AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Understanding Ultrafine Particulate Emissions & Dispersion from Wastewater Treatment Processes in an Urban Environment
PEDRO PIQUERAS, Robiul Md Islam, Fengying Li, Jill Luo, Mark Matsumoto, Elizabeth Stone, Akua Asa-Awuku, University of California, Riverside
Abstract Number: 6 Working Group: Urban Aerosols
Abstract The construction and use of wastewater treatment plants is increasing significantly as water resources become scarce and population grows. Wastewater treatment plants (WWTP) are common in urban environments and their aerosol emissions have been associated with local and regional health burden.
In this study, we present particle concentration and size distribution measurements from Orange County Sanitation District aeration basins and we relate them to filter samples collected from ambient air. In addition, we have used EPA’s model AMS/EPA Regulatory Model (AERMOD) to establish a relationship between basin coverage, source emission and dispersion. Three different scenarios were modeled with annual, monthly and daily meteorological data. The scenarios that were taken into consideration were complete open basins, partially covered basins and mainly covered basins.
Results show that aerobic processes from WWTP generate particles through bubble bursting mainly in the ultrafine size range. Model outcomes suggest that the particles are transported to residential neighborhoods and public spaces such as school and parks within 1000 meters from the plant. Chemical characterization of filter samples further prove that these particles originated in the WWTP due to the incidence of fecal sterols in the collected particles.
From the model it is determined that although OCSD’s aeration basins are partially covered, coverage of the basins does not substantially reduce the particle concentration emitted; therefore a different mitigation design and full coverage of the basins is advised. The relationship presented in this study can also be used in the future to determine the emission rates from other wastewater treatment facilities if area and airflow injected in the aeration basins are known.