Regardless of whether in multi-storey car parks, petrol stations, car washes or vehicle workshops: Wherever there is a risk of mineral light liquids getting into the drainage network, for example, petrol, benzene, lubricants or oils, the wastewater must be pretreated. This prevents pollutants from contaminating the drinking water or groundwater. A light-liquid separator or petrol interceptor uses the difference in density of petrol and water to achieve this. The light liquid is collected and is disposed of regularly by recycling companies. Even better treatment is achieved by using a coalescence element, as used by ACO in its units. Light-liquid separators are available for installation in the ground and for freestanding installation.