In Wolfsburg, Germany, Volkswagen AG operates a new leakage test plant for all new cars. First, the vehicles are dewaxed with isoparaffin, and are then cleaned with water in a high-pressure area. In the three following spraying areas, the vehicles are sprayed with water, and are then manually checked for leakage. Afterwards, they are subjected to a textile washing again, and are then polish dried. The task was to treat the water in the single sections in such a way that it can be re-used.

In the high-pressure cleaning area, only a band filter with disposable filter fabric was possible, due to the waxes contained. For the other areas, there were several alternatives. We had experience with backwashable mesh filters which, however, had to be dismantled and manually cleaned every two weeks. Sand filters would also be possible, but they would lead to a considerably larger footprint and higher costs.