vvEPA
United States
Environmental Protection
Agency
Robert S. Kerr Environmental Research EPA-600/2-80-060
Laboratory April 1980
Ada OK 74820
Research and Development
Ozone for Industrial
Water and
Wastewater
Treatment
A Literature Survey
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
""""v.
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EPA-600/2-80-060
April 1980
OZONE FOR INDUSTRIAL WATER AND WASTEWATER TREATMENT
A Literature Survey
by
Rip G. Rice
Jacobs Engineering Group
Washington, D.C. 20005
and
Myron E. Browning
Allied Chemical Company
Syracuse, New York 13209
Grant No. R-803357
to
International Ozone Association
Cleveland, Ohio 44167
Project Officer
Fred M. Pfeffer
Source Management Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
Protection
230 South Dearborn Street
Chicago, Illinois 60604
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DISCLAIMER
This report has been reviewed by the Robert S. Kerr Environmental
Research Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
U,S. Envfronmentaf Protectfon Agency
i i
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FOREWORD
The Environmental Protection Agency was established to coordinate admin-
istration of the major Federal programs designed to protect the quality of our
environment.
An important part of the Agency's effort involves the search for infor-
mation about environmental problems, management techniques and new technologies
through which optimum use of the nation's land and water resources can be
assured and the threat pollution poses to the welfare of the American people
can be minimized.
EPA's Office of Research and Development conducts this search through a
nationwide network of research facilities.
As one of these facilities, the Robert S. Kerr.Environmental Research
Laboratory is responsible for the management of programs to: (a) investigate
the nature, transport, fate and management of pollutants in ground water;
(b) develop and demonstrate methods for treating wastewaters with soil and
other natural systems; (c) develop and demonstrate pollution control tech-
nologies for irrigation return flows; (d) develop and demonstrate pollution
control technologies for animal production wastes; (e) develop and demonstrate
technologies to prevent, control, or abate pollution from the petroleum re-
fining and petrochemical industries; and (f) develop and demonstrate technolo-
gies to manage pollution resulting from combinations of industrial wastewaters
or industrial/municipal wastewaters.
Increasing concern over the presence of toxic or nonbiodegradable com-
ponents in treated effluents has dictated that research be performed to
establish technologies for removal or conversion of those components to
innocuous or treatable information on the application of ozone technology
to control undesirable contaminents in wastewater streams.
^ a. ^
W. C. Galegar
Director
Robert S. Kerr Environmental Research Laboratory
111
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ABSTRACT
This research project and technology transfer effort was initiated in re-
sponse to growing national concern about the discharge of industrial chemicals
and by-products from industrial processing plants into the environment. The
technology of oxidation of these chemicals by means of ozone, a very powerful
oxidant, offers promise for being able to eliminate some of these chemicals
from industrial wastewaters prior to discharge. Therefore this program was
initiated to survey the published ozone literature and assess how ozone has
been used in the past to cope with specific industrial water and wastewater
problems.
This report includes a section on the fundamental principles of ozone
technology, which describes the generation of ozone on commercial scale, the
various methods of contacting ozone with aqueous solutions and methods of
analysis for ozone from the point of view of process controls.
Industries are grouped into 20 individual categories which are discussed
separately as to the known uses of ozone in treating waters and wastewaters
in each category. More than 500 published articles were reviewed. Some of
these articles were abstracted, and these abstracts have been assembled in a
companion report entitled, "OZONE FOR INDUSTRIAL WATER AND WASTEWATER TREAT-
MENT, An Annotated Bibliography." A literature survey also was conducted on
the subject of the organic oxidation products obtained upon conducting
ozonations in aqueous systems. This review is the subject of a separate
section of the report.
Finally, a section is included which describes the biological activated
carbon (BAG) concept, which is being practiced in certain European drinking
water treatment plants. The BAG subsystem involves ozonation to partially
oxidize dissolved organic materials so that they will become more easily bio-
degradable. The ozonized solution then is filtered through an inert medium
and passed through granular activated carbon (GAG) adsorbers. Because of the
presence of large amounts of dissolved oxygen (DO) and biodegradable dissolved
organic materials, aerobic biological activity grows in the inert and GAG
media. This biomass is capable of converting dissolved organic carbon to
COp and water and of nitrifying ammonia. At the same time, the adsorptive
capacity of the GAG for strongly adsorbed, non-polar organic compounds is
maintained and the useful life before reactivation is required is greatly
extended under certain conditions.
This report was submitted in fulfillment of Grant No. R-803357 by the
International Ozone Association, Inc., under the sponsorship of the U.S. En-
vironmental Protection Agency. This report covers the period July 1974
through July 1977.
IV
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CONTENTS
Foreword ill
Abstract .iv
Figures x
Tables xl-j
Acknowledgements .xvii
1. Introduction 1
2. Conclusions 2
3. Recommendations 6
4. Fundamental Principles of Ozone Technology 8
General history 8
Physical properties of ozone 10
History of ozone use in water treatment . . . .10
Applications of ozone in water treatment. . . .12
Generation of ozone 14
Contacting of ozone with aqueous solutions. . .16
Ozone analysis and process control 23
Ozone/ultraviolet radiation 25
Literature cited 31
5. Industrial Water & Wastewater Treatment With Ozone .34
Introduction and organization of survey ... .34
Aquaculture . 36
Shellfish depuration .36
Marine water quality improvement 40
Freshwater quality improvement 43
Disease prevention measures 45
Toxicity of ozonized seawater 46
Conclusions .48
Literature cited 49
Biofouling Control 53
Conclusions 56
Literature cited 57
Cyanides and Cyanates 59
Cyanides 59
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Cyanates 61
Additional reactions 61
Ozone/UV radiation 62
Conclusions 63
Literature cited 64
Electroplating 67
Ozone/UV radiation 73
Conclusions 75
Literature cited 77
Food and Kindred Products 80
Bottle washing water 80
Sauerkraut brines 80
Bakery wastewaters 83
Extraction of tea 83
Disinfection of poultry processing
wastewaters 85
Breweries 87
Wine making .90
Yeast production 90
Conclusions 91
Literature cited 92
Hospital Wastewaters. . .94
Conclusions 106
Literature cited 107
Inorganics Ill
Iron and manganese Ill
Other heavy metals 112
Ammonia 114
Nitrite 116
Conclusions 116
Literature cited 117
Iron & Steel 119
Phenols in coke plant effluents 119
Conclusions 126
Literature cited 127
Leather Tanneries 129
Conclusions 131
Literature cited 131
Mining 132
Acid coal mine wastewaters . . . .. . . .13-2
Gold mining 135
Conclusions 138
Literature cited 139
VI
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Organic Chemicals ...... 141
Actual organic wastewaters 141
Laboratory studies 146
Polyaromatic hydrocarbons 146
Pesticides 148
Miscellaneous organic chemicals . . 151
Organo-nitrogen chemicals 151
Ozone/UV studies 152
Polychlorinated biphenyls. 154
Conclusions . 157
Literature cited 159
Paints and Varnishes 166
Paint & varnish plant wastewaters. ... 166
Phenolic aircraft paint stripping
wastewaters 170
Conclusions 171
Literature cited 171
Petroleum Refineries 173
Wastewater characteristics 173
Ozonation studies on refinery effluents. 173
The Trafalgar Plant . . 176
Ozonation of used cutting oils 178
Effects on drinking water supplies ... 178
Conclusions 179
Literature cited 180
Pharmaceuticals 183
Conclusions 183
Literature cited 183
Phenols 184
Reactions of ozone with phenol 185
Reactions of ozone with other phenols. . 189
Reactions of ozone with chlorinated
phenols 191
Catalyzed ozonation 193
Conclusions 193
Literature cited 195
Photoprocessing 198
Wastewater composition 198
Treatment of bleach solutions 198
Treatment of organic components 208
Treatment with ozone/UV light 209
Conclusions 219
Literature cited 221
Plastics and Resins 223
Phenol-formaldehyde manufacturing. ... 223
Synthetic polymers 223
vii
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Synthetic leather 223
Synthetic rubber 225
Conclusions 225
Literature cited 226
Pulp and Paper 227
Pulp bleaching ... 227
Wastewater treatment 232
Ozonation for deodorizing kraft mill
gaseous emissions 249
Ozonation of spent sulfite liquor to
generate methane and to grow yeast. 249
Conclusions 251
Literature cited 253
Soaps and Detergents 259
Ozonation of ABS (alkylbenzene sulfonate)259
Other surface active agents 262
Recycle of car wash waters 262
Conclusions 263
Literature cited 263
Textiles 265
Conclusions 281
Literature cited 283
6. Oxidation Products of Organic Materials 286
Introduction 286
Background 287
Fundamental principles 287
Reactions of organic compounds with ozone . . 290
Reactions with phenol 290
Reactions with other phenols 293
Reactions with chlorinated phenols ... 294
Reactions with other aromatics 296
Reactions with aliphatic compounds ... 304
Reactions with miscellaneous compounds . 312
Reactions with pesticides 313
Reactions with humic materials 316
Summary of ozonation reactions 317
Conclusions , 320
Literature cited 327
7. Biological Activated Carbon 332
Introduction 332
Background 332
Fundamental principles 333
Advantages of biological activated carbon in
drinking water treatment 335
European background 336
European drinking water treatment experiences
with BAC 337
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Switzerland 337
Holland 337
Germany 341
Case Histories 348
Millheim, Federal Republic of Germany . . 348
Rouen-la-Chapelle, France 353
BAC in sewage treatment 354
Potentials of BAC for treating industrial
wastewaters 360
Design parameters 3.66
Costs 367
Summary 369
Literature cited 370
IX
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FIGURES
Number Page
1 Schematic diagram of tube type, water cooled
ozone generator 9
2 Schematic diagram of corona discharge ozone generator. .15
3 The oxygen activated sludge process . .17
4 Optimum ozone dosages 19
5 Ozone/UV process flow diagram; mixed chlorinated
aromatics 27
6 Ozone/UV process flow diagram; cyanides and
refractory organics 28
7 Installed cost of UV/ozone reactor stage 29
8 Cost of producing ozone (including oxygen and
amortization) . .30
9 Ozonation of iron complexed cyanide waste . .74
10 UV/ozone oxidation of hospital composite wastewater. . .97
11 Modified Torricelli ozone contactor for U.S. Army
MUST hospital wastewater treatment 101
12 Pilot scale ozone/UV contactor used in U.S. Army
MUST wastewater treatment program 102
13 Ozone generator (26 Ibs/day from air) and control
panel used in U.S. Army MUST program pilot
wastewater testing unit 105
14 Reactions of ozone with phenols 194
15 Flow schematic of a photographic bleach regeneration
system using ozone 202
16 Flow diagram of bleach regeneration system and
concentrated waste oxidation system at Berkey
Photo, Fitchburg, Massachusetts 206
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17 Schematic diagram of lab scale apparatus for mass
transfer and reaction kinetics tests....ozone/UV . 211
18 Schematic diagram of prototype cyanide disposal
system based on ozone/UV treatment 212
19 Effect of UV light and ozone concentration on ferri-
cyanide at 77°F. Starting bleach concn: 53 mg/1 . 214
20 Full-size cyanide disposal system based on ozone/UV. . 215
21 Ozonation of model lignin compounds. ... 229
22 Reduction in BOD values by ozonation . 235
23 Dynamic ozone treatment system 247
24 Ozonation of thiosulfate solution 272
25 Dye wastewater treatment plant at the Kanebo Co., Japan275
26 Reactions of ozone with phenol 297
27 Biological activated carbon sub-system . . .' . . . ... 334
28 Efficiency of removal of COD from rapid filter and act-
ivated carbon at Lengg plant, ZUrich, Switzerland. 339
29 Efficiency of COD removal of BAC over 3 years at
Moos Water Works, Zilrich, Switzerland. 340
30 Behavior of microbial populations on activated carbon
over 3 years at Wiesbaden, Fedl Republic of 6ermany343
31 Microbiological loading of activated carbon -
dependence on adsorptive concentration 344
32 Bremen, Federal Republic of Germany, pilot plant ... 345
33 Westerly plant, Cleveland, Ohio — Original Design . . 357
34 Performance of preozonized activated carbon at
Westerly plant, Cleveland, Ohio 358
35 BAC performance at Cleveland Regional Sewer District . 359
36 Ozonation of Israel lime treated sewage effluents
without BAC 362
37 Biologically extended activated carbon treatment of
ozonated effluent * 363
XI
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TABLES
Number
1 Solubility of Ozone and Oxygen in Water 10
2 Oxidation-Reduction Potentials of Water Treatment
Agents 11
3 Applications of Ozone in Water Treatment. . . 13
4 Types of Ozone Contactors 22
5 Industrial Categories Reporting the Use of Ozone. ... 35
6 Shellfish Depuration Stations Using Ozone 37
7 Ozone Requirements for Depuration 38
8 Depuration Times for Clams and Mussels in Ozonized and
Chlorinated Seawater 39
9 Comparison of Various Biocide System Alternatives ... 55
10 Comparison of Investment Costs and Operating Expenses
for a 100,000 Gallon per Day Plating Waste Disposal
Plant Using Ozone or Chlorine 70
11 Sealectro Corporation, Cost Data Summary 73
12 Typical Cyanide Oxidations With Ozone and Ozone/UV. . . 75
13 Capital Cost Estimate — Ozone/UV Treatment of an
Industrial Wastewater 76
14 Analytical Data for Ozonized and Non-Ozonized
Sauerkraut Brine 82
15 Comparison of Treatment Methods on Cake Shop
Wastewaters 84
16 Estimated Capital and Operating Costs for Ozone
Treatment of Poultry Processing Wastewaters .... 87
17 European Breweries Using Ozone 90
xii
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18 Comparison of Ozone/UV Oxidation of Ethanol by
Various Types of Reactors 100
19 Organic Chemical Composition of Synthetic MUST
Hospital Composite Wastewater 99
20 Analyses of Phenol-Containing Wastewaters 120
21 Costs for Treatment of Foundry Wastewaters 125
22 Comparison of Sulfide Oxidation Systems 129
23 Characteristics of Tannery Hair Burning Wastewaters . .130
24 Analyses of Mine Waters in Wyoming Valley,
Pennsylvania 132
25 Ozone/Limestone Treatment Costs for Acid Mine
Drainages 133
26 Ozone Treatment of Konamai Mine Merrill Press
Liquid (Diluted) 136
27 This table number was not used
28 Ozone Treatment of Serverodonetsk Caprolactam works,
Biologically Treated Caprolactam Wastewaters. . . .142
29 Ozone Treatment of Shchekino Chemical works,
Biologically Treated Caprolactam Wastewaters. ... 143
30 Summary of Batch Ozonation Results for Organic
Chemicals Intermediate Wastewaters . 145
31 Summary of COD Removal From a Chelating Compound
Plant Wastewater. . . 146
32 Ozonation Results for Treatment of a Filtered,
Biologically Pretreated Wastewater From a
Resin and Dye Plant 147
33 UV/Ozonation of Pink Water 155
34 Design & Operating Parameters of Proposed 5,000 gpd
UV/Ozone Reactor for Pink Water (to obtain <1 mg/1
TNT + RDX) 156
35 Estimated Installed Costs for 5,000 gpd UV/Ozone
Reactor for Pink Water 156
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36 Treatment of Wastewater From a Varnish Plant by
Gassing With Ozone (20 mg/1) for 30 Minutes at
19°C. • 167
37 Wastewater Discharge of a Paint & Varnish Plant
Treated 25 Minutes With Ozonized Air 168
j
38 Wastewater From the Canal Near the Outlet of a Paint
& Varnish Manufacturing Plant, Pretreated by
Precipitation and Treated With Ozone (30 Minutes)
