New Plan for Desalting Sea May Make Arid Soil Fertile

Fresh water can now be economically made from sea water. Dr. Walter Juda, research associate at the Medical School, is the head of a group which recently developed a new process for removing chemical impurities.

Based on the use of electrical energy along with recently developed synthetic membranes, the process promises to open vast new supplies of fresh water for use in agriculture, industry, and home consumption wherever water is now scarce.

Dr. Arthur B. Lamb, professor of chemistry, emeritus, and now a director of Ionics, Inc., of Cambridge, said that the much greater economy afforded by the process opens a new era in the purification of sea water.

Certain salts and minerals are removed from the water as it is passed through the membranes by a chemical process known as "ion exchange," which separates the various impurities according to the electrical charges they carry.

A jet of water fed into the apparatus, which has no moving parts and which uses no heat or chemicals, is split into two streams, a fresh water stream containing almost no traces of the salts, and a brine stream half the volume of the fresh one. The brine stream may then be treated to yield magnesium, bromine, salt, and other chemicals found in the sea.

President Conant, in an address before the American Chemical Society made last September, predicted that by 1985 a process for economical desalting would be discovered that would cause desert areas to become crop producers.

In many areas of the western United States, where electric power is cheap, the use of the new membranes, which are themselves produced from cheap coal-tars, will make fresh water available at rates lower than the cost of irrigation water in irrigated areas. Ionics, Inc. scientists, when contacted last night, were of the opinion that they had come a long ways towards fulfillment of Conant's prophesy.

Dr. Juda, vice president and technical director of Ionics, said last night that no information could be released at this time on where or when the new process would be first installed. He added the process is already in the practical stage.

In addition to being a research associate at the Medical School, Dr. Juda was a lecturer in chemistry at Harvard from 1946 to 1948.