Scania

The Client:

Scania is a global leading manufacturer in commercial and heavy vehicles. The client’s active Södertälje recycling facility outside Stockholm city faced problems with disposal of some specific materials left from their engine production business.

The facility was having difficulty in disposing non-recyclable substances including grinding dust, cutting fluid, and wastewater. Containers were temporarily storing a mixture of steel shavings from grinding dust and used cutting fluids. There were also mixtures of the used fluid and abrasive wool which had bound to it as waste from production. Cutting fluid is a hazardous waste requiring specialist disposal, however, the presence of other waste materials in the fluid was making this disposal process more difficult and expensive as the materials first needed to be separated. The wastewater from Scania’s recycling facility contained a layer of oil emulsion alongside hydrocarbon contaminated liquid containing chlorine from the facility’s cleaning agents.

Attempts to clean the oil contaminated wastewater at the facility was producing large amounts of clogged filter paper material. This made it difficult to clean to stormwater hydrocarbon limit values as filter paper had to be continually replaced – making the cleaning process time-consuming and expensive.
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Approach:

MycoMine took samples from across the production site from both the containers of cutting fluid mixtures and the waste-water cleaning tanks (the waste-water recipient tanks, along the production line to the final cleaning tank). With these liquid and partial solid samples, tests were carried out in our lab to isolate strains of fungi suitable for bioremediation use which were able to break down the hydrocarbons and organic compounds in the samples. We carried out two separate lines of testing on the cutting fluid samples and waste-water due to their differing contents and characteristics.
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Outcomes:
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Waste-Water:

In wastewater samples containing large amounts of oil, the hydrocarbons were degraded by 76-88% by our fungal mixture in 7 days. The levels of hydrocarbon present still exceeded the limit levels for storm water – but we are confident a longer period of remediation would achieve safe values. When we started to remove the chlorine from the water, we saw a reduction of hydrocarbons by 96.3% over 10 days by our fungal mixture. It seems entirely feasible to achieve the 99.5% reductions needed for stormwater quality when the water is fully dechlorinated before adding the fungi.
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Cutting Fluid:

Following testing, there was an evident decrease oil compounds. Over a 5-day period, we were able to reduce the total organic carbon content by almost 60% and the oil content alone by over 75%. For the testing on abrasive wool with bonded cutting fluid, there was a 66.3% reduction in total organic compounds in the liquid mixture over 20 days which we believe could be increased through more efficient aeration of the sample.
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Grinding Dust:

We further experimented with bioremediation rates using our chosen fungal strains on grinding dust and cutting fluid mixtures when present together – with extremely promising results. Over a 5-day period, the hydrocarbon content of the samples containing mostly grinding dust decreased by over 95%. With a longer duration for testing, we believe we can further optimise this rate. Again, better air supply, and neutralising the chlorine contamination before adding our fungal mixture are likely to further speed up and maximise our rates of remediation.
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Overall, this was a challenging project covering range of different materials from our client’s recycling plant. Our bioremediation systems for wastewater are suitable for seamless incorporation into existing production lines, which was perfect for the wastewater cleaning house at Scania. With further testing and removal of chlorine from samples we can refine our approach to effective remediation of a host of challenging materials which were otherwise difficult and expensive to recycle or dispose of previously.

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