Bioremediation of Soil Contaminated with Crude Oil using different Weights of Poultry Manure.

Abstract

The exploration of petroleum has led to a huge influx of carbon and decrease in nitrogen and phosphorus contents into the impacted environment. Utilization of this carbon will require external supplies of nitrogen and phosphorus for the oil-consuming microorganisms. Hence, this research investigated the effect of different weights of cow dung on the microbiological properties of crude oil contaminated soils. The crude oil research used was Bonny light crude oil obtained from Kaduna Refining and Petrochemical Company (KRPC). The poultry manure was collected from a poultry farm situated at Kafin Hausa Local Government Area, Jigawa State. The soil samples were collected from the main campus-of Sule Lamido University, Kafin Hausa. Two hundred milliliters (200ml) of crude oil with initial weight of 25g/kg was added to sterile bag containing IKg of soil and thoroughly mixed. The experiments were allowed to stand in screen house for two weeks with adequate watering at 2days interval before application of poultry manure at various weights of 50g/kg, 100g/kg and 150g/kg of soils. The mean total aerobic bacteria Present in the soil samples at the beginning of the experiment (week zero) and subsequently at 1-week intervals for each of the treatment. Associated bacteria were Isolated, identified and estimated using spread plate method on Nutrient Agar. The extent of crude oil biodegradation by the isolates was determined using the gravimetric analysis. From the results, nine bacterial species from 5 Genera were isolated and characterized from amended and control soil used in this research. Genus from Bacillus has the highest representation of five species. The results showed that there was a steady increased in bacterial population in all the amended soil and control from week0 to week 3 and decreased from week 4 to week 6. However, the bacterial populati0n from soil treated with manure at 150g/Kg was significantly higher(P<0.05) while that of control was low. 1he soil amended with poultry manure at 150g/kg gave the reduction (77.6%) of crude oil. This was followed by soil amended with 100g/kg and 50g/kg poultry manure with percentage reduction 0.0470 and 42.00% respectively. Also, 35.80% reduction crude oil contaminated soil may result in reduced microbial population in soil but this concluded can was observed from the control experiment (non-amended sample). From the study, it can be remedied by the addition of organic nutrient supplements especially using poultry manure at 150g/kg as biostimulating agent.