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Bakground
An industrial site in Norrköping, previously used for oil storage and heavily contaminated by oil products has been treated with the Real Biotech-method for a period of 12 weeks during the summer of 2003.
The area, Slottshagen 1:7, measures 13 000 m 2 , with Motala stream located some 30 metres outside the boundary.
The ground is composed by a mixture of clay and sand. Underneath are more layers of clay and mud. The handling of oil products in the area has been going on for 60 years
Execution
In situ treatment according to the Real Biotech method was used for the decontamination work. The area was treated during 12 weeks. Since the area sloped towards the stream we had to dig a cut-off trench. Its purpose was partly to prevent any surplus water to reach the stream and partly so that we could re-use this water for the treatment.
Sampling
Samples were taken every week during the period of the treatment. These samples have been analysed by a certificated laboratory.
The Consultant firm Carl Bro AB in Linköping made a survey and took samples of the area seven months after the treatment was finished (spring of 2004). They also wrote the report to The Environmental Agency.
Results
At the end of the treatment period 2003, approximately 95% of the area shows levels under the target, the levels for MKM (standard level set by the Swedish EPA for land with less sensitive use: offices, industry, roads, i.e. where people do no live).
From the samples taken 2004, it can be concluded that during the winter season the microbes have cleaned the ground by an additional 70-90 % compared to the samples taken in September 2003. Two spots still show some levels slightly above the MKM. The Microbes will continue the cleaning process in the year to come
Results from sampling: >> Sample ponts 1 and 45
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