may be captured in the desalting process as 

 technology advances. 



The quality of water from a desalting plant can 

 be depended upon to fall within certain lirhits, but 

 the quality of many conventional water sources 

 usually varies. The lower Colorado River water has 

 a salinity or hardness of about 900 parts per 

 million (ppm) while water produced from de- 

 salting plants using the distillation process has a 

 hardness of only 5 to 10 ppm. For corrosivity 

 reasons most or all distilled water will probably be 

 mixed with natural water before use in a municipal 

 system. 



Hard water requires much more soap or deter- 

 gent than soft water and is therefore much less 

 desirable. 



It has also been demonstrated that there is a 

 relation between salinity of irrigating water and 

 crop productivity.'^ Water of lower salinity pro- 

 duces better crops; this might be accomplished by 

 mixing soft desalted water with the hard Colorado 

 River water. A current cooperative study by OSW 

 and the Bureau of Reclamation is aimed at 

 determining in a quantitative fashion the value of 

 desalting to irrigation. 



Rainfall varies over the years and reservoir 

 storage and release must be programmed to meet 

 requirements of the statistically worst year. This 

 means the water from conventional sources may 

 have to be rationed at certain times. On the other 

 hand, supply from a desalting plant utilizing sea 

 water is constant, adding a value factor to desalted 

 sea water. 



A great many elements are present in minute 

 quantities in sea water but only magnesium, 

 bromine, and salt can be extracted commercially 

 with existing technology. On the basis of estimates 

 and processes now available it is improbable that 

 more than a small minority of desalting plants will 

 be able to realize any economic return from the 

 recovery of by-product elements and compounds. 

 However, the possibility of a technological break- 

 through that will permit the economic recovery of 

 by-product elements such as uranium, which is 

 present in the amount of $339,000 per cubic mile 

 at current prices, cannot be dismissed. 



12 



Ibid, October 1967. 



VI. COMPATIBILITY OF DESALTING PLANTS 

 WITH ENVIRONMENT 



A major problem, relating especially to large 

 scale desalting plants, is the effect the disposal of 

 large quantities of hot brines will have on the 

 ecology and climatic environment of the nearby 

 area. What will be the deleterious effects? What 

 will be the beneficial effects? What will the net 

 effect be? One study relevant to this problem has 

 been completed by OSW. Other studies are cur- 

 rently underway in relation to the Bolsa Island 

 plant (project cancelled) but results are not yet 

 available. The total OSW budget for studies re- 

 lating to brine disposal in estuaries and the ocean 

 is about $200,000 during the current year. 



Possibly a realistic evaluation of the brine 

 disposal problem cannot be made until after a 

 large plant has been in operation for several years. 

 Nevertheless the problem of compatibility is of 

 such importance that the most comprehensive 

 study possible should be made before construction 

 begins. A complete pre-plant ecological survey will 

 be necessary for every large plant, and must 

 extend over a sufficiently long time to cover aU 

 seasonal and periodic changes. Without this, no 

 post-plant survey can have any meaning. 



Engineering methods for minimizing the envi- 

 ronmental effects of the discharges are available 

 and should be incorporated in the plant design. 



VII. PRESENT LEVEL AND STRUCTURE OF 

 GOVERNMENT ACTIVITY 



The Office of Saline Water of the Department 

 of the Interior, established in 1952, has responsi- 

 bility for encouraging, planning and administering 

 research and development relating to desalting 

 technology and associated problems. Essentially all 

 technical studies and research are contracted with 

 industry and research institutions. The Office of 

 Saline Water is concerned not only wdth the 

 desalting of sea water but also with the enhance- 

 ment of the quality of brackish or saline water 

 from any source. Therefore, the programs of OSW 

 cannot be considered to be marine resource 

 programs per se. However, OSW has earmarked 

 certain of their projects which they feel should be 

 included in the area of marine resources. 



Of a total of 322 contracts active in 1968, 27 

 are considered to be related to marine resources. 



VII-231 