and Chlorine 169
39 Typical Waste Loadings From Refinery Processes 174
40 Analysis of Waste Discharged From EA-4 Photographic
Process, Shaw Air Force Base 199
41 Results of Bench Top Ozonation of Used Photo-
processing Bleach at Berkey Photo 200
42 Costs for the "Combined Average" Hypothetical
Processing Machine 203
43 Costs for Bleach Regeneration by the "Combined
Average" Processor 204
44 Costs for Ozone Destruction of Complex Cyanides .... 204
45 Estimated Savings on Treatment of Ferrocyanide Bleach.
"Combined Average" Processor 205
46 Ozone Material Balances in Prototype Unit Runs 213
47 Cost Estimate for 5 gpm Cyanide Treatment by UV/Ozone . 217
48 Cost Estimate for 1,000 Gal/Week Cyanide Treatment
With Ozone/UV 218
49 Cyanide Bleach Destruction With Ozone/UV;
Ferricyanide Bleach Solution 218
50 Treatability of Photoprocessing Chemicals by
Ozonation 220
51 Wastewater From an Artificial Leather Plant, Mixed With
Sewer Water. Treatment With Ozonized Air:
30 Minutes. (20 mg Ozone/Air) 224
52 Daily Operating Costs & Capital Investment 235
53 Ozone Treatment Costs 236
xiv
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54 Estimated Operating Costs for Treating 15 mgd of Pulp
Mill Secondary Effluent With Ozone. . 242
55 Estimated Ozone Requirements for Synthesized
Unbleached Kraft Black Effluent Decolorization. . . 243
56 Estimated Ozone Requirements for Caustic Stage Bleach
Effluent Extract Decolorization 244
57 Estimated Ozone Requirements for Chiorination Stage
Bleach Effluent Decolorization 245
58 Estimated Ozone Requirements for Total Mill Effluent
Decolorization 246
59 Treatment of Textile Wastewaters With Ozone 265
60 Costs for Treatment of Dyeing Wastewaters by
Ozonation 267
61 Selected Influent Characteristics: Dalton, Georgia
Plant 267
62 Selected Effluent Characteristics: Dalton, Georgia
Plant 268
63 Ozone Transfer Efficiencies Into Dalton, Georgia
Wastewater Treatment Plant Effluent 268
64 Treatment of Unfiltered Dalton, Georgia Effluent
With 45 mg/1 Ozone 270
65 Projected Economics of Ozone and Carbon at Dalton,
Georgia 271
66 Ozonation of Reducing Waste Liquid From Dye
Manufacturing 273
67 Dyeing Wastewater Treatment by Ozone/GAC at Kanebo
Co., Japan 276
68 Products of Ozonation of Azobenzenes 277
69 Cost of Ozone Treatment of Jyoyo Kyogo Dye Plant
Wastewaters 279
70 Oxidation-Reduction Potentials of Water Treatment
Agents 288
71 Comparison of Oxidation of Organic Compounds With
Ozone, Chlorine Dioxide and Chlorine 321
xv
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72 Organochloro Compounds After Breakpoint Chlorination
Treatment (-Donne Plant, MUlheim, Federal Republic
of Germany) 343
73 Process Parameters at the Dohne Waterworks (Mulheim,
Federal Republic of Germany), Before and After
Change of Treatment 350
74 Mean DOC and UV Extinction Values for the Different
Treatment Steps at the Dohne Plant, MUlheim,
Federal Republic of Germany 351
75 Geometric Mean Values of Bacterial Counts at the Dohne
Plant, MUlheim, Federal Republic og Germany Using
Ozone 352
76 Performance of Biological Activated Carbon Filters.
Mean Values for 6-Month Operation After a 3-Month
Starting Period (Dohne Pilot Plant, Mulheim,
Federal Republic of Germany) 352
77 Rouen-la-Chapelle (France) Plant Operational Data (1976)355
78 Ozonation of Lime-Treated Effluents in Israel.
Reaction Rates, COD Removals and pH Changes .... 361
79 Results of Ozone/GAC Treatment of Dyeing Wastewaters. . 364
80 Estimated Costs for GAC Treatment 368
81 Projected Costs for BAC Treatment 369
xvi
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ACKNOWLEDGEMENTS
The authors are grateful for the assistance of many people whose efforts
were essential to the accomplishment of this work. First, we thank the State
of Connecticut, Department of Environmental Protection for their financial
contribution in support of this program.
For the gathering and abstracting of the many articles cited, we are
appreciative of the efforts of Dr. Archibald G. Hill, William J. Geist, Jane
Tofel, James King, Dr. Stanley Padegimas, John Graumann, Teresa Czaposs and
Barbara Cowley-Durst.
We also thank Dr. Walter J. Blogoslawski of the National Marine Fisheries
Service for critically reviewing those sections of this report dealing with
aquaculture and biofouling, Dr. L. Joseph Bollyky of Bollyky Associates for
reviewing the sections dealing with cyanides and cyanates as well as electro-
plating, and Captain Barry W. Peterman of the Army Medical Bioengineering
Research & Development Laboratories for reviewing the section on hospital
wastewaters.
xvn
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SECTION 1
INTRODUCTION
Although ozone has been used to treat drinking water at the city of Nice
since 1906, and today there are more than 1,000 water treatment plants in
Europe alone employing ozone for many different water treatment purposes
(Miller et al., 1978), industrial wastewater treatment with ozone is still,
relatively speaking, in its infancy.
Current water pollution problems with industrial wastewater discharges
have prompted renewed interest in the use of powerful oxidants, including
ozone, for treating these wastewaters for recycle and reuse, or prior to
discharge to the environment.
In addition, where halogenated oxidants such as chlorine and hypochlo-
rite are currently used to treat municipal and industrial wastewaters,
toxicities of these halogenated wastewaters to indigenous aquatic life also
have prompted studies on alternative treatment techniques, including ozonation.
In recognition of the potentials for ozone to alleviate certain industrial
wastewater pollution problems, the U.S. Environmental Protection Agency,
Office of Research & Development, funded a grant (R-803357-01-3) to the
International Ozone Institute to conduct a state-of-the-art review of the
published literature dealing with the use of ozone. This report will summarize
the results of that survey.
This survey is not an exhaustive review of the published literature, in
that only the more readily available articles were obtained. In addition,
much of the Russian, Japanese and German literature could not be translated
due to limitations of time and funding. Nevertheless, some 430 published
articles were reviewed and abstracted. Abstracts of the more pertinent
articles have been compiled in a companion to this report, entitled, "OZONE
FOR INDUSTRIAL WATER AND WASTEWATER TREATMENT, An Annotated Bibliography",
published in the National Technical Information System (NTIS).
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SECTION 2
CONCLUSIONS
1) Systems for generating and applying ozone to water and wastewater
consist of four components:
a) electrical power generation
b) feed gas preparation (air or oxygen)
c) ozone generation
d) contacting of liquid with ozonized gas
2) When oxygen is used as a feed gas to prepare ozone, provisions usually
are made to purify, dry and recycle contactor off-gases to the ozone
generator.
3) Ozonation has been used on full commercial scale for treating drinking
water since 1906 and today there are more than 1,000 drinking water
treatment plants throughout the world using ozone for many purposes.
These applications are based upon the strong oxidizing properties of
ozone in water and upon its ability to disinfect bacteria and inactivate
viruses and are as follows:
soluble iron and manganese
organically complexed manganese
color removal
taste & odor-causing components
algae removal
organics (phenols, detergents, pesticides, etc.)
microflocculation of dissolved organics
inorganics (cyanides, sulfides, nitrites, etc.)
suspended solids removal
pretreatment for biological processes
bacterial disinfection
viral inactivation
4) For treating industrial water and wastewaters, ozone is used for many of
the same oxidative purposes as in treating drinking water:
disinfection
cyanide removal
dissolved organics oxidation
color removal
but in addition:
recovery and reuse of photographic bleach solutions
bleaching of paper pulps
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COMMERCIAL WATER & WASTEWATER APPLICATIONS
5) In Aquaculture, ozone is used for (a) disinfecting seawater in European
shellfish depuration stations and (b) disinfecting and lowering BOD
levels in marine aquaria in the USA (Sea World). Ozonation of seawaters^
destroys red tide organisms.
6) In Food & Kindred Products, ozone is being used for (a) treating waters
for washing baby food bottles and (b) disinfecting water used in the
brewing industry in Europe, Canada and the USA.
7) In Metal Finishing, ozone has been used continuously since 1957 at the
Boeing Co., Wichita, Kansas for lowering cyanide concentrations in their
wastewaters from 0.17 mg/1 to below 0.06 mg/1. Since 1973, Sealectro
Corporation (Mamaroneck, N.Y.) has been using ozonation of copper and
silver plating wastes to lower cyanide concentrations from 60 g/1 to
below 0.1 mg/1. Ozone coupled with ultraviolet (UV) radiation has been
used since late 1976 at a U.S. Air Force base to lower cyanide concentra-
tions in plating wastes from 4,000 mg/1 to less than 0.3 mg/1.
8) In Organic Chemicals, two Russian plants manufacturing caprolactam treat
their wastewaters- biologically, then by ozonation, then store the ozonized
wastewaters in biological ponds prior to reuse as cooling waters. Costs
for ozonation are about 15% of the total costs of biological treatment
at these Russian plants.
9) The only Petroleum Refinery known to be using ozonation is located in
Sarnia, Ontario, Canada. Ozone is used as a polishing agent to reduce
phenolic levels to below 3 parts per billion (ppb). This low discharge
standard is necessary, because the plant outlet is close to the drinking
water intake of a nearby city. The ozone demand of this wastewater is
3.5 to 6 pounds (Ibs) of ozone per pound of phenol destroyed.
10) In Photoprocessing, ozone is used commercially for the regeneration and
reuse of spent ferricyanide bleach. Spent ferrocyanide complexes are
so stable to ozonation that they merely are oxidized back to the ferri-
cyanide form, in which they can be reused. This application has been
commercial since the early 1970s and is claimed to produce a savings of
2 to 3<£/roll of film processed. Investment costs for a 200 grams per
hour (g/hr) ozone bleach recovery system can be recovered in about five
years.
11) In Pulp & Paper, ozonation is being demonstrated commercially in Norway
for bleaching of pulps. If successful, this bleaching process would
eliminate or lower the toxicity of current discharges from pulp bleaching
operations to indigenous aquatic life. Similar demonstrations of ozone
for pulp bleaching are being conducted in Canada and the USA.
12) Also in Pulp & Paper, the potentials of producing yeast from spent
sulfite liquors by ozonation, followed by bacterial fermentation are
showing promise.
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13) In the Soaps & Detergents category, a car wash in Vienna, Austria has
been recycling 19,915 gallons per day (gpd) of washwater since 1970 by
aeration, skimming, sedimentation, flocculation, filtration, ozonation
and activated carbon filtration.
14) In Textiles, at least nine Japanese dye manufacturing or textile process-
ing plants are known to be using ozone on commercial scale for decoloriz-
ing wastewaters. Ozone decolorizes disperse dyes well, without causing
increases in turbidity, but has little effect upon chemical oxygen
demand (COD) content. Sulfur- or chromium-containing dye wastewaters
are not decolorized as effectively with ozone.
15) One of the Japanese plants treats 0.87 mgd of dye wastewaters by 2-stage
ozonation (maximum ozone dosage of 50 mg/1) then filtration through
granular activated carbon (GAC). The process is free from sludges and
cost 34(^/1,000 gallons (gal) in 1974. Operating costs for decolorizing
cationic dyes in wastewaters at a second Japanese textiles processing
plant treating 1,500 cubic meters per day (cu m/day) [0.36 million
gallons per day (mgd)] were 10.19 yen in 1972. Capital costs in 1972
for this treatment plant were 28 million (MM) yen.
GENERAL CONCLUSIONS
16) Ozonation of seawater produces a stable oxidant residual which is toxic
to juvenile but not to adult shellfish. This toxicity is caused by
oxidation products of bromide ion, and is also formed by chlorination of
seawater.
17) Ozonation is being compared with chlorination and other candidate
biocides for treatment of power plant cooling waters in a demonstration
program at Public Service Gas & Electric Co. of New Jersey.
OXIDATION PRODUCTS OF ORGANIC MATERIALS
18) Complete oxidation of dissolved organic materials to C0? and water in
aqueous solutions is rare by means of any oxidant. In general, if an
organic material is resistant to oxidation by ozone (the most powerful
oxidant used in water and wastewater treatment) it will also be resistant
to^oxidation by any other (weaker) oxidant. Conversely, if partially
oxidized intermediates are produced upon ozonation, they also will be
produced when using other oxidants.
19) Oxidation products formed by ozonation do not contain halogen atoms,
unless bromide or iodide ions are present.
20) Heptachlorepoxide may form upon ozonation of aqueous solutions of
heptachlor. The epoxide is stable to further ozonation. However,
epoxides also have been isolated as intermediates from reactions of
unsaturated organic compounds with chlorine or chlorine dioxide. Thus
it is important to know the structure of organic materials being oxidized
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with any oxidant, to understand the mechanisms of oxidation of each type
of compound, as well as to design sufficient oxidant into the treatment
process.
21) Oxidation of some pesticides (aldrin, 3,4-benzopyrene) in clean water
proceeds rapidly, but in waters containing suspended solids, the dissolved
organics can be adsorbed and "protected" against rapid oxidation.
22) Changing oxidants from chlorine to ozone will eliminate the formation of
halogenated organics, but will have little effect upon the formation of
non-halogenated organics which are produced by either oxidant.
23) Ozonation of solutions of biorefractory organic materials generally
increases the biodegradability of these materials, especially during the
early stages of ozonation. Prolonged treatment with ozone then will
lower the BOD as well as the COD.
24) Oxidation rates of solutions of organic materials are rapid during the
early stages of ozonation, but then the rates slow considerably. This
is explained by (a) the concentrations of readily oxidizable organic
materials becoming lower and (b) the organic oxidation products of
ozonation being more refractory to oxidation.
25) Many compounds which are oxidized slowly with ozone will react 100 to
1,000 times faster in the presence of UV radiation or ultrasonic energy.
26) Ozonation of p-aminoazobenzene produces nitrosoazobenzene and nitroazo-
benzene as intermediate products and increases the color of the solution.
Continued ozonation converts these intermediates into oxalic acid,
glyoxalic acid and nitrate ion.
