Evaluation of bioremediation of diesel-contaminated soil amended with poultry droppings and pig dung

The increasing use of petroleum hydrocarbon products as energy source has led to contamination of soil with ripple effects on agricultural products. Therefore, it is essential to devise sustainable ways of cleaning polluted regions. The aim of this study was to evaluate the bioremediation potential of poultry droppings and pig dung on diesel-contaminated soil. Pristine soil was polluted with different levels of diesel and then amended for 40 days using pig dung (PDG) and poultry droppings (PDR) at different mixture. Physicochemical parameters as well as microbiological properties of the polluted soil were evaluated before and after amendments with PDG and PDR. Significant increase (p<0.05) was recorded in the soil available nitrogen, potassium, phosphorus and water holding capacity in the PDG and PDR amended soil. Furthermore, increase in the hydrocarbon utilizing bacteria (30%), and hydrocarbon utilizing fungi (24%) were observed in the amended soil. The total petroleum hydrocarbon level in the amended soil showed significant (p<0.05) reduction after the 40 days amendment with organic manure. Fungi such as Nigrospora sp., Aspergillus sp., as well as bacteria such as Bacillus sp., Proteus sp. and Serratia sp. were isolated in the amended soil. The present study indicated that microorganisms obtained from organic manure can be used in enhancing remediation processes in diesel–contaminated soils.