c

. APPLICATIONS O F ELECTROSTATIC PROCESSES FOR THE CONTROL OF

SCALE, CORROSION AND BIOLOGICS I N COOLING TOWERS

Robert S. Reimers, Ph.D. Department of Environmental Heal th Sc iences*

School of P u b l i c Heal th and T r o p i c a l Medicine Tulane Un ive r s i ty

New Orleans LA 70112

Pau l S. JeKernion C. Paul Lo EIRA, Inc .

P. 0. Box 6978 Metairie LA 70009

Roy C. McMahon E l e c t o s t a t i c s Equipment Corpora t ion

1665 Ja rboe Kansas C i t y MO 64108

Linda Souther land* Ann C. Anderson, Ph.D*

I )

ABSTRACT

The a p p l i c a t i o n of e l e c t r o s t a t i c p rocesses f o r t h e c o n t r o l of s c a l e , c o r r o s i o n , and b i o l o g i c s i n coo l ing towers w i l l be d i scussed . F a c t o r s i n f l u e n c i n g t h e e l e c t r o s t a t i c s p rocess will be e l u c i d a t e d i n t h e s e areas: 1 ) p r o c e s s l i m i t a t i o n s ; 2 ) opera t ions arid maintenance problems; and 3) p rocess r e l i a b i l i t y . I n f a c t , i n many a r e a s , i t appears t h a t complete t r ea tmen t u t i l i z i n g t h e e l e c t r o s t a t i c s process r e q u i r e s chemical a d d i t i v e s .

INTRODUCTION

The o b j e c t i v e s of t h i s paper are f o u r f o l d : 1) t o d i s c u s s t h e mechanisms by which e l e c t r o s t a t i c s p rocesses t r ea t i n d u s t r i a l w a t e r s ; 2 ) t o r e l a t e r e c e n t o p e r a t i o n a l arid maintenance p rob lems ; 3) t o c a p s u l a t e p a r t i c u l a r l i m i t a t i o n s of e l e c t r o s t a t i c 8

processes ; and 4) t o no te t h e p rocess r e l i a b i l i t y .

These "gadget" p rocesses have o f f e r e d an appa ren t "something-for-nothing" o r a k ind of panacea p rocess t o waste and wa te r t r ea tmen t . Such gadge t s are a l s o claimed t o be s p e c i a l dev ices r e q u i r i n g no t e c h n i c a l c o n t r o l which w i l l t r e a t water by non-chemical means t o prevent s c a l e , c o r r o s i o n and t o r e s o l v e o t h e r problems encountered i n t h e i n d u s t r i a l u se of water. t o t h e l ack of s c i e n t i f i c s u b s t a n t i a t i o n of t h e mechanisms. I n most s i t u a t i o n s , the above s k e p t i c i s m should be of major concern , b u t r e c e n t r e s e a r c h h a s b rough t t o t h e f o r e f r o n t d a t a t h a t I n d i c a t e s t h a t a p p l i c a t i o n of induced- f i e ld p r o c e s s e s may be a v i a b l e p rocess f o r water treatment under s p e c i f i c envi ronmenta l c o n d i t i o n s .

Skep t i c i sm is due p r i m a r i l y

BACKGROUND

I n t h e mid-19th cen tu ry t h e f i r s t water c o n d i t i o n i n g "gadget" p a t e n t i n t h e United States was Issued. S i n c e t h a t time, over 100 s u c h p a t e n t s w e r e I s s u e d . These p r o c e s s e s had no t e c h n i c a l c o n t r o l and r e q u i r e d no chemical a d d i t i o n t o p reven t scale , c o r r o s i o n and o t h e r problems encountered in t h e use of water ( 1 ) .

I n the l a t e 1950's E 1 i a s s e n . g . g., (2) no ted no i n h i b i t i o n o f scale fo rma t ion and no r educ t ion i n the r a t e of co r ros ion ove r a fou r month p e r i o d u s i n g induced- f i e ld procces . T h i s I n e f f e c t i v e n e s s w a s s p e c u l a t e d t o be a r e s u l t o f low f i e l d d e n s i t i e s . I n 1977, a p u b l i c a t i o n ques t ioned t h e c l a ims of t h e s e p rocesses t o prevent s c a l e and i n h i b i t c o r r o s i o n . I t was b e l i e v e d t h a t t h e induced- f i e ld p rocesses (magnet ic , e l ec t romagne t i c and e l e c t r o s t a t i c ) were i n c o n f l i c t w i t h the b a s i c p r i n c i p l e s of s c i e n c e and al lowed f a r t o o l i t t l e exposure t o t h e induced f i e l d . n e a u t h o r ques t ioned t h e r e l i a b i l i t y o f c a t i o n s t o adsorb e l e c t r o n s and wofidered about t h e memory of t h i s t r e a t m e n t a f t e r p a s s i n g through t h i s f i e l d (3 ) . Recent ly , two papers warned i n d u s t r y of non-chemical w a t e r t r ea tmen t p rocesses (4.5). One paper (4) emphasized t h e same p o i n t s ( i n t h e exac t wording) as t h e pape r r e l e a s e d i n 1977 (3) . The o t h e r pape r (5) reviewed t h e l i t e r a t u r e concerned w i t h t h e problems r e s u l t i n g from t h e p r o c e s s e s and examined c la ims nade by v a r i o u s induced f i e l d and u l t r a s o n i c water c o n d i t i o n i n g p rocesses .

T h e s k e p t l c i s m sur rounding t h e s e p rocesses is due t o t h e l a c k of s c i e n t i f i c s u b s t a n t i a t i o n of t h e d e s c a l i n g o r d i s i n f e c t i o n . Recent r e s e a r c h f i n d i n g s , however, i n d i c a t e the a p p l i c a t i o n of e l e c t r o s t a t i c s and u l t r a s o n i c s as a v i a b l e p rocess t o water t r ea tmen t . I n t h e l a s t 15 y e a r s , r e s e a r c h has r e i n f o r c e d the b e n e f i c i a l e f f e c t s of magnet ic and e l e c t r o s t a t i c f i e l d s i n t h e r e d u c t i o n of b o i l e r s c a l e ( 6 , 7 ) . Toshi and Kamat (6) no ted a dec rease i n t h e pH of d i s t i l l e d water (0.62 pH u n i t s ) exposed t o magnet ic f i e l d s i n t h e range of 1900-5700 gauss . S i m i l a r o b s e r v a t i o n s have been r e p o r t e d f o r n a t u r a l l y o c c u r r i n g waters . Measurements of t h e p h y s i c a l p r o p e r t i e s of water showed ve ry l i t t l e change, w i th t h e excep t ion of pH, a f t e r p a s s i n g through a magnet ic f i e l d . A v a r i e t y of e x p l a n a t i o n s h a s been proposed for t h i s phenomenon; one such invo lv ing a magne t i ca l ly induced change i n t h e pH o f t h e w a t e r (8). The r e d u c t i o n i n pH i n d i c a t e s an i n c r e a s e i n Lewis a c i d s ( e l e c t r o n a c c e p t o r ) due t o t h e release of a c i d i c s c a l e complexes. Quickendon, et. &., was n o t a b l e t o s u b s t a n t i a t e t h e pH drop, b u t obscrved pH r i s e w i t h d i s t i l l e d water, p o s s i b l y due t o t h e format ion of L e w i s b a s e s ( e l e c t r o n donor s c a l e t o absorb e l e c t o n s .

) i n c o n t a i n e r s which had no

Kobikus (10) found magnet ic f i e l d water t r ea tmen t p r o c e s s e s reduced s c a l e , b u t t h e s e same p r o c e s s e s had no c o n t r o l o v e r c o r r o s i o n . I n a d d i t i o n , t h e i n f l u e n c e of a magnet ic f i e l d tended to change t h e c r y s t a l l i n e s t r u c t u r e of calcium ca rbona te scale from c a l c i t e to a r g o n i t e . J apanese r e s e a r c h e r s (11) r epor t ed s imi l a r r e s u l t s . I n a d d i t i o n , t hey n o t e d c o r r o s i o n i n h i b i t i o n w i t h t h e induced-f ie ld p r o c e s s e s i n b o i l i n g water t r ea tmen t . As a r e s u l t of t h e s e s t u d i e s , Un ive r s i ty of Michigan r e s e a r c h e r s ( 1 2 ) i n v e s t i g a t e d t h e e f f e c t i v e n e s s o f e l e c t r o s t a t i c and magnet ic t r ea tmen t o f water t o p reven t s c a l i n g , t o i n h i b i t c o r r o s i o n , arid t o reduce bioltgica: a c i i v i t y . V i t h d e c t r a m g n e t i c a l l y treated water, they found lower c o r r o s i o n of aluminum and less scale format ion a t 180°F over 48 hours than i n u n t r e a t e d water. somewhat less v i a b l e i n t h e p re sence of e l e c t r o m a g n e t i c a l l y t r e a t e d water; however, t h e r e is some q u e s t i o n conce rn ing t h e s e results. E l e c t r o s t a t i c t rea tment of water produced s o f t scale fo rma t ion , w h i l e non- t rea ted water produces a tenacious scale a t 2000C.

