Modelagem das emissões de H2S da CTR Maceió-AL

Abstract

In several Waste Treatment Centers (WCs), fugitive emissions are a problem of atmospheric pollution that reach local and global levels, as their composition is formed by several harmful gases, such as carbon monoxide (CO), carbon dioxide (CO), methane (CH4), and hydrogen sulfide (H2S). The emission of odorous gases from landfills results mainly from the generation of gaseous compounds during the biodegradation of waste, having a relationship with the cover layer, depth, number of drains, cell dimensions, age of waste, weather conditions and soil properties. Complaints about odor from the population living around the landfill have been reported to the authorities, since the nuisance responsible for health effects occurs in the recipients after their continuous and prolonged exposure. In this context, understanding H2S emissions and the factors that interfere in this process can provide important contributions to the mitigation of environmental and social impacts, intensifying the systematic monitoring of concentrations of this pollutant in the atmosphere. Thus, this study aims to evaluate the degree of impact on the environment caused by emissions from CTR Maceió - AL, through the mathematical simulation of concentrations of hydrogen sulfide (H2S) using the AERMOD View software, a very common atmospheric dispersion model in several surveys, which predict concentrations at selected downwind receptor sites. For this, the change in air quality covering the period from 2016 to 2021 was observed, through reports of H2S measurements and volumetric flows collected in the landfill drains, establishing scenarios for modeling gas concentrations, diagnosing the possible impacts that could harm the health of the population. The results revealed that the maximum concentration of 0.119 mg/m3 of H2S occurred in Scenario 1 (dawn), representing the period in which the stratification of the atmosphere tends to weaken the turbulent activity of the air that reflects in the increase of the concentration of H2S, whose value is 2.8 times higher than the Odor Perception Limit (LPO) of 0.042 mg/m3. Therefore, in this period the H2S plume spreads over an area of 25 km² reaching all the receivers installed to the west of the landfill. The concentrations of H2S contained in the biogas are significant and, therefore, can be treated as relevant questions to make in future studies the energetic use of biogas in the Waste Treatment Center of Maceió.