IJCPE Vol.10 No.1 (March 2009) 

 

 
Iraqi Journal of Chemical and Petroleum Engineering 

 Vol.10 No.1 (March2009) 29-34 
ISSN: 1997-4884 

 

The Factors Affecting the Absorption of Ozone in Water 
 

Abbas H. Sulaymon
*
, Abdul Razzak H. Al.Karaghouli and Mustafa Hassan Flayeh 

*
Environmental Engineering Department - College of Engineering - University of Baghdad – Iraq 

Abstract 

This study was concerned with using ozone gas in drinking water treatment plant at Ibn-Sina Company. The main 

purpose of this research is to find the best contactor for ozone unit proposed. An investigation was conducted to study 

the absorption of ozone by water in two type of absorber. The effects of the process variables (such as height of water 
column, contact time, and pH) on the amount of ozone absorbed were investigated. Box-Wilson central composite 

rotatable design is used to design the experimental work for the mentioned variables. It was found that the optimum 

value of the variables studied was: 

  i)   Height of water column (90 cm) 

  ii)  Contact time (17-18 min) 

  iii) PH (7 - 7.5) 

 

 

 

 

Introduction 

The degradation of raw source water has become a 
worldwide problem, and more serious in developing 

countries. Safe and healthy drinking water are paid 

more and more attention. The rapid economic 

development and increasing polluted sources water 

put forward the need for advanced purification of 

drinking water in order to remove the trace pollutants 

in the water after conventional treatment. Along with 

the pollution of sours water, more and more 

importance has been attached to the technologies on 

advanced purification of drinking water, of which 

ozonation process has got yearly investigation and 

found wide use in the world [1]. 

Ozone (O3) or trioxygen is a molecule composed of 

three oxygen atoms, temporarily existing in a very 

unstable and reactive state. Ozone is so reactive that a 

suitable container for storage probably does not exist.  

 

Unlike the O2 molecule, this triatomic oxygen defies 

man’s attempts to store or liquefy it. 

Compared to O2, O3 is an extremely active molecule, 
probably by a factor of 1,000 times and is sometimes 

referred to as activated oxygen [2].  

Ozone exists as a gas at room temperature. The gas is 

colorless with a pungent odor readily detectable at 

concentration as low as 0.02 to 0.05 ppm (by 

volume), which is below concentration of health toxic 

concern. Ozone gas is highly corrosive and toxic 

[3,4]. 

Since ozone cannot be stored or conveniently 

purchased by the gram, pound, gallon or ton, it must 

be produced on site as needed, (where needed and 

when needed) [3,5]. 

There is many way to produce ozone, all of the 

following can be used [2]. 

 

University of Baghdad 

College of Engineering 
Iraqi Journal of Chemical 

and Petroleum Engineering 

 



The Factors Affecting the Absorption of Ozone in Water 

 

30 
IJCPE Vol.10 No.1 (March 2009) 

 

     1.   Electrical Discharge – Corona Discharge. 

     2. Electrolytically – Electrolysis of an Acid. 

     3. Photo chemically – Ultraviolet radiation. 

     4. Radio chemically. 

Some application of ozone to potable – water 

treatment is sterilization of all forms of bacteria and 

viruses; increased settling; removal of tastes, odors, 

and colors; oxidation of sulfides, cyanides, and algae; 

removal of trihalomethan precursors; and oxidation of 

organic materials. Ozone oxidation followed by 

filtration also can be employed for the removal of iron 
and manganese [8].  

 A unit for treatment of water by ozonation including, 
on the one hand at least one apparatus for the 

production of ozonized white water and, on the other 

hand, at least one contactor in a way that the mixing 

of the water to be treated and the white water occurs 

in said contactor. The installation for the production 

of ozonized white water includes a device for 

dissolution of ozone in a carrier liquid [9]. 

The aim of the present work is concerned with 

detailed study of transfer of ozone into water. 

Several variables have been investigated including, 

height of water column, contact time, and pH on the 

two types of absorbers packed and bubble column.  

 

Experimental and Materials 

 
Experimental Apparatus:  

Ozone was transferred to water by using an absorption 

apparatus. The absorption unit consists of an absorption 

apparatus and ozone generator unit Fig. (1). 

 

Absorption Apparatus: 

1- The packed column:- The experiments in the present 
work were carried out using a (5 cm) I.D 
glass(Q.V.F) column filled with one of three types of 

packing used in experiment, (10 mm in size) glass 

rashig rings, (18 mm in size) intalox saddles, and (15 

mm in size) spherical packing. 

2- Bubble Diffuser:- The bubble diffuser plays a basic 
and indispensable role in the present work. The 

bubble diffuser used was sintered glassware disk 

with diameter of 30 mm and pore size 100-160 

micron. 

