Effect of organic nutrient on microbial utilization of hydrocarbons on crude oil contaminated soil

Abstract

The effect of organic nutrient (poultry manure) on biodegradation of soil (5 kg) contaminated with crude oil (50 g) was investigated for seven weeks. Four different test options were prepared namely; (i) 100 g of contaminated soil + 30 g of poultry manure; (ii) 100 g of contaminated soil + 60 g of poultry manure; (iii) 100 g of contaminated soil + 90 g of poultry manure; (iv) 100 g of contaminated soil only (control). The microbial degradation was monitored by the measurement of total heterotrophic count (THC), hydrocarbon utilizing bacterial count (HUB) and gravimetric loss of the crude oil with time. The cumulative THC of 6.9x107, 9.0x107, 1.03x108 and 3.1x107 cfu/g were recorded for test options (i), (ii),(iii) and (iv), respectively. The hydrocarbon utilizing bacterial counts (HUB) were 1.68x105, 1.63x105, 1.9x105 and 4.8x104 cfu/g for tests options (i), (ii), (iii) and (iv), respectively. There was a corresponding gravimetric hydrocarbon loss of 40.0, 45.26, 49.47 and 29.47% for test conditions (i),(ii), (iii), and (iv), respectively. The results of the study suggest that addition of organic nutrient (especially 90 g poultry manure) will further enhance microbial utilization of hydrocarbons