FRESH WATER FOR ARID LANDS—JENKINS 299 
ad hoc committee to plan and initiate a program of international co- 
operative research in saline-water conversion. Working Party No. 8 
completed its work in 1956, having attained its objectives of estab- 
lishing research and development activities in four fields: the United 
Kingdom conducted research in scale prevention and other methods 
of improving distillation equipment; Algeria and Morocco are de- 
veloping ion exchange and solar distillation; and the Netherlands 
developed an electrodialysis process. The Department of the Interior 
cooperated with the working party and assisted in the researches by 
exchanging technical information and by consultation. 
Other research and development outside the United States includes 
that on electrodialysis in the Union of South Africa, Soviet Russia, 
United Kingdom, Japan, and Israel; distillation in France, Israel, 
England, Sweden, and the Netherlands West Indies; freezing in 
France, Yugoslavia, Israel, and Italy; solar distillation in Spain, 
Australia, Soviet Russia, Italy; and others. The possible use of wind 
power for desalting is being investigated in Spain and Pakistan. 
COST TRENDS 
Saline-water conversion is complicated not only by process difficul- 
ties, but also by the range of water requirements encountered. Saline 
waters often vary widely in chemical composition, and the converted 
water is subject to various demands of quality. Sea water is fairly 
uniform in composition, with about 35,000 p.p.m. of salts. On the 
other hand brackish inland waters are quite variable in total salts and 
often call for special treatment to reduce or eliminate deleterious com- 
pounds, objectionable for use by plants and animals, or for human con- 
sumption or industrial purposes. Hardness may be a further factor, 
and quantities will vary from small household demineralizers to large 
central plants. Thus, desalting is at times a custom process rather than 
merely routine salt-removal treatment. 
In most instances the consumptive demand will be quite variable, 
and storage will be necessary to permit uniform operation of the con- 
version plant. Raw-water storage may at times be necessary to take 
up fluctuations in supply. Depending on source and use conditions, 
also, distribution from a central plant may be more efficient and 
economical than operation of several plants in the same general region. 
Lift and conveyance of desalted water from the seashore will constitute 
a major cost. 
Such variations in the requirements as to practical application of 
saline-water conversion will obviously affect design and cost planning. 
Process costs alone are therefore likely to be an inadequate guide to the 
total cost of converted water. When supply to a population of some 
size is at issue, moreover, reliability of services becomes a vital require- 
