A Comparative Study on the use of Soil - Organic and Inorganic Biostimulants in the Remediation of Oily Waste
Ofonime U. M. John *
Department of Microbiology, University of Uyo, Akwa Ibom State, Nigeria.
Senyene I. Umana
Department of Microbiology, Akwa Ibom State University, Ikot Akpaden, Akwa Ibom State, Nigeria.
Christiana E. Asuquov
Department of Microbiology, University of Uyo, Akwa Ibom State, Nigeria.
Samuel I. Eduok
Department of Microbiology, University of Uyo, Akwa Ibom State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Remediation of oily waste using soil-organic (goat dung, poultry dropping) and inorganic (NPK fertilizer) nutrients was assessed for twelve weeks using culture-dependent microbiological technique and chemical procedures. The results indicate increased counts of Hydrocarbon-utilizing bacteria, fungi and actinomycetes with remediation time for both nutrient types. Bacteria in the remediated waste were members of the genera Bacillus, Pseudomonas, Acinetobacter, Alcaligenes and Serratia, fungi: Penicillium, Aspergillus and Cladosporium, and actinomycetes: Rhodococcus, Nocardia and Streptomyces for all soil-nutrient amendment techniques. pH of the NPK fertilizer ranged between 6.7 ± 0.03 and 7.3±0.06 whereas the goat dung and poultry dropping amendments was 6.5± 0.02 and 7.1 ±0.05. Dehydrogenase activity increased for the biostimulant treatment cells with remediation time. Total Petroleum Hydrocarbon reduction was 99.3 and 99.6% in organic and 99.8% for inorganic amendments. Polycyclic Aromatic Hydrocarbons of the remediated waste for both techniques revealed values below detectable limits (< 0.01) at the end of remediation period. Remediation with soil-goat dung and soil-poultry dropping amendments compared favorably with soil-NPK fertilizer technique because microbial activities were enhanced to produce eco-friendly waste. The use of soil-organic amendments is therefore a low-cost alternative biostimulant for the management of oily waste in the petroleum industry.
Keywords: Eco-friendly, remediation, biostimulant, oily waste, microbial counts, enzyme activity