The water consumed by Wärtsilä can be divided into two categories: domestic use and cooling use. Domestic water is used mainly for sanitary purposes and by industrial equipment such as machine tools and washing machines. Some factories also use domestic water to produce moulds. Heat emissions into water systems arise from engine cooling and process cooling water. Wärtsilä companies use water from the local watercourse for their engine and process cooling needs. In such cases, the cooling water system is kept separate so that only heat is released into the natural water system. Wastewater is sewered and piped to the local wastewater treatment plant. If effluent is not suitable for sewage treatment, it is taken away for appropriate processing, for example to a special treatment plant for hazardous wastes.