Initial test of a bioremediation scheme for the clean up of an oil-polluted waterbody in a rural community in Nigeria

A laboratory-scale bioremediation scheme for the clean up of an oil-polluted waterbody in a rural community in Rivers State, Nigeria, was investigated as follows: (i) a one time addition of 2 g of NPK (1:1.4; N:P) agricultural fertilizer to 100 g of sediment and 850 ml of stream water from the polluted areas; (ii) a one time addition of mineral salts solution comprising NH4NO3, 0.42 g; KH2PO4, 0.83 g; NaCl, 10 g; KCl, 0.29 g to 100 g of sediment and 850 ml of stream water; (iii) a periodic (fortnightly) addition of 0.5 g NPK fertilizer to 100 g of sediment and 850 ml of stream water; (iv) a control comprising a set-up with 100 g of sediment and 850 ml of stream water but no nutrients. All volumes were adjusted to 11 with the stream water. The efficacy of the scheme was monitored by the measurement of heterotrophic bacterial activities, hydrocarbon-degrading activities, including mineralization (CO2 evolution), and by the gravimetric loss of the oil with time. A cummulative CO2 evolution of 3.9, 2.9, 1.8 and 0.5 g was recorded for the test conditions (i), (ii), (iii) and (iv), respectively. There was a corresponding gravimetric hydrocarbon loss of 66.7, 57.9, 41.3 and 13.0% for test conditions (i), (ii), (iii) and (iv), respectively. Nitrogen limitation was detected in the course of the study. The remaining (33.3%) undegraded hydrocarbon was attributable to either recalcitrant groups or nitrogen limitation. It is concluded that there is a great need for application of bioremediation technology for a thorough clean up of oil-polluted waters in this community in Nigeria.