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Using dirty water

June 16, 1999, 10:00 CEST

Polluted water from Statoil's Kårstø complex north of Stavanger is to be used by a Danish waste treatment company to feed bacteria.

Residual sludge from this biological cleaning process will be converted at Stigsnæs Industrimiljø into sand. After being used for sandblasting, the latter is due to be recovered as an insulation material.

"The company needs a source of carbon to achieve the most effective treatment," explains environmental engineer Ragnhild Hagland at Kårstø. "So our dirty water fits well with its production process."

Sending the polluted water - which originates from processing Sleipner condensate - to Denmark represents an environmentally and financially sensible solution to a difficult problem, notes Brian Bjordal, vice president for gas processing.

Environmental specialists in Statoil have assessed several options for handling polluted water from the Kårstø facility, which processes both gas and condensate.

It would have cost more than NOK 100 million to build a biological treatment plant at the site, such a unit is complicated and difficult to operate, and a solution was still needed for the residual sludge.

The Norwegian Pollution Control Authority and its Danish counterpart have issued the necessary permits for treating the Kårstø water in Denmark.

Up to 27,000 tonnes of polluted water will be shipped this year to Stigsnæs Industrimiljø, while the planned volume in 2000 totals 15,000 tonnes. The framework agreement between the Danish company and Statoil runs for up to 20 years.