Solidification/stabilization remediation of heavy metal from petroleum Al-Dura sludge with Portland cement

Abstract

The aim of this research is to evaluate the method of stabilization/solidification in the treatment of cadmium and iron from Al-Dura Oil Refinery sludge. In addition, the effect of organic matter was studied by using treated and untreated sludge. The procedure was applied in three treatments, where the cement was added to a mixture of sludge/sand prepared at three ratios (i.e., 1:2, 1:3, and 1:4) and also without any sludge (as the control), with the treated and untreated sludge used in proportions of 7, 15, and 25% by weight of sand. Tests of unconfined compression strength and a toxicity characteristic leaching procedure were used to evaluate the stabilization/solidification matrix. The highest unconfined compression strength was 3 Mpa for the samples with untreated sludge, while it was 2.1Mpa for samples with treated sludge. However, the results of the leaching test showed that the samples with the untreated sludge had more retention efficiency compared to the samples with treated sludge. The cadmium retention efficiency was 99.1%, while for iron, it was 97.5%. The organic matter (especially aromatic) had no effect on the leaching of either Iron or cadmium. Therefore, this method seems to be highly successful in the treatment of both Iron and cadmium with untreated Al-Dura Oil Refinery sludge.