AW Machinery develops and builds washing units for cleaning underground containers, among other things. Every day, each unit consumes 3,200 to 6,000 litres of water. The wash unit has a load of 3,200 litres of water available and a dirty water storage of 3,200 litres. Because the containers have all kinds of dirt, the contaminated rinse water consists of different components, such as dissolved organic compounds, dissolved metals and undissolved material. The rinsing water that is released during cleaning is contaminated and therefore cannot simply be discharged into the sewer.