ASME 1979 Citrus Engineering Conference CEC1979 March 22, 1979, Lakeland, Florida, USA CEC1979-2506 Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

CHLORINE DIOXIDE AN EFFECTIVE BIOCIDE FOR RECYCLED OR REUSED WATER SYSTEMS

John F. Synan 9 Oriole Drive Norwalk, Conn. 06851

Consultant To Olin Water Services Overland Park, Kansas

The desire and indeed the need of industry to recycle or reuse process waters wherever possible is becoming increasingly more urgent. Limited supplies of quality water in many parts of the country and more stringent EPA regulations for waste disposal and water dis- charge are but two of the many reasons for this.

The feasibility of recycling or reusing process waters, particular- ly in the food processing industry, depends largely on the ability of main- taining effective biological control in these systems. The contaminants picked up by these waters in the processing of fruits and vegetables provide nutrients for biological growths and create excessive dosage rates for the biocides. Further, reaction of the commonly used biocides with these contaminants may produce objectionable tastes and odors in the product.

Time does not permit a detailed discussion of the many biocides available to the food processing industry. The halogens, particularly

Published with permission. and iodine, are the materials most favored. Bromine and bromine compounds have found limited applicability.

An excellent paper comparing and the iodophors was presented to this group at your 1978 conference by Mr. R. B. Barrett of Economics Laboratories, Inc. In summary, this paper states that the iodophors and are essentially comparable in germicidal activity when each product is used under favorable condi-

tions. These conditions, such as pH, concentration and organic load Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 of the systems, are defined. The paper further states that the hypo- are recommended for water treatment and direct food contact applications because of the low toxicity of the degraded by-products.

This presentation will be confined to a comparison of the chemical and biological properties of chlorine and and how these properties affect each product's suitability for recycle and reused water systems. Generation systems for chlorine dioxide will be shown and finally several case histories of chlorine dioxide applications will be presented.

CHLORINATION

Chlorine is the most widely used, cost effective biocide available. It is the standard of reference. Its long history of use in potable water systems and in process streams in the food industry testify to its effec- tiveness, safety and low toxicity. It is the material first considered when selecting a biocide for the treatment of a water system.

Chlorine is available in many forms; as elemental chlorine in the compressed gas state in cylinders or tank cars; in the liquid state as sodium hypochlorite (liquid bleach); in the dry form as calcium hypo- or the organic chloro products such as chloroisocyanurate.

Regardless of form, gaseous, liquid or dry, when added to a water system the resulting active ingredient is the same, hypochlorous acid, HOC1. This is illustrated by the reaction of elemental chlorine with water. (Figure 1)

The chlorine atom in HOCl has a valence of +l. This indicates that the chlorine in this species is in an oxidized state and that HOCl is in fact a derivative of the first oxide of chlorine, chlorine mononoxide. This equation also shows that a rnol of HC1 is produced along with each mol of HOC1.

It is the basic chemical activity of HOCl that causes problems in its use. First it is pH sensitive. HOG1 will dissociate in water to the hypochlorite ion (OC 1)- and this dissociation increases with increasing pH. (2) (Figure 2) Above pH 8. 5 little HOCl remains. It has been con- verted to the hypochlorite ion (0~1)-. Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 The importance of this fact is that the hy chlorite ion has only about 1/10 the biocidal effectiveness of HOC1. P3g (Figure 3)

Next chlorine reacts by substitution as well as by oxidation, It reacts with ammonia to form chloroamines, with phenol, hydrocarbons, organic acids, sugars, starches and in fact with most organics contain- ing a labile hydrogen to form the chloro derivatives. (Figure 4) (Figure 5) These reactions have the effect of rendering the chlorine applied much less effective or completely biocidally inactive.

