Pig Droppings: A Potential Biostimulatory Candidate for Bioremediation of Diesel Oil-Polluted Soil

Abstract

The effectiveness of pig droppings (PD) in enhancing bioremediation of diesel oil-polluted soil was investigated gravimetrically and spectrophotometrically for a period of 42 days. Polluted soil was amended with 5%, 10% and 15% (w/w) of PD. Loss of total petroleum hydrocarbon (TPH), microbial growth and germination indices were all monitored throughout the study period. At the end of 42 days, there was significant oil loss of 48.54% in the amended soil. Hydrocarbon-utilising bacterial (HUB) counts were higher in the amended option ranging from 4.2 x 106 ±0.69 to 10.9 x 106 ± 0.41 CFU/g. The HUB isolated from the oil-contaminated soil were identified tentatively as Bacillus cereus, Pseudomonas putida, Micrococcus variant, and Corynebacteriumsp and Staphylococcus sp. Similarly, fungal counts ranged from 3.0 x 105 ±0.21 to 10.9 x 105 ±0.33 CFU/g. Aerobic fungi isolated wereAspergillusniger, Aspergillusflavus, Fusariumsp, Cladosporiumsp and Penicilliumsp. Germination index of 53.4% was recorded in the amended option. Oil loss and microbial growth were significantly higher ((P≤ 0.05) in the amended option than the control option. Pig droppings, therefore can offer a good alternative in bioremediation of diesel oil-polluted soil.