BMW has developed a new recycling process that eliminates wastewater in an engine plant in Steyr, Austria.
According to the Green Car Congress, the process uses a new combination of various membrane technologies, where all manufacturing wastewater in the plant is treated and fed back into the production system for an annual savings of around 7.9 million gallons of water. BMW has closed the mains drainage connection at the plant.
When manufacturing engines, water is used to create an emulsion with coolants for milling and turning, and for purposes such as washing or rinsing during the finishing of cylinder heads, crank cases, crankshafts and connecting rods.
In 2003, BMW first introduced a wastewater treatment system with nanofiltration technology at Steyr. Franz Hornbachner, the person responsible for “fluid technology”, reports that the results of the technology were so successful that BMW introduced a completely enclosed water cycle for production.
The wastewater goes through three different stages. First, oil residues are removed from the wastewater by ultrafiltration. Next, heavy metals and low-volatility lipophilic substances, like surfactants, are removed from the water by nanofiltration. Lastly, dissolved salts and short-chain organic compounds are removed by reverse osmosis. The process only does not include addition of any chemicals.
The BMW Group has invested around $1.9 million in these technologies over the last three years.