saline water conversion - ACS Publications

Objectives and Status of the Federal Saline Water Conversion Program J. W. O'MEARA

Downloaded by UNIV OF NEW SOUTH WALES on September 5, 2015 | http://pubs.acs.org Publication Date: January 1, 1960 | doi: 10.1021/ba-1960-0027.ch002

Office of Saline Wafer, U. S. Department of the Inferior, Washington 25, D. C.

The objective of the saline water conversion program, need for continuing research, status of the research and development, and the demonstration activities are briefly highlighted.

The experience o f t h e D e p a r t m e n t o f t h e I n t e r i o r o v e r t h e p a s t y e a r s has c l e a r l y re-vealed one b a s i c f a c t — w a t e r p r o b l e m s , i n o n e f o r m o r a n o t h e r , t o u c h a l l 5 0 states o f t h e u n i o n . T h e s e p r o b l e m s v a r y f r o m a r e a t o a r e a , r a n g i n g f r o m s h o r t a g e t o excess. R e g a r d l e s s o f t h e cause, as a n a t i o n w e c a n n o l o n g e r r e g a r d w i t h i n d i f f e r e n c e t h e in-creasing imbalance between the s u p p l y a n d demand f o r water i n the U n i t e d States. A b o u t 2 9 0 b i l l i o n g a l l o n s o f w a t e r p e r d a y are n o w b e i n g u s e d , a n d t h i s r a t e o f d e m a n d i s c a u s i n g i n c r e a s i n g l y severe w a t e r p r o b l e m s i n m a n y sections o f t h e c o u n t r y . I n 1957, a s t u d y c o n d u c t e d b y t h e U . S . G e o l o g i c a l S u r v e y r e v e a l e d t h a t i n o v e r 1000 cities a n d c o m m u n i t i e s , r e p r e s e n t i n g one s e v e n t h o f t h e n a t i o n ' s e n t i r e p o p u l a t i o n , w a t e r shortages o f v a r y i n g degrees r e q u i r e d t h e i r c i t i z e n s t o e n d u r e r e s t r i c t e d use o f w a t e r . I f t h e p r e s e n t r a t e o f d e m a n d c a n cause a p r o b l e m o f t h i s m a g n i t u d e i n a y e a r o f m o d e r a t e d r o u g h t , w h a t w i l l b e t h e scope o f t h e p r o b l e m s one m a y h a v e t o face i n j u s t 20 y e a r s w h e n , a c c o r d i n g t o t h e U . S. G e o l o g i c a l S u r v e y t h e d e m a n d f o r w a t e r w i l l m o r e t h a n d o u b l e , r e a c h i n g t h e i m m e n s e t o t a l o f 497 b i l l i o n g a l l o n s p e r d a y ? T h e y e a r 1980 does n o t m a r k t h e p e a k o f d e m a n d ; t h e c o n s u m p t i o n c u r v e i s e x p e c t e d t o c o n t i n u e t o rise as t h e p o p u l a t i o n c o n t i n u e s t o g r o w . T h e p o p u l a t i o n gain has already created a n increasing imbalance between t h e s u p p l y a n d demand for water i n the U n i t e d States. A l t h o u g h there is a growing public awareness o f t h e p r o b l e m s t h a t m u s t b e f a c e d t o m a i n t a i n a d e q u a t e s u p p l i e s o f w a t e r , t h e a v a i l a b i l i t y o f w a t e r f o r e v e r y n e e d has l o n g b e e n t a k e n f o r g r a n t e d . O n l y i n recent years has t h e public realized that water suitable f o r man's use m a y be a l i m i t e d commodity. W a t e r is c h e a p . I n m o s t U n i t e d S t a t e s cities one c a n p u r c h a s e a t o n o f c l e a r , p u r e , f r e s h w a t e r , d e l i v e r e d t o t h e h o m e o r f a c t o r y , f o r a b o u t 5 c e n t s — o r 2 0 cents p e r 1000 gallons—but water is used i n such tremendous quantities t h a t i t requires vast sums of m o n e y t o p r o v i d e t h e f a c i l i t i e s t o collect i t a n d p u t i t t o b e n e f i c i a l use w h e r e v e r i t i s needed. N a t u r a l l y , w a t e r s u p p l i e s nearest t h e p o i n t o f d e m a n d w e r e t h e first t o be d e v e l o p e d . A s these sources b e c o m e i n a d e q u a t e t o m e e t g r o w i n g d e m a n d s , cities a r e f o r c e d t o r e a c h c o n s i d e r a b l e distances t o t a p a d d i t i o n a l sources o f s u p p l y , a t sites m o r e expensive to develop. L o n g ago, S o u t h e r n C a l i f o r n i a o u t g r e w i t s l o c a l s u p p l i e s a n d h a d t o r e a c h 240 m i l e s across deserts a n d m o u n t a i n s t o t h e C o l o r a d o R i v e r f o r i t s w a t e r s u p p l i e s . T h i s p r o j e c t , once c r i t i c i z e d as a w a s t e f u l o v e r d e v e l o p m e n t , w i l l s o o n be i n a d e q u a t e . I n t h e 1960 3

