Assignment

The sewerage of a motor vehicle workshop can contain almost anything, not only classical dirt. Therefore, it is especially important to accordingly clean it before it passes into the network of public sewers, and to have the contaminated substances disposed of by special companies every now and then. In car-washes, the cleaning can be intensified to such an extent, that the water can be used again.

Function

First of all, all the sewerage water from the drains, and other in-flow sources (see above on the right) must pass through the sludge-trap. It is thus dimensioned, that the speed of the water-flow is reduced to allow the suspended matter, which is heavier than water, (1 kg / dm ³) to sink to the bottom. The chamber is sealed on top with a lid and the sludge can be pumped out from there.It's a little more complicated when substances whose density is lower than that of water, are to be removed. These of course, remain on the surface. The sewerage must be taken from the bottom of the container and also run off downwards. Apart from the lid, a good ventilation is important here to avoid the development of explosive vapours. As a specific feature the actual petrol separator also has a float which lies on the water surface. If this sinks to below a certain level due to rising petrol and/or oil concentration, the drain must, through a mechanical process, prevent this.