Daphnia were found t o b e

Recent s t u d i e s on induced- f i e ld t r ea tmen t i n i n d u s t r i a l s e t t i n g s have produced more i n t e r e s t i n g phenomena. Work a t Clemson by Duffy (13) showed t h a t e l e c t r o - magnet ic t r ea tmen t was on ly e f f e c t i v e when f e r r i c hydroxide was p r e s e n t . hydroxide i n t h e feed water decreased t h e fo rma t ion of scale and t h e c o n t r o l of sca le v a r i e d d i r e c t l y w i t h concentration of f e r r i c hydroxide and conve r se ly w i t h tempera ture ; b u t S c d e was i n h i b i t e d a t pH levels r ang ing from 6 t o 11.

F e r r i c

- 2-

I n 1979, K r a j i i c and Mi l sev ic -Kra j i i c (14) pub l i shed case h i s t o r i e s o f f a c i l i t i e s u s ing e l ec t romagne t i c water t r ea tmen t dev ices . They no ted t h a t s c a l e d b o i l e r s s t a r t e d d e s c a l i n g w i t h i n a month of i n s t a l l a t i o n of such u n i t s . Desca l ing was noted i n s i t u a t i o n s where calcium s u l f a t e , magnesium c a r b o n a t e , calcium c a r b o n a t e , calcium hydroxide, magnesium hydroxide and ca lc ium magnesium ca rbona te were s u p e r s a t u r a t e d a f t e r c o n s i d e r a t i o n o f tempera ture and i o n i c s t r e n g t h . w a t e r d i s t i l l e r .

S i m i l a r r e s u l t s were observed f o r coo l ing towers and a l a b o r a t o r y

The a b i l i t i e s of u l t r a s o n i c s , e l e c t r o s t a t i c s , e l e c t r o m a g n e t i c r a d i a t i o n and magnet ic r a d i a t i o n on microbic r e d u c t i o n have been i n v e s t i g a t e d d u r i n g t h e p a s t f i f t y y e a r s . The f e a s i b i l i t y of t h e s e methods depends g e n e r a l l y on t h e i n t e n s i t y of power r e q u i r e d t o d i s i n f e c t or i n a c t i v a t e (15 ) . Recent s t u d i e s have shown p o t e n t i a l pathogen i n a c t i v a t i o n a t lower i n t e n s i t y of r a d i a t i o n or u l t r a s o n i c s when coupled wi th chemical a g e n t s , ozone o r s o l u b l e o r g a n i c s (15,lC’. With the r e c e n t q u e s t i o n s concern ing t h e envi ronmenta l impact of c h l o r i n a t i o n on human h e a l t h , t h e s y n e r g i s t i c a p p l i c a t i o n s of u l t r a s o n i c s and /o r e l e c t r o s t a t i c s w i t h chemical a d d i t i v e s appea r s t o be a very f e a s i b l e approach t o e f f e c t i v e pathogen i n a c t i v a t i o n a t low c o s t s and reduced impact t o p u b l i c h e a l t h .

Microbia l k i l l w i th u l t r a s o n i c a t i o n was f irst r e p o r t e d i n 1929 (17 ) . Recent i n v e s t i g a t i o n s h o w s t h a t t h i s d i s i n f e c t i o n appea r s t o be a f u n c t i o n of i n t e n s i t y r a t h e r than frequencv. For example, E s h e r i c h i a c o l i B. are i n a c t i v a t e d on ly i f t h e i n t e n s i t y i s k e p t a t 2.25 watts/cmL or g r e a t e r (17 ) . o b s e r v a t i o n s have been noted by Croakly, et. al. (18). w i l l k i l l microbes, l u t no t 100% k i l l . can become a major concern. (18,19)

S i m i l a r All s a y t h a t u l t r a s o n i c a t i o n

T h e r e z r e , t h e problem of regrowth

U l t r a s o n i c a t i o n can be used as a d i s i n f e c t i o n p rocess when coupled wi th h e a t i n g or chemica ls , and, i n f a c t , t h e s y n e r g i s t i c s of h e a t and /o r chemicals can make u l t r a s o n i c a t i o n economical ly f e a s i b l e (15, 20, 21 ) . Murray (22) and O u e l l e t t e , - - e t . a1.(23) r e p o r t e d t h a t u l t r a s o n i c a t i o n a lone d i d n o t have a ge rmic ida l e f f e c t or i n c r e a s e r e a c t i v i t y , bu t when used w i t h o t h e r t r ea tmen t methods or c a t a l y s t s , t h e i n f l u e n c e of t h e u l t r a s o n i c s made t h e r e a c t i o n s o f b i o k i l l magn i tud ina l ly more e f f e c t i v e (22.23) .

Recent s t u d i e s a t Tulane no ted a f i v e - f o l d e x p o n e n t i a l r e d u c t i o n i n t o t a l b a c t e r i a when an ultrasonicfelectrostatic u n i t was connected t o a commercial b o t t l e washing machine. The minimum to t a l b a c t e r i a d e n s i t y w a s observed a t approximate ly two days of t r ea tmen t w i t h a d e f i n i t e regrowth of b a c t e r i a o v e r t h e nex t two days. Concurren t ly , p r e l i m i n a r y r e s e a r c h was conducted i n t h e f i e l d u s i n g a s imi l a r u n i t f o r secondary e f f l u e n t s . This process reduced c h l o r i n e demand by 20% and reduced t o t a l c o l i f o r m by 70% as a f u n c t i o n of bo th f law and initial concentration ( I h ) .

DISCUSS I O N

The d i s c u s s i o n w i l l be d iv ided i n t o two s e c t i o n s . The f i r s t s e c t i o n w i l l be concerned w i t h t h e mechanisms by which e l e c t r o s t a t i c s p r o c e s s e s c o n t r o l s c a l e , i n h i b i t c o r r o s i o n and i n a c t i v a t e pathogens. I n t h e second s e c t i o n , t h e real world problems concern ing o p e r a t i o n and maintenance, p a r t i c u l a r l i m i t a t i o n s , and p rocess r e l i a b i l i t y w i l l b e e l u c i d a t e d .

Specula ted Mechanisms € o r Desca l ing , B i o i n a c t i v a t i o n and A n t i c o r r o s i o n by E l e c t r o s t a t i c P rocesses

S c a l e I n h i b i t i o n

A major o b j e c t i v e of t h i s paper i s t o a t t empt an e x p l a n a t i o n of t h e mechanisms by which e l e c t r o s t a t i c p rocesses d e s c a l e . d e s c a l i n g and /o r s c a l e i n h i b i t i o n p rocess is very complex and invo lves concepts be longing t o c o l l o d i a l chemis t ry , p h y s i c a l . chemis t ry , o r g a n i c chem- i s t r y , etc.

Recent s t u d i e s by Russians and Americans00,11,16,27,28,29) noted f o u r phenomena t h a t i n f l u e n c e the d e s c a l i n g p rocess : 1) t h e bui ld-up of s l u d g e i n t h e water where induced-f ie ld p rocesses are a p p l i e d ; 2) t h e i n c r e a s e d e f f i c i e n c y of induccd f i e l d p rocesses w i t h t h e a d d i t i o n of s o l u b l e i r o n and magensium c o n c e n t r a t i o n s ; 3) the importance of wa te r q a u l i t y i n t h e e f f e c t i v e n e s s of t h e e l e c t r o s t a t i c p rocesses ; and 4) t he i n f l u e n c e of z e t a p o t e n t i a l on t h e a p p l i c a t i o n of e l e c t r o - s t a t i c p rocesses i n wa te r t r e a t n e n t and s o l i d s s e p a r a t i o n . t h e above f o u r phenomena had o f t e n been overlooked and r e s u l t e d i n t h e f a i l u r e of many induced- f i e ld p rocesses which could have been very f e a s i b l e .