BIOLOGICAL ACTIVATED CARBON
27) The processing sequence of ozonation, followed by filtration through an
inert medium (sand, anthracite) then through GAC converts ammonia to
nitrate and lowers the dissolved organic contents of drinking waters in
several European plants. It also meets current discharge standards of a
combined industrial/municipal wastewater in Cleveland, Ohio. However,
the process is not known to have been demonstrated on industrial waste-
waters. It offers the potential for substituting for breakpoint chlorina-
tion (for ammonia removal), thereby eschewing the formation of halogenated
organic materials, and for prolonging the useful life of GAC columns.
Some European drinking water plants have not had to regenerate their GAC
beds or columns for over 2.5 years.
-------
SECTION 3
RECOMMENDATIONS
1) When considering the use of ozonation as part of a water or wastewater
treatment scheme, the desired purpose(s) of ozonation should be related
to the rate(s) of reaction of the impurities to be oxidized. Oxidation
rates of readily oxidized materials will be controlled by the rate of
mass transfer of ozone into solution. Oxidation rates of refractory
materials will be reaction rate controlled. For optimal use of ozone,
different types of ozone contacting devices should be evaluated.
2) In designing an ozonation pilot test unit, always provide for measurement
of ozone in the contactor influent and effluent gases and determine the
ozone utilized, not just the ozone dosage. More than 95% ozone utiliza-
tion generally can be attained with full scale ozone contactors, but
this efficiency rarely can be obtained in the laboratory or with small
pilot scale systems.
3) Always provide for treatment of ozone-containing contactor off-gases,
either by recycling or by destruction. Ozone contactors always should
be covered.
4) Ozonation studies should be conducted with actual wastewaters whenever
possible. Suspended solids in wastewaters may adsorb oxidizable materials
and render them more difficult to oxidize than would be indicated by
studies in pure solutions.
5) If organic oxidation products are of concern, then it will be important
to identify the organic compounds originally present and to understand
their mechanisms of oxidation. In addition, it is important to design
sufficient oxidant into the process to accomplish the amount of oxidation
desired. Some compounds are oxidized first to intermediates which are
more toxic than the starting materials, before being further oxidized to
innocuous compounds.
6) In comparing the cost benefits of using an ozonation technique versus
another process for accomplishing a single pollution control objective,
one should also be aware of the additional functions that ozone performs,
which many times are advantageous technically and economically. For
example, in decolorizing effluents from biologically treated wastewaters
with ozone, disinfection also is obtained, as well as an increase in DO
content.
-------
7) Demonstrations of the BAG technique (ozonation, filtration through inert
media, filtration through GAC should be conducted to determine the
potentials of this technique to extend the useful life of GAC and to
remove ammonia in industrial wastewater treatment.
-------
SECTION 4
FUNDAMENTAL PRINCIPLES OF OZONE TECHNOLOGY
GENERAL HISTORY (Rideal, 1920)
In 1785 Van Marum, a Dutch philosopher, noticed that the air in the
neighborhood of his electrostatic machine acquired a characteristic odor
when subjected to the passage of a series of electric sparks. In 1801
Cruickshank observed the same odor in the gas formed at the anode during the
electrolysis of water.
In 1840 Schonbein reported the odor as being due to a new substance to
which he gave the name ozone, derived from the Greek word "ozein", meaning
to smell. Schonbein also was the first to suggest that ozone may occur
naturally in the atmosphere.
The present construction of electric discharge ozone generators developed
from the apparatus originally designed by Werner von Siemens in 1857 in
Germany. Brodie (England) and Berthellot (France) also designed early ozone
generators.
Siemens' first ozonizer essentially consisted of two coaxial glass
tubes, the outer coated externally and the inner coated internally with tin
foil, air feed gas being passed through the annular space. Brodie substituted
water as the electrode material in place of tin foil, and Berthollet used
sulfuric acid.
The Siemens type of ozone generator has been developed commercially
into a form suitable for industrial production of ozone, and today most of
the ozone generating systems installed in water and wastewater treatment
plants are of this type. Glass tubes are coated internally with a metal
dielectric and the individual tubes are cooled by means of water (see
Figure 1).
Modifications to the original Siemens generator have been made, primarily
dealing with the method of cooling, and today many different types of genera-
tors are available. All operate on the same general principle, corona
discharge, which requires high voltages and/or high frequencies, thus creating
considerable heat. In turn, this requires that the generators be cooled in
order to maximize ozone production yields and minimize power consumed.
Cooling is usually accomplished by means of water (Siemens and Otto genera-
tors), air (Lowther plate type generator) or water and oil (cooling of both
electrodes, one with water, the other with oil).
-------
WATER COOLED STAINLESS
STEEL GROUND ELECTRODE
HIGH VOLTAGE
ELECTRODE
DISCHARGE
GAP A
GLASS TUBE
DIELECTRIC
Figure 1. Schematic diagram of tube type, water cooled ozone generator.
-------
PHYSICAL PROPERTIES OF OZONE
Ozone itself is an unstable gas which boils at minus 112°C (-112°C) at
atmospheric pressure, is partially soluble in water (more than oxygen -- see
Table 1) and has a characteristic penetrating odor, readily detectable at
concentrations as low as 0.01 to 0.05 ppm. It is a powerful oxidant, having
an oxidation potential of 2.07 volts in alkaline solution, and therefore
should be considered a dangerous material, capable of oxidizing many types
of organic materials, including human body tissues. In Table 2 are listed
the oxidation potentials of many of the oxidants currently used or considered
for use in water and wastewater treatment.
TABLE 1. SOLUBILITY OF OZONE AND OXYGEN IN WATER
Temperature
°C
0°
2
20
28
Uzone
Solubility
mq/1
20
10
8.92
1.5
uxygen (from
Solubility
mq/1
6.9
6.6
4.3
3.7
air)
At the relatively low concentrations of ozone produced by industrial
generation equipment (1 to 3% in air; 2 to 6% in oxygen) no explosive
hazard exists, but mixtures of ozone concentrated to 15 to 20% or higher in
air can be explosive. Available ozone generators cannot generate sufficiently
high concentrations of ozone in air to be explosive. On the other hand,
ozone is a toxic gas, and unnecessary exposures can be detrimental to humans.
In aqueous solution, ozone is relatively unstable, having a half-life
of about 20 to 30 minutes in distilled water at 20°C. If oxidant-demanding
materials are present in solution, the half-life of ozone in such solutions
will be even shorter.
On the other hand, ozone in air (especially under dry conditions) is
much more stable than in water. The half-life of ozone in the ambient
atmosphere has been measured by the U.S. Environmental Protection Agency to
be on the order of 12 hours. Thus, ozone can be produced in dry air or
oxygen, then piped considerable distances to the contactors with no fear of
losing the product by decomposition back to oxygen.
HISTORY OF OZONE USE IN WATER TREATMENT (Rideal, 1920)
The earliest experiments on the use of ozone as a germicide were
conducted by de Meritens in 1886 in France, who showed that even dilute
ozonized air will effect the sterilization of polluted water. A few years
later (1891), the bactericidal properties of ozone were reported by Frdlich
from pilot tests conducted at Martinikenfeld in a drinking water treatment
10
-------
TABLE 2. OXIDATION-REDUCTION POTENTIALS OF WATER TREATMENT AGENTS*
REACTIONS
F2 + 2e = 2 F"
03 + 2H+ + 2e = 02 + H20
H202 + 2H+ + 2e = 2H20 (acid)
MnO." + 4H+ + 3e = Mn09 + 2H90
+ -
HC102 + 3H + 4e = Cl + 2H20
MnO/ + 8H+ + 5e = Mn2+ + 4H00
4 , L
4- _
HOC1 + H + 2e = Cl + H20
C12 + 2e = 2C1"
HOBr + H+ + 2e = Br" + H20
0, + H90 + 2e = 09 + 20H"
3 L. L.
C102 (gas) + e = C102~
Br2 + 2e = 2Br"
HOI + H+ + 2e = I" + H20
C102 (aq) + e = C102"
OC1" + H20 + 2e = Cl" + 20H"
H909 + H,0+ + 2e = 4H90 (basic)
L d 3 2
C109" + 2H00 + 4e = Cl" + 40H"
2 2
OBr" + H20 + 2e = Br" + 40H"
I2 + 2e = 2 I"
I3 + 2e = 3 I"
01" + H20 + 2e = I" + 20H"
02 + 2H20 + 4e = 40H"
POTENTIAL IN VOLTS (Ee) 25 °C
2.87
2.07
1.76
1.68
1.57
1.49
1.49
1.36
1.33
1.24
1.15
1.07
0.99
0.95
0.9
0.87
0.78
0.70
0.54
0.53
0.49
0.40
* Handbook of Chemistry and Physics, 56th Edition, 1975-76. CRC
Press Inc., Cleveland, Ohio, p. D-141-143.
n
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plant erected by the German firm of Siemens & Halske. In 1893, the first
drinking water treatment plant to employ ozone was erected at Oudshoorn,
Holland. Rhine River water was treated with ozone, after settling and
filtration. Siemens & Halske next built treatment plants at Wiesbaden
(1901) and Paderborn (1902) in Germany which employed ozone.
A group of French doctors studied the Oudshoorn plant and its ozonized
water and, after pilot testing at St. Maur (in Paris) and at Lille, a 5 mgd
plant was constructed at Nice, France (the Bon Voyage plant), which employed
ozone for disinfection. Because ozone has been used continuously at Nice
since the Bon Voyage plant began operating in 1906, Nice is referred to as
"the birthplace of ozonation for drinking water treatment".
Full scale water treatment plants then were constructed in several
European countries. As of 1916 there were 49 treatment plants in Europe
having a total capacity of 84 mgd (Vosmaer, 1916) in operation, and 26 of
these were in France. By 1940 the number of drinking water treatment
plants throughout the world using ozone had risen to 119, and as of 1977 at
least 1,043 plants are known to be using ozone for drinking water treatment
(Miller et aj_., 1978)
APPLICATIONS OF OZONE IN WATER TREATMENT
Because ozone is a powerful oxidant and because many contaminants in
water supplies and industrial wastewaters are oxidizable, ozone can be used
for many specific applications. The major uses for ozone in modern drinking
water treatment processes are listed in Table 3. With the exception of
taste and odor control, all of these same polluting parameters listed in
Table 3 are encountered in industrial wastewaters. Although the early uses
for ozone in treating drinking waters were predominantly for disinfection
(bacterial kill and viral inactivation), today oxidative applications account
for a significantly increasing number of installations.
In recent years, multiple uses for ozonation in the same water treatment
process have been developed. For example, if ozone is applied for color
removal near the end of the treatment process, a significant amount of
disinfection also will be obtained. The conjunctive use of contactor off-
gases from the primary ozone contacting chambers can be effective in such
treatment processes. These off-gases (which contain as much as 5 to 10% of
the ozone charged to the primary contact chambers) can be recycled to the
initial stages of the treatment process to oxidize iron and manganese, to
aid in flocculation of suspended solids, or simply to destroy excess ozone
while performing useful work.
Alternatively, the ozone in these off-gases either must be destroyed
(thermally, catalytically or by passing through moist GAC ) or diluted with
air before being discharged to the atmosphere. If the volumes of contactor
off-gases are not large, it can be cost-effective to recycle them to an
early stage oxidation step in the total water or wastewater treatment process.
12
-------
Another recent application for ozone involves partial oxidation of
dissolved organic compounds, which makes them more biodegradable than they
were prior to ozonation. At the same time, the aqueous medium is aerated
efficiently, thus saturating the solution with oxygen. This provides an
aerobic medium containing DO and dissolved, biodegradable organic compounds.
When this aerated medium is passed through sand, anthracite or GAC filters,
aerobic bacterial growth is promoted in these filter media. As a result,
those partially oxidized, biodegradable dissolved organic compounds are
converted to C02 and water. At the same time, ammonia nitrogen is converted
biologically to nitrate ions. Some of the dissolved organics are adsorbed
onto the GAC, then appear to be biologically degraded, thus regenerating
active adsorption sites.
TABLE 3. APPLICATIONS OF OZONE IN HATER TREATMENT
Bacterial Disinfection
i/iral Inactivation
Dxidation of Soluble Iron and/or Manganese
Decomplexing Organically-bound Manganese (oxidation)
Color Removal (oxidation)
Paste Removal (oxidation)
Ddor Removal (oxidation)
gae Removal (oxidation)
Removal of Organics (oxidation)
such as pesticides
detergents
phenols
Removal of Cyanides (oxidation)
uspended Solids Removal (oxidation)
Increase Biodegradability of Dissolved Organics
reparation of Granular Activated Carbon
for Biological Removal of Ammonia
and Dissolved Organics
This treatment combination of ozonation, followed by sand filtration,
followed by GAC has been termed "Biological Activated Carbon" (BAC) by Rice
ejt aj_. (1978). The process was first developed by the Germans and French
for treating drinking water. However, the technique also is being employed
at the Cleveland Regional Sewer District (Hanna, Slough & Guirguis, 1977) to
treat combined industrial/municipal wastewaters. The technology of BAC will
be discussed in more detail in Section 8 of this report.
One of the most significant points for the water or wastewater treatment
engineer to learn about ozonation is the multiple application aspect. The
use of ozone for more than one purpose effectively can reduce the cost of
ozone installations. For example, ozone can be installed for disinfection
at a cost of X dollars. If this is the only purpose for ozone, then contactor
off-gases must be disposed of safely. This can be done catalytically or
thermally, but at some additional cost.
13
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Instead, the contactor off-gases can be recycled to the front of the
process and utilized for some wastewater treatment purpose such as the
oxidation of iron and manganese, or as a flocculation aid, or for color
removal, organics oxidation, etc.
In such event, the additional cost for this second ozonation step will
be smaller than if the preozonation were the only ozonation purpose. Such
dual application of ozone could even require a small amount of additional
ozone generation capacity, which might not be economical if only the initial
ozonation process step were to have been considered without the later (and
primary) ozonation step. As part of a dual ozonation process, the relative
costs of ozonation for the terminal ozonation step also will be lowered.
GENERATION OF OZONE
Ozone is made by rupturing the stable oxygen molecule, forming two
oxygen fragments, which can combine with oxygen molecules to form ozone:
Nature generates ozone continuously by means of sunlight acting upon
oxygen in the atmosphere, or intermittently by lightning passing through the
air. Man simulates this natural process of generating ozone by passing high
voltage electrical discharges, high or low electrical frequencies, or high
energy radiation through air or oxygen. Ozone is also generated unintention-
ally by man as a by-product during operation of electrical power generation,
electrostatic precipitators, welding equipment, electrostatic copying machines,
UV lights, and a variety of other electrical devices.
Commercial quantities of ozone are generated on-site and as needed in
a system which includes gas handling, ozone generation and a cooling mechanism.
Generation of ozone is energy intensive, with some 90% of the power supplied
to the generator being utilized to produce light, sound, and primarily heat,
rather than the desired ozone. Thus, minimizing electrical power requirements
is a prime target of the ozone generator manufacturer.
