1. The best approach to water treatment is to avoid contaminating the water in the first place. This approach starts with the design of the furnace and involves the entire blast furnace plant and its operation. 2. Water systems should be arranged to keep clean and dirty streams separate and to concentrate as much of the contamination as practical in the smallest quantity of water as practical. 3. If waste water regulations are wisely drawn, they will result in better water for everyone without unduly penalizing anyone.