Industrial liquid wastes containing low concentrations of heavy metals are applied to a soil bed where evaporation of the liquid occurs. The soil bed is lined with a liquid-impermeable liner of polymeric sheet material, bentonite clay or a laminate of the two to prevent escape of the liquid waste to the surrounding environment. After repeated applications of wastes to the bed, the concentration of metals in the bed reaches a level where the metals may be recovered by standard mining operations.
