Removal of crude petroleum hydrocarbons by heterotrophic bacteria in soils amended with nitrogenous fertilizer plant effluents

Abstract

Nitrogenous fertilizer (NPK) plant effluents from NAFCON were used in amending plots of land experimentally polluted with crude oil. Counts of heterotrophic bacteria (THBC) and fungi (TF), and of petroleum utilizing bacteria (PUB) and fungi (PUF) were monitored during an 8 weeks period. Counts obtained showed that NPK served as a good supplement for the growth of the petroleum degrading/utilizing bacteria in oil-polluted soils. Crude oil disappearance in plots TSP ranged between 8.70 and 34.80% and 20.90 and 60.50% for TST; cumulative loss was 73.0%. The disappearance was influenced by the N/P ratio in the supplementing fertilizer effluent. A total of ten genera of petroleum degraders were isolated, namely, Micrococcus, Pseudomonas, Acinetobacter, Proteus, Bacillus, Actinomyces, Corynebacterium, Enterobacter, Brevibacteria and Citrobacter. Crops grown on the experimental plots at the end of the study period for soil recovery studies indicated good soil recovery.