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 CH 4 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 – 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

Civil, Environmental, and Construction Engineering Dept. 12 Modeling Results with ISC

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 Winter (Oct.-Mar.) vs Summer (Apr.-Sept.) Winter 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 H 2 S/ppb CH 4 ) Site meteorology

Civil, Environmental, and Construction Engineering Dept. 18 Example of Screening Tool Results

Civil, Environmental, and Construction Engineering Dept. 19 Tech Transfer Results Two presentations at conferences: FAWMA – Oct 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