In SALINE WATER CONVERSION; Advances in Chemistry; American Chemical Society: Washington, DC, 1960.

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ADVANCES IN CHEMISTRY SERIES

general election t h e citizens of C a l i f o r n i a w i l l vote o n t h e most expensive proposition e v e r p l a c e d o n a b a l l o t . T h e y a r e b e i n g a s k e d t o a p p r o v e a $1.75 b i l l i o n b o n d issue t o harvest the fresh water of the F e a t h e r R i v e r i n N o r t h e r n C a l i f o r n i a , t r a n s p o r t i t over 4 0 0 m i l e s , l i f t i t a b o u t 4000 feet o v e r t h e T a h a c h a p i M o u n t a i n s , a n d d e l i v e r i t t o t h e M e t r o p o l i t a n L o s Angeles area. T h e increasingly complex p r o b l e m of p r o v i d i n g adequate supplies of water is n o t l i m i t e d t o a few h o t a n d a r i d areas o f t h e S o u t h a n d S o u t h w e s t , b u t also e m b r a c e s regions i n the h u m i d E a s t .


Sources of Water T h e task of p r o v i d i n g ample supplies of fresh water f o r t h e A m e r i c a of t o m o r r o w m a y i n d e e d b e o u r N o . 1 d o m e s t i c p r o b l e m . A t least o n e i m p l i c a t i o n o f t h e e v e r i n c r e a s i n g use o f w a t e r i s u n m i s t a k a b l e : W e m u s t find n e w sources o f f r e s h w a t e r , a n d t w o o f t h e m o s t l i k e l y sources a r e t h e g r e a t oceans a n d t h e v a s t reserves o f b r a c k i s h inland waters. M a n has been t r y i n g f o r a l o n g t i m e t o b r e w a d r i n k o f f r e s h w a t e r f r o m t h e sea, p r o b a b l y a l o t longer t h a n most people realize. F o r centuries people generally have k n o w n h o w t o t u r n t h e t r i c k : J u s t d i s t i l l i t . T h e basic c o n c e p t o f t h e science i s p r o b a b l y as o l d as t h e t e a k e t t l e . B u t w h a t t h e w o r l d i s s t i l l s e a r c h i n g f o r i s t h e a n s w e r t o t h e q u e s t i o n : H o w does one d o t h i s o n a l a r g e scale a t a cost c h e a p e n o u g h t o s u b s t i t u t e for or augment water f r o m conventional sources? T h e first p r a c t i c a l c o n v e r s i o n u n i t s c a m e w i t h t h e a d v e n t o f t h e s t e a m s h i p a n d i t s r e q u i r e m e n t o f f r e s h w a t e r f o r b o i l e r s . T o d a y , m o s t o f t h e l a r g e o c e a n - g o i n g vessels have t h e i r b a t t e r y of evaporators. T h e F o r r e s t a l class c a r r i e r s o f t h e U n i t e d S t a t e s N a v y , for example, carry four 50,000-gallon-per-day evaporators to supply t h e water needs o f those h u g e s h i p s a n d t h e i r l a r g e c r e w s . W h i l e s h i p b o a r d supplies of w a t e r are v i t a l t o navies a n d the m a r i t i m e i n d u s t r y , the s a l i n e w a t e r c o n v e r s i o n p r o g r a m o f t h e D e p a r t m e n t o f t h e I n t e r i o r i s i n t e r e s t e d i n a different phase o f t h e o v e r - a l l p r o b l e m . A b o a r d s h i p t h e p r i m a r y i n t e r e s t i s a r e l i a b l e s u p p l y o f w a t e r ; t h e cost o f t h e w a t e r i s o f s e c o n d a r y c o n s i d e r a t i o n . T h e i n t e r e s t o f t h e Office of S a l i n e W a t e r i s c e n t e r e d o n l a n d - b a s e d p l a n t s t h a t c a n p