I t is impor t an t t o n o t e t h a t t h i s

The importance of

Sludge bui ld-up i n e l e c t r o s t a t i c p rocesses r e s u l t s from t h e observed i n c r e a s e s i n n u c l e i formed i n the water i n s t e a d of on t h e s i d e s of p i p e s , coo l ing towers , b o i l e r s , e t c . The phenomenon had been r e p o r t e d by v a r i o u s r e s e a r c h e r s I t is necessa ry t o remove t h e s e s o l i d s e i t h e r by c l a r i f i c a t i o n o r f i l t r a t i o n . I n coo l ing tower a p p l i c a t i o n s , f i l t r a t i o n i s a d v i s a b l e . Add i t ions of i r o n and magnesium i n c r e a s e the e f f i c i e n c y of magnetic o r e l e c t r o s t a t i c t r e a t m e n t . For example, 0.8 mg/l of f e r r i c hyrdoxide i n c r e a s e d t h e e f f i c i e n c y of coo l ing tower and deep w e l l i n j e c t i o n p rocesses by 50% ( 9 ) . Addi t ion of i r o n i n c r e a s e d t rea tment e f f i c i e n c y i n the pH ranges of 6-11 up t o 2 mg/l as i ron . e f f i c i e n c y is due t o the a l t e r a t i o n of t h e s c a l e s t r u c t u r e of calcium ca rbona te and calcium s u l f a t e and t h e a d d i t i o n of p o t e n t i a l s e e d s i n t h e aqueous media by the f e r r i c hyrdoxide complexes (3) .

(25,25).

I n c r e a s e d

The i n f l u e n c e of wa te r q u a l i t y has been noted by Reimers, e t . a l . and Biochenl-.o and Sapogin (26) These r e s e a r c h e r s have noted t h e fo l lowing:

C o n s t i t u e n t s t h a t Improved E l e c t r o s t a t i c Treatment Hardness A l k a l i n i t y TDS ( T o t a l Dissolved S o l i d s ) Oxidant C o n s t i t u e n t s Ca 1 c ium Bicarbonate N i t r a t e Magensium

C o n s t i t u e n t s t h a t I n h i b i t E l e c t r o s t a t i c Treatment Suspended S o l i d s Organics Reduced Ni t rogen Compounds ,

S i l i c a t e s Reduced C o n s t i t u e n t s S u l f h y d r i l Organic Compounds

It rhould be emphasized t h a t e lectrostat ic treatment will only occur when t h e proper dissolved rolid ( soluble conrt i tuent) l e p r e s e n t . This has been

noted by v a r i o u s ot1it.r r e s e a r c h e r s ( 28.29).

I n a d d i t i o n , t h e e f f e c t of e l e c t r o s t a t i c f i e l d s i n t h e z e t a p o t e n t i a l h a s been r epor t ed by Means and Mour ( 2 5 ) and BiochenkoandSapogin (26 ) . The e l e c t r o s t a t i c f i e l d a l t e r s t h e o u t e r charge of a s o l u b l e c o n s t i t u e n t by changing t h e hydroxide complex s t r u c t u r e . T h i s e x p l a n a t i o n h a s been used t o s u b s t a n t i t a t e t h e e f f e c t i v e n e s s of e l e c t r o s t a t i c p rocesses f o r s o l i d s removed i n va r ious water and was te t r ea tmen t p rocesses . A r e c e n t Russian p u b l i c a t i o n h a s r e p o r t e d t h e e f f e c t i v e n e s s of t he lime s o f t e n i n g improved a f t e r p a s s i n g through a magnet ic f i e l d b e f o r e c l a r i f i c a t i o n ( 2 8 ) .

A s a r e s u l t of t h e above o b s e r v a t i o n s , i t i s s p e c u l a t e d t h a t t h e mechanisms b y which e l e c t r o s t a t i c p rocesses d e s c a l e fo l low t h e chemis t ry desc r ibed i n P e a r s o n ' s Hard and S o f t Acid-Base Theory (30) . I n f i e l d s i t u a t i o n s , d e s c a l i n g h a s been observed only when c o n c e n t r a t i o n s of calcium, magensium, i r o n and o t h e r Pearson Hard Acids are p r e s e n t . These chemical compounds adsorb an e l e c t r o n and becorc Pearson H a r d Bases which tend t o r e a c t w i th oxide type Pearson Hard Ac ids , such as ca rbona te , phosphate , s u l f i t e , e t c . Table 1 shows t h e c h a r a c t e r i s t i c s of Pearson Hard and S o f t Acids. An impor tan t p o i n t i s t h a t Pearson Hard Acids on ly r e a c t w i th Pearson uard Bases and Pearson S o f t Acids r e a c t on ly w i t h Pearson S o f t Bases.

1

I n o u r s t u d i e s , t h e r o l e of t h e e l e c t r o s t a t i c f i e l d (low b e t a f i e l d ) i n w a t e r t r ea tmen t h a s been a s a c a t a l y s t which induces chemical r e a c t i o n s . When o r g a n i c s ( a s shown i n Table 2 ) which tend t o form f r ee r a d i c a l s were exposed t o an e l e c t r o s t a t i c f i e l d , had a capac i t ance of 7000 v o l t s (no h e a t release a t 3500 v o l t s ) . I t h a s been specu la t ed t h a t a s i m i l a r phenomena occur s i n t h e i n o r g a n i c r e a c t i o n s and t h a t t h e i n f l u e n c e of i n c r e a s i n g t h e capac i t ance on t h e e l e c t r o d e i n c r e a s e s t h e s t a b i l i t y of calcium ca rbona te two f o l d from f i v e times i t s s o l u b i l i t y t o ten times i t s o l u b j l i t y . A schemat ic of t h i s mechanism i s shown below:

exothermic r e a c t i o n s occurred on lv when t h e e l e c t r o d e

+ Ca 2 + ~ C ~ C O ~ = Ca +2 + 2 ~ a +2 + 2CO3 - 2

2

2 . I n a d d i t i o n ,

- e - f i e l d Fe +2 * FeS3 + e + 4

Mg+* - e - f i e l d 3. Mg+2 + e -- -b 4-

2Mg' + 2 C a C 0 3 i-t +2 2 2Mg + C a 2 - 2 + 2CO3

* a l t e r s t h e e x i s t i n g CaCO s t r u c t u r e

A s s t a t e d e a r l i e r , t h e c o n s t i u e n t s which enhancc t rea tment a rc Pearson Hard Acids which tend t o r e a c t w i th o x i d a l s c a l e .

3

B i o i n a r t i va t ion

B i o k l l l ranged from 0 t o 99 p e r c e n t f o r bo th f e c a l and t o t a l c o l i f o r m s i n secondary e f f l u e n t . E f f e c t i v e n e s s o f t h i s i n a c t i v a t i o n f o r c o l i f o r m s i n c r e a s e d w i t h flow a s shown i n F igu re 1. This t e n d s t o s u b s t a n t i a t e t h e premise t h a t b i o k i l l is due t o t h e a c t i v a t i o n of o r g a n i c s p r e s e n t i n

- 5-

Table 1. Classification ofMetal Ions

A-Type Metal Cations

Electron configuration of inert gas; low polarizability; "hard spheres"

(H+), Li+,Na+, K+, Be2+ .Mg2+ ,Ca2+, S r 2 + ,A13+,Sc3' L a 3 + , Si4+, Ti4', z++ ,TI? + .

