A few years ago, an oil company in Oman initiated an approach to deal with hydrocarbon-contaminated soils that created environmental problems. These soils where collected in their oilfields and transported to their hazardous waste yards in the country's interior areas. The client entrusted several service providers to carry out de-contamination processes and landfill activities unfortunately with limited success.

One of the Waste Yards has stock piled large quantities of hydrocarbon contaminated soil, with contamination concentrations ranging from 15,000 mg/kg total Total Petroleum Hydrocarbons (TPH) soil up to 40,000 mg/kg TPH. The hydrocarbon molecule chains are from various types – starting with short chains i.e. C5 up to long chains C35.

In 2012, the client decided to implement a new remediation approach by deploying eco-friendly technologies to properly manage degradation and remediation of the contaminated soil by using modern bio-remediation technology developed and applied by a renowned German remediation company. The technology brings degradation results of reducing hydrocarbon contamination to less than 50%, lower than the international treatment standards and this within the first few weeks of treatment.

This paper will provide an overview of the bio-remediation approach used to treat stockpiled TPH contaminated soil. It will present remediation results from the field, but more over it will look into the opportunities and barriers for reusing the treated soil in civil projects without harming the environment and nature. In this specific case, the treated soil was used in one of the world's largest constructed wetlands, which handles 95,000 m3/day produced water. In April/May 2013, new soil tests will be taken to assess the quality of the soil material and subsequent hydrocarbon degradation after being in the wetland for one year.

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