Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
ANALYSIS OF EMISSIONS OF ODORANT COMPOUNDS WITH CHANGES TO THE INTERNAL SETUP OF THE USEPA DYNAMIC FLUX CHAMBER
Submission Author:
Laize Nalli de Freitas , ES , Brazil
Co-Authors:
Kamila Furtado Cupertino, jane meri Santos, Bruno Furieri, Philipe Uhlig Siqueira
Presenter: Philipe Uhlig Siqueira
doi://10.26678/ABCM.COBEM2023.COB2023-2398
Abstract
Odorant compounds are air pollutants that originate from various sources, both anthropogenic and natural. Among these sources, Wastewater Treatment Plants (WWTP) are particularly notable due to their significant environmental impact on surrounding neighborhoods, causing inconvenience through the emission of pollutants. These plants also serve as significant sources of hydrogen sulfide (H2S) and volatile organic compounds (VOCs), which are produced during the digestion of organic matter. For the measurement of such emissions, dynamic flow chambers (DFCs) are commonly used enclosed devices. Our objective was to evaluate the impact of inserting internal gas mixers in the USEPA DFC on the emission of different odorant compounds. To accomplish this, we examined three different inlet flows: 2, 5, and 10 liters per minute (LPM). For the 5 LPM flows, we introduced two fans of varying sizes, creating an ascending flow and a descending flow. The chosen odor compounds were hydrogen sulfide (with volatilization dominated by the liquid phase) and acetic acid (HAAc), whose volatilization is dominated by the gas phase. Quantification of these compounds was performed through separate experiments. For H2S, the analysis involved analyzing the liquid phase using spectrophotometry, while for HAAc, the analysis focused on the gas phase using gas chromatography. The results showed that the variation in inlet flow directly influenced an increase in the emission flux (p < 0.005), with emissions varying proportionally to the inlet flow. Furthermore, the addition of the two internal fans also resulted in increased emissions (p < 0.005), ranging from 2.94E-08 to 5.23E-08 kg.m−2 s −1 . When comparing the emissions with the addition of fans, the impacts on the compounds differed. For H2S, there was an increase in emission in all cases, reaching 131.23% for the Large Fan down (LFD) configuration. As for HAAc, the impacts varied, with the largest increase observed for the Large Fan up configuration (20.66%), but a reduction of 9.16% in emissions for the LFD configuration. This difference is primarily due to the different volatilization behavior of the compounds and how the increase in friction velocity at the liquid-gas interface leads to an increase in the emission of only compounds dominated by the liquid phase. In conclusion, our study highlights the significance of considering the chemical characteristics of odorant compounds when measuring emissions. The results demonstrate that variations DFC directly influence the emission flux.
Keywords
odorous compounds, dynamic flux chamber, Wastewater Treatment, Hydrogen Sulfide