Transition-Metal Cations B-Type Metal Cation%

One to nine outer shell Electron number corresponds

to NiO, PdO, and PtO(10 or 12 outer shell electrons;

low electronegativity;

"soft 8pheres" , Cut ,Ag+ Au+ ,TI + , G a t , Zn2+,Cd1+ ,Hg2+ ,Ph2*,

In3+ ,Bi 3+

e1ectrons;not spherically

v , Cr2+, h2+, high polarizability . Fe2+, Co2+, Ni2+, Cu2+, Ti3+, V3+, Cr3+, Mn3+, Fe3+, C O ~ J . Sn2? ,T13+ ,Au3+,

sJ?e ri ;

1 According to Pearson's (1963) Hard and Soft Acids

Hard Acids Borderline Soft Acids

A l l A-type metal cations All bivalent transition All B-type metal cations plus Cr3+ ,Mn3+ ,Fe3+, metal cations plus minus Zn2+,Pb2+,Bi3+, CO~+,UO~+ ,vo2+ Also species such as BF3,BCl j,SOj SO,,NO+,B(CH,) 3 All metal atoms, bulk metals RSO 2,RP02 ,CO:,

Zn2+ ,Pb2+ ,Bi 3 + ,

I2 ,Br2, ICN, I+ .Br RCO+ , R 3C'

Preference of ligand atom:

N* P o>> s F>> C1

Qualitative generlaizations on stability sequence: Cat ions Cat ions

charge Stability a radius

Ligands : F > O > N =C1 > Br > I > S OH- > RO- > RCOp

Irving-Wi$liams ?:der: Mn2; < Fe l,',C;nz+ <Ni + < Cu

Ligands : S > I > Br > C1

= N > O > F

- 1. R. C. Pearson, J.- Amer. Chem. S O C . , 85, 353'3 (1963).

Table 2. memica1 Groups Emploved w i t h U l t r a s o n i c s and E l e c t r o s t a t i c s

(which caused exothennic r e a c t i o n s )

Aromatic Ni t rogen Croup Amine Yi t rogen Croup

Phenylhydraz ine H C l P-Toluidine HC1 Benzami de

Organic Acid

B u t y r i c Acid O r a l i c Acid ?ialeic Acid Lactic Acid

Aldehydes I

Acetaldehyde Butyra ldehyde Propioanaldehyde

Keytones I

2-Propanone 2-Butanone Diacetonamine Chloroace tone

S u l f u r Croup I

Cys te ine Thiocyanic Acid 2- !4e~hyl th iopscudourea

Gly r ine Hydroxylamine DL Alanine

HC1

Organic Acid I1 2 Furoic Acid C h l o a c e t i c Acid Tannic Acid C i t r i c Acid A n t h r a n i l i c Acid

Aldehydes I1 I s o n i t r o s o a c e tone 2 , 2 , 3 T r i c h l o r b u t a n o l D i e t h y l Acety l Acetaldehyde

Ketones I1 0-Aminopropiophenone Methyl Vinyl Ketone 2 -He~ tanone

S u l f u r Group XI Thiophenine Ethoxyl S u l f i d e Ethy Is u l f one Buty l 'rlydrogen S u l f a t e 2-Amino-Yethyl Theve t in

- 7-

>. Y .+ u. C w C U

u

c1 3 m 3

v) U U

? N

U C ell

N I: 3

0 rA

V .d

c 0 v) cp L, U 4 3 bc C .+

N 2 y.

br U

2

L, Q z

I

N

0 V

&I

C al

i U L

i U

Y v)

C .d ‘.

\

4 0 s X

c

0 ‘42

0 N

secondary e f f l u e n t . A s i m i l a r phenomena was observed wi th microbes p r e s e n t i n a s o f t d r i n k b o t t l e wanner i n an e a r l i e r p u b l i c a t i o n ( 1 6 ) .

An obse rva t ion of major importance, shown i n Table 3, was t h a t t h e u l t r a s o n i c p rocess was e f f e c t i v e t o 13% b i o i n a c t i v a t i o n f o r t o t a l c o l i f o r m and t h i s u l t r n - s o n i c i n a c t i v a t i o n was a f u n c t i o n of i t s i n t e n s i t y and n o t i n f l u e n c e d by the o r g a n i c s . This is i l l u s t r a t e d i n F igu re 2. The e f f e c t i v e n e s s o f t h e e l e c t r o - s t a t i c f i e l d was d i r e c t l y a func t ion of t he s o l u b l e o r g a n i c s w i t h s u l f h y d r y l o r g a n i c s and a romat i c amines noted t o b e the most e f f e c t i v e . The o r g a n i c s appeared t o be a c t i v a t e d by the e l e c t r o s t a t i c f i e l d w i t h a h e a t i n c r e a s e o f one t o two k i l o c a l o r i e s p e r l i t e r ove r t h e c o n t r o l The s u l f h y d r y l o r g a n i c s appear t o be good c a n d i d a t e s as d i s i n f e c t i o n a g e n t s due t o t h e i r low t o x i c i t y t o humans, y e t t he hydraz ine compounds could p o t e n t i a l l y b e used bo th as c o r r o s i v e inh ib i to r s (0xygen scavenge r s ) and b i o c i d e s .

The o rgan ic chemicals t e s t e d belong t o t h e n i t r o g e n a romat i c group and t h e s u l f u r g r o u p . The;* inc!i:Jed phenylhydrazine HCL, p - to ludine HCL, benzamidcb, c y s t e i n e , t h iocyan ic a c i d , and 2-methyltheiopseudourea. The b a c t e r i a l moni tors used were t o t h e t o t a l co l i fo rm t e s t , t h e f e c a l c o l i f o r m t e s t and t h e e n t r - occcus t e s t .

It was found t h a t phenylhydraz ine H C 1 a t a c o n c e n t r a t i o n of 20 ppm and a tempera ture of 25OC and 3500 v o l t s e x h i b i t e d t h e b e s t a b i l i t y t o i n a c t i v a t e t o t a l c o l i f o r m numbers. S t a t i s t i c a l tests done t o de te rmine whether o r n o t there was a t r u e d i f f e r e n c e i n t h e s l o p e s of t h e test and c o n t r o l d a t a i n t h e r educ t ion of t o t a l co l i fo rms w i t h t i m e showed t h a t a t t h e .95 l e v e l of con- f i d e n c e a d i f f e r e n c e i n s l o p e s d id e x i s t . F u r t h e r t e s t i n g a l s o showed t h a t t h e r e d u c t i o n of t o t a l co l i fo rms wi th time fol lowed f i r s t o r d e r k i n e t i c s .

Th i s d a t a shows t h a t phenylhydrazine i n con junc t ion wi th e l e c t r o s t a t i c s undc,r t h e p r e s c r i b e d c o n d i t i o n s does reduce t o t a l c o l i f o r m p o p u l a t i o n s . The use of e l e c t r o s t a t i c s a t 3400 v o l t s a long wi th the chemical phenylhydraz ine HC1 could prove e f f e c t i v e i n s i t u a t i o n s where t o t a l c o l i f o r m p o p u l a t i o n s are a problem. However, u n t i l t h e h e a l t h e f f e c t s of t h e a c t i v a t e d o r g a n i c s have been a s c e r - t a i n e d , t h i s a p p l i c a t i o n should no t be used f o r p o t a b l e water. I n i n d u s t r i a l s i t u a t i o n s , s u l f h y d r y l and hydraz ine - l ike compounds could be put t o use i n t h e b o t t l e - r i n s i n g i n d u s t r y o r perhaps commercial water c l e a n i n g , s i n c e hydraz ine - l ike compounds Flave been a c t i v e l y used as oxygen scavenge r s i n b o i l e r and c o o l i n g w a t e r t rca t m n ? t . Corros ion Cont ro l

Corros ion is very s i t e dependent no matter what i n d u s t r i a l w a t e r t r ea tmen t p rocess is involved . I n d u s t r y s t i l l does not f u l l y unders tand t h e probltwi o f c o r r o s i o n . I n i n v e s t i g a t i n g c o r r o s i v e s i t u a t i o n s , t he environment and n a t u r e of equipment must be e v a l u a t e d thoroughly . e i g h t un ique forms: uniform c o r r o s i o n s ( g e n e r a l a t t a c k ) 34 .2%; galvanic- o r two meta l c o r r o s i o n ( 4 . 6 % ) ; c r e v i c e c o r r o s i o n (1.8%); p i t t i n g c o r r o s i o n ( 1 5 . 7 % ) ; i n t e r g r a n u l a r c o r r o s i o n (10 .2%); s e l e c t i v e l e a c h i n g ( 1 . 1 X ) ; e r o s i o n c o r r o s i o n (9,07!); and stress c o r r o s i o n ( 2 3 . 4 % ) . There fo re , t h e c o n t r o l of c o r r o s i o n i s a very complex s i t u a t i o n r e q u i r i n g a de t e rmina t ion of t h e type of c o r r o s i o n , t h e n a t u r e of t h e environment and knowledge of s p e c i f i c equipment b e i n g u t i l i z e d ( 3 1 , 3 2 ) .

