The main component of the benzo -captive system is special filters designed for enlargement and separation of particles of oil products. Each coalescent filter has a cassette with embossed plates. Wastewater, passing through such a filter, fall into the cassette, where they are in contact with the surface of the plates made of hydrophobic material. At the same time, oil products are besieged on it, and then, due to their low density, they rise to the surface, where they accumulate.