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Correlating emissions with time and temperature to predict worst-case emissions from open liquid area sources
Archana Nagaraj1, Melanie L Sattler
1Weaver Boos Consultants, Fort Worth, TX, USA.
Journal of the Air & Waste Management Association (1995)
|September 29, 2005
Summary
This study introduces a method to improve air pollution modeling by varying emission rates based on temperature and time. This approach more accurately predicts odor impact from wastewater treatment plants, unlike constant emission models.
Area of Science:
- Environmental Science
- Atmospheric Chemistry
- Chemical Engineering
Background:
- Ambient air pollutant concentrations depend on emission and dispersion rates.
- Dispersion models often use constant emission rates, which is inaccurate for sources like wastewater treatment plants with variable emissions.
Purpose of the Study:
- To develop and validate a method for varying emission rates based on temperature and time of day to predict worst-case air pollution impacts.
- To improve the accuracy of odor impact predictions from open liquid area sources, such as wastewater treatment plants.
Main Methods:
- Developed a method to vary emission rates using linear functions of temperature (Henry's law) and polynomial functions of time.
- Estimated equation coefficients using field measurements of hydrogen sulfide (H2S) and temperature data logger.
- Inputted hourly varying emission rates into the ISCST3 dispersion model.
Main Results:
- Varying emission rates hourly predicted 384 acres of odor impact.
- Constant emission rates predicted only 103 acres of odor impact.
- Constant emission rates underestimated odor impact by 73% when sampling occurred on cooler days.
Conclusions:
- Varying emission rates with temperature and time significantly improves odor impact predictions compared to constant emission models.
- Accurate air quality modeling requires accounting for dynamic emission rates influenced by environmental factors.
- The developed method provides a more realistic assessment of odor impact from wastewater treatment plants.
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