Finally, HOG1 has a high oxidizing potential. The couple MOCl -Cl- has a redox potential of 1. 49V. Thus HOCl is capable of oxidizing most organic contaminant present in recycle systems. These reactions natural- ly increase the chlorine demand of a system and in many cases to a point where chlorination will fail without massive dozages being applied. (Figure 6)

Two other factors must be considered when considering the use of chlorine. As shown in Figure 1 one mol of HC 1 is produced for each mol of HOCl and the application of large chlorine dosages could create corrosion problems in neutral or acidic pH systems. Finally, it is well known that many of the organic chloro derivatives have objectionable tastes and/or odors, as for instance the chlorophenols. This is a very important consideration in the food processing industry.

Having extolled the virtues of chlorine and pointed out its drawbacks, let's now look at the properties of chlorine dioxide.

CHLORINE DIOXIDE

Chlorine dioxide is the second oxide of chlorine with the formula CIOZ. Its chlorine atom has a valence of +4 indicating a high level of oxidation. The next figure (Figure 7) shows the basic structure of the two chlorine oxides. Chlorine dioxide is a yellow-green gas in dilute concentration, its color changing- - to yellow- orange- with increasing concentration. Its molecular weight is 67. 5. It has a disagreeable odor similar to chlorine and somewhat resembling ozone. The sensitivity of chlorine dioxide to temperature and pressure preclude its production and shipment in bulk. It must be generated and used on site. It is quite water soluble with its solubility depending on temperature and pressure. At room temperature and 30mm partial pressure it is soluble to the extent of 2, 9 gms/liter (2900 ppm) and in chilled water solutions of over 10. 0 gmslliter (10, 000 ppm) can readily be produced. (Figure 8). Chlorine dioxide does not react with water. It remains a true dissolved gas. It does not dissociate as does HOC1. As is chlorine, chlorine dioxide is subject to photodecomposition. This decomposition is a function of time and the intensity of the ultraviolet light source. Solutions Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 of C102 will retain their strength for several months when stored in the dark and at low temperature as in a refrigerator. Chlorine dioxide is harmless and safe to use when handled in a water solution.

In its chemical properties chlorine dioxide is most different from HOC1. As stated before, C102 does not react with water. It does not form its acid derivative HC102-chlorous acid or dissociate to the chlorite ion (~10~)-except at high pH values, 10. O+. Even here, it is a reaction with the alkali rather than the water.

The significant difference between C102 and HOCl is its chemical reactivity. C102 does not react by substitution. It does not react with ammonia or ammonia compounds to form the chloro derivatives. It will react by oxidation but in a more limited scope than HOC1. It will not react with or oxidize ammonia, ammines except the tertiary, poly saccharides, such as sugar, starch, cellulose, organic acids, alcohols, or hydrocarbons, even the unsaturated types. It will react and destroy phenols, even the chloro derivatives, humic acids, mercaptans, etc. It will react with reducing materials such as sulfides, sulfites and cyanides. This more limited reactivity may be explained partially by the lower -. redox potential of CIOZ as compared to HOC1. The couple C102 -C102 has a potential of 1. 15V (3). This lack of chemical reactivity as compared to HOCl means that in contaminated water systems the chlorine dioxide demand will be substantially lower than for HOCl and effective biological control can be more easily maintained, particularly in systems where chlorine fails.

BIOLOGICAL PROPER TIES

The biological properties of chlorine dioxide have been extensively studied over the past twenty-five years with significant results reported by Ridenour and associates at Michigan, Trakhtman and co-workers in Russia, the Bernarde and associates at Rutgers, among others. Early work by Ridenour and associates of the Department of Environmental Health, School of Public Health, University of Michigan at Ann Arbor, Michigan, during the period 1946-1950 (4* 5, 6* 7, proved chlorine dioxide to have biocidal effectiveness equivalent to chlorine. This work has been reported in the Journal of the American Water Works Association, Water and Sewage Works and the American Journal of Public Health. This work established that chlorine dioxide is not only an effective bactericide but is also a potent viricide and

sporicide. This work included not only the test organism E. Coli, Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 but also several common water -borne pathogens.

