FREMGANGSMAADE TIL FJERNELSE AF FORURENINGER FRA SPILDEVAND VED BIOLOGISK OMSAETNING OG APPARAT TIL UDOEVELSE AF FREMGANGSMAADEN

1417920 Treating waste water AUTOTROL CORP 9 Nov 1973 [15 Nov 1972] 52164/73 Heading C1C Horizontal baffle 16 divides waste water treatment tank 10 into an upper zone having rotating biological contactors 13, and a lower settling zone through which the water flows in the opposite direction, having passed round the end of the baffle. Contactors 13 comprise a plurality of discs, drums, cylinders or brushes mounted on shafts 14 whose speed of rotation may be automatically controlled in response to variations in the water flow rate. The contactors may have a discontinuous honeycomb structure (see Specification 1,394,552). The atmosphere above may be enriched with oxygen (40-70 vol. per cent). Sludge collected by means 18 is removed through sump 19. To treat raw waste, additional sludge-removing means may be provided in the biological zone, or baffle 16 may be perforated (Fig. 5, not shown). Fig. 2 (not shown) is a plan view of Fig. 1. Figs. 3 and 4 (not shown) include fixed water entering and leaving the tank. In Fig. 4, water enters at (23), flows through the region of contactors (13), backflows along the bottom of the biological zone, passes round end of baffle (25) and through the settling zone, and leaves via weir (21) and conduit (22). A circular tank may be used.