Leaching of VOCs from cement-based stabilized/solidified refinery oily sludge using solid phase microextraction

Cement-based Stabilization/Solidification was applied to refinery oily sludge. Zero Headspace Extraction was employed for the investigation of the leaching behavior of volatile organic compounds from untreated and stabilized/solidified oily sludge in water. A method is described combining zero headspace extraction, solid phase microextraction and gas chromatography with flame ionization detector for determination of volatile organic compounds in aqueous leachates. For stabilization/solidification of the waste, two types of cement were used, I42.5 and II42.5. The I42.5 is a Portland Cement whereas the II42.5 is a Blended Cement, which contains pozzolanic material. In general, the I42.5 cement showed better immobilizing characteristics than the II42.5 cement, but the difference was small. The leaching behavior of toluene, o-xylene, p,m-xylene and ethylbenzene from stabilized/solidified samples was similar for both types of cement. The reduction in the maximum leached amount of stabilized/solidified specimens compared with that of the untreated oily sludge alone, varied from 80% to 98%, for specimens with 10% cement addition (both types). Increased leaching was observed with increasing cement addition. In the case of naphthalene, stabilized/solidified samples leached more than threefold the amount leached from the untreated oily sludge alone.