A system was developed and facilities were installed at Interlake, Inc., Chicago Blast Furnace Plant, to treat, clarify, cool, and recirculate the blast furnace and sinter plant wet scrubber effluents in one unified system, in order to effectively re-use these waters and eliminate their discharge into the Calumet River. Prior to recirculation of scrubber waters, the concentration of contaminants (specifically suspended solids, hexane solubles, ammonia nitrogen, cyanide and iron) in effluent waters consistently exceeded the Illinois code limitations with gross contaminant discharges totaling about 4,100 tons per year. The contaminant intake from the river was about 2,900 tons per year, so the net contaminant discharge to the river was 1,200 tons per year or about 2 pounds per ton of hot metal produced. After the recycle system was placed in operation, the gross contaminant discharge decreased to 1,900 tons per year, and the net discharge became a negative quantity. The construction cost of the unified blast-furnace and sinter plant recirculating system was $1,109,400 for this 2-furnace plant producing about 3,200 tons of hot metal and 3,300 tons of sinter per day. Operating costs are about $285,000 per year higher than the costs of operating the old 'once-through' water system. Elimination of dredging costs, and increased iron recovery produce savings of about $10,000 per year, so the net increase in plant operating costs is about $275,000 per year. This amounts to about $.0001 per gallon of throughput. Portions of this document are not fully legible.