Cor ros ives can be d i v i d e d i r l t c i

The use of t h e e l e c t r o s t a t i c process to i n h i b i t c o r r o s i o n h a s been met wi th a g r e a t d e a l of s k e p t i c i s m by t h e s c i e n t i f i c c o m u n i t y . As a r e s u l t of f i e l d

-9-

Table 3. Influence of Ultrasonics and/or ZlectrostaLics on the Inactivation of Total Coliform in Wastewater Effluent

A: Effect of Uattage on Total Coliform Inactivation at a Constant Temperature Flow and Exposure by Ultrasonics in Wastewater Effluent

Test Power Setting (watts)

400 500 650 800

Control 62% 892 30% 4 6 % Test (unit operating) 3 7% 90% 38% 7 8% Corrected K i l l -25% 0% a ;: 32%

Flow rate - 8 liters per minute Number of contacts with ultrasonics - 3 ( run time - 38 rulnutes) Temperature - 25OC

B: Effect of Flov Rate on Total Coliform Inactivation at a Constant Temperature and Wattage by Ultrasonics in Wastewater Effluent

Test Flow Rate (l/min)

1 3 8 12 Con t ro 1 52% 34 % 61% 54% Test (unit operating) 7 8% 53% 76% 61:! Corrected K i l l 26% 19 9. 15 % 7 %

Ultrasonics Power - 800 Watts Number of Contacts with Ultrasonics - 3 (run time varied) Temperature - 25°C

C: Effect of Exposure on Total Coliform Inactivity at a Constant Temperature, Wattage and Flow.

Test Time of Exposure (minutes)

11.7 38 63.3 88.7 Con t r o 1 49% 5.0 % 6 4 % 59% Test (unit operating) 6 3% 6 5 2 80% - 77% Corrected K i l l 14% 15% 16% 18%

Ultrasonic Power - 800 Watts Flow rate - 8 liters per minute Temperature - 2 5 ' C

D: Effects of Electrostatics and Ultrasonics Processes in the Inactivation of Total Coliforms in Sewage Effluents

Test Systems Energized

U1 t rasonics Electrostatic Ecth

Control 50% 4 7% 502 Test (unit operating) 65% 502 69:: Corrected K i l l 15% 3% 19?!

Ultrasonic Power = 800 Watts Flov rate - 8 liters per minute Number of Contacts - 3 (38 minute run time) Temperature - 25OC

- 10-

T a r c e n t Kill Above Control

60

5 5

50 S u l f u r Croup I ( 'J/E)* Total Yltrogcn (Aromatic and .Imine Y i r o g c n ) ( t i / E )

45 Aroma tic X i trogen (U/E

40 Aromatic Yitroqcn (Electrostatics) S u l f u r Croup I (Elcctros t r t i c s )

35

30

25

20

15 Sulfur Croup I (Ultrasonics) Organic A c i d s 11 (U/E) u o m a t i c Y i t t o g e n (U1:ruonf cs) , Ketones I (U/E) O r p n i c Acids I (Ultrasonics)

10 Aldehydes I (U/E) Aldehydes If ( U / E ) , Su l iur Croup 11 ( U / E ) Amine Yltrogcn ( U / E ) , Ketones I1 ( U / E ) -

5

0

*(U/Z) - Ultruoaics/Eltc:ros: l t ics

-11-

s td i e s , -the e l e c t r o s t a t i c p rocess has been f m d t o c o n t r o l c o r r o s i o n i n some c i ies a n d not i n o t h e r s . d i s s o l v a d OxygTq, pH, tempera ture , ox ida t ion - reduc t ion p o t e n t i a l , w a t e r q u a l i t y , and t h e n r t d e ' o f t h e m i n e r a l s i n t h e coo l ing tower sys tem. I n two systems i n Lou i s i ana , t h e m e t a l l i c s u r f a c e had an oxide p r o t e c t i v e l a y e r form and t h u s had no c o r r o s i o n problems, y e t i n Texas, a n o t h e r c o o l i n g tower s y s t e m had problems once t h e tower was desca led ( 3 3 , 3 4 , 24).

The c o n t r o l o f . p e c r o a i o n is a f u n c t i o n of t h e

I n b o i l e r sys t ems , e l e c t r o s t a t i c a l l y t r e a t e d w a t e r g e n e r a l l y does n o t need oxygen scavenge r s i f t h i s t r e a t e d water h a s been deoxygenated by d e a e r a t i o n . I f t h e w a t e r is d e a e r a t e d b e f o r e treatment, t h e t r e a t e d w a t e r needs t h e a d d i t i o n of oxygen scavengers . The re fo re , t h e t r e a t m e n t appea r s t o enhance t h e d e a e r a t i o n s t e p . However, f u r t h e r t e s t i n g shou ld b e conducted b e f o r e scavenger a g e n t s a r e e l i m i n a t e d from c o r r o s i o n c o n t r o l .

A s t u d y of t h e i n f l u e n c e of magnet ics on c o r r o s i o n c o n t r o l h a s provided ev idence t h a t magnet ic t r ea tmen t i n h i b i t s t h e r a t e of c o r r o s i o n (35). I n t h i s s t u d y , t h e r a t e of c o r r o s i o n was a f u n c t i o n of t h e w a t e r q u a l i t y and t h e f i e l d s t r e n g t h . Maximum c o n t r o l was observed a t 500 Oe and t h i s c o n t r o l was r e l a t e d t o t h e i n h i b i t i o n of t h e oxygen s a t u r a t i o n l e v e l s . T h u s , i t was s p e c u l a t e d t h a t r e d u c t i o n i n c o r r o s i o n rates by magnet ic f i e l d s was due t o reduced d i s s o l v e d oxygen l e v e l s , y e t a major producer of magnet ic sys t ems c u r r e n t l y adds oxygen scavenge r s t o t h e c o o l i n g tower sys t ems .

I n summary, e l e c t r o s t a t i c p rocesses can reduce t h e r a t e of c o r r o s i o n , bu t t h e c o r r o s i o n problems are mainly due t o t h e environment i n which t h e equipment is l o c a t e d . T h e r e f o r e , c o r r o s i o n i n h i b i t o r s w i l l g e n e r a l l y b e needed except f o r s p e c i f i c envi ronmenta l s i t u a t i o n s .

Fac to r s Con t ro l l i n g E l e c t ros t a t i c P r o c e s s e s -- "liese f a c t o r s have been a s c e r t a i n e d from both l a b o r a t o r y and f i e l d t e s t i n g . T h i s is t h e most r e c e n t a v a i l a b l e d a t a as of September, 1981. The f a c t o r s c o n t r o l l i n g e l e c t r o s t a t i c p r o c e s s e s have been c l a s s i f i e d i n t h r e e c a t e g o r i c s : ( 1 ) o p e r a t i o n a l and maintenance problems; (2) process r e l i a b i l i t y and (3) p rocess l i m i t a t i o n s .

Opera t iona l and Maintenance Problems

O p e r a t i o n a l and maintenance problems have been noted due t o t r apped and accumulated s c a l e . The r e s u l t i n g problems can b e r e s o l v e d depending upov t h e s p e c i f i c t r e a t m e n t (e .g . , b o i l e r water t r ea tmen t and c o o l i n g water t r e a t m e n t ) . As a r e s u l t o f b o i l e r water t r e a t m e n t by t h e e l e c t r o s t a t i c s p r o c e s s e s , l a r g e p i e c e s of s c a l e have dropped from t h e upper tube and tank w a i l siiiiface m d have accumulated on areas of t h e t u b e s below (on t o p of lower bund les ) . I f t h i s s c a l e is n o t removed soon a f t e r i t c o l l e c t s , t h e r e s u l t i n g "hot spo t s " w i l l r e q u i r e tube replacement and expens ive down-time. Frequent i n s p e c t i o n and, i f n e c e s s a r y , s c a l e d e p o s i t removal by t h e customer is s t r o n g l y recommended. Accumulation of s c a l e i n t h e bottom of t h e b o i l e r can a l s o occur a s c l e a n i n g p r o g r e s s e s . T h i s can c l o g blowdown openings and a l s o cause a b u i l d up i n s o l u b l e s a l t c o n c e n t r a t i o n s which cou ld r e s u l t i n p r e c i p i t a t i o n f o r a p a r t i c u l a r b o i l e r system. I f c a r e f u l and r e g u l a r maintenance is n o t c a r r i e d o u t , a renewed s c a l i n g problem is l i k e l y t o o c c u r . The h igh s o l i d s i n c o o l i n g towers can cause two problems: (1) c l o g g i n g of downstream equipment and (2 ) i n c r e a s e d s c a l i n g . The c logg ing of downstream

-12-

equipment is a r e s u l t of t h e f l a k i n g of a s o l i d from t h e c o o l i n g tower. I n a d d i t i o n , t h e s e suspended s o l i d s can i n c r e a s e t h e s o l u b l e s a l t l e v e l s t o above maximum c a p a c i t y l i m i t s and t h i s h i g h e r l e v e l of s o l u b l e s a l t s w i l l cause inc reased p r e c i p i t a t i o n . The above problems can be r e so lved by f i l t e r i n g the suspended s o l i d s .

