Case Study
Crude Oil Contaminated Land Study
In summer 2003, one of our consultants was instructed by SPDC to carryout laboratory investigations to determine the level of oil in contaminated farmlands and possible application of biological origin surfactants in treating the contaminated sites. The contaminated soil samples were collected in the rainy season from two oil spilled areas located more than 30 km apart, Niger-Delta area Port Harcourt.
We believed that the site was spilled with oil over fifteen years ago. The contaminated soils were subjected to various laboratory investigations in Edinburgh, Scotland to understand the best technology that could reduce the oil contents from these samples. The contaminated soils were oven treated for 24hours at temperature of 105 ± 50C before determining the soil physical and chemical properties which aid in simulating real life situation of treating contaminated sites during the major seasonal periods in the Niger-delta area. It was found that water content of 20% significantly affect the oil content in soil.
The surface active material used was later characterised in a laboratory in Port Harcourt, Nigeria and was compared with some extracts from natural occurring plants within the South Eastern area of Nigeria. Our study suggested that both SAM and the naturally occurring plant have the same effectiveness and efficiencies under similar laboratory conditions to reduce the oil contents of the contaminated soils. Soil washing carried out with the extracts from naturally occurring plants achieved up to 85% oil reduction and peaked after 45minutes of washing. The applicability of the naturally occurring plants is site specific thus required considerable amount of laboratory classifications and experiences to avoid misused of materials and waste generation.
There are many cost benefit using this technology if well developed and implemented correctly. Our understanding is that if the chemistry is well understood, with the naturally occurring surface active material easy accessible, this technology will remove the overarching time of waiting for the government to respond to crude oil clean up. However, the overriding priority will be management of the waste water resulting from the washing process not to be contacted. However, there is a rule of thumb that, the owners of the site or the person that carried out the activities resulting to the contamination is responsible for liquid effluent and other solid waste generated.