DTIC ADA280036: Landfill Gas Characterization and Leachate Removal at the Alachua County Southwest Landfill, Alachua County, Florida Through Utilization of a Mechanical Gas Collection System

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by  Defense Technical Information Center

AD-A280 036
LANDFILL GAS CHARACTERIZATION AND LEACHATE REMOVAL AT THE
ALACHUA COUNTY SOUTHWEST LANDFILL, ALACHUA COUNTY, FLORIDA
THROUGH UTILIZATION OF A MECHANICAL GAS COLLECTION SYSTEM
DTIC
ELECTE
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KURT R. GIES, P.E.
94-1750'1 l'- &oc uzie" t -°"
A NON-THESIS PROJECT, PRESENTD TO THE DEPARTMENT OF
imirinNNTIL ENGINEmRNG scImCS
OF THE UNIVERSITY O FLORIDA IN PARTIAL FULFILMENT
OF THE REQUT FOR THE DERE OF
MASTER OF ENGINEERING
UNIVERSITY OF FLORIDA
1994
94 6 8 131S
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LANDFILL GAS CHARACTERIZATION AND LEACHATE REMOVAL AT THE
ALACHUA COUNTY SOUTHWEST LANDFILL, ALACHUA COUNTY, FLORIDA
I THROUGH UTILIZATION OF A MECHANICAL GAS COLLECTION SYSTEM
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Accesion For
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Unannounced 0
JustiJfuisctiafctaitoion ............... ....... BB
y. .... KURT R. GIES, P.E.
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Availability Codes
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A NON-THESIS PROJECT PRESENTED TO THE DEPARTMENT OF
ENVIRONMENTAL ENGINEERING SCIENCES
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILlMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF ENGINEERING
UNIVERSITY OF FLORIDA
1994
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Dedicated to my family, Peggy, Cory, Magic and Taylor?.
Without your love and support, this vould have been
meaningless. Thanks for alvays making me smile.
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ACKNOWLEDGMENTS
I would like to thank the members of my graduate
committee, Dr. W. Lamar Miller, Chairman; Dr. Jonathan
Earle; and Dr. Michael Annable. Without your vast range of
expertise and knowledge, I would not have been able to
complete this project. Dr. Annable taught me more when it
comes to engineering and applying its principles than I
really thinks he realizes. Dr. Earle's ability to say the
right things at the right time in order to help me focus my
work was invaluable. Finally, Dr. Miller deserves special
recognition for his ability to put out those troublesome
fires that could have potentially caused disaster.
My acknowledgments would definitely be incomplete if I
failed to mention my fellow students in my research group.
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Thanks goes out to Randy Sillan, Tim Townsend, Frank Pohl,
Jim LaForest, Frank Redway, Kim Shank, Jim Nelms, Jason
Lynch, Anne Lerner, Chris Pericano, and Steve Kropt. Their
academic support, ability to put up with me, and friendship
have allowed me to keep my perspective on what this all
means. I would also like to mention the staff of the
Alachua County Office of Waste Management. Without their
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strong interest and financial support this project would
have never been completed.
My parents Walter E. and Yvonne R. Gies and my brothers
and sisters Scott, Russell, Gretchen, Eric, Sheila, Helen,
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Dave, and K.C. all deserve thanks for their years of
support. They are all true "Geyersol
Last, and definitely most important, I would like to
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thank my lovely bride of six years, Peggy. Her ability to
be a wife, a mother, a teacher, a provider and a friend
during those long weeks of seemingly endless tests, term
papers and homework assignments is the main reason I
survived graduate school. This degree is more hers than
mine. "a"
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TABLE OF CONTENTS
ACKNOWLEDGflENTS a....d...L.eah ei onHazards..................i
ABSTRACT o on........................*...... *0*ooe*o.0 ...... vi
INTRODUCTIONoeoo.ooooeeo~eoooooo~eooo
o Poce.....
OBectop ....... o...... ........ ............... 1
FjeActoRes AEcting.Gas................................
Landfill Gas and Leachate Migration Hazards ............. 5
Gas Production .......................................... 7
Decomposition Processa .... o............................7
Factors Affecting Gas Production ..................... 12
Gas Yield Projections ................................ 19
Theoretical Models ................................ 20
Mathematical Models ............... ................ 22
Leachate Production ...y........................ ...... 22
Leachate Management .................................... 25
Gas Management ...........................
Flow in Porous adia ................................. 27
o......
SW Conductivity .........
Landfill Gas Flow .................................... 34
Active Collection Systems ............................ 36
Gas Collection .................................... 36
Gas Condensate .................................... 37
SITE DESCRIPTION ... ................... .......... ... 39
Site Location .......................................... 39
Site Characteristics ................................... 41
Unit I ............................................... 4
Unit I . . . . . . . . . . . . . . . . . . . . . . .4
Unit III ............................................. 61
METHODS AND NATEZRIALS ..................................... 67
Sampling Equipment and Materials ....................... 67
Well Field ................................. .. 67
Well Design .......................................... 67
Gas Collection System................................