Ridenour also studied the effect of pH and temperature on the biological efficiency of chlorine dioxide. Chlorine dioxide proved less pH sensitive than chlorine with its effectiveness enhanced with increasing pH values. Temperature affects the activity of chlorine dioxide as it does chlorine being somewhat less effective at lower temperatures. Ridenour theorized from his data that C102 is absorbed on the organisms thus concentrating itself at the most effective site for maximum kill. ( Figures 9, 10, 11) Trakhtman and co-workers report- ed in 1946 and 1953(~99) that chlorine dioxide is at least as effective a germicide as chlorine.

The most sophisticated and critical studies were reported in 1965 and 1966 by Bernarde, Israel, Olivieri and Granstrom of the Bio-Engineer- ing Laboratory at Rutgers, the State University, New Brunswick, New Jersey, and published in the Journal of Applied Microbiology (lo*ll. 12)- Bernarde's work confirmed the findings of the previous researchers in all respects. He further advanced a theory for the kinetics and mechanism of bacterial disinfection by chlorine dioxide. Bernarde states that the results of his experiments clearly show that "Chlorine Dioxide markedly inhibits protein synthesis, and apparently does so abruptly. A lag-phase is not seen. This indicates the lethal lesion to be directly related to protein synthesis, rather than inactivation of the enzyme system in the catabolism of glucose, wherein protein, sufficient to produce a lag-phase, would be expected to be synthesized. 'I Bernarde et a1 had the advantage of the ad- vanced analytical techniques and physio-chemical findings of Granstrom and Lee, published in 1958, and had the use of a spectrophotometer for their analytical work. (Figures 12, 13, 14)

All of these studies and many others, although different in detail, arrived at the same conclusions:

1. Chlorine dioxide is as effective as chlorine as a disinfectant.

2. Chlorine dioxide is less sensitive to pH than chlorine. Between practical pH values of 6. 0 and 10. 0, chlorine dioxide maintains its effectiveness and is in fact more effective at the higher pH values. This is counter to the effect of pH on the efficiency of chlorine.

3. Being less reactive with ammonia and many organics than chlorine, it requires less chlorine dioxide than chlorine to achieve equivalent residuals and kill where systems contain such contaminants.

GENERATION OF CHLORINE DIOXIDE Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

The Chlorine System - For water treatment applications, chlorine dioxide is best generated by the reaction of chlorine with sodium chlorite in aqueous solution. The overall reactions being:

2 NaClQ2 + C12 2 C102 + 2 NaCl

Actually, the process involves two steps:

C12 + H20 HOCl + HC1 HE1 + HC1 + 2 NaC102 2 C102 + NaCl + Hz0

In this reaction (Figure 15), 1 lb. of chlorine reacts with 2. 55 lbs. of sodium chlorite to produce 1. 9 lbs. of chlorine dioxide. In practice, however, a small excess of chlorine is used to depress the pH in the generator to insure complete reaction of the chlorite. A pH of 3. 5 and a chlorine concentration in the generator of 500 ppm are recommended for this reaction. Under these conditions, the reaction is practically instantaneous and better than 90% efficient, even at ambient temperatures.

Figures 16 and 17 show the schematic layout for this generation.

HYPOCHLORITE GENERATION

This is a variant of the chlorine generation process and may be used where a gas chlorinator is not available. Sodium hypochlorite is reacted with sodium chlorite in solution with the pH adjusted to pH 4. 0 maximum with sulfuric or muriatic acid.

NaOCl + HC1 NaCl + HOCl HOCl + 2 NaC102 + HC1 2 C102 + 2 NaCl + H20 Like the chlorine generation system (Figure 18), this process allows the generation of chlorine dioxide free of excess chlorine or in any ratio of the two products. It lends itself to small operations where the use of liquid chlorine is not feasible. (Figures 19 and 20) These figures show the schematic layout for this generation system.

CASE HISTORIES

The Green Giant Canning Company, Le Sueur, Minnesota, evaluated Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 chlorine dioxide in recycle water systems in its Blue Earth plant during the pea and corn pack season in 1957. The objective was to study the feasibility of water conservation through water recycle while maintaining acceptable bacteria counts in the complete system.

