GB1307621A - Process for the treatment of ground waters surface waters and effluents - Google Patents

Abstract

1307621 Flocculating METALLGESELLSCHAFT AG 10 July 1970 [19 July 1969 1 June 1970] 33686/70 Heading C1C Water containing suspended solid matter is purified by treating in five stages in five separate zones as follows, (i) flocculent is added, (ii) sludge formed in the process is mixed in, (iii) a flocculation aid is added and the mixture agitated for 30 sees. to 5 mins. with an agitator having a power output of at least 20 watts per cubic metre of liquid, (iv) coarse flakes of impurity are formed, (v) the coarse flakes are settled to sludge, some of which is recycled to stage (ii) and the clarified water is removed. In stage (iii) several different flocculation aids may be used and zone (iii) may be divided into a corre- sponding number of sub-zones. When the water being treated is particularly impure, a secondary flocculation may be effected by adding a small amount of flocculent to the clarified water from stage (v), furthermore, the resulting liquid may finally be filtered. The secondary flocculation is preferably effected with a progressively diminishing quantity of flocculent, which increases the effective life of the filter. Small amounts of zone may be added with or after the addition of the secondary flocculent. In Fig. 1, impure water to which flocculent has already been added enters at A into chamber C where sludge is added, up into chamber D where a flocculation aid is added and agitation provided by rotating agitator H, which has depending blades as shown and upstanding blades (not shown) which project into chamber D. In reaction zone E coarse flakes are formed and these pass to sedimentation zone F whilst clear water is discharged at B. Fixed baffles (not shown) are attached to the periphery of chambers D and E.