Patent ID: 7332079

Claim:
An apparatus for removing heavy metals from an effluent stream comprising: (a) a bubble generator for producing a stream of aerated water having a population of air bubbles for introduction into the effluent stream; (b) a means for introducing the stream of aerated water into the effluent stream; (c) a source of at least one of a metal salt or metal scavenger; (d) a first chemical supply means for introducing at least one of a metal salt or metal scavenger into the effluent stream, said first chemical supply means in fluid communication with said source of at least one of a metal salt or metal scavenger; (e) a source of a flocculating polymer; (f) a second chemical supply means for introducing the flocculating polymer into the effluent stream; (g) a flocculation unit formed of a coiled cylindrical conduit having an inlet, an outlet and a finite length, said flocculation unit in fluid communication with the effluent stream at said inlet and said bubble generator and said first and second chemical supply means along said length, said second chemical supply means positioned downstream of said first chemical supply means and said flocculation unit combining the at least one of a metal salt or metal scavenger, flocculating polymer, and air bubbles with the effluent stream to form buoyant floc including the heavy metals in the effluent stream; (h) a separation chamber in fluid communication with the outlet of said flocculation unit for separating the buoyant floc from the effluent stream by allowing the buoyant floc to rise to the surface of a volume of the effluent stream; (i) means for removing the buoyant floc from the effluent stream adjacent the surface; and (j) means for dividing said population of air bubbles into portions, and a plurality of means for introducing said air bubble population portions into the flocculation unit (i) prior to said first chemical supply means; (ii) prior to said second chemical supply means; and (iii) prior to said outlet to said flocculation unit, wherein said bubble generator and said means for introducing the stream of aerated water are disposed downstream of said second chemical supply means.