Ozone Generator: 

Ozone generator used to generate the ozone has the 

following specification: Type: Fisher, Model: 502, Max 

Dos:  10 g/hr   at   500 Liter O2/ hr 

 

 pH-Meter: 
The pH value of water before and after treating was 

measured by means of a digital pH-held with 

specifications as following: 

Type: Schott Gerate, Model:  820, Range: 0-14 

    

The Experimental Procedure: 

The raw water was transferred from Tigris River at Al-

tarmyya city in the north of Baghdad to the laboratory 

and left for one week to settling. The raw water was 

pumped by dosing pump from the top of column and 

distributed over the packing of column by buechnner 

funnels.  

Ozonized oxygen gas produced from ozone generator, 

which calibrate first before starting the experiments at 

constant flow rate of oxygen gas and at different time 

(stripping the ozone gas by iodide solution), passes in 

counter current to water at the bottom of column and 

diffused through water by sintered glass disk. The 

diffuser at the first time, hot hydrochloric acid followed 

by several rinses of distilled water sucked through it 

under a good vacuum, this removes dust particles and 

powdered glass. The sintered glassware should remain in 

the oven at a temperature of (110 –150) C°. 

Excess of ozone which was not absorbed by water passes 

through the contact column to the two gas washing 
bottles contain potassium iodide solution to captured the 

escaped ozone. 

With reference to (Fig.1), an installation for the ozonation 

of water was essentially constructed from Q.V.F column 

of 5 cm inside diameter and 200 cm height that permits 

the supply of a fluid. 

Q.V.F column forms an absorption column, so as to 

obtain maximum dissolution of the ozone in the water 

with the help of the gas-liquid contactor with a minimum 

of loss, a packed column has been chosen. The column 

was filled with a packing material, in bulk, which in 

context of this research comprises of one of three types 

used, raschig ring, intalox saddle, and spherical packing. 

The column was fitted with an inlet for the water destined 

to be saturated with ozone. So as to allow a good 

distribution to the carrier liquid inside the column, a 

distribution device having the form of a sprinkler unit is 

installed at the inlet. 

The column has, in addition, to its lower part, a gaseous 

inlet. Furthermore, the homogeneous distribution of the 
ozone over the whole cross-section of the column is 

achieved by a porous sintered device. 

 

                                                                                                                                                                                                                                                                                                                                                                                                                                                               



 
Abbas H. Sulaymon, Abdul Razzak H. Al.Karaghouli and Mustafa Hassan Flayeh 

31 
IJCPE Vol.10 No.1 (March 2009) 

 

(1) Q.V.F Column,                 (6) Ozone Generator, 

(2) Inlet Liquid Device,          (7) Oxygen bottle,  

(3) Inlet Gas Device,              (8) Washing bottle,  

(4) Sprinkler,                          (9) Water tank. 

                 (5) Porous Sintered Device, 

Fig.1 Absorption Unit 

 

Results and Discussion 

 Effect of Height of Water Column: 

The effect of height of water on the amount of ozone 
absorbed was studied in order to determine the height at 

which absorption process is best performed. 

Figure (2) shows that for all contact time studied the 
amount of ozone absorbed by water increase as the 

height of water increases. 

Similarly the relation between ozone concentration 

and the height of water was plotted for given pH 

values as shown in (fig. 3). The highest value of 

ozone concentration was obtained approximately at 

pH=7. 

Referring to this figures it can be seen that the 
concentration of ozone increases with increases of 

height of water until height value of ( 90 cm ) after 

which the concentration of ozone is decreased with 

height of water column because the rise velocity of 

the bubbles decreased as well as the diameter of the 

bubble decreased. 

Hieght of Water Column (cm)

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

20 40 60 80 100 120 140 160

t= 25 min  

t= 20.7 min  

t= 15 min  

t= 9.2 min  

t= 5 min  

Fig. 2 Ozone Concentration Vs Height of Water Column 

at Various Contact Times. 

 

Height of Water Column (cm)

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

1.6

2.2

2.8

3.4

4.0

4.6

20 40 60 80 100 120 140 160

pH= 9  

pH= 8.1  

pH= 7  

pH= 5.8  

pH= 5  

Fig. 3 Ozone Concentration Vs Height of Water Column 

at Various pH. 

 

Height of Water Column (cm)

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

3.3

3.5

3.7

3.9

4.1

4.3

4.5

20 40 60 80 100 120 140 160

t = 15 min   
pH = 7.0  

  Fig. 4 Ozone Concentration Vs Height of Water Column 

 



The Factors Affecting the Absorption of Ozone in Water 

 

32 
IJCPE Vol.10 No.1 (March 2009) 

 

Effect of Contact Time: 

The significant interaction effect between contact time 

and height of water column and between contact time and 

pH was shown in figs. (5) and (6). 

 The best time of absorption of ozone by raw water is an 

important factor in water treatment affecting the 

concentration of ozone. 

