Start-up, Shut-down, and Malfunction (SSM) Plan –Semi-Annual NSPS/EG Reporting –Deviation Reporting

28. SCS ENGINEERS 28 MACT STANDARD (cont.) Conventional Landfill Applicability –New Sites: All NSPS Sites that Commenced Construction/Reconstruction after November 2000 –Existing Sites: All Other NSPS Sites –Only Triggered When Required to Install GCCS Under NSPS

29. SCS ENGINEERS 29 MACT STANDARD (cont.) Conventional Landfill Due Dates –New Sites: By January 16, 2003 or Date GCCS is Required to be Installed –Existing Sites: By January 16, 2004 –There Should be No New Sites Between November 2002 and Present –SSM Plan Must Be Implemented by January 16, 2004

30. SCS ENGINEERS 30 MACT STANDARD (cont.) Bioreactor MACT –Draft Issued Separately –Final: Concurrent with Landfill MACT –Applies to NSPS Landfills with Anaerobic Bioreactor Operations –Aerobic Landfills Specifically Exempted

31. SCS ENGINEERS 31 MACT STANDARD (cont.) Bioreactor MACT (cont.) –Comply with NSPS and Landfill MACT –New Sites: GCCS Installed Before Liquids Addition –Existing Sites: GCCS Installed By January 16, 2006 or When Required by NSPS, Whichever is Earlier

32. SCS ENGINEERS 32 MACT STANDARD (cont.) Bioreactor MACT (cont.) –Both Types: GCCS Operational within 180 Days of Liquids Addition or –180 Days of Achieving 40% Moisture, Whichever is Later

33. SCS ENGINEERS 33 GCCS DESIGN CHALLENGES  Higher Gas Temperatures  Higher Gas Pressures  Higher Gas Production Rates  Higher Liquid Levels  Increased and More Rapid Settlement

34. SCS ENGINEERS 34 Drill Cuttings from gas well with temps > 150º F HIGHER TEMPERATURES

35. SCS ENGINEERS 35 HIGHER LIQUID LEVELS (Leachate Filled Extraction Trench)

36. SCS ENGINEERS 36 HIGHER GAS PRESSURE

37. SCS ENGINEERS 37 GCCS DESIGN OPTIONS  Vertical Extraction Wells  Horizontal Collectors  Interconnection with Leachate System  Common Conduit - HYEX® System

38. SCS ENGINEERS 38 VERTICAL WELL ISSUES  Rapid settlement can pinch casing  Liquids can plug perforations  More air intrusion if permeable caps used  Smaller diameter wells may not be able to carry increased flows  Well spacing and radius of influence concerns

39. SCS ENGINEERS 39 HORIZONTAL COLLECTOR ISSUES  Rapid settlement can pinch collectors  Liquids can fill trench and water-in collector  More air intrusion if permeable caps used; deeper trenches

40. SCS ENGINEERS 40 LIQUIDS MANAGEMENT ISSUES  Increased condensate generation  Leachate in LFG system  Dewatering of extraction wells  Rapid settlement creates low points in header and lateral lines  Pipe and well sizing issues

41. SCS ENGINEERS 41 DUAL CONDUIT  Common trench or piping for gas collection and liquids addition  HYEX® System uses common carrier drain pipe for separate liquid injection and gas collection pipes.  Demonstration at Ste. Sophie Landfill, Quebec and Fauquier County, VA

42. SCS ENGINEERS 42 Interior of HYEX reinforced landfill conduit; 12 inch ID

43. SCS ENGINEERS 43 Terminal end of HYEX conduit with liquid and gas lateral lines and optional CCTV insertion lateral.

44. SCS ENGINEERS 44 SYSTEM MODIFICATIONS  Larger diameter bore holes and casing sizes for vertical wells  Tighter well spacing; more wells  Wells designed to accommodate liquid pumping for dewatering  Increase header and lateral pipe sizes to accommodate flow and settlement

45. SCS ENGINEERS 45 MODIFICATIONS (cont.)  Dual conduit or dual use trenches for gas and liquids  Possibly combined gas and leachate collection components  Design trenches for horizontal collectors to drain liquids better  High temperature materials for wells - CPVC, Fiberglass, steel, etc.

46. SCS ENGINEERS 46 MODIFICATIONS (cont.)  Proper blower and flare sizing to accommodate additional LFG generation  Enhanced liquids management system, including condensate  Design for rapid settlement  Plan for early GCCS installation and expansion

47. SCS ENGINEERS 47 OTHER TECHNIQUES  Emissions Control via Biocovers  Compost cover material  Oxidizes methane as gas passes through  Aerobic reaction  Allows liquids addition  EREF-funded research ongoing at Outer Loop Landfill, KY

48. SCS ENGINEERS 48 QUESTIONS