Characterization of Florida Landfills with Elevated Temperatures Debra
Characterization of Florida Landfills with Elevated Temperatures Debra Reinhart, Ph. D, PE, BCEE Ryan Joslyn Department of Civil, Environmental, and Construction Engineering University of Central Florida, Orlando, FL TAG Meeting November 1, 2018
Presentation Overview • • Research Goals and Objectives Methodology and Timeline Results to Date Q&A
Research Goals • To develop a more complete understanding of the reactions and conditions leading to elevated temperatures in Florida landfills through data analysis and landfill characterization. • Focus of this research is on subsurface reactions that are more difficult to characterize, understand, or mitigate than site, surface, or near surface fires. Picture of Mumbai Deonar Landfill fire captured by sensors on the Terra, Aqua, and Suomi NPP satellites
Year 2 Objectives • Expanding analysis of historical leachate and gas data • Utilization of the NCSU Elevated Temperature Model to create two case study models of Florida landfills • Use Arc. GIS to explore the propagation of landfill temperatures over time • Determination of appropriate design and operating parameters to safely manage ash and waste
Methodology - Task 1: Expanded Landfill Analysis • Historical leachate quality, wellhead gas data, waste disposed, and landfill geometry was examined for landfill cells throughout Florida during Year 1. • Data for additional landfills will be obtained directly from FDEP or through individual landfill databases. • Analyzing the historical data will allow us to observe changes in characteristics over time and correlate the findings with operational events (type of waste accepted, installation of gas wells, etc. ).
Methodology - Task 2: Elevated Temperature Modeling • The NCSU Elevated Temperature model will be applied to understand the impacts that certain biological and chemical reactions may have on temperatures within MSW landfills. • This model designs a landfill as a batch reactor, describing a single addition of MSW to the landfill. Heat Generation and Accumulation in Municipal Solid Waste Landfills (Hao et. al, 2017)
Methodology - Task 2: Elevated Temperature Modeling • As batch reactors are closed systems, temperature and gas concentrations in this model do not vary spatially within the landfill. • However, heat transfer through gas and liquid movement does occur through convection. • Thus, leachate collection, gas extraction, and evaporation are all heat removal mechanisms included in the model.
Methodology - Task 2: Elevated Temperature Modeling • The following heat sources will be tested: aerobic and anaerobic biological reactions, anaerobic metal corrosion, acid-base reactions, and ash hydration and carbonation. • Two case study models of Florida landfills will be developed to understand the impact these reactions may have on heat generation in Florida landfills.
Methodology - Task 2: Elevated Temperature Modeling • Elevated Temperature modeling is also being conducted using Arc. GIS to show the propagation of landfill temperatures over time. • Different interpolation methods (Kriging, IDW, Spline) will also be tested to determine the optimal interpolation method for landfill temperature and gas modeling. • This will be completed for 5 landfills, 4 ETLFs and 1 Non-ETLF.
Methodology - Task 3: Defining Operating Parameters for the NCSU Elevated Temperature Model • The NCSU Elevated Temperature model will be used to determine appropriate design and operating parameters required to safely manage ash and unburned waste. • Impact of certain variables (gas flow rate, moisture content, ratio of methane/carbon dioxide, etc. ) on internal temperatures will be studied. • Ash and unburned waste reactions will be modeled in landfills to determine if they produce elevated temperatures in the modeled landfills.
Project Timeline Month Tasks 1 -2 3 -4 5 -6 7 -8 9 -10 11 -12 Task 1. Expanded Landfill Analysis Task 2. EREF Elevated Temperature Modeling Task 3. Defining Operating Parameters for the EREF Elevated Temperature Model Annual and Quarterly Reports TAG Meetings
Results to Date
Task 1. Historical Gas Temperature Data Analysis • A total of 27 landfills cells was studied (64% of active landfills): • 22 of these landfill cells provided landfill gas well monitoring data. • 5 landfill cells were evaluated using exceedance reports. • Of the 27 landfill cells, 78% reported temperature exceedances (greater than 131°F). 22% 78% Exceedance Non-Exceedance
Task 1. Elevated Temperature Well Graphs Temperature and CH 4: CO 2 Profile (ET gas well) 180 1. 4 160 Interruption in gas extraction 1. 2 1. 0 120 100 0. 8 80 0. 6 60 0. 4 40 0. 2 20 0 Feb-08 0. 0 Feb-09 Feb-10 Feb-11 Feb-12 Feb-13 Adj Temp (o. F) Feb-14 CH 4/CO 2 Feb-15 Feb-16 Feb-17 Feb-18 CH 4/CO 2 Temperature (o. F) 140
Task 1. Cumulative Gas Temperature Data Analysis • Percent of Gas Well Data > 131°F • Elevated Of the 22 landfill cells that provided monthly monitoring data, 64% had elevated temperatures. 10% had >15% of wells with elevated temperatures Non-Elevated 36% 64% 35 30 25 20 15 Non- 10 5 0 0. 0 10. 0 20. 0 30. 0 40. 0 50. 0 60. 0 70. 0 Percent of Landfills (of 22 total) 80. 0 90. 0 100. 0
