PARTICULATE DISPERSION MODELING OF SALT HARVESTING ACTIVITIES FROM LAKE URMIA

Abstract

Introduction: Drying of parts of Lake Urmia has exposed to salt domes in various areas of the lake. As such, the economic incentive for salt harvesting has been improved due to the easier access. Nonetheless, these operations have the potential of generating particulate air pollutants that can adversely impact immediate and distant agricultural and residential areas. Dispersion modeling is needed to evaluate the effect of various operational parameters on the generation and transport of these particulates.
Materials and methods: A mine with the capacity of 1250 tons /day in the area of Qobadlu and two other salt sites around lake Urmia were considered for modeling. Major activities that contribute to pollutant production include transport vehicles and wind erosion from storage salt piles. Wind erosion from the piles was evaluated under different scenarios using CFD approach. Using emission factors for other activities, topographic and climate data, Gaussian dispersion of particles was conducted using ADMS modelling system.
Results: The results showed that transportation of particles occurs towards the lake with negligible concentrations for distances within the 150 m radius; observed trend was a reduction from concentrations of around 100 μg / m3 at the site to 5 μg / m3 at the afore - mentioned distance. Layout optimization of storage piles and erection of barriers respectively resulted in up to 17 % and 44 % reduction in particulate generation from pile surfaces.
Conclusions: The results of this research have been used in the preparation of the environmental guidelines for salt harvesting in compliance with the lake Urmia restoration directives.