r o d u c e f r e s h w a t e r f r o m t h e sea a t l o w cost, t h e l a t t e r b e i n g t h e i m p o r t a n t f a c t o r . L a n d - B a s e d P l a n t s . T h e U n i t e d S t a t e s G o v e r n m e n t ' s w o r k i n t h i s field goes b a c k t o 1952, w h e n C o n g r e s s passed t h e S a l i n e W a t e r A c t t o p r o v i d e f o r r e s e a r c h a n d d e v e l o p m e n t o f p r a c t i c a l m e t h o d s o f p r o d u c i n g f r e s h w a t e r f r o m saline sources. T h e 1 9 5 2 A c t a u t h o r i z e d $2,000,000 f o r a 5 - y e a r p r o g r a m . I n 1955, t h e A c t w a s a m e n d e d b y i n c r e a s i n g t h e a u t h o r i z a t i o n t o $10,000,000 a n d e x t e n d i n g t h e l i f e o f t h e p r o g r a m t h r o u g h fiscal y e a r 1963. A p l a n t o n t h e I s l a n d o f A r u b a , i n t h e C a r i b b e a n , i s n o w p r o d u c i n g 2,700,000 g a l l o n s o f f r e s h w a t e r p e r d a y a t a cost o f a b o u t $ 2 p e r 1000 g a l l o n s . O f t h e l a n d - b a s e d p l a n t s s c a t t e r e d a r o u n d t h e g l o b e , w i t h a c o m b i n e d c a p a c i t y o f a b o u t 20,000,000 g a l l o n s of f r e s h w a t e r p e r d a y , t h e p l a n t a t A r u b a i s t h e m o s t efficient. B a s e d o n p r e s e n t cost s t a n d a r d s , these p l a n t s a r e e x p e n s i v e p r o d u c e r s , b u t t h e y a r e i n existence because t h e cost o f w a t e r f r o m a l t e r n a t i v e sources i s e v e n h i g h e r . O v e r t h e p a s t s e v e r a l y e a r s t h e d e p a r t m e n t h a s b a r g e d o v e r 100,000,000 g a l l o n s o f f r e s h w a t e r f r o m P u e r t o R i c o t o s u p p l y t h e m i n i m u m r e q u i r e m e n t s o f t h e p e o p l e o f S t . T h o m a s , V i r g i n I s l a n d s , a t a cost of a b o u t $6 p e r 1000 g a l l o n s . P u b l i c L a w 8 5 - 8 8 3 , a p p r o v e d b y P r e s i d e n t E i s e n h o w e r o n S e p t e m b e r 2 , 1958, a d d e d a n e w r e s p o n s i b i l i t y t o t h e office. I t a u t h o r i z e s $10,000,000 f o r t h e d e s i g n , c o n s t r u c t i o n , a n d o p e r a t i o n o f five saline w a t e r c o n v e r s i o n p l a n t s t o d e m o n s t r a t e t h e r e l i a b i l i t y , e n g i n e e r i n g , o p e r a t i n g , a n d e c o n o m i c p o t e n t i a l s o f sea o r b r a c k i s h w a t e r c o n v e r s i o n processes. T h e l a w p r o v i d e s t h a t t h r e e o f these p l a n t s s h a l l b e f o r t h e c o n v e r s i o n o f sea w a t e r to fresh water—one each t o be located o n the E a s t Coast, the W e s t Coast, a n d the G u l f C o a s t . A t least t w o o f these p l a n t s s h a l l h a v e a c a p a c i t y o f 1,000,000 g a l l o n s o f f r e s h w a t e r p e r d a y . T w o o f t h e p l a n t s w i l l b e designed t o c o n v e r t b r a c k i s h w a t e r t o f r e s h


O'MEARA—FEDERAL PROGRAM

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w a t e r — o n e t o b e l o c a t e d i n t h e N o r t h e r n G r e a t P l a i n s a n d t h e o t h e r i n t h e a r i d areas o f t h e S o u t h w e s t . O n e of these p l a n t s m u s t h a v e a c a p a c i t y of a t least 250,000 g a l l o n s p e r d a y . E a c h p l a n t m u s t u t i l i z e a different process.