Examining these figures, it can be seen that the amount of 

ozone absorbed increases with increasing the time of 

absorption. It is clear that when the contact time is less 

than 18 minute, the ozone concentration is highest. While 
increase the contact above this value will decrease the 

ozone absorbed because the temperature of ozone 

generator increased and this will accelerate 

decomposition of ozone.  

Contact Time (min)

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

2 6 10 14 18 22 26 30

L= 150 cm  

L= 124.6 cm  

L= 90 cm  

L= 55.3 cm  

L= 30 cm  

Fig. 5 Ozone Concentration Vs Contact Time at Various 

Height of Water Column. 

 

Contact Time (min)

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

1.4

1.8

2.2

2.6

3.0

3.4

3.8

4.2

4.6

2 6 10 14 18 22 26 30

pH= 9  

pH= 8.1  

pH= 7  

pH= 5. 8  

pH= 5   

Fig. 6 Ozone Concentration Vs Contact Time at Various pH. 

 

 

Contact Time (min)

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

2.6

3.0

3.4

3.8

4.2

4.6

2 6 10 14 18 22 26 30

pH=7.0
L= 90 cm

             Fig.7 Ozone Concentration Vs Contact Time 

          

Effect of Acidity Function: 

 The effect of pH is clearly observed by the concentration 

of ozone in water. 

Figures (8) and (9) show that increasing the pH will 

increase the concentration of ozone in water. It is clear 

from these figures that when pH is equal to 7-7.5 the 

ozone concentration is highest. 

The pH of the water is important because hydroxide ions 

initiate ozone decomposition, which involves the 
following reaction [18]: 

          O3    +    OH                      HO2   +   O2 

          O3     +    HO2                     O2     +   O2 

 

 

pH

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

1.6

2.2

2.8

3.4

4.0

4.6

4.5 5.5 6.5 7.5 8.5 9.5

L= 150 cm  

L= 124.6 cm  

L= 90 cm  

L= 55.3 cm  

L= 30 cm  

 Figure (8) Ozone Concentration Vs pH at Various 
Height of Water Column. 



 
Abbas H. Sulaymon, Abdul Razzak H. Al.Karaghouli and Mustafa Hassan Flayeh 

33 
IJCPE Vol.10 No.1 (March 2009) 

  pH

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

1.4

1.8

2.2

2.6

3.0

3.4

3.8

4.2

4.6

4.5 5.5 6.5 7.5 8.5 9.5

t= 25 min  

t= 20. 7 min  

t= 15 min  

t= 9. 2 min  

t= 5 min  

                          

Figure (9) Ozone Concentration Vs pH At Various 

Contact Time. 

 
 

pH

O
z
o

n
e
 C

o
n

c
e
n

tr
a

ti
o

n
 (

p
p

m
)

3.5

3.7

3.9

4.1

4.3

4.5

4.5 5.5 6.5 7.5 8.5 9.5

L= 90 cm
t = 18 min

Figure (10) Ozone Concentration Vs pH 

 
 
Analysis of Experimental Results: 

The absorption processes that take place between ozone 

gas and raw water start immediately when the gases come 

into contact with water. The two-film theory, the 

penetration theory, the surface renewal theory or others 

can describe this mass transport. In this work, however, 

two-film theory was considered as a basis of description 

of the transport characteristic for the absorption of ozone 

into water in bubble and packed bed absorber. 

The following assumption will be considered to treat the 

experimental result: 

1- ozone is the only active species that physically 

dissolves in water. 

2- there is no chemical reaction. 

 

  

 

 
Comparison In Results Between Two Types of 

Absorber Used: 

 

Comparison between types of absorber used in our 

experiments was represented in tables (1) and (2) these 

tables’ shows that the maximum amount of ozone 

absorbed achieved by using glass packing of rachig ring 

type and when the effective area increased the mass 

transfer coefficient decreased. 

 
Table (1) Amount of Ozone Absorbed by Different Type 

of Absorber. 
Height of 

Water 

Column 

Ozone Absorbed (ppm) 

Bubble 

Column 

Packed Column 

(cm) Rachig 

Ring 

Spherical Saddle 

30 3.2 3.5 2.05 3.3 

55.3 3.7 3.93 2.92 3.74 

90 4.28 4.93 3.1 3.76 

124.6 3.48 4.94 3.2 3.98 

150 3.2 4.0 3.1 3.5 

 
 

        Table (2) Values of Mass Transfer Coefficient 

 
 

Type of 

Absorber 
 

Effective 
Area 

m
2
/m

3 

KL 
Experimental 

m/s 

KL 
Theoretical 

m/s 

P
a
c
k

in
g
 

Rachig 
Ring 

163.39 1 * 10
-5

 3.5  * 10
-5

 

Intalox 

Saddle 

99.6 1.6 * 10
-5

 4.7  * 10
-5

 

Spherical 76.97 2.1 * 10
-5

 4.5  * 10
-5

 

B
u

b
b

l

e
 

Swarms 

Bubble 

133 1.2 * 10
-5

 9  * 10
-5

 

 
 
Conclusions          
The following conclusions could be drawn from this 

investigation: 

1- The second order polynomial regression 
analysis of the objective function i.e.; the 

amount of ozone absorbed by water and three 

variables (i.e.; height of water column, contact 

time, and pH) for bubble column contactor. 

