Water purification with two stage thickening of sludge

摘要

Water treatment is carried out in two settlers. One settler (5) is lamellar and produces thickened sludge, and to which coagulants or flocculants may be added. The other (2) uses fine sand ballast and produces a non-thickened, weighted sludge. This sludge is transferred to the settler-thickener to further concentrate the sludge before final treatment (4). The two settlers may be used in parallel or separately. An Independent claim is included for the apparatus for carrying out the above treatment.