Idrasand™ is a simple unit, very reliable thanks to very few mowing parts and no submerged mechanical parts i.e. supports and seals.
The sewage containing sand and/or inert material is fed by gravity, low wear pumps or air-lift into the Idrasand™ through a feeding chamber properly designed to reduce the turbulence, creating an optimal flow to obtain a sedimentation of sand in a very small area. The solids sediment at the hopper bottom where special shaftless screw conveyor with no supports is installed. It is equipped with low wear sliding liners. The open screw conveys slowly, with rotation below 5 rpm, the sediment through the water level to the draining area and subsequently to the discharge mouth while the water overflows the Thompson profile weir. We would like to underline that the best performance of Idrasand™ is obtained by operating with long times and low concentrations of solids.
The removal of sand/grit has a great importance in the mechanical treatment of municipal sewage and industrial waste effluents, before the biological or chemical-physical treatment. The goal is to separate inert matter (mostly sand) but also dust, industrial inert waste which, being very abrasive, could cause an early wear of piping, valves, propellers, pumps.
There are two types of sand separating systems : by gravity and centrifuge (PISTA sand separators). In case the flow rates of water-sand mixture is below 100 m3/h, it is possible to install just one unit as the Idrasand™ besides classification can be used also as a real sand separator.