SCREENING

The first mechanical treatment of the waste water is the screening to remove any kind of bodies which could clog the pipings or damage the other equipments. The screens are usually placed in the incoming flow channel, but they can be installed even out of the channel, downstream the lifting pumps. We recommend, when possible, to protect the lifting pumps by means of mechanical fine screens for channels. The screens can be manual or automatic, coarse or fine. The coarse screening separates the bodies having a larger size than 20 mm. The fine screening separates the bodies having a smaller size than 20 mm. The most common spacings are 40 mm. for the coarse screens and 3 mm. for the fine screens. The coarse screens are made of rectangular bars, installed in vertical.