Biological filter for water purification plants

摘要

The invention relates to a filter 4 in particular for biological water purification plants, which filter is composed of a plurality of chambers 5, 5', 5'' connected in parallel which can be disconnected individually for backwashing. The side walls 8 of the chambers and if appropriate the base are covered by perforated sheets 9, as a result of which filtrate collection areas are formed downstream of the perforated sheets from which the purified water can be led off in accordance with arrow 2'''. In the filter 6 are provided contact bodies made of organic material which are formed, e.g. from sawdust or bark pieces and in the moist state have adopted roughly the specific gravity of the liquid to be purified so that they float in the entire filter and are offered as colonisation surfaces for the biological sludge. To avoid the digestion effect in aerobic operation and also to swirl up the sludge for cleaning, aeration devices are provided at different heights. In anaerobic operation, the biogas formed can be used to reinforce the swirling. <IMAGE>