A n a c c u r a t e b a r o m e t e r of t h e n a t i o n w i d e i n t e r e s t i n t h e saline w a t e r c o n v e r s i o n p r o g r a m i s p r o v i d e d b y t h e n u m b e r of requests r e c e i v e d f r o m c i v i c bodies, p u b l i c o f ficials, i n d u s t r i a l o r g a n i z a t i o n s , a n d p r i v a t e c i t i z e n s a s k i n g c o n s i d e r a t i o n f o r t h e i r a r e a as a site f o r one of t h e a u t h o r i z e d p l a n t s . N e a r l y 2 0 0 a p p l i c a t i o n s h a v e b e e n r e c e i v e d f r o m cities a n d c o m m u n i t i e s i n e v e r y s t a t e o n t h e c o a s t a l p e r i m e t e r , f r o m 12 i n l a n d states, a n d f r o m A l a s k a a n d H a w a i i . S e c r e t a r y S e a t o n h a s selected five processes a n d f o u r sites f o r t h e d e m o n s t r a t i o n p l a n t p r o g r a m . S e v e r a l of those processes a r e d e s c r i b e d i n c o n s i d e r a b l e d e t a i l i n t h e papers that follow. T h e first d e m o n s t r a t i o n p l a n t w i l l be located a t F r e e p o r t , T e x . U t i l i z i n g t h e l o n g t u b e v e r t i c a l m u l t i p l e - e f f e c t d i s t i l l a t i o n process, i t w i l l b e designed t o p r o d u c e f r e s h w a t e r f r o m t h e sea a t t h e r a t e of 1,000,000 g a l l o n s p e r d a y . W . L . B a d g e r A s s o c i a t e s , I n c . , A n n A r b o r , M i c h . , p e r f o r m e d t h e a r c h i t e c t u r a l a n d e n g i n e e r i n g services. Invita t i o n s f o r c o n s t r u c t i o n b i d s w e r e i s s u e d o n M a r c h 14 a n d t h e Office o f S a l i n e W a t e r s o l d o v e r 125 sets of p l a n s a n d specifications f o r t h i s p l a n t , w h i c h p r o v i d e s a second i n d i c a t i o n of t h e s h a r p i n t e r e s t i n t h e saline w a t e r c o n v e r s i o n p r o g r a m . B i d s were o p e n e d o n M a y 24. O n J u n e 8, a c o n t r a c t f o r $1,246,250 w a s a w a r d e d t o t h e successful l o w b i d d e r , the Chicago B r i d g e & I r o n C o . T h e second d e m o n s t r a t i o n p l a n t w i l l consist o f a m u l t i s t a g e flash process f o r a 1 , 0 0 0 , 0 0 0 - g a l l o n - p e r - d a y p l a n t t o b e l o c a t e d o n t h e W e s t C o a s t . A site o n P o i n t L o m a a t S a n D i e g o h a s been selected f o r t h i s p l a n t . T h e F l u o r C o r p . , W h i t t i e r , C a l i f . , h a s been awarded t h e a r c h i t e c t u r a l a n d engineering contract for the distillation p l a n t , a n d it is planned t o let a construction contract i n N o v e m b e r . A process t h a t w a s n o m o r e t h a n a l a b o r a t o r y p h e n o m e n o n w h e n t h e Office of S a l i n e W a t e r w a s a u t h o r i z e d i n 1952 h a s been r a p i d l y d e v e l o p e d t o t h e p o i n t w h e r e i t is n o w o n e of t h e m o s t e c o n o m i c a l processes f o r t h e c o n v e r s i o n of b r a c k i s h w a t e r t o f r e s h . T h i s process, e l e c t r o d i a l y s i