Identification and simulation of atmospheric dispersion patterns of odour and VOCs generated by a waste treatment plant
M.C. Gutiérrez, M.A. Hernández-Ceballos, P. Márquez, A.F. Chica, M.A. Martı́n
Abstract
The impact of odorous gases emitted from waste treatment plants (WTP) has been a major concern of communities living near these facilities. This paper describes the methodology used to estimate the dispersion of odorous and volatile organic compound (VOC) emissions from a WTP situated in Vacarisses (Barcelona). The steps are as follows: (1) collection of gaseous samples at the WTP chimney outlet to the atmosphere; (2) olfactometric and chemical characterization of gaseous samples; (3) identification of the main atmospheric dispersion patterns using air mass trajectories and (4) modelling of the WTP emissions using a dispersion model. The impact on nearby populations such as Tarrasa, Esparraguera, Martorell, Castellar del Vallés and Manresa (Catalonia, Spain) was evaluated. The mean removal efficiency of the WTP biofilter was 37.0 ± 5.0%. Therefore, the remaining 63.0 ± 5.0% accounted for emissions into the atmosphere for average odorous (1,700,000 ouE/s) and VOC emissions (1,476,500 μg/s). VOCs were classified into 19 chemical families, of which terpenes, ketones, alcohols and aliphatic hydrocarbons were the most abundant, with concentrations ranging from 4000 to 8000 μg/m3. The air mass trajectory analysis identified six airflow patterns from the WTP with a clear seasonal distribution. The simulation of the dispersion revealed that Tarrasa (to the southeast) was the most affected community, with odorous and VOC impacts of approximately 4.0 ou/m3 and 3.5 μg/m3 (in summer, wind speed = 1.51 m/s). Although these values are not relevant for the safety and well-being of humans, they do deteriorate air quality.