The treatment of petroleum hydrocarbons from contaminated water by bioremediation via a food chain of microbes is an achievable process. The conversion of fuel oils to biomass derived from microbes has demonstrated that it is an environmentally friendly procedure with no secondary pollution generated. Black petroleum oils with a mean TPH (total petroleum hydrocarbons) concentration of 15,900 mg/L were transformed into a light orange solution with a mean TPH level of 10 mg/L after a bioremediation process of 64 days. A bacterial Bacillus species was identified as the primary degrader for dominating biodegradation of the contaminated materials. Its abundance in turn supported the increase in biomass of a bacterivore nematode. The nematode was introduced successfully from the aeration tank of a sewage treatment plant (STP) to the petroleum contaminated cultures giving its maximum number of 72 individuals/mL A reduction in the content of TPH was inversely proportional to an increase in bacterial population as well as an abundance of nematode. The cooperation of the microbes promotes the biodegradation rate of the petroleum hydrocarbons. (C) 2011 Elsevier B.V. All rights reserved.