A detailed discussion of the factors affecting ozone generation by the
corona discharge technique is given by Rosen (1972). In general, however,
type, thinness and surface area of the dielectric medium used, width of
discharge gap distance between electrodes, degree of flawlessness of the
dielectric medium (no pin-holes), pressure, temperature and rate of flow of
feed gas through the ozone generator, composition (air vs. oxygen), and
moisture content of the feed gas are among the most important factors (Figure
2). If clean, dry, oxygen-rich gas is fed to the ozone generator, and an
efficient method of heat removal is available, then the production of ozone
by means of corona discharge under optimum conditions is represented by the
following relationships (Rosen, 1973):
14
-------
V a pg
(Y/A) a feV2/d
where: (Y/A) = Ozone yield per area of electrode surface
under optimum conditions,
V = Voltage across the discharge gap (peak
volts)
p = Gas pressure in the discharge gap (psia)
g = Width of the discharge gap
f = Frequency of the applied voltage
e = Dielectric constant of the dielectric
medium
d = thickness of the dielectric medium
ELECTRODE
— DIELECTRIC
ELECTRODE
Figure 2. Schematic diagram of corona discharge ozone generator.
Ambient air contains moisture which, if allowed to remain in the feed
gas during ozone generation will (a) react with ozone and reduce the yield
of ozone per kwhr (kilowatt-hour) of electrical energy applied, and (b) form
nitric acid, which can result in severe corrosion of some generator components
as well as downstream ozone handling equipment. For these reasons, air to
be fed to the generator should be adequately dried. This is the function of
the gas handling equipment mentioned earlier. In modern ozone generating
systems, air is dried to a dew point of at least minus 40°C (-40°C), and
preferably to minus 60°C (-60°C) or below.
When dry air is used to generate ozone, a mixture of"\% ozone in air
is produced for the lowest power expenditure consistent with generating
ozone at a reasonably rapid rate; when dry oxygen is used to generate
ozone, a mixture of 2% ozone in oxygen is produced.
15
-------
Increasing the rate of feed gas flow through the ozone generator at
constant power will increase the amount of ozone generated per unit time and
per unit of electrical energy applied, and will reduce the concentration of
ozone in the output gas mixture. Reducing the rate of feed gas flow will
increase the concentration of ozone per unit of electrical power applied,
will increase the amount of ozone produced per kwhr of power applied, but
will decrease the amount of ozone produced per unit of time. Proper choice
of parameters for the particular ozonizing job at hand will guide the user
to produce the optimum amount of ozone for minimal expenditure of power.
Generation of ozone by electrical discharge produces heat, and heat
causes decomposition of ozone in the product gas. Thus it is important that
the heat generated in producing ozone be removed as quickly and efficiently
as possible. This is normally accomplished by water, air or heat transfer
fluid cooling of the dielectric media.
In recent years, the efficiency of ozone generation has been increa-
sing. It has been noted that the Bon Voyage plant of Nice in 1906 originally
required 33 kwhrs/lb of ozone generated (Gagnon, 1976). By contrast, the
Charles-J. Des Baillets drinking water treatment plant of the City of Montreal
is now under construction and will house one of the largest ozone generation
capabilities in the world (15,000 Ibs/day). When this plant is completed in
1980, it will produce ozone for 10.63 kwhrs/lb of ozone generated (Bouchard,
Use of oxygen as the feed gas rather than air will allow production of
essentially double the amount of ozone per kwhr of electrical energy (2%
ozone in oxygen), and will also eliminate the need for gas drying. Thus,
capital requirements for ozone generation will be approximately halved by
using oxygen. The discerning engineer will recognize however, that the
gases now exiting the ozone generator will be 98% oxygen and 2% ozone.
Therefore, to minimize loss of oxygen, contactor off-gases, still very rich
in oxygen, should be recycled to the ozone generator (after removing contami-
nants and water) or utilized in some fashion. For example, in biological
oxygen activated sludge processes, for which dry oxygen is available, ozone
can be generated from oxygen and the contactor off-gases can be used to
supplement the oxygen supply to the biological reactor (Figure 3).
CONTACTING OF OZONE WITH AQUEOUS SOLUTIONS
Because ozone is only slightly soluble in aqueous media, contacting
ozone with water involves bringing bubbles of ozone-containing air or
oxygen into intimate contact with the water. Mass transfer of ozone from
the gaseous bubbles occurs across the gas/liquid interface into the water.
Factors which affect the mass transfer of ozone into liquids, and which
themselves are affected by design and operation of the contactor system,
include:
« the tniscibility with water and ozone demand of the substance(s) to
be ozonized,
16
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-' wastewater
oxygen
generating
system'
ozone
generator
oxygen stream
ozonation +
super-
oxygenation
activated
sludge
reactor
secondary
clarifica-
tion
filtration
sludge recycle
to outfall
Figure 3. The oxygen activated sludge process.
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• concentration of ozone in the gas,
• whether the carrier gas is air or oxygen,
t method and time of contact,
• bubble size, and
t pressure and temperature.
Generally speaking, there are two major categories of reaction which
ozone undergoes in solution: (a) those which are so rapid that they are
limited only by the rate of mass transfer of ozone into solution, and (b)
those which are slower than the mass transfer rate, thus are limited by the
reaction kinetics of the material to be ozonized. Reaction rates of such
materials as bacteria, nitrites, hydrogen sulfide, phenols, unsaturated
organic compounds, etc., are very rapid with ozone, and thus are limited
only by the rate at which ozone is "mass transferred" into solution.
Other materials react with ozone very slowly, such as acetic acid,
urea, saturated aliphatic alcohols, ammonia, oxalic acid and the like. Even
in the presence of large excesses of ozone, the rates of these reactions are
very slow, and thus are "reaction rate limited".
Thus, in designing an ozone contacting system, it is important to
minimize the amount of ozone required for the specific purpose for which the
ozone is to be used. If disinfection only is desired, a contactor which
causes rapid mass transfer of ozone should be used. For oxidation of bio-
refractory organic materials, the rate of ozone mass transfer is less impor-
tant than maintaining a specific, often low, concentration of ozone for a
longer contact period.
These two situations are illustrated graphically in Figure 4. The
upper curve shows that a high ozone dose for a short period of time uses the
minimum amount of ozone for maximum mass transfer. On the other hand, the
lower curve shows that low ozone dosages for long periods of time provide
the minimum amount of ozone necessary for reaction rate controlled reactions.
Basically, there are only four different types of gas/liquid contacting
systems (Stahl, 1975). These include:
1. Spray towers (liquid sprayed into gas)
2. Packed-beds
3. Bubble plate or sieve plate towers (an intermediate situation
between 1 and 2)
4. Units for dispersing gas bubbles into liquid.
18
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CONCN.
OF
OZONE
FOR DISINFECTION
(Mass Transfer Controlled Reactions)
TIME
CONCN.
OF
OZONE
FOR COD REMOVAL
(Reaction Rate Controlled Reactions)
TIME
Figure 4. Optimum ozone dosages.
19
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The most common ozone contacting systems are based on some method for
dispersing gas bubbles within a liquid (category 4). Generally there are
two ways of accomplishing this:
1. Gas is introduced initially into the fluid as bubbles of the
desired size, or as smaller bubbles which grow to the desired size
as contact time continues, or
2. A massive bubble or gas stream is disintegrated into the fluid.
These two techniques are exemplified by the diffuser (or sparger) and
the injector (or eductor) contactors, respectively. Both of these types of
contactor were developed originally for treating potable water supplies, and
have been utilized throughout the world for this purpose for many years.
Many variations of each type have evolved.
With the diffuser, ozone is added at the bottom of the contact chamber,
through a porous medium (ceramic, Teflon, stainless steel, etc.), and the
gas bubbles rise through the water which is passed co-currently or counter-
currently through the chamber. Many installations utilize a multiplicity of
diffuser chambers, alternating liquid flow first co-currently then counter-
currently with the gas stream. Diffusers can be operated with little energy
being added, and are especially useful when large volumes of water are being
passed through the plant by gravity flow. Additional power costs to effect
contacting thus are minimized. However, contacting chambers to house the
diffusers are rather large, because of the relatively long contact time
required to achieve maximum mass transfer.
Injectors require added energy, the simplest involving pumping of water
to be ozonized rapidly past a small orifice, into which the ozone is either
pumped or drawn into the liquid by the vacuum created by rapid flow of water
past the orifice. In those installations in which water already is being
pumped about the plant, injectors are especially suitable, because of their
smaller size and high mass transfer rates.
Ozonation of sewage treatment plant effluents and some industrial
effluents recently has pointed up the need to study ozone contacting more
carefully. Potable water supplies generally are relatively clean, and do
not contain much suspended matter or dissolved organic material. With
primary and secondary sewage treatment plant effluents, however, higher
concentrations of these types of materials are present. During ozonization,
much of the organic material is transformed into more polar oxygenated
compounds. Lower valent inorganic ions, such as iron and manganese, are
oxidized to higher valence states, at which they will hydrolyze, precipitate,
and absorb other material present. The net result is formation of a froth,
or scum (Foulds, 1972) and provision for its removal must be made. It has
been estimated that for each one mgd of secondary effluent ozonized, 550 gal
of sludge will be formed in the froth of an ozonation system (Nebel et al.,
1974).
20
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In a recent study of disinfection of municipal wastewater (Ward et al_.,
1976) it was found that disinfection by means of ozonation could be acFieved
consistently only if the secondary effluent was filtered prior to ozonation.
Thus the mechanical performance of an ozone contacting system is
expected to be different when treating secondary sewage and/or industrial
plant effluents, than when treating potable water supplies, and the engineer
should keep this point in mind in determining the amount of pretreatment the
particular wastewater should receive before ozonation.
Detailed discussions of the theory of contacting have been published by
Nebel, Unangst & Gottschling (1973); Sherwood & Pigford (1952) and Treybal
(1955). For purposes of this report, however, it is sufficient to point out
that all contactors have their advantages and their limitations (Table 4),
and the engineer is advised to consider the specifics of the ozonation job
at hand, with respect to material(s) to be ozonized, volume of liquid to be
treated, etc. A pilot study should be conducted with the contactor(s)
selected, and the following parameters should be studied over practical and
economic limits (McCammon, 1975; Nebel, Unangst & Gottschling, 1973; Massche-
lein, Fransolet & Genot, 1975, 1976):
1. Liquid head on total pressure at initial point of gas/liquid
contact,
2. Distribution of ozone throughout the contact period,
3. Total contact time necessary,
4. Concentration of ozone applied,
5. Gas surface area, or volume rates of liquid to gas,
6. Minimal ozone residual.
Once these parameters have been determined satisfactorily, design of the
full-scale ozone contacting system can proceed with a high degree of confi-
dence.
In conducting any laboratory treatability or pilot plant study with
ozone, it is essential to measure both the ozone dosed and the amount of
ozone remaining in the off-gases from the contactor. The difference between
the two values is the value for ozone consumed, which is a much more pertinent
number for the wastewater treatment engineer than is the ozone dosage. The
significance of this point is as follows.
Mass transfer theory suggests that for porous diffuser contactors, the
minimum water column height should be 4 meters (about 13 ft) in order to
transfer the maximum amount of ozone from bubbles of ozone-containing air
into the water. Only when the ozone contactor system is designed to provide
the maximum amount of mass transfer can the ozone dosage be a meaningful
number.
21
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TABLE 4. TYPES OF OZONE CONTACTORS
contactor
Type
Advantages
Disadvantaaes
ro
ro
Spray
Towers
Packed
Columns
Plate
Columns
Spargers
(bubblers)
Agitators,
Surface aera-
tors,
Injectors,
Turbines,
Static mixers
High rate of mass transfer
Uniform ozone in gas phase
Wide gas/liquid operating range
Small size and simplicity
Same as packed columns, but no
channeling and broader gas/-
liquid operating range
Require only gravity feed; no
added energy
Wide gas/liquid operating range
allows intermittent operation
High degree of flexibility
Small sizes
Intimate contact and good
dissolution
- Requires high energy to spray liquid
- Solids can plug spray nozzles
- Short contact time
- Easily channeled and plugged
Easily clogged, but easier to clean
Best suited for very large
installations
Intermittent flows may cause plugging
of porous media
Longer contact times require larger
housings
Tendency to vertical channeling of gas
bubbles, reducing contact efficiency
Require addition of energy
Narrow gas/liquid operating ranges
Cannot accomodate significant flow
changes (injectors and static mixers),
therefore require multiple contactor
stages
-------
Under laboratory conditions, however, it is rarely practical to employ
contactor heights higher than 1.2 to 1.5 m (4 to 5 ft). Therefore mass
transfer of ozone to the water will be inefficient, and much of the ozone
dosed to the reactor will pass through the contactor unreacted. In such
cases of poor mass transfer, the amount of ozone dosage employed to attain a
specific amount of oxidative work (color removal, COD removal, disinfection,
etc.) will be very high. In the case of diffuser contactors, the shorter
the contactor and the faster the ozone is applied, the more ozone will pass
through the contactor and the higher will be the apparent ozone dosage.
If the poor mass transfer conditions of laboratory ozone contactors are
compensated for, however, by considering the ozone consumed rather than the
ozone dosed, a more realistic appraisal will be made of the effectiveness of
ozonation. The amount of ozone consumed is determined by measuring the
ozone remaining in the contactor off-gases and subtracting this number from
the amount of ozone dosed to the contactor:
°c -Vog
Where: 0 = Ozone Consumed
V*
0 . = Ozone Dosed
d
0 = Ozone in contactor off-gases
og
This point also is of critical importance when reviewing literature
articles describing ozonation studies. Laboratory tests reporting only
ozone dosages are indicative only of the fact that ozone can or cannot
perform a specific function. Ozone dosages for mass transfer limited
reactions can never be extrapolated directly to determine full-scale plant
conditions for industrial wastewaters unless the test system was designed to
attain optimum mass transfer.
OZONE ANALYSIS AND PROCESS CONTROL
The most generally used technique for determing ozone (actually total
oxidants) in water is by the starch-potassium iodide (KI) technique. As
with other strong oxidants, ozone will liberate iodine from solutions of
KI. The liberated iodine then can be titrated, with standard sodium thiosul-
fate, for example. However, in the presence of other strong oxidants (chlor-
ine, chlorine dioxide, hydrogen peroxide, potassium permanganate, some
oxidation products of organic materials, etc.) the total oxidant content of
the solution will be determined by this technique.
The orthotolidine-manganese sulfate method is more specific for ozone,
being subject to fewer interferences than iodometry.
Perhaps the most accurate and specific method for residual ozone in
water involves spectrophotometry [UV absorption at 254 nanometers (nm)]
(Hann & Manley, 1952), but the solution must be free of other UV absorbing
materials. Many types of residual ozone monitors based upon UV absorption
are used in European drinking water treatment plants, because ozonized
23
-------
drinking water is relatively free of extraneous materials which absorb at
254 nm.
Unique to the use of ozone for water treatment is the need to measure
ozone in the gas phase, just before the ozonized air or oxygen is added to
the contacting system (so as to determine the dosage being applied), and
again in the contactor off-gases, so as to be able to determine the amount
of ozone utilized, the amount of ozone to be destroyed, to be discharged to
the atmosphere, or to be recycled. Ozone in the gaseous phase can be deter-
mined by UV absorbance, by iodometry in aqueous solution, or by reacting
with gaseous ethylene and measuring the UV absorption of the ethylene-ozone
adduct.
