Bioreactor Design & Operation; Demonstration Projects ...

1 Bioreactor Design &. Operation; Demonstration Projects , Results & Future Directions Debra Reinhart, PhD, PE, DEE. University of Central Florida Presentation Overview Florida Bioreactor landfill Demonstration project Overview Results Economics Methane generation by wet cell landfills Future directions of Bioreactor landfills Florida Bioreactor Landfill Demonstration project project Objective To Design , construct, operate and monitor a full-scale landfill Bioreactor in Florida in a manner that permits a complete and fair evaluation of this technology as a method of solid waste management in Florida, with appropriate consideration of science, engineering.

2 Environmental and economic issues. Florida Bioreactor Demonstration project Goals and Objectives The objectives of the landfill Bioreactor Demonstration are to: Design and operate the Bioreactor technology using innovative techniques and concepts. Control and measure all major inputs and outputs. Develop standardized Design and operation procedures for this technology. Further define and quantify the true costs and benefits of landfill bioreactors. Florida Bioreactor Demonstration project Goals and Objectives Evaluate the use of aerobic Bioreactor landfill technology Compare the aerobic approach to the use of anaerobic Bioreactor technology.

3 Instrument the landfills to permit in-situ monitoring of Bioreactor activity Monitor the landfills in a manner to measure the impact of Bioreactor activities New River Regional Landfill New River Regional Landfill Located in Union County Florida Manages waste from several North Florida Counties (approximately 800 tons per day). Retrofit Bioreactor project History project Leachate Development Well Field Recirculation & Design Installation Initiated 1998 1999 2000 2001 2002 2003 2004 2005 2006. Construction Air Permit Permit Injection Application Awarded Initiated Submitted Bioreactor Features Leachate recirculation system Air injection system Exposed geomembrane cap (EGC).

4 Gas collection system In-situ instrumentation Segregated leachate collection system New River Regional Landfill NRRL Bioreactor Construction Aerials View to North June 24, 2002. Top of Landfill Installation of Vertical Wells 10 ft Top of Sand Drainage Blanket Vertical Injection Well Clusters Leachate Distribution Manifold MTG Sensors In addition to leachate/air injection wells, the researchers will also be installing instrumentation within the landfill to measure Moisture, Temperature and Gas composition. Future updates will discuss the operation of these MTG.

5 Sensors in more detail. In short, these gravel- packed slotted PVC cylinders contain a device for sensing the degree of moisture present, as well as a temperature thermocouple and a tube for collecting gas samples. Vertical Injection Well Clusters Instrumentation Cluster Toe Drain Toe Drain Under Construction NRRL Gas Extraction System Gas is collected from the horizontal trenches underneath the exposed geomembrane cap Geomembrane Cap Subsurface Collector Gas Extraction Manifold Candle-Stick Flare Two Positive Three Displacement Centrifugal Gas Air Blowers Extractors Moisture Distribution Higher moisture content 70.

6 67. 66. 65. 60. 50. 40. 30. Before recirculation After recirculation Lower After recirculation After recirculation (Day 150) (3,200 m3) moisture (10,000 m3) (14,700 m3). (Day 318) content (Day 491) (Day 578). Estimated Moisture Content 70. Moisture Content (% w/w). Based on mass balance 60 Based on conductivity =8 mS/cm Based on conductivity =16 mS/cm 50. 40. 30. 20. 0 100 200 300 400 500 600. Days (Day 1 = 01/01/03). Settlement Around a Vertical Well Settlement (ft). 0 10 20 30 40 50 60. Radial distance from the well Cluster (ft). Settlement and Moisture Addition Settlement (feet).

7 0 100000 200000 300000 400000. Moisture Added (in Gallons). The Presence of Moisture can Greatly Impact Air Permeability 70. Period of Leachate Recirculation Air Permeability (X10-13 m2). 60. 50. 40. 30. 20. 10. 0. 0 50 100 150 200 250 300. Days (0= day of start of recirculation). Hydraulic Conductivity The hydraulic conductivity of waste (Ks) was determined by conducting borehole permeameter tests. These tests involve measuring the steady-state pressure at the bottom of the well for a constant flow rate. 50 Pressure 40 Flow rate Pressure (ft ). Flow rate (gpm).

8 30. 20. 10. 0 0 10 20 30 40 50 60 70. Time (Days). Hydraulic Conductivity Number Field saturated hydraulic of conductivity, Ks ( 10-6. Locations cm/sec). AM SD. Upper Layer 8 (3-6 m deep). Middle Layer 10 (6-12 m deep). Deep Layer 5 (12-18 m deep). Summary Florida Bioreactor project has met its objectives to develop Design and operating criteria, if not to achieve Bioreactor status Multiple publications, theses, and dissertations have been published Bioreactor continues to be operated with leachate and air injection Data compilation and release will occur over the next year.

9 Florida Bioreactor Landfill Demonstration project was funded by the Hinkley Center for Solid and Hazardous Waste Management. Bioreactor Landfill Economics Objectives: Evaluate the economic feasibility of aerobic and anaerobic Bioreactor landfills, comparing their costs to conventional landfills Total Present Worth Cost Comparison 60. Present Worth (Million $). 50. 40. 30. 20. 10. 0. Traditional Retrofit Bioreactor As built Bioreactor (anaerobic) (anaerobic). Gas recovery (%). Type Settlement (%)* During filling After filling Traditional 0 0 90. Retrofit Bioreactor (anaerobic) 20 0 90.

10 As built Bioreactor (anaerobic) 25 50 90. *Air space recovery is assumed to be utilized at the end of the retrofit Bioreactor life and as it occurs in the as-built Bioreactor Post Closure Savings 5. Post-Closure Cost (Million $). 4. 3. 2. 1. 0. 30 yrs 30 yrs 25 yrs 20 yrs 15 yrs 10 yrs Traditional Bioreactor Bioreactor Bioreactor Bioreactor Bioreactor PW Cost of a Hybrid Landfill as a Function of Duration of Air Addition With Gas Recovery 55. Retrofit As-Built Present Worth (Million $). 50. 45. 40. 35. 0 1 2 3 4 5. Air addition (years). PW Cost of a Hybrid Landfill as a Function of Duration of Air Addition No Gas Recovery 55.