A marine accident in the summer of 2003 caused a disastrous spill of heavy fuel oil to be washed up on one of Sweden’s most pristine white sand beaches at Löderups Strandbad. The Swedish National Rescue Corps immediately determined that all of the contaminated oily sand should be dug up and removed to a safe, bunded site where it could be treated.

4000 tonnes of contaminated sand was removed to the nearby site at Ystad on the southern tip of Sweden. An analytical survey revealed that the incoming sand contained between 8% and 16% of Total Petroleum Hydrocarbons (TPH).

Oily sand being loaded into the inlet hopper, waste oil tanks in background

A programme was put in place to wash the sand without the use of chemicals, recover as much oil as possible, and clean up the wash water so that it could be discharged to sewer.

The discharge limits were set as follows:
TPH on sand	Less than 400 mg/kg
Water to sewer	Less than 5 mg/l TPH
Water in recovered oil	Less than 15%

Process description

A coarse screen removes any oversize rocks that could damage the plant.
The oily sand is fed by conveyor into a slurry tank where it is mixed with water and, if necessary, heated.
This slurry is then pumped through the OPS AEV system, where shear is used to separate the contamination from the soil and suspend it in the water phase. No chemicals were used in this process.
The oily water and solids are separated in a classification process and the solids are rinsed.
The oil is separated from the wash water in a first stage process and pumped to waste oil tanks.
The oily water is passed to the water treatment section of the plant where RM 25 media is used to remove final traces of hydrocarbons in a second stage process. Other RM media products can be used to remove heavy metals if necessary. The cleaned water is then recycled.

Results

As the photos below demonstrate, the oily sand was cleaned up to the required levels and replaced on the beach. The sand was cleaned to an average level of 130 mg/kg of oil (< 0.1%). More than 175,000 litres of waste oil were recovered with a water-in-oil content of less than 5%.

Oily Sand Samples before and after treatment

Treated sand before replacement on beach

Press coverage

"... and the oil was turned into sand"
Christina Salomonsson, Director General of the Swedish National Rescue Corps, re-opens the beach to visitors.