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TAG Progress Report: Landfill Odors Modeling Research. C. D. Cooper, CECE Dept., Univ. of Central Fla. December 16, 2008. Background. People are moving closer to Landfills Odors can cause significant complaints, even though the landfill was there first - PowerPoint PPT Presentation
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TAG Progress Report: Landfill Odors Modeling Research
C. D. Cooper, CECE Dept.,
Univ. of Central Fla.December 16, 2008
Civil, Environmental, and Construction Engineering Department
2
Background
People are moving closer to Landfills Odors can cause significant complaints, even
though the landfill was there first Odors are hard to predict – Counties need a
buffer zone to limit development and provide a margin of safety
Hinkley Center project UCF was contracted to model the dispersion of
odors from landfills, and develop a method to predict a buffer zone
A two-year project that started in 2007
Civil, Environmental, and Construction Engineering Dept.
3
Tasks
Find a cooperating landfill Create a way to estimate emissions of odors
from a landfill Model dispersion using CALPUFF and
AERMOD to estimate buffer distances Choose the “best” model Create graphical tool for estimating buffer
zones
Civil, Environmental, and Construction Engineering Dept.
4
Seminole County Landfill
Civil, Environmental, and Construction Engineering Dept.
5
Methane as a Surrogate
Methane is a major emission from landfills For many landfills, quarterly methane
monitoring data are routinely available In a “flash of genius,” we decided to use
methane as a surrogate for odors
Civil, Environmental, and Construction Engineering Dept.
6
Ambient Methane Data
We now have 3 different quarters of methane monitoring data December 22, 2006 June 29, 2007 June 26, 2008
Typical monitoring report gives hundreds of measurements of CH4 concentrations near the landfill surface
Civil, Environmental, and Construction Engineering Dept.
7
Methane Measurement Locations
Civil, Environmental, and Construction Engineering Dept.
8
Matrix Inversion Technique
Normally, we use the Gaussian model to predict concentrations, given source strengths
By inverting the equations, we can calculate source strengths, given the concentrations
For hundreds of concentrations and hundred of sources, we needed matrix inversion
Accomplished by Dr. Kevin Mackie, a UCF faculty member
Civil, Environmental, and Construction Engineering Dept.
9
New Method for Placing Sources
Voronai diagram theory Applied to this research by Dr. Mackie Automatically locates sources for optimal
positioning relative to receptors Results show good agreement for the three
independent data sets for the same landfill Dec. 2006 – 631 g/sec June 2007 – 707 g/sec June 2008 – 1233 g/sec
Civil, Environmental, and Construction Engineering Dept.
10
Example of Source Locations
Civil, Environmental, and Construction Engineering Dept.
11
Example of Modeled Emissions Strengths
491200 491300 491400 491500 491600 491700 491800 491900 492000 492100
3184900
3185000
3185100
3185200
3185300
3185400
3185500
3185600
Civil, Environmental, and Construction Engineering Dept.
12
Modeling Results with ISC
Trendline:y = 1.0447xR2 = 0.651
0
100
200
300
400
500
0 100 200 300 400 500
Measured Ambient VOC Concentration (PPM as methane)
Pred
icte
d M
etha
ne C
once
ntra
tion
(PPM
as m
etha
ne)
Civil, Environmental, and Construction Engineering Dept.
13
Times of Highest Concentrations
In one whole year the highest modeled concentrations at each receptor (264 total items) occurred in: Day (7 a.m. to 7 p.m.) vs Night
Day - 0 Night - 264
Winter (Oct.-Mar.) vs Summer (Apr.-Sept.) Winter - 133 Sumer – 131
All occurred with winds < 2 mph
Civil, Environmental, and Construction Engineering Dept.
14
Comparing Models
Advantages of AERMOD Run time is matter of minutes rather than hours Smaller input file that makes errors easier to find Easier to learn and use.
Advantages of CALPUFF Puff tracking nature (“memory” and better handling of
calm winds). Better for longer distance dispersion
Concentration results Both give similar outputs of concentrations (CALPUFF
concentrations are slightly higher).
Civil, Environmental, and Construction Engineering Dept.
15
CALPUFF vs AERMOD
We spent considerable time making dispersion modeling runs with each program
Results are different from each other, but without actual off-site monitoring data, we cannot tell which is “right”
Choice was made based on reports of accuracy in the literature and ease-of-use considerations
And the winner is….
Civil, Environmental, and Construction Engineering Dept.
16
… AERMOD
Civil, Environmental, and Construction Engineering Dept.
17
Preliminary Screening Method
Chose to develop a graphical Screening Method Green, Yellow, Red: analogy to traffic signal
Green – OK to build Yellow – Caution Red – Stop; do not build
To use the Method for a specific landfill, must have data for:
Methane emissions, spatially distributed Odor-to-methane ratio (e.g., ppb H2S/ppb CH4) Site meteorology
Civil, Environmental, and Construction Engineering Dept.
18
Example of Screening Tool Results
490500 491000 491500 492000 492500 493000
3184000
3184500
3185000
3185500
3186000
3186500
0 ppm20 ppm40 ppm60 ppm80 ppm100 ppm120 ppm140 ppm160 ppm180 ppm200 ppm220 ppm240 ppm260 ppm280 ppm300 ppm320 ppm340 ppm360 ppm380 ppm400 ppm
Methane
Civil, Environmental, and Construction Engineering Dept.
19
Tech Transfer Results
Two presentations at conferences: FAWMA – Oct. 2007 AWMA – June 2008
Two papers submitted to journals: J. Air & Waste Mgmt Assoc. Env. Modeling & Software
One MS student (Veronica) graduated and working in the solid waste field (SCS-Tampa)
Another MS student (Nick) will graduate in May, 2009
Civil, Environmental, and Construction Engineering Dept.
20
Conclusions
We have developed an excellent method for estimating methane emissions from landfills Can use existing methane monitoring reports (or may use
a special monitoring study) Method is being published
AERMOD was chosen as best dispersion model for this application Accuracy (based on literature) Ease of use
Graphical Screening Method Easy to apply Needs site specific data
Civil, Environmental, and Construction Engineering Dept.
21
Plans for Next Semester
Nick will graduate in May Still must run sensitivity tests (stability class
and wind speed and wind angle) Develop final buffer zone Screening Tool Write thesis
Final Report CDC to write draft final report by April TAG to review in May or June Submit to Hinkley Center by June 30