Abstract

Since 1994, PT Caltex Pacific Indonesia has committed to gradually discontinue using oily soil for any application that may be of environmental concern such as premixed-soil for supporting and burying pipeline and as a road surface stabilizer. To address this situation, PT Caltex Pacific Indonesia has been developing a reliable and cost effective bioremediation process for crude oil contaminated soil. This biological process utilizes microbes that can degrade oil in soil to yield environmentally-acceptable remediated soil which is rich in nutrient and can be used safely for farming.

The development project included laboratory testing for the crude oil biodegradability, a pilot test and field implementation of a full scale bioremediation process. A two-hectare bio-treatment unit (BTU) has been constructed in Minas field that is capable of processing about 4,000 m³ of crude oil contaminated soil per cycle. The first operation cycle of the BTU revealed that, with proper operation to maintain the required parameters at optimum conditions, it could reduce the total petroleum hydrocarbon (TPH) level of the crude oil contaminated soil from about 3% to less than 0.5% after three months exposure. After performing an intensive risk-based evaluation, especially for the heavy metals and BTEX (benzene, toluene, ethyl benzene and xylene), the remediated soil could be removed from the BTU to be used for re-greening or farming and then the second cycle of operation could be initiated.

This paper describes the details of the project development including oily soil characterization, site assessment, design, construction, operation, monitoring and performance of the BTU. The use of remediated soil as well as treatment cost is also discussed.