This BREF includes installations for the surface treatment of metals and plastics using an electrolytic or chemical process. Many installations operate a mixture of small and large production lines, and a mixture of electrolytic and chemical processes, as well as associated activities. Thus all processes, irrespective of the scale on which they are carried out, were considered in the information exchange. In practical terms, the electrolytic and chemical processes currently used are water-based. Directly associated activities are also described.