Recycled water replaced fresh water in 13 ear washers, each re- quiring 10 gals/min also at the huskers, cob belt sprays, flumes and on the husk and kernel belt sprays.

Recycled water was used in the pea box washers at the rate of 60 gallons /min, in the scavenger reels and the waste flumes from the gravity separators.

The recycled water was treated with CIOZ at dosage ratios varying between 5. 0 and 10. 0 mg /liter. The results of this study were presented in a paper by Mr. J. Lo Welch of the Green Giant Company at the 1958 annual meeting of the Institute of Food Technologists, Chicago, Illinois. The paper was published in the Journal of "Food Technology, " March 13, 1959.

The following conclusions were drawn from this study:

The chlorine dioxide treatment of once used water is highly effective in curtailing bacteria and slime formation in pea and corn canneries. The persistent residuals and the lack of reaction with ammonia nitrogen make possible one point rather than multiple point application as is required with rechlorination of used water. Bactericidal residuals maintained in the used water did not result in the generation of offensive odors in the factory nor resulted in off flavors in the product, Total bacteria counts on the product were significantly lower when chlorine dioxide was used.

Only minor deposits of slime were detected on equipment or belts containing or being sprayed with water containing chlorine dioxide even after many hours sf factory operation. 'When in-plant chlorination alone was used slime was evident within twelve hours after a major cleanup.

Substantial savings in water may be realized through reuse of water treated with chlorine dioxide for bacterial control. Figure 21 shows the reduction plate counts during the corn pack. LAMB - WESTON DIV, AMFAC FOODS, INC. POTATO PROCESSING PLANT

This large western potato processing plant conducted tests in 1975 to determine the feasibility of installing a retrograde process water system using chlorine dioxide to maintain biological control. Conven-

tional chlorination could not produce acceptable results. Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

During the first year of evaluation low bacterial levels were maintained in the retrograde water system resulting in a reduction of fresh water makeup. Chlorine dioxide dosages between 3. 5 and 5. 0 ppm were used.

In comparison with historical microbial levels maintained with chlorine alone, chlorine dioxide at dosage levels of about 5. 0 ppm gave 95-9970 reduction in the bacteria plate count. Levels below 5000 APC /ml and often as low as 100 APC/ml were attained along with a reduction of coliform and other indicator bacteria. It was established that a dosage level of 3. 5 ppm chlorine dioxide is the most effective, economic level of treatment.

One of the interesting observations made during the use of chlorine dioxide was the brighter appearance of the stainless steel processing equipment due to the elimination of organic material caused by slime accumulation.

Further it was demonstrated that chlorine dioxide can be used in the water used to transfer partially processed potatoes from one building to another without the carryover of bacterial contamination.

Extensive tests by an outside laboratory found no residual in the product and no effect on quality factors such as texture, color, brightness, nutritional values or shelf life.

As a result of treating this new retrograde water system with C102, a savings in water consumption of over 3070 was achieved, excellent micro- bial control was maintained, and by-product recovery was improved.

The new system not only reduced water consumption but allowed plant expansion through a unique transfer system for partially processed potatoes to a new co-product plant several blocks away. Results of this study have been published in "Food Processing" April 1977. (14) The article is by Douglas J. Bruce and Paul B. Stevens of Lamb-Weston entitled "Chlorine Dioxide Key to Successful Retrograde Water System. "

TOMATO PROCESSER

Company policy does not allow me to disclose the identity of this Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 plant. It is one of the major food companies and the plant processes better than 1000 tons of tomatoes per day.

