water treatment

1. OZONE TECHNOLOGY FOR
WASTEWATER TREATMENT
: APPLICATION & LIMITATION
CHANGHYEON BAK
2017.06.08
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2. CONTENTS
 Introduction
 Background
 What is Ozone?
 Ozone’s strength
 Application to wastewater treatment
 Actual cases
 AOP (Advanced Oxidation Process)
 Combination application
 Conclusion
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3. INTRODUCTION
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4. Pathogen & harmful chemicals in wastewater
 Pathogens and harmful chemicals in wastewater can
cause problems in ecosystem.
 So, disinfection and destruction of harmful chemicals is
needed.
 Disinfection technologies
1) UV 2) Chlorine 3) Ozone
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BACKGROUND
Viruses Bacteria Protozoa Helminths Phenol Cyanide

5. Comparison
Criteria UV radiation Ozone Chlorine
Harmful byproducts NO NO YES
Environmental impact LOW LOW HIGH
Bacteria removal SOME YES YES
Virus removal NO YES SOME
Lead removal NO YES NO
Manganese removal NO YES SOME
Iron removal NO YES YES
Odor removal NO YES YES
Color removal NO YES SOME
Operational cost MED LOW MED
Capital cost MED HIGH MED
Maintenance HIGH MED MED
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BACKGROUND
(Marianne, 1997)

6. What is ozone
 O3
 Unstable structure -> High reactivity
 Pale blue gas
 Distinctively pungent smell
INTRODUCTION
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7.  Much higher solubility into water than O2
 Strong oxidizing agent
 Easy to produce with air or oxygen gas and electricity
Ozone’s strength
INTRODUCTION
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● Oxygen
Reactions :
1) O2 + e → 2O + e
2)O2 + O + M → O3
water
O2
O3
1)
2)
O3 109mg/L ≫ O2 18mg/L at 25℃
(Ozone solutions, 2014)

8. pH dependence of dissolved ozone
 Dissolved O3 has pH dependence.
 In basic environment, ozone decomposes rapidly.
 And OH-radicals are produced.
 OH-radical is the strongest oxidant.
 The higher pH, the more OH-radicals.
INTRODUCTION
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(Lenntech, 2010)

9.  Disinfection
INTRODUCTION
9
Application to wastewater treatment

10.  Destruction of organic compound
 Deodorization
 Decolorization
 Removal of taste
Ozone can control water quality.
INTRODUCTION
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H2S + O3 → SO2 + H2O
Cyanides : CN− + O3 → CNO − + O2
CNO- + OH- + H2O → CO32- + NH3
2CNO- + 3O3 + H2O → 2HCO3- + N2 + 3O2
Urea : (NH2)2CO + O3 → N2 + CO2 + 2 H2O
Before After
Application to wastewater treatment

11.  Reactions with metal ions
 Iron
 Manganese
 Lead
Ozone makes precipitation with metal ions.
And those can be filtered.
INTRODUCTION
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2 Fe2+ + O3 + 5 H2O → 2 Fe(OH)3(s) + O2 + 4 H+
2 Mn2+ + 2 O3 + 4 H2O → 2 MnO(OH)2(s) + 2 O2 + 4 H+
PbS + 4 O3 ⟶ PbSO4(s) + 4 O2
Application to wastewater treatment

12. ACTUAL CASES
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13.  Ozone treatment system is placed at the end of
wastewater treatment system.
ACTUAL CASES
Ozone treatment system
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Wastewater treatment system

14. Disinfection performance
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Coliform : E.coli-like
(Hoveid H. et al, 2008)
ACTUAL CASES
 Bacteria totally removed in 10 min. of contact time and
with 1ppm of ozone concentration

15. Decolorization performance
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(Abidin. et al, 2016)
ACTUAL CASES
 Red dye RR120 decomposed all in 10 min. with an
ozone flow rate of 10.2 mg/min.

16. COD removal performance
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(Preethi V. et al, 2009)
ACTUAL CASES
 COD of tannery effluent decreases by ozonation.
 COD removal efficiency is related to concentration of
ozone and pH.

