The treatment of aqueous or oily effluents is one of the most serious environmental issues faced by the minerals and metallurgy industries. Main pollutants are residual reagents, powders, chemicals, metal ions, oils, organic and some may be valuable (Au, Pt. Ag). The use of flotation is showing a great potential due to the high throughput of modern equipment, low sludge generation and the high efficiency of the separation schemes already available. It is concluded that this process will be soon incorporated as a technology in the minerals industry to treat these wastewaters and, when possible, to recycle process water and materials. In this paper, the use of flotation in environmental applications is fully discussed. Examples of promising emerging techniques and devices are reported and some recent advances in the treatment of heavy metal containing waters and emulsified oil wastes are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.