The silt trap consists of a monolithic basin with an inlet and an outlet where the discharged wastewater is first of all allowed to settle. Solids that are heavier than water such as sand or mud will be deposited at the bottom of the basin (sedimentation).

The size of the silt trap depends on the mud volume supplied and the nominal size of the downstream separator (e. g. class II separator/oil and petrol separator). The minimum size is 600 litres. For portal-type car washes or carwash systems the silt trap needs to be able to hold a minimum of 5,000 litres.

Available useful capacities from 0.7 → 50 cbm (larger upon request)