17. AOP (advanced oxidation process)
 AOP is a set of chemical treatment procedure to remove
organic materials in wastewater by oxidation through
reactions with the strongest oxidant ·OH.
 Better than ozonation alone
 Combinations
1) O3/H2O2 : peroxonation
2) O3/UV : ozone photolysis
3) H2O2/UV
4) H2O2/Fe2+/UV
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(Mehmet A. et al, 2014)
.
.
.
AOP

18. Peroxonation (O3/H2O2)
 Reaction
 H2O2 accelerates the decomposition rate of O3.
 It produces a larger number of very reactive ·OH
radicals.
 Peroxonation process is more efficient than ozonation
alone.
 Essential step of disinfection
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AOP
(Mehmet A. et al, 2014)

19. Ozone photolysis (O3/UV)
 Reaction
 Effective on eliminating various volatile chlorinated
organic compounds
ex) CHCl3, CCl4, trichloroethylene(TCE) etc.
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(Mehmet A. et al, 2014)
AOP

20. AOP in Petrochemical wastewater treatment
 190 tons/months of phenolic wastes disposes by petrochemicals,
pharmaceuticals, and polymer industries.
 2-Nitrophenol(2NP) is a main pollutant from petrochemical
wastewater.
 Shokri applied ozone to degrade 2NP.
 Ozonation at high pH (pH = 9) generates OH-radical rapidly. (=AOP)
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(Shokri A., 2015)
AOP
Removal rate (%)
2NP 99.8
TOC 31
COD 72.5

21. Coking wastewater treatment
 O3 & H2O2/O3 is applied to remove cyanide from coking wastewater.
 Oxidation process is combined with coagulation-flocculation-
decantation and lime-soda ash softening pretreatment.
 Using lower concentrations of ozone, cyanide is not removed.
 Ozone consumption without softening pretreatment is twice as much
as that with softening pretreatment because wastewater contains
bicarbonate ions.
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(Pueyo N. et al, 2016)
COMBINED TREATMENT

22. Textile wastewater treatment
 Textile wastewater contains acute toxic chemicals.
 Pazdzior et al studied the effect of ozonation & biodegradation on
toxicity.
 Ozonation is combined with aerobic biodegradation.
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(Pazdzior K. et al, 2016)
COMBINED TREATMENT
Toxicity removal
O3 →Bio 76.2 – 92.2%
Bio→ O3 93.7 – 94.2%
Bio→ O3 →Bio ~ 96%
raw
O
3
Bio
O
3
→Bio
Bio
→
O
3
Bio
→
O
3
→
Bio
Toxicity after treatment

23. Oilfield wastewater treatment
3 steps to enhance biodegradability of oilfield produced water(OPW)
1. Microwave demulsification : to remove oil
2. Ozone oxidation : to enhance the biodegradability of wastewater
3. Biological aerated filter : aerobic digestion
 BOD5/COD shows the biodegradability of wastewater.
 The optimum ozone treatment condition
- Dosage : 7mg/L
- Contact time : 15min
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(Kang J. et al, 2015)
Parameter Initial value
pH 6.6
COD (mg/L) 648
BOD5 (mg/L) 45
BOD5/COD 0.07
Oil (mg/L) 68
TPH (mg/L) 76
SO4
2- (mg/L) 34
NH3-N (mg/L) 52
PS (mg/L) 589
TSS (mg/L) 3,346
Microtoxicity (EC50, %) 8.6
▶Charateristics of OPW
(Rajakovic V. et al 2006)
COMBINED TREATMENT

24. Oilfield waster treatment
 Result
 After biological treatment, effluent satisfies Chinese discharge
standard.
 Ozone decomposes complex chemicals biodegradable.
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(Kang J. et al, 2015)
Parameter Initial value After microwave treatment After ozonation
COD (mg/L) 648 382 260
BOD5 (mg/L) 45 21 86
BOD/COD 0.07 0.08 0.33
Oil (mg/L) 68 25 16
TPH (mg/L) 76 28 18
NH3-N (mg/L) 52 43 37
PS (mg/L) 58 58 12
Microtoxicity (EC50, %) 8.6 8.8 31
COMBINED TREATMENT

25. Conclusion
 Ozone can degrade various types of chemicals or microbe with its
strong oxidizing power.
 Many studies proved that ozonation is effective not only on
municipal wastewater but also on industrial wastewater.
 pH of wastewater and concentration of ozone is important on
effectiveness of ozonation.
 Basic environment(>pH 7) is favorable for ozonation.
 Lower concentration of ozone may not be effective.
 Ozonation can need pretreatments according to condition of
wastewater.
 Ozonation shows better performance when it is combined with
other water treatment technologies.
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CONCLUSION

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Thank you!