Oy Metsä-Botnia Ab's Kaskinen mill produces ECF and TCF bleached softwood and hardwood pulp on a single continuous production line. Production capacity has been raised from 250,000 tonnes to 420,000 tonnes a year after the commission in 1977. The basic process solutions date mainly from the 1970s. However, process technology has been gradually modernised. With systematic and well-timed process development investments the mill has remained competitive and among frontrunners in terms of environmental protection. Today, Kaskinen represent the best available technology (BAT) applicable to old mills. Effluent loading in general and nutrient emissions in particular has diminished during the development projects of the mill. Comparison to other mills shows that as far as effluent emissions are concerned, Kaskinen is one of the best pulp mills in Finland and Scandinavia. In this presentation, Kaskinen is also compared to Metsä-Rauma, the first greenfield TCF mill in the world, which was started up in 1996. Kaskinen's pioneering work on TCF technology was used as a basis for process solutions in the Rauma greenfield project.