The step screen is used for the solid-liquid separation operations, as a system for the mechanical separation of grits, detritus and floating solids. Its typical field of usage is in the wastewater treatment plants, where an effective primary screening is the best way to achieve efficiency in the following processes
The filtering unitis divided in two interpenetrating blocks, one mobile and one steady, whose relative movement produces a steady going of the filtered solids towards the discharge, leaving the filtering spaces always free and clean. Furthermore, the deposit of the solid particles on the screening bed can be used to improve the percentage of removed floating debris. When choosing the filtration spacing, must be took into account the wide filtering surface that allows to work with low fluid speed through the grid, reducing the resulting headloss.