In operations where wastewater containing, this wastewater must be treated separately using a separator before being discharged to the sewer system. A recipitation system works according to the phase separation principle. It consists of a precipitation area, a grease collector, a sludge trap and a sampling point. The system reduces the flow rate of the wastewater to allow solids – such as food leftovers – to sink and settle in the sludge trap. Fats, which have a lower density than water, float to the surface. Once the grease is removed, the wastewater is flowing to the sewer system. The choice of nominal size for the separator is specified in EN 1825. The wastewater requirements of the relevant authority must be complied with (e.g. 14-day emptying; monthly emptying with the approval of the relevant authority).