Investigation of method for preventing oil spilled on the ground surface to migrate downwards and contaminate groundwater : Theoretical modeling, experimental study and practical technique

The project aims at investigating how effectively the groundwater can be isolated from diesel oil that has leaked from a failed tank by covering the ground surface in a few hundred square meters large area confined by soil dikes. The scenario to be considered is a sudden outflow of oil over the ground followed by removal of the oil after a period of time taken here to be 2 weeks. The depth of the oil fill in this period is assumed to be 0.5 m, which will cause oil to penetrate and migrate into the membrane built on the ground surface. The problem to be solved is to predict to what depth the membrane will be contaminated by oil, i.e. how much of it that has to be removed and replaced after the two weeks. The ground surface is assumed to be perfectly horizontal. The project comprised oedometer testing of the artificially prepared membrane clay, which contains a small amount (11 % by weight) and which is a candidate material for isolation of the ground from oil that can leak out from failing tanks or valves. The oedometer tests were made for determining the (fluid) conductivity and swelling pressure of the membrane material for water and for diesel oil and they were complemented by column tests for simulating of the function when oil is let into air-dry membrane material, and into water saturated material, respectively. The aim was to find out if and how oil molecules move in the membrane.Validerat; 20120918 (anonymous