Nutritional Requirements for the Biodegradation of Oily-Sludge Waste from Petrochemical Industry

A soil with previous exposure to hydrocarbons was collected to perform a bench-scale biodegradation study of oily sludge in order to evaluate nitrogen requirements for the microbial mineralization of hydrocarbons contained in oily sludge. A degrading bacterial consortium isolated from the soil was capable of degrading hexadecane, octadecane, naphthalene and phenanthrene within 5 days of incubation. Addition of nitrogen to achieve C:N of 100:20, 100:10 and 100:1 increased carbon mineralization by 2.3, 2.7 and 4.7 folds, respectively. The same trend was observed for oily sludge hydrocarbons removal from soil, which demonstrates that microbial mineralization of hydrocarbons is the primary removal mechanism. Results in liquid culture were not different; oily sludge mineralization was 980 and 725 mg C-CO2 l-1 culture, for nitrogen supplementation of 100:1 and 100:10, respectively. Supplying a co-carbon source such as glucose, succinate and glycerol tripled carbon mineralization from oily sludge mainly because it aided in a fast build-up of high numbers of degraders