Real-Time Ultrafine Aerosol Measurements from Wastewater Treatment Facilities

Abstract

Airborne particle emissions from wastewater treatment plants (WWTP) have been associated with health repercussions but particulate quantification studies are scarce. In this study, particulate matter (PM) number concentrations and size distributions in the ultrafine range (7-300 nm) were measured from two different sources: a laboratory-scale aerobic bioreactor and the activated sludge aeration basins at Orange County Sanitation District (OCSD). The relationships between wastewater parameters (total organic carbon (TOC), chemical oxygen demand (COD), and total suspended solids (TSS)), aeration flow rate and particle concentrations were also explored. A significant positive relationship was found between particle concentration and WWTP variables (COD: r(10) = 0.876, p <.001, TOC: r(10) = 0.664, p <.05, TSS: r(10) = 0.707, p <.05, aeration flow rate: r(8) = 0.988, p <.0001). A theoretical model was also developed from empirical data to compare real world WWTP aerosol number emission fluxes with laboratory data. Aerosol number fluxes at OCSD aerated basins (9.8 × 10 lbs/min·cm) and the bioreactor (7.95 × 10 lbs/min·cm) were calculated and showed a relatively small difference (19%). The ultrafine size distributions from both systems were consistent, with a mode of ∼48 nm. The average mass concentration (7.03 μg/cm) from OCSD was relatively small compared to other urban sources. However, the in-tank average number concentration of airborne particles (14 480 lbs/cm) was higher than background ambient concentrations.

Probabilistic Analysis of a French Legionellosis Outbreak Shows Potential Role of Wastewater Basin

“…Even if measurement of Legionella in air is not yet scientifically approved, the concentrations measured show a Legionella air concentration never before seen elsewhere. Some studies have measured or modeled the quantity of aerosols emitted by these facilities [36][37][38] and could explain the high concentrations of Legionella measured in the air due to the high concentration of Legionella found in the wastewater basin.…”

Sources, fates and treatment strategies of typical viruses in urban sewage collection/treatment systems: A review

“…The mechanical rotation and aeration of wastewater during the primary and secondary treatment creates bubbles with diameters of approximately 60–600 μm that travel as much as ~8 cm above the wastewater surface of the aeration tanks [246] , [247] . Thus, aerosol inhalation or direct contact with infectious viral particles leads to a higher exposure risk of viruses for WWTP workers ( Fig.…”

Assessment of personal deposited dose of bioaerosols and particles in a wastewater treatment plant facility

“…Widiana et al (2017) found in a municipal WWTP in North Taiwan that the annual PM 10 concentration was equal to 45 μg/m 3 , a value that exceeds the annual value recommended by the WHO (20 μg/m 3 ) and EU (40 μg/m 3 ) for the protection of human health. Furthermore, Piqueras et al (2016) asserted that semi covered aeration tanks emit airborne particles which can affect the health of nearby residents. Specifically, the number concentration in the aeration tank at Orange County Sanitation District (Fountain Valley, CA) ranged from 7000 to 18,000 #/cm 3 (Piqueras et al 2016).…”

“…Furthermore, Piqueras et al (2016) asserted that semi covered aeration tanks emit airborne particles which can affect the health of nearby residents. Specifically, the number concentration in the aeration tank at Orange County Sanitation District (Fountain Valley, CA) ranged from 7000 to 18,000 #/cm 3 (Piqueras et al 2016). In addition, Yang et al (2021) performed field measurements with a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS) at moving bed biofilm reactor (MBBR) at a municipal WWTP located in China.…”