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Indoor air dynamics and quality in high density residential buildings can be complex as it is affected by both building parameters, pollution sources, and outdoor meteorological conditions. The present study used CONTAM simulations to investigate the intra-building transport and concentration of an inert pollutant continuously emitted from an underground garage of a 15-floor building under moderate Mediterranean weather. The effects of outdoor meteorological conditions (air temperature, wind speed and direction) on indoor distribution of the emitted pollutant was tested under constant conditions. The importance of using actual transient meteorological data and the impact of their temporal resolution on calculated concentrations and exposure levels were also investigated. Vertical profiles of air exchange rate (AER) and CO concentration were shown to be sensitive to indoor-outdoor temperature difference, which controls the extent of the stack effect and its importance relative to wind effect. Even under constant conditions, transient mode simulations revealed that the time needed for pollutant distribution to reach steady state can be quite long (>24h in some cases). The temporal resolution (1h vs. 8h) of the meteorological data input was also found to impact calculated exposure levels, in an extent that varied with time, meteorological conditions and apartment position. [ABSTRACT FROM AUTHOR]

Despite growing apprehension regarding the fate of organic micropollutants (MPs) of emerging concern, little attention has been paid to their presence in domestic greywater, where they mainly originate from personal care products. Many MPs are not fully removed in conventional greywater treatments and require additional treatment. Vacuum-UV radiation (VUV) can generate ·OH in situ, via water photolysis, initiating advanced oxidation process (AOP) without any chemical addition. Despite growing interest in VUV-based AOP, its performance in real-life grey- or wastewater matrices has hardly been investigated. The present study investigates the removal of triclosan (TCS) and oxybenzone (BP3), common antibacterial and UV-filter MPs, in deionized water (DIW) and in treated greywater (TGW) using combined UVC/VUV or UVC only radiation in a continuous-flow reactor. Degradation kinetics of these MPs and their transformation products (TPs) were addressed, as well as bacterial growth inhibition of the resulting reactor's effluent. In DIW, MP degradation was much faster under the combined UVC/VUV irradiation. In TGW, the combined radiation successfully removed both MPs but at lower efficiency than in DIW, as particles and dissolved organic matter (DOM) acted as radical scavengers. Filtration and partial DOM removal prior to irradiation improved the process efficiency and reduced energy requirements under the combined radiation (from 1.6 and 167 to 1.1 and 6.0 kWh m−3·ּorder−1 for TCS and BP3, respectively). VUV radiation also reduced TP concentrations in the effluent. As a result, bacterial growth inhibition of triclosan solution irradiated by VUC/VUV was lower than that irradiated by UVC light alone, for UV dose > 120 mJ cm−2. [ABSTRACT FROM AUTHOR]

Removal of heavy metals (HM) from industrial wastewater is of primary environmental importance. The seeded ambient temperature ferrite process, in which heavy metals are removed from solution by their incorporation into a magnetite structure, is an attractive alternative for both complete metals separation and generation of stable magnetic sludge. Despite its potential, the effects of various operational parameters on the composition and stability of the final product are not fully understood to-date. The current paper addresses the combined effect of selected operational parameters on Co2+ incorporation efficiency. Co2+, which is used in many industries (e.g., plating, alloys manufacturing, catalytic converters, and paint pigments) and hence may pose a significant environment risk, was shown previously to be incorporated successfully into ferrite structures. Co2+-bearing ferrites were synthesized from Fe(II) solutions at ambient temperature (20 and 30°C), applying slow oxidation, pH 10.5, 20 g (as Fe) l−1 ferrite seed, and different Fe2+ to Co2+ influent ratios. Pure magnetite was used as an initial seed, which was gradually exchanged, as the reaction proceeded, by the Co2+-bearing ferrite generated within the reactor (until full exchange at steady state). Under all conditions investigated >99% of the Co2+ was removed from solution (yielding Co2+ levels below 20 μg/l in the effluent) while the generated precipitates were composed predominately of magnetite/ferrite (based on XRD analysis). Favorable results in terms of Co2+ incorporation efficiency and sludge stability were obtained when the following operational conditions were applied: 1:10 Co2+:Fe2+ molar influent ratio, 30°C, 1,500 mgFe2+ l−1 metal intermediate concentration, and 16 h aging period (pH 10.5). [ABSTRACT FROM AUTHOR]

Particle transport phenomena in the deep alveolated airways of the lungs (i.e. pulmonary acinus) govern deposition outcomes following inhalation of hazardous or pharmaceutical aerosols. Yet, there is still a dearth of experimental tools for resolving acinar particle dynamics and validating numerical simulations. Here, we present a true-scale experimental model of acinar structures consisting of bifurcating alveolated ducts that capture breathing-like wall motion and ensuing respiratory acinar flows. We study experimentally captured trajectories of inhaled polydispersed smoke particles (0.2 to 1 μm in diameter), demonstrating how intrinsic particle motion, i.e. gravity and diffusion, is crucial in determining dispersion and deposition of aerosols through a streamline crossing mechanism, a phenomenon paramount during flow reversal and locally within alveolar cavities. A simple conceptual framework is constructed for predicting the fate of inhaled particles near an alveolus by identifying capture and escape zones and considering how streamline crossing may shift particles between them. In addition, we examine the effect of particle size on detailed deposition patterns of monodispersed microspheres between 0.1-2 μm. Our experiments underline local modifications in the deposition patterns due to gravity for particles ≥0.5 μm compared to smaller particles, and show good agreement with corresponding numerical simulations. [ABSTRACT FROM AUTHOR]