An excellent discussion of the various analytical techniques by which
ozone can be determined in gaseous and aqueous phases is given by Kinman
(1975).
Process control of modern ozonation systems is achieved readily by
monitoring residual ozone in the water just after the contacting chamber
exit. This technique is employed in many modern European drinking water
treatment plants. The analyzer is coupled with the ozone generators so that
if the level of dissolved ozone drops below a pre-determined level, the
generators are signaled to increase production.
Alternatively, contactor off-gases can be monitored by a gas phase
ozone monitor, also coupled with the ozone generators. When the level of
measured ozone falls, indicating increased consumption of ozone by the
aqueous medium, the generators are signaled to increase ozone production.
When the level of monitored ozone in the gas phase rises above a pre-deter-
mined level, the generators are signaled to decrease production (Thompson,
1976).
By thus instrumenting, programming and monitoring either dissolved
ozone after contacting or contactor off-gases, the normally varying loadings
of ozonizable materials in wastewater treatment plants can be handled on an
automated basis using minimum quantities of ozone.
In an exactly similar manner, the amount of ozone present in ambient
plant atmospheres can be monitored by another analyzer, or series of analyzers.
In the event of an ozone leak from the generators, from the contactors or
from the associated downstream piping, the ozone sensors will react by
signaling the ozone generators to be turned off. Once electricity ceases to
pass through the ozone generator, ozone generation ceases.
An outstanding discussion of the engineering details of air preparation
equipment, ozone generation equipment, contactors and ozone monitoring
equipment is given by Miller et, aJL (1978) in their "Assessment of Ozone and
Chlorine Dioxide Technologies for Treatment of Municipal Water Supplies",
which was conducted for the U.S. Environmental Protection Agency (EPA 600/2-
78-147).
24
-------
OZONE/UV RADIATION
This recently developed process combines ozone oxidation with photo-
chemical excitation to increase the rate of oxidation reactions considerably
over the rates observed with UV radiation or with ozonation applied separately.
As a result, compounds normally refractory to ozonation alone, such as
acetic and oxalic acids, are rapidly converted to CC>2 and water when subjected
to the combination. In addition, cyanide complexes of iron, normally not
easily affected by ozonation, are rapidly decomposed by the combination, and
the cyanide concentration rapidly is destroyed to below the detectable
limit. Finally, solutions of polychlorobiphenyls (PCBs) which are very
stable to oxidation, are destroyed rapidly by the ozone/UV combination to
concentrations below 0.1 mg/1. The technology has been specified as Best
Practicable Control Technology Currently Available (BPTCA) by the EPA (U.S.
EPA, Feb. 1977) for PCBs.
The combined ozone/UV process has developed from research efforts
initially conducted by scientists at Houston Research Inc., in the early
1970s, under contract to the U.S. Air Force Special Weapons Laboratory,
Kirtland Air Force Base, New Mexico (Garrison, Mauk & Prengle, 1974).
Initial work was conducted on mixed concentrated cyanide wastewaters (iron,
copper and nickel complexed cyanides) and the results were dramatic --
cyanide was destroyed to below the detectability limit (Garrison, Mauk &
Prengle, 1975; Mauk, Prengle & Legan, 1976).
Since this initial research using cyanide-containing wastewaters was
first conducted, a substantial body of information has been developed on
the applicability of the ozone/UV combination to a broad range of inorganic
and organic species, including:
metal cyanide complexes
organic and ami no acids
alcohols
pesticides and insecticides
organic nitrogen, sulfur and phosphorus compounds
chlorinated organic compounds
Even at this early stage of development, the process has been specified
as BPTCA for wastewaters containing PCBs, and is in commercial use at several
metal finishing plants for treatment of cyanide containing wastewaters
(Prengle, 1977).
A detailed discussion of the theoretical aspects of the ozone/UV
process is given by Prengle (1977), and references cited therein, to which
the reader is referred. The addition of UV radiation at wavelengths in the
180 to 400 nm range provides energy in the range of 72 to 155 kcal/mole to
aqueous solutions. These amounts of energy are quite ample for producing
free radicals and other species in varying degrees of photochemical excitement,
which are not formed during ozonolysis. Examples are excited atomic oxygen
species (0), hydroxy radicals (HO*), hydroperoxy radicals (H02') and carbon-
containing excited species. Significantly, addition of even small amounts
25
-------
of UV radiation to aqueous solutions containing dissolved ozone immediately
reduces the dissolved ozone level to zero, yet the oxidative power of the
solution is considerably higher than when ozone alone is present (Glaze,
1978).
In practice, UV radiation is applied to aqueous solutions simultaneously
with the ozone. Typical reaction schemes for the ozone/UV oxidation of
mixed chlorinated aromatics and for cyanides and refractory organics are
shown in Figures 5 and 6, respectively. Dosages of UV radiation applied are
expressed as 'watts of useful radiation energy per liter'. The amount of UV
energy applied normally for this process ranges from 0.44 to 1.32 watts/1 at
ambient temperatures.
For oxidations which are reaction rate limited, with respect to ozonation
alone, the addition of UV radiation requires somewhat more energy. However,
because the added UV radiation decreases the reaction time now required to
attain the desired degree of oxidation, there is less total ozone required.
Therefore, less total energy is required for the reactions involved.
In its current configuration, the ozone/UV process equipment includes
high speed agitation and multiple reactor stages for reaction. Those
wastewaters which contain materials whose oxidations are both mass transfer
and reaction rate limited (for example, free cyanide ion in the presence of
iron-complexed cyanide) are treated in the first stage reactor with ozone
only (to oxidize free cyanide). The effluent from the first stage reactor
then enters the second reactor, in which it is treated with both ozone and
UV radiation. Treatability studies on specific wastewaters are recommended
to determine the optimum number of stages required, as well as optimum ozone
and UV radiation conditions to produce maximum oxidation at minimum energy
costs.
Costs for a single stage reactor system, including mixer, UV lights,
etc., are shown in Figure 7, and are related to reactor volume. Costs for
ozonation equipment are shown in Figure 8, and it should be remembered that
about twice the amount of ozone can be generated using oxygen as the feed
gas instead of air. Pertinent capital and operating costs for these systems
as applied to specific wastewater streams will be discussed in the appropriate
industrial wastewater sections of this report.
It has also been shown that coupling higher temperatures with ozonation
or with UV/ozonation also increases reaction rates (Garrison, Mauk & Prengle,
1974; 1975).
Because the radiation output from UV bulbs decreases with time, annual
replacement costs for these bulbs may turn out to be a major operating cost
factor. A promising alternative catalytic process involves the coupling of
ultrasonic energy with ozonation. Sierka (1977) has shown that the same ;
increase in rate of oxidation of refractory organic compounds can be obtained
by substituting ultrasonic energy for ultraviolet radiation. This research
was sponsored by the U.S. Army Medical Bioengineering R&D Command, Ft.
Detrick, Maryland.
26
-------
RECYCLE OXYGEN TO
ro
INFLUENT
IOMG/L CHLORINATEC
AROMATIC
OZONE IN
i
{
C
*• P-1
j
vMIXER
UV
"^
b
OXYGEN
£
~ ™"\^;
JJ-cCi —
-J
J
•*
•
c
.••—
c
I
^
— .
u
i-H 1
ll
£
/
s^
J*
a— tAj- —
' C
/p""
c
1
— — _^
ZONE GENERATOR
L
^** •
b
T
(\
^^
• ~~®
$ EFFLUENT
i O.I MG/L
CHLORINATED
AROMATICS
Figure 5. Ozone/UV process flow diagram; mixed chlorinated aromatics.
Source: Prengle & Mauk (1977)
-------
CHEMICAL COAGULATION
INFLUENT
WASTEWATER
ro
oo
SEDIMENTATION. CLARIFICATION 0, OXIDATION(I)
AND EQUALIZATION 3
pH ADJUSTMENT
03OXIDATION(II)
Figure 6. Ozone/UV process flow diagram; cyanides and refractory organics.
Source: Prengle & Mauk (1977)
-------
Further discussion of the ozone/ultrasonics process will be found in
Section 5, under Hospital Wastewaters.
200
100
80
o
o
0 60
•00-
4J
cn
o
40
20
10
10
20 40 60 80 100 200 400 600
Reactor Volume, Cubic Feet
Figure 7. Installed cost of UV/ozone reactor stage.
Source: Prengle (1977)
1000
29
-------
0.1
4 6 8 10 20 40 60 100 200 400 600
Ozone Production, Ib/day
Figure 8. Cost of producing ozone (including oxygen and amortization),
Source: Prengle (1977)
30
-------
LITERATURE CITED — SECTION 4
U.S. Environmental Protection Agency, 1977, Federal Register, February,
Foulds, J.M., 1972, "Removal of Surface Active Agents From Wastewaters With
Ozone", J. Boston Soc. Civil Engrs. 59:151-159, July, 1972.
Gagnon, M., 1976, in Ozone: Analytical Aspects and Odor Control, R.G. Rice &
M.-E. Browning, editors. Intl. Ozone Assoc., Cleveland, Ohio p. 111-
113.
Garrison, R.L., C.E. Mauk & H.W. Prengle, Jr., 1974, "Cyanide Disposal by
Ozone Oxidation." Final Report to U.S. Air Force Weapons Lab., Kirtland
Air Force Base, New Mexico, Feb. 1974, #AFWL-TR-73-212, Nat!. Tech.
Info. Service, U.S. Dept. of Commerce, Washington, D.C. #AD-775,152/WP.
Garrison, R.L., C.E. Mauk & H.W. Prengle, Jr., 1975, "Advanced Ozone Oxi-
dation System For Complexed Cyanides", in Ozone for Water & Wastewater
Treatment, R.G. Rice & M.E. Browning, editors. Intl. Ozone Assoc.,
Cleveland, Ohio, p. 551-577.
Glaze, W.H., 1978, "A Comparison of Ozone and Ozone/Ultraviolet for the
Destruction of Refractory Organic Compounds in Water", presented at
Ozone Technology Symposium, Los Angeles, Calif., May, 1978. Intl.
Ozone Assoc., Cleveland, Ohio.
Hann, V.A. & T.C. Manley, 1952, "Ozone", in Encyclopedia of Chemical Tech-
nology. 9:735.
Hanna, Y., J. Slough, Jr. & W.A. Guirguis, 1977, "Ozone as a Pretreatment
Step for Physical Chemical Treatment - Part II", presented at the
Symposium on Advanved Ozone Technology, Toronto, Ontario, Canada, Nov.
1977. Intl. Ozone Assoc., Cleveland, Ohio.
Kinman, R.N., 1975, "Analysis of Ozone --Fundamental Principles", in Ozone
For Water & Wastewater Treatment, R.G. Rice & M.E. Browning, editors,
Intl. Ozone Assoc., p. 56-68.
Masschelein, W., G. Fransolet & J. Genot, 1975, "Dispersing and Dissolving
Ozone in Water, Part I", Water & Sewage Works, Dec. 1975, p. 57-60.
Masschelein, W., G. Fransolet & J. Genot, 1976, "Dispersing and Dissolving
Ozone in Water, Part II", Water & Sewage Works, Jan. 1976, p. 34-36.
Mauk, C.E., H.W. Prengle, Jr. & R.W. Legan, 1976, "Chemical Oxidation of
Cyanide Species by Ozone With Irradiation From Ultraviolet Light",
Trans. Soc. Mining Engrs., AIME 20:297.
McCammon, W.H., 1975, "Ozonation Contacting Systems", Proc. 68th Ann.
Meeting, AIChE, Nov. 1975. Am. Inst. Chem. Engrs., New York, N.Y.
31
-------
Miller, G.W., R.6. Rice, C.M. Robson, R.L. Scullin, W. Kfihn & H. Wolf, 1978,
"An Assessment of Ozone and Chlorine Dioxide Technologies for Treatment
of Municipal Water Supplies", U.S. EPA Report #EPA 600/2-78-147. U.S.
Environmental Protection Agency, Municipal Environmental Research
Laboratory, Cincinnati, Ohio.
Nebel, C., P.C. Unangst & R.D. Gottschling, 1973, "An Evaluation of Various
Mixing Devices for Dispersing Ozone in Water", Water & Sewage Works,
Reference Issue, p. R-6.
Nebel, C., R.D. Gottschling, R.L. Hutchison, T.J. McBride, D.M. Taylor,
J.L. Pavoni, M.E. Tittlebaum, H.E. Spencer & M. Fleischman, 1973,
"Ozone Disinfection of Industrial-Municipal Secondary Effluents", 0.
Water Poll. Control. Fed. 45(12):2493-2507.
Prengle, H.W., Jr., 1977, "Evolution of the Ozpne/UV Process for Wastewater
Treatment", presented at Symposium on Wastewater Treatment & Disin-
fection With Ozone, Cincinnati, Ohio, Sept. 15. Intl. Ozone Assoc.,
Cleveland, Ohio.
Rice, R.6., G.W. Miller, C.M. Robson & W. Kuhn, 1978, "A Review of the
Status of Preozonation of Granular Activated Carbon for Removal of
Dissolved Organics and Ammonia From Water & Wastewater", in Carbon
Adsorption Handbook. P.N. Cheremisinoff & F. Ellerbusch, editors. Ann
Arbor Science Publishers, Inc., Ann Arbor, Michigan, p. 485-537.
Rideal, E.K., 1920, Ozone, Constable & Company, Ltd., London, England.
Rosen, H.M., 1972, in Ozone. For Water & Wastewater Treatment. F.L. Evans,
III, editor. Ann Arbor Science Publishers, 'Inc., Ann Arbor, Michigan.
Rosen, H.M., 1973, "Use of Ozone and Oxygen in Advanced Wastewater Treat-
ment", J. Water Poll. Control Fed. 45(12):2521-2536.
Sherwood & Pigford, 1952, Absorption and Extraction. McGraw Hill, New York,
N.Y.
Sierka, R.A., 1977, "The Effects of Sonic and Ultrasonic Waves on the Mass
Transfer of Ozone and the Oxidation of Organic Substances in Aqueous
Solution", presented at Third Intl. Symp. on Ozone Technology, Paris,
France, May, 1977. Intl. Ozone Assoc., Cleveland, Ohio.
Stahl, D.E., 1975, "Ozone Contacting Systems", in Ozone for Water & Waste-
water Treatment, R.G. Rice & M.E. Browning, editors. Intl. Ozone
Assoc., Cleveland, Ohio, p. 40-55.
Thompson, G.E., 1976, "Ozone Applications in Manitoba, Canada", in Proc.
Sec. Intl. Symp. on Ozone Technology, R.G. Rice, P. Pichet & M.-~A.
Vincent, editors, Intl. Ozone Assoc., Cleveland, Ohio, (1976), p. 682-
693.
32
-------
Treybal, 1955, Mass Transfer Operations, McGraw Hill, New York, N.Y.
Ward, R.W., R.D. Giffin, G.M. DeGraeve & R.A. Stone, 1976, "Disinfection
Efficiency and Residual Toxicity of Several Wastewater Disinfectants",
U.S. EPA Report #EPA-600/2-76-156, Oct. 1976. U.S. Environmental
Protection Agency, Municipal Environmental Research Laboratory, Cincinn-
ati , Ohio.