 



The Factors Affecting the Absorption of Ozone in Water 

 

34 
IJCPE Vol.10 No.1 (March 2009) 

 

2- The amount of ozone absorbed increase with: 
a- increasing the height of water column. 
b- increasing contact time. 
c- increasing pH. 

                 The best operating conditions are: 

d- height of water( 90  cm ). 
e- contact time( 18  min ). 
f- pH ( 7 ). 

3- The use of packed contactor (raschig ring) is 

better than bubble  contactor, because the 

contact area is larger.          

           

References 
 

1- Jinsong Zhang, "Studies and Application on Advanced    

Purification of 

    Drinking Water", "By Internet". 

 

2- Jim Eaglton,  "Ozone  In  Drinking  Water  Treatment" 

,  Feb. ( 1999 ) 

    "By Internet". 

  

3- Rip G.Rice & Paul K.Overbeck,  "Ozone and The Safe   

Drinking Water  

    Act", GDT Corporation, (1998), "By Internet". 

 

4- Dee Smell & Leslie S.Ettre, "Encyclopedia of 

Industrial Analysis", Vol.16, Pg. 538-551, (1972). 

 

 

 

5- Ozone, National Drinking Water Clearinghouse Fact 

Sheet, "By Internet.” 

 

6- Kirk Othmer,  "Encyclopedia of Chemical 

Technology", 3
rd

 ed. Vol.16, 

    P.683-713, Wiley, New York, (1981). 

 

7- US. Patent, No. 5 843 307, Des. (1998). 

 

 

8- Rip G.Rice & M.E.Browning, "Ozone Treatment of 
Industrial Waste 

    Water", Pollution Technology Review, No.84, (1981). 

 

9- United States Protection Agency (EPA), Office of  

     Water, "Alternative 

    Disinfectants and Oxidants Guidance Manual", April 

    (1999),  

    "By Internet". 

 

10- Rip G.Rice, Paul K.Overbeck  & Ken Larson,  

"Ozone Treatment of 

    Small Water System", GDT Corporation, Oct. (1998), 

"By Internet".  

11- Colson J.M. & Richardson J.E., "Chemical 

Engineering", Vol.6, 2
nd

. Ed., Pergamon Press. 

(1968). 

 

12- Treybal R.E,  "Mass – Transfer Operation", Mc 

Graw- Hill, 3rd
 
ed., 

       (1980). 

 العوامل المؤثرة على أمتصاص االوزون في الماء
عجذ انشصاق انقشِ غٕني ٔ يصطفى حسٍ فهيح, عجبس حًيذ سهيًٌٕ

*

انعشاق- ثغذاد- جبيعخ ثغذاد- كهيخ انُٓذسخ-قسى ُْذسخ انجيئخ 
*
 

:الخالصه  
ٔصاسح انصُبعـّ /        نـقـذ اْـتى ْزا انـجحث ثـذساسخ استخذاو االٔصٌٔ في يجبل يعبنجخ ييبِ انششة نصبنح ششكخ اثٍ سيُب انعبيّ

انٓذف انشئيسي يٍ ْزا انجحث ْٕ ايجبد افضم انطشق الَتقبل االٔصٌٔ نهًبء ثبستخذاو َٕعيٍ يٍ اثشاج  .ٔانًعـبدٌ انـعشاقيّ

ٔانـذانـّ , صيـٍ انتًبس, تـى دساسـخ عـذح يتغيشاد ْـي استـفبع عـًٕد انـًبء في انـجشج. االيتصبص، انجشج انفقبعي ٔثشج رٔ حشِٕ

(. pH)انحـبيـضـيّ نـهـًـبء انًـسـتـخـذو 

(Box-Wilson Central Composite Rotatable Design)   تـى تـحذيـذ انتـجـبسة حـسـت طشيـقخ 

: نـهًـتغـيشاد انًجـيـُّ أعالِ ٔقذ ٔجـذ ثأٌ افضم ايتصبص نالٔصٌٔ يكٌٕ عُذ انقيى انتبنيّ

 ( سى90)طـٕل عًـٕد انًـبء في انجـشج -1
 (  دقيق18ّ- 17)صيـٍ انتًـبس -2
  (7.5 - 7 )انـذانّ انحـبيضيـّ -3