Mani fold .......... .... ............... •.. ..... ... 74
Blowers ............. •... ........ •................ ;.. 75
Flare ........... .... .0...........................75
Active Tie-i..n.. ......... .. 00.........*000.....0...76
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HIL Tie-lin .......................................... 81
Sampling Methods ..................................... 83
At The Flare ......................................... 81
Gas quality ....................................... 83
Pressure, Temperature and Flow .................... 83
At The Wells ......................................... 83
Gas quality ....................................... 83
Pressure and Flow ................................. 84
Leachate Levels ................................... 84
Leachate Pumped ................................... 85
RESULTS AND DISCUSSION .................................... 86
initial Set-up ...O....................................1..86
Approach ............................................... 87
Phase I .............................................. 89
Phase II ............................................ 101
Phase III ........................................... Ill
Phase IV ............................................ 118
Phase V ............................................. 130
CONCLUSIONS ...................... ......... ....... ...... 150
APPENDIX A, CONDENSATE CALCULATIONS ...................... 154
APPENDIX B, FLARE OPERATION PROCEDURES ................... 157
APPENDIX C, GAS SAMPLING PROCEDURES ...................... 166
APPENDIX D, WELLFIELD PREESURE DATA ............ 9.9*e.......173
APPENDIX E,, ACCU`-FLO WELLHEAD INFORMATION ................ 188
Methods of LFG Control ................................ 189
Well Field Adjustment - Purpose And Objectives ........ 190
Taking Measurements At The Accu-Flo Wellhead .......... 191
Using the GEM-500 to Gather Data ...................... 191
REFERENCES.**..........o......s...... o............ ........... 200
BIOGRAPHICAL SKETCH ............................ 0
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Abstract of a Non-Thesis Project Presented to the Department
of Environmental Engineering Sciences
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Engineering.
LANDFILL GAS CHARACTERIZATION AND LEACHATE REMOVAL AT THE
ALACHUA COUNTY SOUTHWEST LANDFILL, ALACHUA COUNTY, FLORIDA
THROUGH UTILIZATION OF A MECHANICAL GAS COLLECTION SYSTEM
Kurt R. Gies
April 1994
Chairman: Dr. W. Lamar Miller
Major Department: Environmental Engineering Sciences
In November 1992, a landfill gas collection system for
the Alachua County Southwest Landfill was activated and set
so that it was collecting gas from all the wells in a 30-
acre area (operational from 1972 to 1985), and all the wells
from an 11-acre area (operational from 1985 to 1988) at a
flow rate in excess of 1,000 scfm. In February 1993, an
analysis of the system commenced in an effort to optimize
the flow and the quality of the extracted gas.
Additionally, an attempt to determine the quantity of gas
that can be expected over the next several years was made.
Samples of gas were collected on the downstream side of the
system's centrifugal blowers. Analysis of the gas
components for CH , C0 , N , and 02 concentrations were
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conducted. Results indicated that the 30-acre area and the
11-acre areas were producing 264 scfm of methane. Based on
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an average half-life of 14 years, the Scholl Canyon Landfill
Gas Kinetic Model predicted the total flow from these two
areas would average 116 scfm of CH until the year 2000.
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The production of gas from a 27-acre operating cell
also was examined. In determining the amount that can be
extracted, every effort was made to use the existing
systems, while at the same time providing the least amount
of disruption of the daily landfill operations. By
connecting to the active cell leachate collection system
clean-out line, 286 scfm of methane was captured from the
operating cell. Based on the data from this study and other
studies at this site, the Scholl Canyon model predicts a
half-life of 5 years. The half-life was reduced because
this area had been wetted.
Finally, an examination of the feasibility of using a
landfill gas collection system to remove ponded leachate
from degraded waste was conducted. It is predicted that 900
gal/day of moisture can be removed based on a temperature
difference of 40OF and flow of 1000 scfm. The method used
for this study estimated that leachate was removed at a rate
of 8,228 gallons/day. Because of this method, various
assumptons that were made in determining this rate resulted
in an over estimation of the volume removed. Leachate was
removed from the waste, but the quantity needs to better
defined.
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CHAPTZR 1
INTRODUCTION
Throughout history, land disposal of solid waste has
been the primary means for processing this waste. Nan would
generate products and discard the waste, usually with little
thought to the impact. Franklin Associates (1988) estimated
that approximately 80 percent of the waste produced in the
United States was deposited in landfills in 1987. Most of
the public thinks that once the waste is thrown away that
this is the end of the process. This is far from the truth.
When waste is deposited, the organic portion begins to
decompose. Initially, refuse placed into the landfill
contains trapped air. Aerobic bacteria begin to decompose
the waste until the oxygen has been consumed. The anaerobic
bacteria then begin to develop. In the anaerobic
environment, the organic fraction of the waste is broken
down into methane, carbon dioxide and water. If for any
reason oxygen is reintroduced in the waste, the anaerobic
bacteria begin to die, thus impeding degradation and methane
production.
Gas production in landfills is an area of increasing
environmental concern. Uncontrolled emission or migration
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