Biodegradation of total petroleum hydrocarbon (TPH) in Jordanian petroleum sludge

Abstract

Bioremediation, or the use of micro-organisms to decontaminate soil or groundwater, is being increasingly seen as an effective, environment-friendly treatment for oil-contaminated sites. In this study, the results are presented concerning a laboratory screening of several natural bacterial consortia and laboratory tests to establish the performance in degradation of hydrocarbons contained in oily sludge from the Jordan Oil Refinery Plant. As a result of the laboratory screening, 18 isolates were selected and grouped into two main clusters; cluster 1 containing 12 isolates grown at 43°C, and cluster 2 containing six isolates grown at 37°C. Three natural bacterial consortia with ability to degrade total petroleum hydrocarbons (TPH) were prepared from these isolates. Experiments were conducted in Erlenmeyer flasks under aerobic conditions, with TPH removal percentage varying from 5.9% to 25.1%, depending upon consortia type and concentration. Consortia 7B and 13B exhibited the highest TPH removal percentages of 25% and 23%, respectively before nutrient addition. TPH removal rate was enhanced after addition of nutrients to incubated flasks. The highest TPH reduction (37%) was estimated after addition of a combination of nitrogen, phosphorus and sulphur to consortia 7B. This is the first report concerning biological treatment of total petroleum hydrocarbon by bacteria isolated from the oil refinery plant, where it lay the ground for full integrated studies recommended for hydrocarbon degradation that assist in solving sludge problems.