GB980305A - Improvements in and relating to a process and apparatus for the purification of waste water - Google Patents

Abstract

<PICT:0980305/C1/1> <PICT:0980305/C1/2> A pulp catcher comprises the cylindrical housing 1, preferably conical, with central rising pipe 2 for the waste water and spaced built-in fall pipe 3 for the clear water, which is discharged through the bottom pipe 4. Waste water is forced from its collecting tank 21 by the pressure pump 22 into the pressure vessel 25, a branched partial stream being charged with air by means of the injector 23, the quantity of which air is adjusted at 24. The air-charged waste water passes from the pressure vessel through the upper pipe to the dispersing system 7 of the first stage, is relieved at the dispersing nozzles 9, the thick pulp floats up and is skimmed off while the clear water descends. Through the pipe 11 about 10 to 20% of the clear water produced in the pulp catcher is aspirated by a second pressure pump and forced into the second pressure vessel, where a partial stream is charged with compressed air by means of the injector 27 and pre-connected air-quantity regulator 28, in the same way as the water to be clarified was charged in the circuit 22, 23, 24, 25. The air-charged partial stream of clear water from the second pressure vessel 29 passes into the pipe system 8 of the second stage, is there relieved at the dispersing nozzles 9 and produces the second flow with increased flotation effects.