The problem at this plant involved unacceptable microbial levels in the secondary flume system. This system transports the fruit into the plant and to the inspection and grading areas as well as acting as a washing operation. The system has a capacity of 35, 000 gallons and is recirculated at a rate of 1500 gallons/minute. The makeup water was treated with 8. 0 ppm chlorine. Slime buildup was so bad that two full- time employees per shift were used to brush down the sides and bottom of the flume to discourage slime buildup. Also, frequent dumping and flushing of the system was practiced. Failure to meet EPA standards threatened to force this plant to a one pass or limited recycle system resulting in a much higher water consumption,

Chlorine dioxide was fed to the recycle water through the suction side of the recirculating pumps. An initial dosage of 1. 0 ppm was used which resulted in a trace residual in the system. The dosage was increased to 2. 0 ppm because of the heavy slime accumulation there at the start of the test and desire to clean up the system more quickly. The dosage was re- duced to 1. 0-1. 5 ppm as standard operating procedure after the system was cleaned.

Results of the test were:

The CIOZ treatment resulted in a drastic reduction in the standard plate counts to a point where sterile conditions were occasionally produced.

No further slime buildup occurred. Manpower requirements for flume cleaning were reduced to normal periodic cleaning.

Geotricum mold was eliminated from the equipment. A consistent CIOZ residual was maintained in the system.

Although this application did not result in any major water savings, it did allow the plant to continue their present recycle system. CITRUS PROCESSING

I realize a story on results in a citrus processing plant would be of much more interest to this meeting, but data in this area to date is in- complete and preliminary.

Work at the Minute Maid plants is in progress and encouraging results are evident. However, the tests have not been finalized to the point where absolute conclusions may be drawn. Nevertheless, the Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 pattern appears to be similar to that found in other food processing plants.

The application of 1. 0-3. 0 ppm ClO2 in the fruit wash system gives counts on the orange surfaces superior to those obtained with 15-20 ppm chlorine.

C102 residuals were present below the belt wash.

ClO2 is effective at pH 8. 5. Operation at this pH level should improve corrosion control.

Use of chlorine dioxide in the oil recovery water system appears to have potential in controlling contamination without adverse effects on oil quality.

Chlorine dioxide will not produce objectionable tastes or odor in the products and no other deleterious effects on the product have been observed.

Later it is planned to study a recycle system to effect water savings, but this has not been done at this time. REFERENCES

R. P. Barrett, A Comparison of Iodophor and Sodium Hypo- chlorite Sanitizers. Transactions of 1970 Florida Citrus Engineering Conference.

G. C. White, Handbook of Chlorination.

G. C. White, Handbook of Chlorination. Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

Ridenour and Ingols, 1947. Bactericidal Properties of Chlorine Dioxide, J. of A. W. W. A. , June 1947, 561 - 567.

Ridenour and Ingols. Inactivation of Poliomyelitis Virus by "Free" Chlorine, J. of Public Health, Vol. 36, No. 6, June 1946.

Ridenour and Armbruster. Bactericidal Effect of Chlorine Dioxide, J. of A. W. W.A., June 1949, 537-550.

Ridenour, Ingols and Armbruster. Sporicidal Properties of Chlorine Dioxide, Water and Sewage Works, Vol. 96, No. 8, August 1949,

Trakhtman (1946). Chlorine Dioxide in Water Disinfection, Gig. Sanit. 11, 10.

Trakhtman, Bedulevich and Svellakova. New Data on the Use of Chlorine Dioxide in Water Purification, Gig. Sanit., 19: 14 1953.

Bernarde, Israel, Olivieri, and Granstrom, 1965, Efficiency of Chlorine Dioxide as a Bactericide, J. of Applied Microbiology, Vol. 13, No. 5.

Berarde, Snow, Olivieri and Davidson. Kinetics and Mechanism of Bacterial Disinfection by Chlorine Dioxide, J. of Applied Microbiology, Vol. 15, No. 2, March 1967.

Benarde, Snow and Olivieri. Chlorine Dioxide Disinfection Temperature Effects. J. of Applied Bacteriology, 30 (1) 159-167, 1967.

Welch and Folinazzo. Use of Chlorine Dioxide for Cannery Sanitation and Water Conservation, Food Technology, March 1959.