s , w a s selected f o r t h e t h i r d d e m o n s t r a t i o n p l a n t . I t w i l l be located at Webster, S. D . T h e B u r e a u of R e c l a m a t i o n Laboratories i n D e n v e r , C o l o . , p r e p a r e d t h e specifications f o r t h i s p l a n t w h i c h w i l l b e designed t o p r o d u c e 250,000 g a l l o n s o f f r e s h w a t e r p e r d a y . O p e r a t i n g o n w a t e r c o n t a i n i n g b e t w e e n 1500 a n d 1800 p a r t s o f s a l t p e r m i l l i o n p a r t s o f w a t e r , t h i s p l a n t w i l l r e m o v e m o r e t h a n 1 t o n of s a l t d a i l y t o p r o d u c e p r o d u c t w a t e r w i t h less t h a n 5 0 0 p a r t s o f s a l t p e r m i l l i o n p a r t s of w a t e r w h i c h is r e q u i r e d t o m e e t U . S . P u b l i c H e a l t h S t a n d a r d s f o r g o o d d r i n k i n g w a t e r . C o n s t r u c t i o n specifications f o r t h i s p l a n t w e r e a v a i l a b l e A u g u s t 1, a n d sealed b i d s w i l l b e o p e n e d o n O c t o b e r 4, 1960. T h e f o u r t h p r o c e s s — f o r c e d - c i r c u l a t i o n v a p o r - c o m p r e s s i o n — w i l l b e designed t o p r o d u c e a t least 250,000 g a l l o n s o f f r e s h w a t e r p e r d a y i n a p l a n t t o b e l o c a t e d a t R o s w e l l , Ν . M . A s i d e f r o m p r o v i d i n g b a d l y needed s u p p l e m e n t a l w a t e r t o t h e c i t y , t h e p l a n t offers a second e x c i t i n g p o s s i b i l i t y . C o n t i n u e d h e a v y p u m p i n g necessary t o m e e t t h e g r o w i n g d e m a n d i s g r a d u a l l y lowering t h e water table i n RoswelFs present fresh water aquifer. I t has reached a p o i n t w h e r e saline w a t e r i s b e g i n n i n g t o e n c r o a c h a n d e n d a n g e r t h e source of f r e s h w a t e r . B y p u m p i n g saline w a t e r s f r o m t h e b r a c k i s h w a t e r a q u i f e r , t h i s e n c r o a c h m e n t m a y b e retarded a n d at the same t i m e , b y p r o v i d i n g fresh water f r o m t h e conversion p l a n t , t h e c i t y can reduce its p u m p i n g f r o m t h e fresh water aquifer, w h i c h m a y p e r m i t a g r a d u a l recharge of the aquifer. F o r t h e fifth p l a n t , a f r e e z i n g process w i l l b e u t i l i z e d . T h i s p l a n t w i l l b e l o c a t e d a t a y e t t o b e selected site o n t h e E a s t C o a s t . I t w i l l b e designed t o p r o d u c e f r e s h w a t e r i n t h e r a n g e o f 150,000 t o 350,000 g a l l o n s p e r d a y . T h e site w i l l b e selected t h i s f a l l , b u t c o n s t r u c t i o n is n o t c o n t e m p l a t e d b e f o r e t h e fiscal y e a r 1962. T h e conversion of saline w a t e r t o fresh w a t e r b y freezing is r e l a t i v e l y new, b u t i t is believed t o have great potential. T h e o r e t i c a l l y , freezing has several inherent a d v a n i a g e s o v e r c o n v e n t i o n a l d i s t i l l a t i o n p r o c e s s e s — f o r e x a m p l e , t h e lesser t e n d e n c y t o w a r d