P rocess R e l i a b i l i t y

The r e l i a b i l i t y and c a p a b i l i t y of t h e p rocesses were observed i n r e l a t i o n t o t h e performance of t h e t r a n s d u c e r and power pack components. These components as provided by t h e same manufac turer performed e r r a t i c a l l y ; t h e t r a n s m i t t e d f r e q u e n c i e s v a r i e d a c r o s s t h e e n t i r e d e s i g n range and f o r d i f f e r e n t t i m e d u r a t i o n s . Some of t h e c i r c u i t r y i n t h e power pack con- s i s t e n t l y f a i l e d due t o des ign f a u l t s . However, much v a l i d d a t a was ob ta ined a f t e r c l o s e moni tor ing of t h i s equipment.

Other manufac turers have providedproven and r e l i a b l e power supp ly systems t h a t have n o t on ly m e t t h e des ign requi rements , bu t a l lowed f o r o p t i m i z a t i o n of t h e s y s t e m . These manufac turers have taken a g r e a t d e a l of e x p e r i e n c e from t h e e l e c t r o s t a t i c s p r e c i p i t a t o r s u t i l i z e d f o r a i r s y s t e m s .

P rope r placement of t he u n i t is i n f l u e n c e d b y b o t h t h e p rocess be ing t r e a t e d and t h e placement b e f o r e o r a f t e r t h e pump. Many f a i l u r e s have been a result of t h i s very problem. Major problems have r e s u l t e d when an e l e c t r o - s t a t i c s p rocess was i n s t a l l e d on r i n s e t anks of b o t t l e washing and r i n s e machines. In g e n e r a l , t h e r e was a b u i l d up of s o l u b l e s a l t s ( p a r t i c u l a r l y a l k a l i n i t y ) no ted and u n c o n t r o l l a b l e pH f l u c t u a t i o n s (due t o c a u s t i c r e s i d u e s from p r e - r i n s e w a t c r and soak t a n k s ) . Th i s pH f l u c t u a t i o n can s c a l e up t h e u n i t by i t s e l f because t h e s o l u t i o n was n e a r t h e s o l u b i l i t y l i m i t s f o r e f f e c t i v e u n i t o p e r a t i o n a t pH 8. T h i s pH i n c r e a s e (8 t o 10) i n c r e a s e d t h e ca rbona te c o n c e n t r a t i o n appoximately 100 times (which w i l l c ause p r e c i p - i t a t i o n due t o t h e common i o n e f f e c t ) . Th i s s i t u a t i o n can be avoided by i n s t a l l i n g the u n i t on t h e f r e s h water supp ly ( f i n a l r i n s e l i n e ) . When i t is i n s t a l l e d i n t h i s l o c a t i o n , bo th t h e upper and lower s p r a y heads must be s u p p l i e d by t h e t r e a t e d water. By p l a c i n g t h e u n i t b e f o r e t h e pump (on i t s vacuum s i d e ) , t h e r e s u l t i n g p r e s s u r e h a s been found t o b e f a r less than 85 p s f . Thereby, t h e e f f e c t i v e n e s s o f t h i s p rocess h a s been g r e a t l y inc reased . O the r e l e c t r o s t a t i c p r o c e s s e s which do n o t use u l t r a s o n i c t r a n s d u c e r s o r have a f l o a t i n g type e l e c t r o d e have been a b l e t o o p e r a t e a t p r e s s u r e up t o 250 p s i .

P rocess l i m i t a t i o n s

P r o c e s s l i m i t a t i o n s i n c l u d e p h y s i c a l f a c c o r s , chemical pa rame te r s , and new s o l u b i l i t y l i m i t a t i o n s . The p h y s i c a l f a c t o r s are p r e s s u r e , t empera tu re , and r e s i d u e from t r e a t m e n t . A t p r e s e n t , ultrasonic/electrostatic u n i t s are r a t e d f o r 85 p s i a t 14S°F maximum p r e s s u r e and tempera ture . is t h e l i m i t i n g p r e s s u r e f o r t h e e f f e c t i v e t r ea tmen t by t h e u l t r a s o n i c t r a n s d u c e r a n d t h e 145 F I s t h e maximum tempera ture a t which a submerged e l e c t r o d e w i l l o p e r a t e e f f i c i e n t l y . I f t h e p rocess is ope ra t ed abovc. e i t h e r or bo th l i m i t s , t r ea tmen t is r a d i c a l l y reduced. Recent e l e c t r o s t a t i c p r o c e s s e s can o p e r a t e a t p r e s s u r e s g r e a t e r than 200 p s i because t h e e l e c t r o d e i s no t f l o a t i n g and no t r a n s d u c e r is u t i l i z e d . However, i t must be ope ra t ed a t less than 250 p s i due t o t h e e l e c t r o d e c g a t i n g l i m i t s . c o a t i n g h a s a tempera ture l i m i t o f approximate ly 250 F.

The 85 p s i

0

The I t must be no ted

-13-

t h a t these a b i o t i c f a c t o r s i n f l u e n c e t h e t rea tment w i t h i n t h e p r o c e s s . A f t e r t h i s t rea tmEnt , t h e temperature and p r e s s u r e s of t r e a t e d w a t e r can be r a i s e d t o ZOO+ F and 200+ p s i . If t h e water h a s less than a s i x second r e s idence time i n t h e u n i t , t h e e f f e c t i v e t r ea tmen t can be g r e a t l y reduced . Although t h e r e are times when t r ea tmen t can be e f f e c t i v e w i t h a lower r e s i d e n c e ' t i m e , t h i s i s only f e a s i b l e under s p e c i f i c s i t u a t i o n s ( i . e , water q u a l i t y and s c a l e d environments) . From l a b o r a t o r y and f i e l d r e s u l t s , t r e a t e d water from t h e ultrasonic/electrostatic process r e t a i n s e f f e c t i v e n e s s f rom 30 to 60 minutes a f t e r d i s c h a r g e from t h e t r ea tmen t p r o c e s s . must be used w i t h i n t h i s time pe r iod t o o b t a i n p o s s i b l e d e s c a l i n g .

T r e a t e d water

The chemical parameters o f much concern are suspended s o l i d s and o r g a n i c c o n t e n t . A s t h e suspended s o l i d s c o n c e n t r a t i o n i n c r e a s e s t o greater than 20 mg/l ( o r g a n i c , l e . , v o l a t i l e suspended s o l i d s , o r i n o r g a n i c , i . e . , i n e r t suspended s o l i d s ) , t h e e f f e c t i v e n e s s of t h e e l e c t r o s t a t i c p r o c e s s is s i g n i f i c a n t l y reduced or comple te ly i n h i b i t e d . The re fo re , i t i s recommended t h a t water of t h i s q u a l i t y be p r e t r e a t e d ( i . e , f i l t r a t i o n , s e d i m e n t a t i o n , e t c , ) b e f o r e p a s s i n g through the t r ea tmen t u n i t . The i n f l u e n c e of d i s s o l v e d o r g a n i c s on e l e c t r o s t a t i c s t ends t o vary. I n some i n s t a n c e s , t h e o r g a n i c s a c t as a b i o c i d e and reduce b i o l o g i c a l a c t i v i t y , b u t i n g e n e r a l , i t h a s been noted t h a t i n c r e a s e s i n d i s s o l v e d o r g a n i c s tend t o reduce e f f e c t i v e t r e a t m e n t by t h e s y s t e m . as carbon, t he e f f + c i e n c y of t h e p rocess can be g r e a t l y reduced and a t 50 mr/l as carbon, i t is comple te ly i n h i b i t e d . Recent s t u d i e s have noted t h a t t h e o rgan ic s can e i t h e r induce or i n h i b i t t r ea tmen t . O i l and g r e a s e w i l l r e a c t s i m i l a r l y ( 2 f l mg/1 and 50 mg/l) b u t g e n e r a l l y a re l i m i t e d t o lower v a l u e s ( 10 t o 25 mg/l) due t o p o s s i b l e c o a t i n g of t h e e l e c t r o d e .