33
-------
SECTION 5
INDUSTRIAL WATER & WASTEWATER TREATMENT WITH OZONE
INTRODUCTION AND ORGANIZATION OF SURVEY
In conducting this state-of-the-art survey, the categorization of
industrial manufacturing categories which has been adopted by the Effluent
Guidelines Division of the EPA was followed. The published literature then
was surveyed, and pertinent articles were grouped into the appropriate
categories.
Those industrial categories for which pertinent articles were found are
listed in Table 1. Many of these articles then were abstracted for content.
Originally, the investigators had hoped to find data on actual wastes used,
such as raw waste loading, composition of wastewater streams to be ozonized,
details of the ozonation equipment and contacting apparatus, data on the
contact time, dosage of ozone applied, amount of ozone utilized, analytical
data on the ozonized wastewater effluent, etc. The investigators were
searching for descriptions of ozonation as applied to actual wastewaters, as
opposed to laboratory or pilot plant program discussions.
As the survey progressed, however, it became apparent that very few
articles address all of these points, and that there is very little published
information dealing with actual full-scale commercial operations. Some
published pilot plant and laboratory studies on industrial wastewater treat-
ment with ozone provide pertinent data for consideration, and these articles
are included in the survey.
From this point onward, Section 5 is organized by industrial categories.
At the end of each subsection dealing with a specific industrial category,
the pertinent literature cited for that category is listed. References are
arranged alphabetically, according to the senior author. Most of the articles
cited have been given a 2-letter code, representing the industrial category,
and a number. In many instances, this 2-lettered code plus a number has
been asterisked. The asterisk indicates that an abstract for that particular
article is included in the companion document to this report, entitled,
"OZONE FOR INDUSTRIAL WATER AND WASTEWATER TREATMENT -- An Annotated Biblio-
graphy", NTIS Report System. In other instances, the reference cited has
not been assigned a category code and number. This is because the reference
is a general one, and does not contain information specific to the particular
industrial category. These non-category-specific references are included
alphabetically as well.
34
-------
TABLE.5. INDUSTRIAL CATEGORIES REPORTING THE USE OF OZONE
Category
Aquaculture
Breweries (under Food &
Kindred products)
Biofouling Control
Cyanides & Cyanates
Electroplating
Food & Kindred Products
(except Breweries)
-lospitals
Inorganics
Iron & Steel
Leather Tanneries
fining
Organic Chemicals
Paint & Varnish
3etroleum Refineries
Pharmaceuticals
Phenols
Photoprocessing
Plastics & Resins
Pulp & Paper
Soaps & Detergents
Textiles
TOTALS
Code
AQ
BR
BF
CY
EP
FO
HE
1C
IS
LT
MI
OC
PV
RE
PC
PH
PF
PL
PU
SD
TX
No. of Articles Found
Actual Wastes*
19
5
4
--
17
5
16
3
10
0
11
25
4
22
0
--
8
4
37
7
30
227
Total
39
9
10
24
27
9
30
5
14
3
15
60
4
27
2
29
12
4
60
12
35
430
* also, actual process waters
35
-------
AQUACULTURE
In this category, the reported literature shows that ozone is being
used industrially for (1) treating influent waters to shellfish depuration
s*a*1?"?' (2> disease prevention in aquaculture systems through disinfection
of holding waters and (3) toxin inactivation. Blogoslawski & Stewart (1977)
have reviewed the applications of ozone treatment for these purposes and
Blogoslawski (1977) has reviewed the uses of ozone in mariculture. Recent
research conducted by the National Marine Fisheries Service, Mil ford, Connect!
cut, has shown ozonation to be useful for preventing the detrimental effects
normally encountered during "red tide" blooms.
Although ozone decays rapidly in freshwater, doses of ozone in seawater
exceeding 0.5 mg/1 react with bromide ions to produce a residual "oxidant"
which, if not removed through post-ozonation treatment, can be toxic to
delicate larval stages of some bivalve shellfish.
Discussion of the use of ozone in the aquaculture field will be divided
into five broad areas:
(1) Shellfish Depuration
(2) Marine Water Quality Improvement
(3) Freshwater Quality Improvement
(4) Disease Prevention
(5) Toxicity of Ozonized Seawater
The authors are especially grateful to Dr. Walter J. Blogoslawski of the
National Marine Fisheries Service, Northeast Fisheries Center, Mil ford,
Connecticut, for his assistance in the organization and presentation of this
section.
Shellfish Depuration
The advantages of using preozonized seawater for the cleansing of
shellfish at depuration stations were confirmed by early experiments of
Violle (1929) and by Fauvel (1963). Since then, the process has been
employed commercially, the most completely described installation being at
Sete, on the Mediterranean coast of France (Anonymous, 1972). At present,
there are at least 12 other depuration stations in France known to be ozoni-
zing seawater, five in Spain, one in Greece and one in Tunisia (see Table
6). The larger commercial depuration stations process up to 6,000 kg/day of
shellfish. Up to 4,800 cu m/day (1.27 mgd) of seawater are disinfected with
1 to 3 mg/1 dosages of ozone.
Depuration takes place simply by placing the live adult shellfish
harvest in disinfected seawater, and allowing the shellfish to ingest and
expell large quantities of water from which they extract their food (Fauvel,
1977). If the water ingested contains bacteria and viruses, these will
become concentrated in the shellfish flesh. Depuration in disinfected water
(storage up to several days in ozonized water) allows time for the bacteria
36
-------
TABLE 6. SHELLFISH DEPURATION STATIONS USING OZONE*
Location
France
Arromanches
La Roche! le
Harache
Le Crotoy
St. Primel
Brilemeau
Viviers
(Cote d'Argent)
Coop le Dauphin
(Se-te)
Palavas
Grandcoup
Bouzigues
Saintes
Plougosnou
Other Countries
Rosas (Spain)
4 installations in
Tunis (Tunisia)
Salonique (Greece)
Daily Water Flow
(cu m)
1400
1400
1680
2400
500
1900
3600
4800 1
(qal)
369,000
444,000
634,000
132,000
502,000
951,000
,268,000
Year
Ozonation
Installed
1967
1968
1970
1970
1970
1971
1972
1972
1974
1974
1975
1966
Spain, unknown locations 1969
1450
383,000
1971
1975
Amount of
Shellfish
Processed
(kq/dav)
'
1400
1400
* Sources: (a) Trailigaz, Cie Ge"ngrale de 1 'Ozone, Garges-l&s-
Gonesse, France, Reference List, 1976.
(b) W.J. Blogoslawski & M.E. Stewart (1977).
(c) DEMAG Metallgewinnung, Duisburg, Germany, Referenzliste.
37
-------
and viruses to be expelled from the shellfish into the water, where the
bacteria are killed or the viruses are inactivated by the disinfectant.
At the Sete Laboratory in France, near the Institute of Marine Fisheries
(Anonymous, 1972), the depuration station consists of 7 cleansing tanks or
troughs, each of which is 20 m long by 2 m wide and 0.95 m high (average),
with a capacity of 37 cu m. Metal baskets containing the shellfish to be
cleansed are placed on runners longitudinally down the middle and along both
sides of the tanks. The floor of each tank has a 2% slope from one end to
the other, and ozonized seawater flows through each tank at the rate of 100
cu m/hr.
Shellfish are charged to the tank area at the rate of 35 kg of shellfish/-
sq m; the preozonized water in each tank is recirculated and changed daily.
One basket from each lot is tested for E. coli prior to treatment and after
every 24-hr period. The presence of residual ozone in the seawater is
checked from time to time by addition of a 10% KI solution containing starch
to a seawater sample. The blue color (starch/iodine) which develops confirms
the presence of ozone or one of its oxidation products capable of liberating
iodine from iodide ion. As long as oxidant is present in the water, no
fecal coliforms can be detected and the water is presumed to be disinfected.
Seawater is ozonized using an emulsifier contactor, which is a bell-
mouthed water tube through which ozonized air is drawn into the water under
slight vacuum, or by using a porous tube diffuser contactor.
The depuration of clams and mussels using seawater which is ozonized
with varying doses depends upon the initial degree of E. coli contamination
of the shellfish. The amounts of ozone required to destroy E. coli concentra-
tions are shown in Table 7.
TABLE 7. OZONE REQUIREMENTS FOR DEPURATION
Degree of Initial
Pollution (E. coli/1)
less than 250
250 to 1,000
1,000 to 2,000
2,000 to 5,000
Ozone Required
(q/cu m)
0.45 to 0.75
0.75 to 1.15
1.15 to 1.50
1.50 to 2.10
Depuration times also vary according to the level of shellfish pollution;
2 to 4 days being required for clams and 2 to 3 days for mussels. Cleansing
is much more rapid for mussels than for clams. In the more highly contaminated
clams, depuration in chlorinated water requires about 50% longer to attain
the same degree of purity as when using ozonized water (6 days versus 4
days). With clams having low initial coliform counts, the depuration times
in chlorinated or ozonized waters are the same (see Table 8).
38
-------
Preozonation of seawater is accomplished by supplying ozone until the
KI test shows an excess of oxidant. This excess ozone can be eliminated by
passing the ozonized water through a desaturator placed at the outlet of the
contact tower. The desaturator is a cascading device (Fauvel, 1977), in
which ozonized seawater flows over a 6 to 8 ft high dam. At the base of the
waterfall, excess gas is eliminated because of the mixing of air with the
ozonized water. Thus, disinfected water containing the desired traces of
ozone may be prepared for depuration tank addition.
TABLE 8. DEPURATION TIMES FOR CLAMS AND MUSSELS IN OZONIZED AND
CHLORINATED SEAWATER
Clams
Mussels
Degree of
Initial Pollution
(E. Coli/llter)
10,000 or less
10,000-30,000
50,000-75,000
25,000 or less
30,000-50,000
50,000-75,000
25,000 or less
25,000-75,000
Average
Cleansing
time (days).
2
3
4
2-3
4
6
2
3
Disinfectant
ozone
ozone
ozone
chlorine
chlorine
chlorine
ozone
ozone
Initial laboratory studies by Violle (1929) were conducted on the
depuration of oysters. Seawater was seeded with various strains of pathogenic
bacteria and the samples were ozonized to determine the doses necessary to
achieve disinfection. Apparently, the doses were the same as those used in
ozonizing fresh water (which is 1 to 3 mg/1 in European drinking water
treatment plants -- Miller ejt a]_., 1978). No oxidation of bromide ion was
observed even at double the amount of ozone necessary to produce disinfection.
Oysters were kept 18 to 20 days in water using twice the amount of
ozone necessary for disinfection, but the ozonized seawater was aerated to
remove large excesses of ozone. After 5 to 6 hrs of exposure to the ozonized
and aerated seawater, the oysters were free of bacteria. No change in
oyster protoplasm was observed visually after exposure to ozonized and
aerated seawater for 18 to 20 days. Violle (1929) recommended that the
depuration process consist of rapid sand filtration of seawater, ozonation,
aeration and flow-through at the rate of 100 ml/hr/oyster.
Salmon, Le Gall & Salmon (1937) reported preliminary test results for
oysters and mussels depurated in ozonized seawater. Mussels were cleansed
in 24 hrs; oysters and other shellfish were depurated for 48 hrs and showed
complete destruction of pathogenic bacteria. These authors also point out
that Article 16 of the Decree of 31 July 1923 (France) requires that contami-
nated shellfish cannot be released to the public until after they have
39
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stayed one month in a depuration station. "Since using ozonized seawater
can reduce this holding time to 24 to 48 hours, the practical benefits of
using ozone can be of great economic significance".
Salmon, Salmon, Le Gall & D'Loir (1937) described tests conducted at
the depuration stations at Le Havre (which cleanses 2,000 kg/day of shellfish)
and at Boulogne-sur-Mer (6,000 kg/day) using ozonized seawater. Mussels
were depurated successfully at an ozonized seawater flow rate of 20 ml/mussel/-
hr with 100 mussels/1 of water.
Fauvel (1963) compared depuration tests in seawater treated with ozone
versus chlorine and conducted on 200 kg lots of bacterially contaminated
mussels and on 10 kg lots of clams. He confirmed that depuration rates for
clams are slower than those for mussels. After 5 days, clams depurated in
ozonized seawater showed zero tissue coliform counts, whereas clams depurated
the same length of time in chlorinated seawater gave counts of 1,200 coliforms/-
liter. Thus, depuration in ozonized seawater is to be preferred over depura-
tion in chlorinated seawater. In addition, shellfish depurated in ozonized
seawater "retain their original taste, whereas those treated in chlorinated
water appear soft and chewey". No detrimental health effects were observed
in shellfish depurated in ozonized seawater.
A further advantage of ozonation is that a chlorine contact time of 12
hrs is recommended for disinfection, versus 6 minutes for ozone (Fauvel,
1977).
Marine Water Quality Improvement
The economics or physical location of some aquaculture facilities may
necessitate the use of water in the hatchery which has been microbially or
chemically contaminated. Such facilities must employ an adequate and
economically reasonable disinfection system to insure the use of optimal
culture waters, preventing waterborne disease in the stock or fouling of the
physical operation. Ozone gas has long been recognized as an excellent
disinfectant, capable of rapidly killing bacteria, viruses and fungi.
In 1929, H. Violle of the University of Marseille, France, seeking to
expand ozone's disinfection capability in freshwater to seawater, demonstrated
that the oxidant could easily disinfect seawater seeded with around 1 x 106
bacterial cells/ml within 8 minutes.
More recently, Combs and Blogoslawski (1975) studied the effects of
ozonization on seawater suspensions of the marine-occurring yeast, Sporobolo-
myces roseus. No cells survived ozonization periods of 90 seconds and
above. In an earlier report, Giese and Christensen (1954) reported that
ozone directly affected respiration in yeast cells, often resulting in a
complete kill of the cells, thereby reducing yeast respiration. After
subsequent tests with other yeasts, Combs and Blogoslawski suggested that
ozone was effective in removing both pathogenic and non-pathogenic marine-
occurring yeasts. Blogoslawski and Stewart (1977) note that ozonization of
40
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hatchery water would prevent the exposure of workers to pathogenic yeasts as
well as improve the holding water quality for adult shellfish.
Blogoslawski, Brown, Rhodes & Broadhurst (1975) described a pilot plant
seawater disinfection system employing filtration through activated carbon,
ozonization, then filtration through activated carbon. The system treated
13,000 gal/day of raw seawater. When the residual ozone concentration
reached 0.5 to 0.56 mg/1, no microorganisms were observed on inoculated agar
plates incubated 5 days at 18°C. Fish held 90 days in the ozonized seawater
showed no fin rot or necrotic lesions and exhibited only limited mortality.
Control fish held in non-treated seawater developed fin rot, necrotic lesions,
and showed 78 to 100% mortality over the same 90-day period.
The ozone contactors, associated piping and post-ozonation filters did
not foul, whereas the non-ozonized seawater pipes became heavily fouled over
a 3-day period. This indicates the potential for ozone to control biofouling
in cooling water applications.
Honn and Chavin (1976) have noted the necessity for a supplement to
regular biological filtration in closed marine systems as bacterial filtration
usually is inadequate to deal with the toxic wastes accumulating in these
operations. Their work indicates that when ozone is added to the system as
a supplementary filtration method, it rapidly stabilizes the system.
