Sand filters, with a bed of sand – or sand and anthracite – operating by gravity without the need of backwashing pumps, thanks to an automatic system activated by siphons. Available in single bed or in two beds design, one placed on top of the other, operating in parallel, which allows to double the flowrate treated in the same space.

It is also available in the “Combi” version, with the two beds operating in series: the upper sand bed for the removal of suspended solids and the lower one, with activated carbon, for reduction of the residual BOD.