F i n a l l y , t h e s o l u b i l i t y l i m i t for calcium c a r b o n a t e a t 100 F is approximate lv 400 mg/l as ca lc ium ca rbona te . T h i s is a ten- fo ld i n c r e a s e i n s o l u b i l i t y (from t h e 40.0 mg/l as ca lc ium ca rbona te ) f o r sys tems w i t h t h e e l e c t r o s t a t i c s p rocess having a c a p a c i t a n c e on t h e e l e c t r o d e of 7000 v o l t s . The s o l u b i l i t y l i m i t f o r ca lc ium ca rbona te h a s been noted t o drop from t en - fo ld t o s i x - f o l d w i t h a drop i n c a p a c i t a n c e from 7000 v o l t s t o 3500 v o l t s on t h e e l e c t r o d e . Probably t h i s p rocess e f f e c t on s o l u b i l i t y should be similar f o r o t h e r sa l t s ( c o a g u l a t i v e s a l t s , f e r r i c ions, magnesium i o n , c h l o r i d e s , e t c . ) and should be cons ide red b e f o r e u t i l i z i n g t h i s system f o r o t h e r d e s c a l i n g a p p l i c a t i o n s

C u r r e n t l y , i f t h e d i s s o l v e d o r g a n i c s are greater than 20 mg/l

0

SUMMARY

The d e s c a l i n g a n d / o r scale i n h i b i t i o n p r o c e s s is h i g h l y complex and is governed by chemical r e a c t i o n s of several areas of chemis t ry . Russian r e s e a r c h showed t h a t c e r t a i n phenomena i n f l u e n c e t h e d e s c a l i n g p r o c e s s : 1) t h e bui ld-up of s ludge i n t r e a t e d water; 2) i n c r e a e e d e f f i c i e n c y a f t e r the a d d i t i o n of soltible ircn and mgnes ium; 3) water q u a l i t y ; and, 4 ) t h e ze ta p o t e n t i a l . I n t h i s s t u d y , a t empera tu re phenomenon was n o t e d . I t i s recommended t h a t r e s e a r c h e r s and manufac tu re r s c o n s i d e r t h e s e phenomena i n f u t u r e r e s e a r c h and b e f o r e p r o v i d i n g e l e c t r o s t a t i c equipment f o r v a r i o u s f i e l d a p p l i c a t i o n s .

American and

The b i o i n a c t i v a t i o n h a s been no ted t o b e a f u n c t i o n of t h e s o l u b l e o r g a n i c s and t h e i n t e n s t i y o f t h e e l e c t r o s t a t i c f i e l d . , The s u l f h y d r y l organohydraz ine i n d i c a t e d p o t e n t i a l t o i n a c t i v a t e microbes. by u l t r a s o n i c and e l e c t r o s t a t i c p r o c e s s e s is c a p s u l a t e d i n Table 4 .

o r g a n i c and The d i s i n f e c t i o n

-14-

Table 4. Summary of Exper imenta l Data Concerning B i o k i l l f o r U l t r a s o n i c s / E l e c t r o s t a t i c s P rocesses I n d i c a t o r 3rqanisms

.Toxocara Asca r i s T o t a l F e c a l To t a l Bac t e r i a FACTORS Eggs Eggs Col i f o m s C o l i f 0 m s

Flow >Flow w i 1 l< e f f e c t i v e - ness

Apparent ly op t i m u m f low

Ap p a re n t 1 y optimum flow

Apparen t ly op t i m u m f low

App a ren t 1 optimum f l o w

< l e v e l s wi 11 > e f i e c t i v t n e s s

< l e v e l s will> e f f e c t i v e n e s s

Depends o Disso lved S o l i d s

Depends o r g a n i c s

Ap pa r e n t 1 op t ism Frequency

> I n t e n s i c will> c f f e c t l v e n e s s

>Expos urE v i l l > e f f e c t i v e n e s s

> D u r a t i o r will< e f f e c t i v c n e s s

>Tempera t wi 11> ef f e c t i v t n e s s

< E f f e c t i ' ness

I n i t i a l Concen t r a t ion

<levels w i 11 > e f f e c t i v e - n e s s

< l e v e l s w i l l > e f f e c t i ve - n e s s

< l e v e l s w i l l > e f f e c t i v e - nes s

l e v e l s w i l l > e f f e c t i v e - n e s s

Suspended S o l i d s

< l e ve Is w i l l > e f f e c t i v e - n e s s

< l e v e l s w i l l > e f f e c t i v e - ncs s

< l a v e Is w i l l > e f f e c t i v e - n e s s

< l e v e l s w i l l > e f f e c t i v e - n e s s

T o t a l Disso lved S o l i d s

Organics

s

Depends on Di s so lved S o l i d s

Depends on Disso lved S o l i d s

Depends on Disso lved S o l i d s

Depends on D i s s o l v e d S o l i d s

May depend on o r g a n i c s

Nay depend on o r g a n i c s

Depends on o r g a n i c s

Depends on o r g a n i c s

I Frequency Ap p ar en t 1 y Optimum Frequency

> I n t e n s i t y w i l l > e f f e c t ive- n e s s

>Exposure will > e f f e c t i v e - n e s s

Appa r en t l y Optimum Frequency

> I n t e n s i t y W i l l > e f f e c t i v e - n e s s

>Exposure w i l l > c f f e c t i v e - ness

Apparent ly Op t i m u m Frequency

> I n t e n s i t y w i l l > e f f e c t i v e - n e s s

>Exposure w i l l > e f f e c t i v e - ness

Apparen t ly Optimum Frequency

> I n t e n s i t y w i l l > e f f e c t i v e - n e s s

>Exposure w i l l > e f f e c t i ve- n e s s

Dura t ion >Dura t ion w i l l > e f f e c t i v e - ness

>Dura t i o n w i l l > e f f e c t i v e - ness

>Dura t i o n w i l l < e f f e c t ive- ness

>Dura t i o n w i l l < e f f e c t i v e - n e s s

Tempe ra t u r e >Temperature w i l l > c f f e c t i v e - ness

>Temp e ra t u r e w i l l > e f f e c t i v e - ness

>Temperature w i l l > e f f e c t i v e - n e s s

>Temper a t u re w i l l > e f f e c tive- n e s s

No e f f e c t No e f f e c t < E f f e c t i v e - n e s s

< E f f e c t i v e - n e s s

Ac clima t i za t ion

Prcrsu re No e f f e c t * No e f f e c t

No e f f e c t No e f f e c t

-15-

No e f f e c t No e f f e c t No e f f e c

Induced F i e l d > F i e l d vill> ef f e c t i v e - ness

> F i e l d w i l l > e f f e c t i v e - ness

> F i e l d will> ef f e c t i v n e s s

The c o n t r o l of c o r r o s i o n appea r s t o be system and s i t e dependent . e l e c t r o s t a t i c p rocesses tend t o reduce d i s s o l v e d oxygen levels and work w e l l w i t h oxygen sFavengers such as hydraz ine .

The

The e l e c t r o s t a t i c method of water t r ea tmen t is l i m i t e d i n a p p l i c a t i o n by p rocess l i m i t a t i o n s , l o c a t i o n of t h e equipment and o p e r a t i o n and main tenance problems.

E l e c t r o s t a t i c t r ea tmen t sys tems are g e n e r a l l y l i m i t e d by t empera tu re , p r e s s u r e and s o l u b i l i t y . Where t h e maximum l e v e l s of t h e s e pa rame te r s are exceeded , l i t t l e or no t r ea tmen t is e f f e c t e d . Flow ra te is a l s o an impor t an t f a c t o r . The water must have a minimum exposure time t o t h e e l e c t r o s t a t i c f i e l d of about s i x seconds .

Other l i m i t a t i o n s a r e h igh suspended s o l i d s and o r g a n i c c o n t e n t as w e l l a s o i l and g r e a s e , F l u c t u a t i o n s i n pH a l s o l i m i t t h e e f f e c t i v e n e s s .

