Debra Reinhart PhD PE BCEE Ryan Joslyn Department of Civil Environmental and Construction Engineering University of Central Florida Orlando FL TAG Meeting November 1 2018 Presentation Overview ID: 788174
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Slide1
Characterization of Florida Landfills with Elevated Temperatures
Debra Reinhart, PhD, PE, BCEERyan JoslynDepartment of Civil, Environmental, and Construction EngineeringUniversity of Central Florida, Orlando, FL
TAG Meeting
November 1, 2018
Slide2Presentation Overview
Research Goals and ObjectivesMethodology and TimelineResults to DateQ & A
Slide3Research 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
Slide4Year 2 Objectives
Expanding analysis of historical leachate and gas dataUtilization of the NCSU Elevated Temperature Model to create two case study models of Florida landfillsUse ArcGIS to explore the propagation of landfill temperatures over timeDetermination of appropriate design and operating parameters to safely manage ash and waste
Slide5Methodology - 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.).
Slide6Methodology - 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)
Slide7Methodology - 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.
Slide8Methodology - 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.
Slide9Methodology - Task 2: Elevated Temperature Modeling
Elevated Temperature modeling is also being conducted using ArcGIS 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.
Slide10Methodology - 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.
Slide11Project Timeline
Tasks
Month
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
Slide13Task 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).
Slide14Task 1. Elevated Temperature Well Graphs
Slide15Task 1. Cumulative Gas Temperature Data Analysis
Of the 22 landfill cells that provided monthly monitoring data, 64% had elevated temperatures.10% had >15% of wells with elevated temperatures
Slide16Task 1. Cumulative Gas Quality Data Analysis
A CH4:CO2 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 CH4:CO2 ratio < 1 increasesMethane generation impacted at temperatures > 145
Slide17Task 1.
Landfill Size and Depth
N = 8 landfill cells (no elevated temp)
N =11 landfill cells (with elevated temp)
Slide18Task 1.
Leachate Treatment
N = 7 landfills
Slide19Task 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:
Slide20Task 1. Example ETLF
Leachate characteristics (Ketones)
Slide21Task 1. Cause of Elevated Temperature – Air Intrusion?
Slide22Task 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 CO2 and H2 gases
Slide23Task 1.
Effect of Ash Disposal on Maximum Temperature
N = 14 landfill cells (no ash)
N =8 landfill cells (with ash)
Slide24Task 1.
Effect Of Ash Disposal On Percent Of Elevated Temperature Readings
N = 14 landfill cells (no ash)
N =8 landfill cells (with ash)
Slide25Task 1. Effect of Ash Disposal on Percent of Elevated Temperature Readings
Effect of ash disposal on temperature over time: Landfill with medium ash concentration
Slide26Task 1. Effect of Ash Disposal on Percent of Elevated Temperature Readings
Effect of ash disposal on temperature over time: Landfill with high ash concentration
Slide272007
2008
2009
2010
2011
2012
2013
2016
Task 2.
Propagation of Elevated Temperatures
Slide28Task 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 WorkshopDecision was made to utilize the batch reactor model, applying the landfill geometry data UCF has compiled for Florida landfillsRyan will travel to NC State within the next month to learn how to use the model
Slide29Preliminary Conclusions
Significant fraction of Florida landfills have elevated temperatures Methane generation impacted at temperatures > 145oFETLFs had greater depth than normal landfillsWhile other factors are important, ash disposal appears to have significant impact on ETLandfills with medium ash content had greater tendency for elevated temperature than low or high ash contents
Slide30Future Work
Define operating and design parameters and apply the NCSU elevated temperature model to explore causes of elevated temperaturesUpdate landfill propagation using GIS software on multiple case study ETLFsComplete landfill gas/temperature data analysis for additional ETLFs without ash
Slide31Presentations
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 23-25, 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
Slide32AcknowledgementHinkley Center for Solid and Hazardous Waste Management
Environmental Research and Education Foundation S2Li
Slide33Suggestions?
Image Courtesy of Google Images