| dc.description.abstract | Oil is the main source of energy for humans activities such as industries and transportations. The oil exploration activities have potential to pollute the environment (i.e.soil, water, and air). The sludge released bysuch activities can be degraded by bacteria into non-harmful compounds. Biodegradation process is done to achieve the concentration of Total Petroleum Hydrocarbon (TPH) in the contaminated soil less than 1%. The result showed that the bacteria of Bacillus sp. ICBB 7859, ICBB 9461, ICBB 5071 were able to degrade the concentration of TPH of heavy oil from 9.5082% to 0.4673%, 10.7747% to 0.3607% and 9.2442% to 0.6713%, respectively. The three isolates of bacteria needed nine weeks to complete the process. For light oil, Bacillus sp. ICBB 7859 was able to decrease the TPH from 2.9407% to 0.4378%, ICBB 9461 from 3.1433% to 0.4702%, and ICBB 5071 from 3.0742% to 0.5991% respectively, within four weeks. For iv lubricant wastes, Bacillus sp. ICBB 7859 was able to decrease the TPH of lubricant wastes from 7.6949% to 0.9067, ICBB 9461 from 7.4556% to 0.9222%, and ICBB 5071 from 7.3459% to 0.6796% respectively. The three isolates of bacteria completed the degradation process in different time. Bacillus sp. ICBB 7859 and ICBB 9461 degraded lubricant wastes within six weeks, and Bacillus sp. ICBB 5071 degraded the lubricant wastes within five weeks to reach the TPH concentration of less than 1%. | en |