Bruce and Stevens. Chlorine Dioxide Key to Successful Retrograde Water System. Food Processers' APAK 1977. 1) 2CI2 + H20 *CI20 + 2HCI

2) Cf20+ H20 '2HOCI Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

3) Clp + H20 * HOCI + HCI

Figure 1. Chlorine /Water Reactions

Figure 2. Distribution of Hypochlorous Acid in Water At Different pH Values at 20'~ 10

1 .o Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021 TITRABLE CHLORINE 0.1 (P-P-~.)

HYPOCHLOROUS

0.01

0.001 1 10 100 1000 MINUTES 99 per cent destruction of E. coli at 2-6" C.

Figure 3. Germicidal Efficiency Comparison

AMMONIA C12 ----cMONOCHLORAMINE

MONOCHLORAMINE -GI2 --+ DICHLORAMINE DICHLORAMINE -GI, ---+ NITROGEN TRICHLORIDE

Figure 4. Chlorine -Ammonia Reactions OL+ HOCl * MONOCHLOROPHENOLS R@HOCHLOROPHENOLS + HOCl --- DICHLOROPHENOLS WMLOROPHENOLS + HOCl -TRICHLOROPHENOLS Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

Figure 5. Chlorine-Phenol Reactions

0 4 8 12 16 20 24 28 32 36 40

C12 or C102 added - mg/l

Figure 6. CHLORINE MONOXIDE +1 +1 CI - 0 -. CI

CHLORINE DIOXIDE Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

Figure 7. Chlorine Oxide Structures

Figure 8. Solubility of Chlorine Dioxide in Water Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

a,-ac,--ppnw* Figure 9. Comparison of The Bactericidal Effects of Chlorine And Chlorine Dioxide on Esch. Coli at Different Temperatures And pH with Five Minute Contact (3)

Figure 10. Comparison of The Bactericidal Effects of Chlorine And Chlorine Dioxide on Ps. aeruginosa and Staph. aureus at Different pH with Five Minute Contact (3) Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

Figure 11. Comparison of the Bactericidal Effects of Chlorine And Chlorine Dioxide on A. aerogenes at Different Temperatures And pH with Five Minute Contact (3)

80 120 1m 240 MAXIMUM TIME FOR 99+% KILL, SECONDS

Eflect of pH on kill

Figure 12. Disinfection of E. coli in Organic Free Buffer, 15, 000 Cells /ml at 24O~(1) isms Remaining % Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

CI2 or ClQ added-ppm by weight Figure 13. Comparison of The Bactericidal Effects of Chlorine and Chlorine Dioxide on A. aerogenes At Different pH With Five Minute Contact

Figure 14. Effect of Contact Time on Organism Survival Disinfection of E. coli in Sewage Effluent Chlorine Dioxide vs. Chlorine pH 8. 5, 83. 15, 000 Cells /rnl at 24'~ Dosages in mg/l(l) CI2 + Ha0 HOCI + HCI HW + MI + 2NaCllh 2Cl02 + 2NaCI + H20 Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

Figure 15. Chlorine Generation of Chlorine Dioxide

~oluti6n b to Process

GENERATOR i CHLORINATOR

Olin 4107 BUrB - a11 Piping to C troll O.ner8tor to be Sch. 80 or 40 Type I OYC. I

rchlorine Dioxide Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

cR.ci.ion m-11 or 9721-ll Pq?

Figure 17. Chlorine Dioxide Generator Typical Hook-Up

NaOCl + HCI NaCl + HOCl HCI + HOCl + 2NaCIb 2C102 + 2NaCI + H20

Figure 18. Hypochlorite Generation of Chlorine Dioxide GENERATOR

A Dilution Water Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021

Olin 4107 NaOCl HCI or H2S04

Figure 19.

Figure 20. Chlorine Dioxide Generator 3-Pump System Typical Hook-Up Downloaded from http://asmedigitalcollection.asme.org/CES/proceedings-pdf/CEC1979/99663/66/2370405/cec1979-2506.pdf by guest on 30 September 2021