Task 1. Cumulative Gas Quality Data Analysis • A CH 4: CO 2 ratio less than 1 is often an indicator of elevated temperatures within landfills. • As gas well temperature increases, the percent of gas wells reporting a CH 4: CO 2 ratio < 1 increases • Methane generation impacted at temperatures > 145 % ET Wells with CH 4: CO 2 ratio < 1 90 80 % ET Wells < 1 70 60 50 40 30 20 10 0 130 140 150 160 Temperature (°F) 170 180
Task 1. Landfill Size and Depth N = 8 landfill cells (no elevated temp) N =11 landfill cells (with elevated temp)
Task 1. Leachate Treatment Onsite Treatment (non-elevated) Onsite Treatment (elevated) 14% 25% 43% 75% N = 8 landfills N = 7 landfills Recirculation Other No information Recirculation Other
Task 1. Example ETLF Leachate characteristics (Aromatics) • Leachate characteristics prior to ET (2005 -2008) and during the period of ET (2008 -2012) for an ETLF landfill:
Task 1. Example ETLF Leachate characteristics (Ketones)
Task 1. Cause of Elevated Temperature – Air Intrusion? Temperature and Bal/CO 2 Ratio Profile (ET gas well) 200 2. 0 1. 8 Interruption in gas extraction 160 1. 6 140 1. 4 120 1. 2 100 1. 0 80 0. 8 60 0. 6 40 0. 4 20 0. 2 0 0. 0 Feb-08 Feb-09 Feb-10 Feb-11 Feb-12 Feb-13 Adj Temp (o. F) Feb-14 Bal/CO 2 Feb-15 Feb-16 Feb-17 Feb-18 Bal/CO 2 Ratio Temperature (o. F) 180
Task 1. Cause of Elevated Temperatures -Ash Disposal? • Data from 22 landfill cells analyzed; 14 (64%) landfills had elevated temps; 8 reported history of accepting ash. • 7 of these 8 landfills with ash report elevated temperatures (88%) • Hydrolysis reactions with the metal oxides can generate significant energy by producing CO 2 and H 2 gases 13% 88% Elevated Non-Elevated
Task 1. Effect of Ash Disposal on Maximum Temperature N = 14 landfill cells (no ash) N =8 landfill cells (with ash)
Task 1. Effect Of Ash Disposal On Percent Of Elevated Temperature Readings N = 14 landfill cells (no ash) N =8 landfill cells (with ash)
Task 1. Effect of Ash Disposal on Percent of Elevated Temperature Readings 6. 0 60. 0 50. 0 40. 0 30. 0 20. 0 10. 0 Jan-15 Apr-15 Jul-15 Oct-15 Jan-16 Apr-16 % Data points > 131°F Jul-16 Oct-16 Jan-17 % total waste as ash Apr-17 0. 0 % of total waste as ash % Data points > 131 o. F • Effect of ash disposal on temperature over time: Landfill with medium ash concentration
5/ 1 19 2: 0 0 6/ 0 26 5 1 : 00 2: A /1 6/ 905 00: M 00 27 AM /1 12: 0 9 6/ 05 0: 0 28 0 A /1 12: 0 9 0 M 6/ 0 29 5 1 : 00 2: A /1 6/ 905 00: M 00 30 AM /1 12: 0 9 7/ 05 0: 00 1 1/ 19 2: 0 AM 0: 0 7/ 5 12 00 A 2/ 19 : 0 M 7/ 05 0: 0 12 0 A 3/ 19 : 0 M 7/ 05 0: 0 0 1 4/ 19 2: 0 AM 0 : 7/ 05 1 00 5/ 19 2: 0 AM 7/ 05 0: 0 0 1 6/ 19 2: 0 AM 7/ 05 0: 0 0 1 7/ 19 2: 0 AM 0 : 7/ 05 12 00 A 8/ 19 : 0 M 7/ 05 0: 0 0 1 9/ 19 2: 0 AM 05 0: 0 12 0 A : 0 0: M 00 AM 6/ 2 19 05 4/ 6/ 2 % Data points > 131 F 50 45 40 35 30 25 20 15 10 5 0 100 90 80 70 60 50 40 30 20 10 0 % Points >131°F % total waste as ash % of total waste as ash Task 1. Effect of Ash Disposal on Percent of Elevated Temperature Readings • Effect of ash disposal on temperature over time: Landfill with high ash concentration
Task 2. Propagation of Elevated Temperatures 2007 2011 2008 2012 2009 2010 2013 2016
Task 2. Elevated Temperature Modeling • Steps have been taken to begin modeling using the NCSU elevated temperature model: • A conference call was conducted between UCF and NCSU (Dr. Barlaz and Zisu Hoa) • Meeting with NCSU next week at EREF ETLF Workshop • Decision was made to utilize the batch reactor model, applying the landfill geometry data UCF has compiled for Florida landfills • Ryan will travel to NC State within the next month to learn how to use the model
Preliminary Conclusions • Significant fraction of Florida landfills have elevated temperatures • Methane generation impacted at temperatures > 145 o. F • ETLFs had greater depth than normal landfills • While other factors are important, ash disposal appears to have significant impact on ET • Landfills with medium ash content had greater tendency for elevated temperature than low or high ash contents
Future Work • • • Define operating and design parameters and apply the NCSU elevated temperature model to explore causes of elevated temperatures Update landfill propagation using GIS software on multiple case study ETLFs Complete landfill gas/temperature data analysis for additional ETLFs without ash
Presentations • • • Florida Water Resources Conference, Palm Beach, FL. April 23, 2017. World Environmental & Water Resources Congress 2017, Sacramento, Ca. May 21 -25, 2017. SWANA Summer Conference, Fort Myers, FL. July 2325, 2017. Sardinia Symposium, Forte Village, Italy. October 2 -6, 2017. Global Waste Management Symposium, Indian Wells, Ca. February 11 -14, 2018. SCS Solid Waste Seminar, UCF. October 12, 2018. http: //www. cece. ucf. edu/people/reinhart/research/Elevated. Temperature/index. html
Acknowledgement • Hinkley Center for Solid and Hazardous Waste Management • Environmental Research and Education Foundation • S 2 Li
Suggestions? Image Courtesy of Google Images
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