NATURE OF THE CASE --TECHNICAL BACKGROUND COKE IS BURNED IN THE IRON-MAKING PROCESS (E.G. IN BLAST FURNACES) IN ORDER TO PROVIDE THE HEAT NECESSARY TO CONVERT FROM IRON ORE INTO IRON. COKE ITSELF IS REFINED COAL. THE REFINEMENT PROCESS CONSISTS OF BAKING COAL IN SO-CALLED COKE OVEN BATTERIES TO REMOVE UNWANTED WATER VAPOR AND GASES. THE COKING PROCESS (INCLUDING THE OPERATION OF ASSOCIATED BY- PRODUCTS PLANTS) PRODUCES CERTAIN BY-PRODUCT LIQUID STREAMS KNOWN AS PROCESS WASTEWATER STREAMS. ONE WAY OF DISPOSING OF THESE STREAMS IS TO POUR THEM ON HOT COKE TO COOL IT UPON ITS REMOVAL FROM THE COKE BATTERIES. THE PROCESS OF POURING LIQUID ON HOT COKE IS CALLED QUENCHING. THE TYPE OF QUENCHING JUST DESCRIBED IS KNOWN AS DIRTY WATER QUENCHING AND CREATES AIR POLLUTION PROBLEMS BECAUSE THERE ARE POLLUTANTS ENTRAINED IN THE WASTEWATER STREAMS WHICH ARE RELEASED TO THE AMBIENT AIR WHEN THE QUENCH WATER VAPORIZES ON THE HOT COKE. ONE SOLUTION TO THIS AIR POLLU- TION PROBLEM IS TO USE CLEAN WATER TO QUENCH (EG WATER FROM A NEARBY RIVER). THIS IN TURN RAISES THE QUESTION OF WHAT TO DO WITH THE THEN USELESS WASTEWATER STREAMS. OFTEN THESE STREAMS CANNOT BE DISPOSED OF DIRECTLY INTO PUBLIC WATERWAYS BECAUSE OF CLEAN WATER ACT EFFLUENT LIMITATIONS. WHEN SUCH IS THE CASE, A METHOD FOR TREATING THE STREAMS PRIOR TO DIS- POSAL--E.G. A WASTEWATER TREATMENT PLANT-