Sander and Rosenthal (1975), citing the need for seawater sterilization
in mariculture facilities, selected ozone as the most likely method to
achieve disinfection without causing physiological damage to the stock being
cultured. These authors, basing their work on the studies of Frese (1974),
demonstrated that as long as the ozone concentration in air bubbled through
holding water is lower than 0.5 mg/1 by weight, no harmful effects will
occur to gills of fish during treatment procedures lasting less than 6
hrs/day. Sander and Rosenthal (1975) also report that ozonization very
often is used in connection with protein skimming in commercial aquaria and
aquafarms because of the rapid decomposition of ozone coupled with its
oxidative efficiency and simultaneous aeration of the waters during the
ozone contacting process. Descriptions of commercial protein skimmers used
in conjunction with various ozone contactors are given. To destroy residual
ozone before ozonized water is returned to algal or fish tanks, the treated
water usually is passed through an activated carbon tower.
Edwards (1975) describes the engineering design of an enclosed raceway
for aquaculture, which consists of totally enclosed and insulated raceway
tanks complete with an air lift pump system, solid and waste removal system,
solid and waste separator and biological filter, water purification unit, pH
control and chemical additive system, water heating or cooling system and
the necessary pumping equipment. The water purification system can include
either ozone or UV light treatment. Blogoslawski (1977) reports that Stopka
(1975) has shown that oxidation or foam fractionation degrades dissolved
organics in mariculture systems and that Spotte (1970) indicated that ozone
is more efficient than air in the oxidation of dissolved organics. The use
41
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of ozone in the lift pumps of Edwards' closed raceway culture system effec-
tively removes any dissolved organics from the system.
A critical key to locating oceanaria inland is the ability to recycle
the aquatic environment. Murphy (1975) describes the recycling of marine
aquaria waters which house the bottlenose dolphins at Sea World of Florida.
Continuous chlorination of the recycled water was unsatisfactory because
animal irritability increased as the chloramine concentrations increased.
In addition, bacterial and algal populations became more and more difficult
to control as several species developed resistance to sublethal treatment
procedures. Breakpoint chlorination was preferable, but required isolating
the animals from the treated water, then dechlorinating. Two small scale
studies were conducted successfully using ozonation and a full-scale ozone
treatment system was designed and installed in late 1973 for the 2,000,000
gal aquarium housing bottlenose dolphins.
Ozone dosages of 0.8 to 1.0 mg/1 are applied through fine pososity
Teflon diffusers (0.01 cm bubble size produced) to dolphin tank water
which first is passed through high pressure dual media filters. The ozone
contact "chamber" is an open, rectangular 330,000 gal tank. The Teflon
diffusers are installed in the front one-half of the tank, and the total
time water is in contact with ozone is 30 to 40 minutes. The ozone generator
is capable of producing 100 Ibs/day of ozone from air, but normally is
operated at 70 to 90 Ibs/day. After ozonation, the water is passed through
two ammonia scrubbing towers, stored in a return sump, then sent back to the
exhibit tanks. A chlorine dioxide generator is available after the sump in
the event of ozonation system failure.
The ozone dosage of 0.8 to 1.0 mg/1 maintains BOD in the water at a
maximum level of 2 mg/1, even though the marine mammals living in this
facility consume nearly 2,000 Ibs of food every day. The ozonation facility
at Sea World of Florida has been in operation since late 1973. As of June,
1976, the facility was still using the original water, and bacterial popula-
tions have remained low (Blogoslawski and Stewart, 1977).
Sea World of Ohio exhibits only marine mammals. Using two ozone
generators (capacity 20 to 40 Ibs/day of ozone from air), the facility
ozonizes 450,000 gal of water in a closed system. The wastewater is ozonized,
then passed through a high rate sand filter, after which it is returned to
the aquarium tank. Because of the nature of their exhibit, Sea World of
Ohio uses only water and sodium chloride. At the doses employed, the facility
encounters no ozone residual. The skin integrity of the animals is preserved,
the normally yellow colored water in the tanks is turned blue, and no bac-
terial slime formation is observed (Blogoslawski and Stewart, 1977).
A 170,000 gal coral reef exhibit containing marine fishes, sharks and
turtles at Sea World of Orlando, Florida incorporates very efficient physical
and biological filter components which negate the need for supplementary
treatment for BOD reduction. In this case, ozone is used to eliminate
accumulated color from the seawater system. The yellowish color character!'s-
42
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tic of recycled aquaria water is removed effectively by treating a side
stream with 0.1 to 0.2 mg/1 of ozone (1.0 to 1.5 Ibs/day of ozone; Murphy, ,
1975).
Blogoslawski (1977) notes that ozone is of use in the raising of
marine animals for experimental purposes. He cites studies of Giese and
Christensen (1954) which indicate that ozonized seawater provides a bacteria-
free medium for culture of eggs of the sea urchin (Strongylocentrotus purpura-
tus) without affecting the division of the eggs, and he suggests that this
work shows that ozone does not adversely affect the deeper structures of the
cell or the nucleic acid components at the dose levels examined.
Tchakhotine (1937) used ozonized seawater to sterilize the external
surface of the worm Sabellaria. He found the motility of the sperm destroyed,
permitting him to work with the unfertilized eggs necessary for his research.
Ciambrone (1975) described the use of ozonized municipal sewage to grow
algae which then was used as food for raising oysters. Municipal sewage was
filtered, ozonized, then refiltered and mixed 1:4 with filtered seawater.
The ozonized sewage contained 30 mg/1 of BOD, 15 mg/1 of COD, 20 mg/1 of
suspended solids (SS) and 20 MPN (most probable number) of coliforms/100 ml.
Algae were allowed to grow and stabilize in this medium; then the water was
diluted with 18 to 22 volumes of fresh seawater and oysters were raised in
this medium. Effluent water from the oyster tanks then was ozonized "to
oxidize ammonia to nitrates" (questionable that this occurs) and for disinfec-
tion before discharging. It was found that a newly-set oyster spat could be
grown to market size oysters by the above procedure in about 1 to 1.5 normal'
growing seasons (12 to 15 months), or about twice as fast as oysters grown
conventionally.
The ozone dosages for treating filtered sewage were stated by Ciambrone
(1975) to be 1 mg/1, but this number appears to be too low to produce the
quality of ozonized sewage described. A similar municipal sewage at Indian-
town, Florida is treated first by a trickling filter, then by chemical
precipitation, lamella settling, and still requires ozone dosages of 5 to 6
mg/1 to attain fecal coliform counts of 2 MPN/100 ml. Total coliform counts
of less than 70 MPN/100 ml are obtained at Indiantown, Florida with ozone
dosages of 7.5 mg/1 (Novak, 1977).
Freshwater Quality Improvement
The use of ozone to improve water quality long has been recognized in
treating freshwaters for drinking purposes (Miller et_ aJL, 1978). Its
published uses in aquaculture include the hatching of trout eggs and the
rearing of fish.
Benoit and Matlin (1966) hatched rainbow trout in ozonized water from
two batches of eggs contaminated with mycelial filaments of Saprolegnia.
Water was pumped through a temperature controller, then through a head box
containing 0.75 inch of glass wool on top of 1 inch of bone charcoal. This
water was ozonized with a stream of air containing 26 to 65 mg/1 of ozone by
43
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volume. Ozone concentrations were increased when the mycelial filaments
were observed to be spreading, and were decreased when the mycelia were
observed to "shed" from the dead eggs. Ozone dosages were varied by means
of a rheostat connected to a Sander ozone generator.
Live eggs of the older group hatched completely, even though a large
number of younger eggs were covered with filaments of Saprolegnia. Overall
yield of the advanced fry from the older group of eggs was 84% and overall
yield of sac fry from the younger group was 34%. Based on these excellent
results, the authors recommended that the use of ozone for treatment of fish
hatchery waters be reexamined.
Rosenlund (1975) found that residual ozone concentrations of 0.01 to
0.06 mg/1 in ozonized lake water influent to aquarium tanks resulted in high
mortality of rainbow trout within 4 hrs. However, if the ozonized water was
aerated (to eliminate any gas supersaturation) and allowed to stand 11
minutes (to allow excess ozone to decompose), trout could be held successfully
with no detrimental effects.
Thompson (1976) reported on the design of an ozonation system to be
installed at the Freshwater Institute of Environment Canada in Winnipeg.
The Institute plans to import fish diseases for study and requires a means
to ensure that these diseases do not escape into the Canadian environment.
Design of the treatment process must guarantee total elimination of bacteria
and viruses in the fish holding tank effluent, not simply the attainment of
"normal" disinfection.
This fish holding tank effluent is of high quality, with the exception
of baterial counts. BOD-5 consistently is below 5 mg/1 (average 3), suspended
solids are rarely above 2 mg/1 (average 1), COD averages 21 mg/1 and TOC
averages 5 mg/1. Total bacterial counts exceed 800,000/ml and total coliforms
average 1,500/100 ml.
Pilot ozonation studies were conducted using a 7-ft contact chamber
with a sintered polyethylene diffuser. These tests indicated that an ozone
dose of 5 mg/1 at a 5-minute contact time would meet the required bacterial
standards. For assurance, the system design will allow the Institute to
apply 22 mg/1 of ozone for 44 minutes at average flow and 12 mg/1 for 24
minutes at peak flow. Installed ozone generation capacity will be 44 Ibs/day
by means of 2 units, with a contact tankage of about 3,000 Imperial gal
(Igal).
The ozone contacting system to be installed at the Freshwater Institute
consists of an ejector device in a first contact chamber and a surface
turbine aerator in a second chamber. Ozone and wastewater flow will be
countercurrent, so that the incoming wastewater in effect will clean the
vent gas of ozone. The time of contacting will be 15 minutes in the first
stage and 7 minutes in the second stage at average flow.
44
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It is noteworthy that many European drinking water treatment plants
which process polluted surface waters and which incorporate ozonation,
monitor their product waters for the presence of toxic pollutants by passing
product waters through aquaria stocked with trout. Because there is no
residual ozone in the processed drinking water, the trout thrive, unless a
toxic pollutant happens to have passed through the water treatment process.
If any stress is observed with these trout, the water treatment process is
shut down and the cause is investigated (Miller e_t al_., 1978; Poels, 1977).
Haraguchi, Simidu & Aiso (1969) found that the storage lives of fresh
jack mackerel and shimaaji fish were lengthened by 1.2 to 1.6 times upon 30
to 60 minute treatment once every 2 days with water containing 0.6 mg/1 of
ozone.
Disease Prevention Measures
Waters used to support cultured species necessarily must be free from
disease. Therefore, aquaculture facilities which draw their waters from
areas subject to contamination must use some method of disinfecting the
water before exposing the animals to it.
As mentioned earlier, Sander and Rosenthal (1975) have cited the need
of aquaculture facilities to prevent disease by sterilizing their intake
waters. These authors recommended ozonation as the most efficient method to
accomplish this.
Blogoslawski and Stewart (1977) and Blogoslawski (1977) have noted that
man is not always responsible for undesirable water conditions for aquaculture,
but that blooms of toxic dinoflagellates (including the so-called red tide
blooms) occur throughout the world periodically. These toxin-bearing organ-
isms can be lethal to fish or can be concentrated in the tissues of shellfish
so as to be poisonous to man.
Blogoslawski, Thurberg & Dawson (1973) first showed that the toxicity
of material extracted from Gymnodiniurn breve cultures is deactivated upon
treatment with ozone. After ether extraction of the cultures, the toxic
powder was suspended in mammalian saline and injected intraperitoneally into
19 to 21 g of mice and into 6 to 10 g of killifish. Mouse dosage was 6.0 mg
of toxin in 0.4 ml of saline and fish dosage was 6.0 mg in 0.2 ml of saline.
After data were obtained on the toxicities of the extract, the material was
subjected to ozonation. Samples of toxin (3 mg/1) suspended in the appro-
priate saline were ozonized in 2-dram glass vials by passing 1% ozone-
containing air through the solution for 15 minutes by means of a 21-gauge
hypodermic needle. At a flow rate .of ozone-containing air of 110 ml/minute,
the toxicity of the extract was destroyed in 5 minutes.
These authors concluded that ozone treatment of marine aquarium systems
could detoxify influent waters containing toxic dinoflagellate blooms provided
that the proper dosage was used and would produce no undesirable effects,
and provided that no residual ozone remains in the water. Residual ozone
may be removed by filtration through activated carbon.
45
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Blogoslawski, Thurberg, Dawson & Beckage (1975) described the successful
use of ozone to detoxify the G. breve (red tide) bloom which occurred during
April, 1974 on the Florida west coast. However, insufficient data are
reported in this article to be able to determine the amounts of ozone utilized.
Dawson £t aj_. (1976) also applied ozonization to the G. tamerensis
bloom along the coast of northern New England in September, 1974. Bivalves
exposed 8 days in ozonized seawater containing G. tamerensis remained non-
toxic.
More recently, Blogoslawski and Stewart (in press) have shown that
paralytic shellfish poison (P.S.P.) toxified surf clams (Spisula solidi-
ssima) may be detoxified with ozone-seawater treatment. These authors also
have indicated the anatomical location of the poison within the clam.
Finally, Stewart & Blogoslawski (1977) have reviewed the status of
ozone detoxification of the phytoplankton blooms and another marine toxin,
tetrodotoxin. Tetrodon poison, also known as fugu or puffer fish poison, is
caused by tetrodotoxin (TTX). Ozonation of 1 mg of crystalline TTX in 25 ml
of water 30 minutes with 2% ozone in air at a gas flow rate of 110 ml/min
was carried out. ATI experimental mice injected with 1 ml of the ozonized
solution survived, whereas those injected with non-ozonized TTX solution
died within 2 to 4 minutes.
Toxicity Of Ozonized Seawater
Although Rosenlund (1975) has shown that exposure to low levels of
residual ozone in freshwater can be lethal to rainbow trout, if ozonized
lake water is aerated and allowed to stand 11 days, the trout now are not
adversely affected. On the other hand, ozonization of seawater produces a
much longer residual toxicity.
In 1975, Blogoslawski, Brown, Rhodes & Broadhurst recognized that
ozonized seawater prevented fertilized oyster eggs from developing into
normal larvae at the ozone dose levels being used (up to 0.56 mg/1). In a
68-hr test, only 44.2% of the eggs developed normally in ozonized seawater.
The authors concluded that this toxicity could not be caused by residual
ozone because of the short half-life of the oxidant and because residual
ozone is destroyed by passage of the treated water through activated carbon.
Therefore, they hypothesized that the toxic activity must have been caused
by an oxidation product (organic or inorganic).
A more detailed account of the effects of ozonized seawater on fertile
oyster eggs is presented by Maclean, Longwell and Blogoslawski (1973).
Unfertilized eggs spawned by the same female in the control and ozonized
water showed no cytological differences. In ozonized seawater, fertilization
occurred less readily. More than double the number of eggs were retarded in
their completion of meiosis, a 3-fold increased incidence in abnormal polar
bodies was observed, and more than double the number of cleaving eggs had
abnormal nuclei. These nuclei showed signs of metabolic difficulties or of
46
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degeneration and were pycnotic, pale, diffuse or even fragmented. The
cytological and cytogenetic effects of ozone appeared to be radiomimetic,
which may be caused by free radical decomposition products of ozone.
