Screening is one of the physical purification processes in which solid and floating materials with diameters greater than 0.5 cm are removed and separated, and according to the amount of incoming water or wastewater, manual or mechanical garbage collectors can be used. The most common type is the manual bar screen, which is generally used in small treatment plants, and in large treatment plants, due to the large amount of waste, mechanical filters with automatic operation must be used.
In wastewater treatment plant, this Screening is used to protect pumps, valves, pipelines and other accessories from being damaged or blocked by old and large objects. Industrial treatment plants may or may not need them depending on the characteristics of the pollutants. Hydraulic drops in bar screen depend on the speed of passing through the bars.The pressure drop increases with the increase in the fouling of the bar screen.
In mechanical screen, Screening is cleaned by a mechanical arm controlled by a switch upstream of the Screening.