MODELLING OF ENVIRONMENTAL LEACHABILITY OF PETROLEUM REFINERY OILY SLUDGE

Abstract

In the recent years there has been increased concern worldwide of air and water contaminants and their possible consequences to human, animal and plant life. Oily sludge is generated in the petroleum refineries primarily due to storage or processes that removes impurities from the crude oil or the fuel oil produced from the crude oil. A significant quantum of which may be hazardous in nature and can cause health risk, when dumped in the environment, without adequate safety measures. There has been no systematic study on the quality of sludge being generated and on the composition with particular emphasis to the presence of hazardous chemicals/ substances. Recently there have been some developments in the treatment and disposal techniques but the selection of technique has not been based on understanding of the hazards posed by the sludge and adequacy of selection techniques in abatement of these hazards. To understand the potential risk associate with any hazardous waste requires modeling of its behavior in the environment. The present modeling is carried out utilizing the framework of Source- Pathway- Receptor analysis. However, the application of this analysis framework has been inadequate in India leading to unspecific approach to hazardous waste management. The most important consideration in this modeling understanding of contaminant transport process through soil into the groundwater which entails identification of important parameters. Many models are available for the simulation of contaminant fate and transport but in present study the Hydrocarbon Spill Screening Model (HSSM) has been used to understand the important factors and process which control the fate and behavior of lesser number of contaminants present in the sludge in the environment. There are 36 physical and chemical parameters required to run HSSM. Each of these has an impact on the model results. Seven major parameters as given below have been selected to study the 111 sensitivity of Non Aqueous Phase Liquid (LNAPL) in the receptor wells. These seven parameters in turn led to variation in many of the other 36 parameters. i. Sources of oily sludge ii. Initial concentration of the contaminant iii. Soil type iv. Depth to water table v. Average recharge rate vi. Source strength (flux rate) vii. Contaminant and soil partition coefficient The results provide site- specific treatment and disposal alternatives for different type of sludges. With the use of these results the influence of major parameters on the final out come i.e. concentration in drinking water well can be predicted.