With painting walls and cabinets of water separator, instead of screen blankets, it is the water that catches the mis-sprayed paint. The paint aggregated needs to be separated from the painted water, after a while. That is for the so-called separators are applied. The system can be operated in both semi-automatic and automatic modes.

With semi-automatic equipment, the separator is fitted with a storage tank divided into two parts. One half of the tank is designed with a conical bottom part. In this conical part is the painted water fed by the pump of the painting wall/cabinet. The painted water can be fed to the separator by opening a valve on the bottom of the conical tank. The separated paint remains in the separator, while the cleaned water is directed to the part of the tank for clean water. From there, the cleaned water is usually returned to tank of the painting cabinet. The separated paint sludge needs to be removed from the separator manually. The automatic mode automates the certain manual parts of the operations e.g. the feeding, process control etc. There is no significant difference in performance; the main difference may be resulted from the efficiency the operators can run semi-automatic system. The physical performance of the two systems has no difference.