Bioremediation of Crude Oil Polluted Soil Using Animal Waste

Abstract

Crude oil contaminated soil from Isaka mangrove in Okirika local government area of Rivers state was treated with three different organic wastes (goat manure, poultry droppings and cow dung), for a period of 28 days. The four treatment samples were tilled twice a week and watered with 50 ml of distilled water weekly. There was a general increase in microbial count for all the treatments with the amended samples having a higher microbial count. The total heterotrophic bacterial count for the A, B, C and D treatment options increased from 2.85x105-1.95x106cfu/g, 3.02x105-3.09x106cfu/g, 2.75x105-2.69x106cfu/g and 2.88x105-2.51x106cfu/g respectively. The hydrocarbon utilizing bacterial count for the A, B, C, and D treatment options increased from 2.51x105-1.74x106cfu/g, 2.85x105-2.95x106cfu/g, 2.63x105-2.51x106cfu/g and 2.51x105-2.29x106cfu/g respectively. There was a progressive increase in total heterotrophic fungal count, with B treatment option showing the highest increase at 3.02x106cfu/g. The hydrocarbon utilizing fungal count for the A, B, C and D treatment options increased from 1.05x105-1.26x106cfu/g, 1.10x105-2.24x106cfu/g, 1.12x105-2.09x106cfu/g, and 1.10x105-1.99x106cfu/g respectively. By day 28, the percentage loss of biodegradation of total petroleum hydrocarbon for the B, C, D and A treatment options as measured with GC-FID were 87.1%, 76.6%, 70.7%, and 32.1%, respectively. Ten hydrocarbon utilizing bacterial isolates identified were Escherichiacoli ., Citrobacter sp., Bacillus sp., Micrococcus sp., Pseudomonas sp., Flavobacterium sp., Alicagenes sp., Corynebacterium sp., Arthrobacter sp., Aeromonas sp., and seven hydrocarbon utilizing fungal isolates obtained were Aspergillus sp., Candida sp., Fusarium sp., Mucor sp., Penicillum sp., Rhodotorula sp., and Rhizopus sp. The results of this study indicated that nutrient amendment can enhance the rate of biodegradation of crude oil polluted soil.