Placement ( l o c a t i o n ) of the e l e c t r o s t a t i c equipment can a l s o de t e rmine t h e degree of e f f e c t i v e n e s s of t h e t r ea tmne t . Exposure of t h i s equipment t o any of the l i m i t i n g c o n d i t i o n s l i s t e d w i l l e i t h e r dec rease o r e l i m i n a t e t h e e f f e c t s of t h e t r ea tmen t .

Opera t ion and maintenance l i m i t a t i o n s are due p r i m a r i l y t o t h e b u i l d up of loose s c a l e i n t h e t rea ted equipment. I f t h e s c a l e is n o t removed, s o l u b l e s a l t c o n c e n t r a t i o n b u i l d up and h o t s p o t s w i l l form on t h e s u r f a c e of h e a t exchange tubes . Renewed s c a l i n g and c logg ing can a l s o t a k e p l a c e .

- 16-

REFERENCES

1.

2 .

3.

4.

5 .

6 .

7.

8.

9.

10.

11.

12.

13.

14.

Welder, B.Q. and Partridge, E.P., "Practical Performance of Water

pp 954-960 (H.y 1954). Condi t ion ing Gadget SI', Industrial E- * I VOl. 5 0 ,

Eliassen, R., Skrinde, P.T., and Davis, W.B., "Experimental Perfor- mance of 'Mracle'Water Conditioners", Journal American Water Works Association, Vol. 50, pp. 1371-1384 (Oct. 1958).

Dearborn Chemical Division of Chemed Corporation, "Watch Out for a New Round of Water Treatnent 'Gadgets'," Water Conditionina (July, 1977).

Dromgoole, J.C., and Forbes, M.C. "The Fatal Lure of Water Treatment Gadgets". Presented at the 40th Annual International Water Conference, Pittsburgh, PA. (Oct. 31,1979).

Wilkes, J.F., and Brown, R., "Water Conditioning Devices - An Update", Presented zt the 40th Annual International Water Conference, Pittsburgh, PA. (Oct. 31, 1979).

Joshi, K.M., and Kamat, P.V., "The Effect of Magnetic Fields on the pH of Water", J. Indiana Chem. COC., p. 4 3 (1966).

Kirgintsev, A.N., "Mechanism of the Hagnetic Treatment of Liquids", Zh. Fit. Khim., Vol. 45(4), pp. 857-859 (1971).

Lazorenko, B. R. , and Bautysh, L . A . , "Properties of Water Subjected to the Action of Electrical or Magnetic Fields", Elektron Obrab. Mater., No. 3 pp 46-48 (1970).

Quickenden, T.L., Betts, D.M., Cole, B., and Noble, M., "The Effect of Magnetic Fields on the pH of Water", The Journal of Physical Chemistry, Vol. 75(18), pp. 2839-2831 (1971).

Kaubikova, H., "Research Regarding the Effects of Nagnetic Treat- ment on Water", The Institute of Hydraulic Research, Praque, Czechoslovakia (Feb., 1969).

Hokkaido University, Internal Report Japan (no date).

Ar, E., "Study of Electric and Magnetic Treatment of Water to Prevent Scaling and Corrosion; Biological and ?ledical Implications", Partial contents of a Proposal releasing research results, U. of Michigar! (Mar. 1973).

Duffy, E.A., "Investigation of Magnetic Water Treatment Devices", Dissertation presented to the Graduate School of Cleason University (Aug., 1977).

Krajiic, G., and Milosevlc-Kraj, P I . , "Magnetic Field Conditioning of .Industrial Waters", Presented at the 40th Annual International Water Cbnference, Pitts. PA. (Oct. 31, 1979).

-17-

15.

16.

17.

18.

19.

2 0 .

21.

2 2 .

2 3 .

2 4 .

2 5 .

26.

27.

Cheremisinoff, N . P . , Chermisinoff, P.N., and Tratter, R . B . , Chemical and Non-Chemical Disinfection, Ann Arbor Science Publishers, Inc., Ann Arbor, Hich. pp 1-172 (1981).

Reimers, R . S . , deKernion, P.S., Robtdeau, F.C., "Appllcatfon of Ultrasonics and Electrostatics - An innovative and Energy Saving Approach to Industrial Water Treatment", Symposium on Environmental and Energy Saving Process supported by Department of Energy (Dec. , 1979).

Dakubu, S., "Cell Inactivation by Ultrasound", Biotechnology and Bioengineering, Vol. 18 pp 465-471 (1976).

Croakley, W.T., Bater, A.J., and Lloyd, D. "Disruption of Micro- organisms" Advances in Microbial Physiology edited by Rose, A.H., and Tempest, D.W., Vol. 16, Academic Press, N.Y., p p . 279-341 (1977).

Schmitt, F.O., and Uhlemeyer, B., "The Mechanism of Lethal Effects of Ultrasonic Radiation", Proc. SOC. Expcl. B i o l . F l e d . , Vol. 2 7 ( 7 ) pp. 626-628 (1930).

Ordonez, J.A., and Burgos, J., "Effect of Ultrasonic Waves on the Heat Resistance Bacillus Spores", Applied and Environmental Micro- biology, Vol. 32(1), pp. 183-184 (July, 1976) .

Wang, L.K., Wang, M.H., and Peery, G . C . , "General Theories of Chemical Disinfection and Sterilization of Sudge - Part 2 * ' , Water and Sewage Works, Vol. 125(8) pp. 58-63 (August, 1978).

Murry, E.J., An Ultrasound Future or a Sound Sleep Part 111- Uses in Variety", Chemical Technology-, Vol. 5, pp. 376-381 (June, 1975).

Quellette, R.P., King, J.S., and Cheremisinoff, P.N., Electrotech- nology Volume I. Wastewater Treatment and Separation Methods, Ann Arbor Science Publishers Inc. Ann Arbor, Michigan, p.609 (1978).

Reimers, R. S., deKernion, P . S . , Robedeau, F.C. and Leftwich, D.B., "A Viable Approach to Water and Waste Treatment - Part I and 11", Water Technology, pp. 44-47, 64-65, (May-June, 1980) and 26-32, 60-65 (July-Aug. 1980)

Means, F. A . and Mour, A.A., "How Electrostatics Water Treatment Worksii, Journal of the 'n'atiiinal Associat?on ~f Power Engineersi May, 1975.

Biocheno, V.A. and Spogin, L.G., "Theory of Magnetic Water Treat- ment", Journal of Engineering Physics, Vol. 33 ( 2 ) , pp. 980-984 Russian (August, 1977).

Hibben, S. G., Magnetic Treatment of Water, NTIS Report No. AA-757-887, Washington Dc, June (1973).

-1a

,

28. Shahko A. I . , Shiryayeva and A. S. Avet i sov , "The Use of a Magnetic F i e l d i n t h e Sof t en ing of Water", I z v e s t i y a , VIZov. SSR. No. 12, Moscow, 1966.

29. Klassen , Doctor of Technica l Sc iences , I n s t i t u t e of Minera l Fue l s of t h e USSR Academy of Sc iences , Moscow, Khimiya i Zhizn ' , Russ i an , No. 9 , September, pp.24-27 (1969).

%. Stamm, W . and Morgan, J.J., Aquat ic Chemistry - An I n t r o d u c t i o n Emphasizing Chemical E q u i l i b r i a i n Na tu ra l Waters, John Wiley and Sons, 2nd ,Ed i t ion , New York (1891) p.780.

31. Pludek, V. R . , Design and Corros ion Cont ro l . John Wiley and Sons , N e w York, (1977) p. 383.

32. Fontana, M.G. and Greene, N . D . , Cor ros ion Engineer ing . McGraw H i l l Book Company, 2nd E d i t i o n , N e w York (19781, p. 465.

33. Reimers, R.S. and deKernion, P.S., "The A p p l i c a t i o n of Aqua-Scrubber 's Ultrasonic/Electrostatic Treatment of a Cooling Tower and Heat Exchanger System of M t . Airy Ref in ing Company", Repor t by Aqua- Scrubber Corpora t ion t o M t . A i r y Re f ine ry , Garyville LA (January , 1981) .

34. deKernion, P.S., Unpublished d a t a f o r Aqua-Scrubber Corpora t ion , Kenner LA (1980).

35. Tobenikhin, E. F., P ron in , Z.F., and Rybal'Chenko, U.S., "The E f f e c t of a Magnetic F i e l d on the Corro iosn of S t e e l i n a Cor ros ive Medium", Tep leone rge t ika , Vol. 19 ( l o ) , pp. 9-71, (1972).

-19-