Stabilization/Solidification of used lubricating oil containing Fe and Pb with Portland cement and bentonite

Used lubricating oil belong hazardous waste based on the Government Regulation Number 101 in 2014 about Hazardous Waste Management. Used lubricating oil contain hydrocarbon and heavy metals such as Fe and Pb. One of method to immobilize used lubricating oil is stabilization/solidification (S/S). S/S method always uses Portland cement to immobilize the heavy metals, but Portland cement can not immobilize the hydrocarbon. In this research, S/S method used Portland cement and bentonite are binding the heavy metals and hydrocarbon in the used lubricating oil. The composition used was cement bentonite 25:75, cement bentonite 75:25, cement 100%, and bentonite 100%. Used lubricating oil was added in 5%, 10%, and 15% weights. The S/S products were examined by measuring the TCLP of the Fe and Pb. The TCLP test was compared with the Fe and Pb concentration in the used lubricating oil. The results showed that the TCLP test of the Fe on the S/S product containing 5%, 10%, 15% used lubricating oil with cement 100% was 371.14 mg/L, 403.66 mg/L, and 417.89 mg/L respectively. Meanwhile, the Fe concentration in the used lubricating oil was 47.78 mg/L. The adding of bentonite to the S/S product decreased the Fe concentration that was leached. The TCLP test of the Fe in the S/S products that contained 5%, 10%, and 15% used lubricating oil with bentonite 100% were 15.24 mg/L, 0.085 mg/L, and 0.428 mg/L respectively. The S/S method using Portland cement and bentonite decreased the Pb concentration leached into the environment.