ADVANCES IN CHEMISTRY SERIES

6


s c a l i n g a n d c o r r o s i o n because o f t h e l o w o p e r a t i n g t e m p e r a t u r e s i n v o l v e d , a n d t h e l o w e r e n e r g y r e q u i r e m e n t t o freeze s e a w a t e r as c o m p a r e d t o t h e e n e r g y r e q u i r e d f o r t h e evaporation of sea water. F r e e z i n g i s so n e w t h a t t h e w o r l d ' s first f r e e z i n g process p i l o t p l a n t b e g a n o p e r a t i n g i n O c t o b e r 1959 a t t h e C a r r i e r C o r p . p l a n t i n S y r a c u s e , Ν . Y . P r e l i m i n a r y tests h a v e b e e n c o m p l e t e d a n d t h e e q u i p m e n t i s b e i n g d i s m a n t l e d f o r s h i p m e n t t o a seashore l o c a t i o n f o r f u r t h e r o p e r a t i o n a l t e s t i n g . T h e B l a w - K n o x C o . o f P i t t s b u r g h has been a w a r d e d a c o n t r a c t t o b u i l d a 3 5 , 0 0 0 - g a l l o n - p e r - d a y p i l o t p l a n t t o test a n o t h e r f r e e z i n g process d e v e l o p e d a t C o r n e l l U n i v e r s i t y . T h i s process i s b a s e d o n t h e flash e v a p o r a t i o n o f a v o l a t i l e a n d i m m i s c i b l e h y d r o c a r b o n , s u c h as b u t a n e , i n d i r e c t c o n t a c t w i t h sea w a t e r t o cause p a r t o f t h e w a t e r t o freeze. O t h e r p i l o t p l a n t a c t i v i t y i n c l u d e s t e s t i n g of s o l a r s t i l l s a t a n e x p e r i m e n t a l s t a t i o n near D a y t o n a B e a c h , F l a . A t the B u r e a u of R e c l a m a t i o n L a b o r a t o r i e s i n D e n v e r , t h e Office o f S a l i n e W a t e r has t w o e l e c t r o d i a l y s i s u n i t s , one b u i l t b y I o n i c s , I n c . , C a m b r i d g e , M a s s . , a n d the o t h e r b y the C e n t r a l T e c h n i c a l I n s t i t u t e , T . N . O . , o f the N e t h e r l a n d s . A J a p a n e s e e l e c t r o d i a l y s i s u n i t is o n o r d e r a n d w i l l be t e s t e d a t t h e D e n v e r L a b o r a t o r i e s . V a r i o u s t y p e s o f m e m b r a n e s are also b e i n g t e s t e d a t D e n v e r . D i s t i l l a t i o n e x p e r i m e n t s are c o n t i n u i n g i n r e s e a r c h f a c i l i t i e s l o c a t e d a t W r i g h t s v i l l e B e a c h , N . C . Research a n d development contracts w i t h universities, research organizations, a n d i n d u s t r i a l firms are p r o b i n g i n t o t h e fields o f heat t r a n s f e r , scale p r e v e n t i o n , c o r r o s i o n , m e m b r a n e s , gas h y d r a t e s , s o l v e n t e x t r a c t i o n , a n d m a n y o t h e r s , a l l designed t o h e l p a t t a i n the goal of low-cost converted water. T h e p l a n t s a b o u t t o be b u i l t w i l l d e m o n s t r a t e the progress t h a t has been a c h i e v e d t h r o u g h 8 y e a r s o f r e s e a r c h t h a t has been s u p p o r t e d b y a n a v e r a g e a n n u a l a p p r o p r i a t i o n of less t h a n $725,000. W h e n t h e Office o f S a l i n e W a t e r w a s a u t h o r i z e d i n 1952, t h e cost of c o n v e r s i o n r a n g e d u p w a r d f r o m $ 5 p e r 1000 g a l l o n s . T h e t w o 1,000,000-gallon-perd a y d e m o n s t r a t i o n p l a n t s a r e e x p e c t e d t o p r o d u c e f r e s h w a t e r f r o m t h e sea f o r a b o u t $1 p e r 1000 g a l l o n s . E n g i n e e r i n g e x t r a p o l a t i o n s i n d i c a t e t h a t w h e n these processes a r e incorporated i n m u l t i m i l l i o n - g a l l o n - p e r - d a y plants savings w i l l be obtained w h i c h w i l l reduce t h e t o t a l cost of c o n v e r s i o n t o a b o u t 5 0 cents p e r 1000 g a l l o n s , a n d p r i c e s e v e n l o w e r t h a n t h a t m a y b e e x p e c t e d f o r t h e c o n v e r s i o n of c e r t a i n b r a c k i s h w a t e r s . T h e s e e s t i m a t e s o f cost a r e b a s e d o n t h e s t a n d a r d i z e d p r o c e d u r e f o r e s t i m a t i n g saline w a t e r c o n v e r s i o n costs p u b l i s h e d b y t h e Office of S a l i n e W a t e r . T h a t p r o c e d u r e i n c l u d e s a l l costs a t t o d a y ' s p r i c e s — l a n d , c a p i t a l i n v e s t m e n t , i n t e r e s t , o p e r a t i n g costs, m a i n t e n a n c e , taxes, i n s u r a n c e , a n d a r a t h e r severe 2 0 - y e a r a m o r t i z a t i o n s c h e d u l e . T h e d e m o n s t r a t i o n p l a n t p r o g r a m has c a p t u r e d t h e i n t e r e s t a n d i m a g i n a t i o n o f t h e n a t i o n a n d the w o r l d , b u t p l a n t c o n s t r u c t i o n is n o t t h e k e y t o l o w - c o s t c o n v e r s i o n . W h i l e these p l a n t s are b e i n g c o n s t r u c t e d , t h e r e s e a r c h a n d d e v e l o p m e n t p r o g r a m w i l l b e c o n t i n u e d — f o r r e s e a r c h is t h e k e y t o progress. O n e m u s t t u r n t o scientific a n d t e c h n o l o g i c a l r e s e a r c h t o d e v e l o p a n e w source o f s u p p l y t h a t c a n p r o v i d e a n e v e r - g r o w i n g p e r c e n t a g e of t o m o r r o w ' s w a t e r . RECEIVED for review J u l y 7 , 1 9 6 0 . A c c e p t e d A u g u s t 2 , 1 9 6 0 .


saline water conversion - ACS Publications

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