An Investigation on the Environmental Impact of a Petroleum Refinery and Proposed Methods for Decontamination of Soil and Groundwater

Abstract

Toxicity of crude oil for the living world and ecosystems in general is a global problem of both aquatic and terrestrial environments. Therefore, the remediation of oil contaminated soils, sediments and groundwater is a major challenge for environmental research. In the target area of this survey which is a petroleum refinery near Tehran, soil and groundwater pollution, its source, contaminated area and distribution of pollution were studied. The investigations showed that the contamination of soil which is mainly silt and clay is expanded until the surface of region groundwater and formed an oily layer with different thicknesses in the whole area. According to the result of free product analysis, the free product is a multi-type mixture of oil and its main ingredients are assumed to be gasoline, kerosene, and gas oil. In addition, pollution sources in the field are thought to be underground pipes, tanks, pipeline and so on. For decontaminating of soil and water resources there are different ways including physical, chemical and biological methods or combination of two or three types of them to reduce the extent of contamination and its dangers for the region ecosystem. The free oil existing over the groundwater table could be removed by physical ways like pump and treat method but decontamination of soil is more complex. Due to long lasting contamination of the field, the existence of accumulated indigenous microorganisms and the probable ability of them to effectively biodegrade pollutants by man-assisted interventions are expected. In this survey the feasibility assessment of bioremediation alongside other ways of treatment in the investigated area is performed.