The article presents the results of experimental research for final treatment of gold mining enterprise waste waters using water lentil (Lemna minor) of (Lemna L. ) genus, (Lemnactat S.F. Gray) family, and common red grass (Phrágmites austrális (Cav.) Trin. Ex Steud.). It was shown that a level of heavy metals extraction, cyanides and rhodanides from the industrial waters of gold processing plant is greatly higher in comparison with chemical method used at the plant. The proposals are given to the gold mining enterprise to establish a pilot plant for final biological treatment, its novelty is confirmed by the Patent of Russian Federation of 20.01.2014.