Feasibility of on-site bioremediation of loam soil contaminated by diesel oil

This study originated from an accidental event of diesel oil contamination in a loam soil area of 7000m(2). Approximately a volume of 1300m(3) of dies el oil was released into the environment. Reclamation of the contaminated s oil by on-site bioremediation was selected as the most appropriate treatmen t method. A major concern was associated with the nature of the local loam soil. Loam has a very low hydraulic conductivity and very quickly becomes i mpermeable after its contact with water. The bioremediation approach incorp orated excavation of the contaminated soil, mixing it with an agent, which increased its permeability. Following this preliminary treatment came the c onstruction of bioreactors as a suitable environment of nutrients, moisture , dissolved oxygen, and enriched culture of microorganisms, which enabled b reakdown of the diesel oil. This case study indicated that the target of 99 % of diesel oil clean up could be achieved by using the technology of on-si te bioremediation. The selected treatment method was found to be technologi cally and economically feasible. However, some improvement in the applicati on of the basic treatment approach might increase the bioremediation effici ency.