Process for biological and physical elimination of undesired substances from water

摘要

Biologically-purified (3) waste water is passed through a filter and sent to a storage tank for recycling. A pump (6) exerts a reduced pressure of 0.2-0.7 bar on the permeate side of the filter (5), drawing the water through. The filter comprises plastic, hollow-fiber membranes numbering 50-5000, with pore sizes of 0.01-1 micro m. The filter removes suspended matter and bacteria. An Independent claim is included for the corresponding plant, in which the tank is a monolithic construction of polyethylene and polyurethane, a sandwich composite. Preferred Features: The filter is installed in the settlement tank following the biological stage, or in the biological stage itself. The water is prepared using a cross-flow filtration unit. The storage tank is installed outside the treatment plant. Total thickness of the tank is 5-10 cm.