Discussed is a new process of concentrating the dissolved inorganic and organic contaminents in the waste stream from a tertiary treatment process by eutectic freezing or hydrating. In this process a substantial fraction of the water(93 to 98%) is first removed by any means such as freezing, hydrating, evaporation, or reverse osmosis. The remaining 2 to 7% of the waste, which presumably contains all or most of the original dissolved material, is subjected to temperatures low enough to precipitate ice and the majority of the organics and inorganic salts simultaneously. The report is a description of the work accomplished during the period June 1962 to February 1964 in checking certain key assumptions made in designing the eutectic process on paper and also in observing the behavior of waste water samples subjected to concentration by freezing.