These authors concluded that post-ozonation treatment steps, such as
activated carbon adsorption, should be developed to remove the offending
substances.
Demanche, Donoghay, Breese & Small (1975) made a detailed study of
post-ozonation treatments of ozonized seawater and determined the residual
toxicities of such samples to oyster larvae. Allowing ozonized seawater to
stand up to 4 weeks (by which time residual dissolved ozone no longer could
be present) did not reduce the toxicity. Neither did bubbling air through
ozonized seawater to remove excess air and/or excess ozone. Treatment with
ethylenediaminetetraacetic acid (EDTA) removed heavy metals (iron and mangan-
ese) but had no effect upon the residual toxicity. The only treatment
technique that was effective in eliminating the residual toxicity of ozonized
seawater proved to be filtration through activated carbon, but the effective-
ness of different types of carbon was highly variable. Darco D-60 (20 to 40
mesh) satisfactorily removed the toxicity caused by ozonation.
The cause of this residual toxicity in ozonized seawater has been shown
to be the oxidation of bromide ion to a bromine-containing species which is
long-lived and produces a positive test by the Kl-starch test procedure.
Blogoslawski ejb al_. (1976) ozonized distilled water solutions of sodium
bromide and measured the dissolved ozone by spectrophotometry. When the
characteristic ozone peak at 254 nm had disappeared, the Kl/starch test
procedure still gave a strong positive test.
Pichet & Hurtubise (1976) added bromide ion to artificial seawater and
showed that ozonation produced bromine or hypobromous acid. Helzs Hsu &
Block (1976) showed that treating natural estuarine water with ozone or with
chlorine produces bromoform and negligible amounts of chlorine-containing
haloforms. Ingols (1976) also concluded that ozonization of seawater oxidizes
bromide ions to bromine and hypobromite, and discusses the mechanisms involved,
More recently, Crecelius (1977) has conclusively demonstrated the
formation of bromate in ozonized seawater.
The corresponding oxidation of bromide ion in seawater by chlorination
to form hypobromous acid and hypobromite ion is well known (Eppley, Renger &
Williams, 1976, and references cited therein). Macalady, Carpenter & Moore
(1977) have shown that when seawater is chlorinated (producing hypobromous
acid and hypobromite ion) then subjected to photolysis by exposure to natural
sunlight, the hypobromite is converted to bromate ion, which is a strong
oxidizing agent, but which does not show up well with analytical procedures
involving oxidation of iodide ion.
Thus, when ozone is applied to seawater for aquaculture purposes, the
dosage levels must be monitored carefully, especially during the susceptible
47
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egg and larval stages, so that genetic and physiological damage to the
growing animals may be avoided. Alternatively, the oxidized bromine-contain-
ing species may be removed from the ozonized seawater by passage through the
proper activated carbon adsorbent.
Conclusions
1. Ozonization is an appropriate disinfection treatment for fresh water
applications where residual disinfecting agents or toxic oxidation
products (such as chlorinated amines) cannot be tolerated, or for
seawater used for depuration of shellfish. Ozone dosages to achieve
disinfection generally are 1 to 3 mg/1.
2. Coliform or toxin-contaminated adult shellfish cleanse rapidly, without
detrimental effects, during depuration in (exposure to) ozonized seawater.
3. Residual dissolved ozone must be removed from the water before exposing
fish or eggs; this is normally done by passage of the ozonized seawater
through activated carbon. Alternatively, ozonized freshwater can be
aerated and allowed to stand for at least 11 minutes (for fresh water
juvenile trout).
4. In marine (salt water) applications, ozone doses which exceed 0.5 mg/1
will oxidize bromide ion to bromine, which then forms hypobromous acid
and hypobromite ions. In the presence of UV light, these will produce
bromate ion. All of these oxidized bromine species may cause abnormali-
ties to occur in fertilized oyster eggs and juvenile shellfish. This
residual toxicity (after ozonation) can be removed from ozonized seawater
by passage through activated carbon, although not all activated carbons
give the same performance in this regard.
5. Chlorination of seawater also gives rise to the same oxidized bromine
species as does ozonation.
6. Conclusions 4 and 5 imply that if a non-marine water containing both
bromide and organic matter is ozonized or chlorinated, bromine-containing
organic compounds will be formed.
7. The fact that seawater does not biofoul when it contains 0.50 to 0.56
mg/1 of residual ozone, indicates the potential for ozone to be an
alternative biofouling control material to chlorination. However, the
same long-lived toxicity (from the presence of oxidized bromine species)
should be present in seawaters used for cooling purposes when treated
with ozone dose levels in excess of 0.5 mg/1 as with Chlorination.
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LITERATURE CITED -- AQUACULTURE (AQ)*
AQ-01 Anonymous, 1972, "Use of Ozone in Sea Water for Cleansing Shell-
fish", Effluent and Water Treatment 0., 12:260-262.
AQ-02 Blogoslawski, W.J., 1977, "Ozone as a disinfectant in mari-
culture", in Proc. Third Meeting of the I.C.E.S. Working Group on
Mariculture, Brest, France, May 10-13, 1977. Actes de Colloquies
de C.N.E.X.O. 4:371-381.
AQ-03 Benoit, R.6. & N.A. Mat!in, 1966, "Control of Saprolegnia on Eggs
of Rainbow Trout (Salmo qairdneri) with Ozone", Trans. Am. Fish
Soc. 95(4):430-432.
AQ-04* Blogoslawski, w.J., C. Brown, E.W. Rhodes & M. Broadhurst, 1975,
"Ozone Disinfection of a Seawater Supply System." in Proc. First
Intl. Symp. on Ozone for Water & Wastewater Treatment, R.6. Rice &
M.E. Browning, Editors, Intl. Assoc., Cleveland, Ohio, p. 674-687.
AQ-05 Blogoslawski, W.J., F.P. Thurberg & M.A. Dawson, 1973, "Ozone
Inactivation of a Gymnodiniurn breve Toxin." Water Research 7:1701-
1703.
AQ-06* Blogoslawski, W.J., F.P. Thurberg, M.A. Da'wson & M.J. Beckage,
1975, "Field Studies on Ozone Inactivation of a Gymnodiniurn breve
Toxin," Environmental Letters, 9(2):209-215.
AQ-07 Blogoslawski, W.J.', L. Farrell, R. Garceau & P. Derrig, 1976,
"Production of Oxidants in Ozonized Seawater", in Proc. Sec. Intl.
Symp. on Ozone Technol., R.G. Rice, P. Pichet & M.-AV Vincent,
editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 671-681.
AQ-08 Blogoslawski, W.J. & M.E. Stewart, 1977, "Marine Applications of
Ozone Water Treatment", in Forum on Ozone Disinfection, E.G.
Fochtman, R.G. Rice & M.E. Browning, editors, Intl. Ozone Assoc.,
Cleveland, Ohio, p. 266-276.
AQ-09 Blogoslawski, W.J. & M.E. Stewart, 1978, "Paralytic Shellfish
Poison in Sp isu 1 a solidis s ima: Anatomical Location and Ozone
Detoxification", Marine Biology, in press.
AQ-10* Burkstaller, J. & R.E. Speece, 1970, "Survey of Treatment and
Recycle of Used Fish Hatchery Water." New Mexico State Univ. Engr.
Exptl. Sta., Technical Rept. #64, June, 1970.
AQ-11 Ciambrone, D.F., 1975, "Ozone Treated Sewage for Oyster Culture",
in Aquatic Applications of Ozone, W.J. Blogoslawski & R.G. Rice,
editors. Intl. Ozone Assoc., Cleveland, Ohio, p. 81-86.
* Abstracts of asterisked" articles will be found in EPA 600/2-79- b.
49
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AQ-12 Combs, T.J. & W.J. Blogoslawski, 1975, "Effects of Ozone on a
Marine-Occurring Yeast, Sporobolomyces", in Aquatic Applications
of Ozone. W.J. Blogoslawski & R.G. Rice, editors. Intl. Ozone
Assoc., Cleveland, Ohio, p. 43-49.
AQ-13 Crecelius, E.A., 1977, "The Production of Bromine and Bromate in
Seawater by Ozonization", presented at Symp. on Advanced Ozone
Technology, Toronto, Ontario, Canada, Nov. 1977. Intl. Ozone
Assoc., Cleveland, Ohio.
AQ-14 Dawson, M.A., F. Thurberg, W.J. Blogoslawski, J. Sasner, Jr. &
M. Ikawa, 1974, "Inactivation of Paralytic Shellfish Poison by
Ozone Treatment", Proc. Food-Drugs from the Sea Conf., Marine
Technology Soc., p. 152-157.
AQ-15* DeManche, J.M., P.L. Donaghay, W.P. Breese & L.F. Small, 1975,
"Residual Toxicity of Ozonized Seawater to Oyster Larvae."
Oregon State Univ., Sea Grant College Prog. Pub. #ORESU-T-75-003,
November, 1975, 5 pp.
AQ-16 Edwards, H.B., 1974, "Closed Raceway System for Mariculture", Pre-
sented at World Mariculture Soc. Meeting.
AQ-17 Edwards, H.B., 1975, "A New Concept for Aquaculture Closed Raceway
Systems", Presented at World Mariculture Society, Seattle, Washing-
ton, Jan. 30.
AQ-18 Eppley, R.W., E.H. Renger & P.M. Williams, 1976, "Chlorine React-
ions With Seawater Constituents and the Inhibition of Photosynthesis
of Natural Marine Phytoplankton", Estuarine & Coastal Marine Sci.
4:147-161.
AQ-19* Fauvel, Y., 1963, "Use of Ozone as a Sterilizing Agent in Seawater
for the Depuration of Shellfish", Intl. Comm. for Scientific
Exploration of the Mediterranean Ocean, Reports and Verbal Proceed-
ings 17(3):701-706.
AQ-20 Fauvel, Y., 1964, "Nouvelles observations sur Tutilisation de
1'ozone comme agent st§rilisateur de 1'eau de mer pour Tepuration
des coquillages", Comm. Int. Explor. Sci. Mer Medit., Symp. Pollut.
Mar. par Microorgan. Prod. Petrol. 293-298.
AQ-21 Fauvel, Y., 1967, "1'Epuration des Coquillages", Rev. trav. Inst.
Pfiches marit., 31(1).
AQ-22 Fauvel, Y., 1977, "Utilisation de L'Ozone en Ostreiculture et dans
les Industries Connexes", Presented at 3rd Intl. Symp. on Ozone
Technol., Paris, France, May, 1977, Intl. Ozone Assoc., Cleveland,
Ohio.
50
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AQ-23 Frese, R., 1974, "Ozonisierung odor Biologische Filterung. Eine
Vergleichende Studie mit Einbeziehung der Erfahrungen am Kieler
Aquarium". Diplomarbeit Christian Albrecht. Univ. Kiel, 58 p.
AQ-24 Giese, A. & E. Christensen, 1954, "Effects of Ozone on Organisms",
Physiol. Zool. 27(2):101-115.
AQ-25 Haraguchi, T., U. Simidu & K. Aiso, 1969, "Preserving Effect of
Ozone to Fish", Bull. Japanese Soc. Sci. Fisheries, 35(9).
AQ-26 Helz, G.R., R.Y. Hsu & R.M. Block, 1978, "BromofornrProduction by
Oxidative Biocides in Marine Waters", in Ozone/Chlorine Dioxide
Oxidation Products of Organic Materials, R.G. Rice & J.A. Cotruvo,
editors, Intl. Ozone Assoc., Cleveland, Ohio, 68-76. *
AQ-27 Honn, K. & W. Chavin, 1976, "Utility of Ozone Treatment in the
Maintenance of Water Quality in a Closed Marine System", Marine
Biol. 34:201-209.
AQ-28 Ingols, R.S., 1978, "Ozonation of Seawater", in Ozone/Chlorine
Dioxide Oxidation Products of Organic Materials, R.G. Rice & J.A.
Cotruvo, editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 77-81.
AQ-29 Macalady, D.L., J.H. Carpenter & C.A. Moore, 1977, "Sunlight-
Induced Bromate Formation in Chlorinated Seawater", Science 195:-
1335-1337.
AQ-30* Maclean, S.A., A.C. Longwell & W.J. Blogoslawski, 1973, ^'Effects
of Ozone-treated Seawater on the Spawned, Fertilized, Meiotic and
Cleaving Eggs of the Commercial American Oyster." Mutation Rsch.
21:283-285.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, W. KUhn & H.
Wolf, 1978, "An Assessment of Ozone and Chlorine Dioxide Tech-
nologies for Treatment of Municipal Water Supplies", U.S. EPA
Report #EPA 600/2-78-147. U.S. Environmental Protection Agency,
Municipal Environmental Research Laboratory, Cincinnati, Ohio.
AQ-31 Murphy, W.K., 1975, "The Use of Ozone in Recycled Oceanarium
Water", in Aquatic Applications of Ozone, W.J. Blogoslawski & R.G.
Rice, editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 87-95.
Novak, F., 1977, "Two Years of Ozone Disinfection of Wastewater at
Indiantown, Florida", presented at Seminar on Current Status of
Wastewater Treatment and Disinfection With Ozone, Cincinnati,
Ohio, Sept. 15. Intl. Ozone Assoc., Cleveland, Ohio.
AQ-32 Pichet, P. & C. Hurtubise, 1975, "Reactions of Ozone in Artificial
Seawater", in Proc. Sec. Intl. Symp. on Ozone Techno]I., R.G. Rice,
P. Pichet & M.-A. Vincent, editors, Intl. Ozone Assoc., Cleveland,
Ohio, p. 665-681.
51
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AQ-33 Rosenlund, B.D., 1975, "Disinfection of Hatchery Influent By
Ozonation and the Effects of Ozonated Water on Rainbow Trout", in
Aquatic Applications of _0zone_. W.J. Blogoslawski & R.G. Rice,
editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 59-69.
AQ-34* Salmon, J., A. Salmon, J. Le Gall & D. Loir, 1937, "A Depuration
Station for Shellfish Using Ozonized Seawater." Ann. Hyg. 15:581-
584.
AQ-35* Salmon, J., J. Le Gall & A. Salmon, 1937, "Preliminary Note on
Several Experiments of Purifying Edible Marine Molluscs by Ozonized
Seawater", Ann. Hyg. Publique, Industrielle et Sociale 15:44-50.
AQ-36 Sander, E. & H. Rosenthal, 1975, "Application of Ozone in Water
Treatment For Home Aquaria, Public Aquaria and for Aquaculture
Purposes", in Aquatic Applications of Ozone_. W.J. Blogoslawski &
R.G. Rice, editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 103-
114.
AQ-37 Spotte, S.H., 1970, Fish and Invertebrate Culture: Water Manage-
ment in Closed Systems. Wiley-Interscience Publishers, Inc., New
York, N.Y., 145 p.
AQ-38 Stewart, M.E. & W.J. Blogoslawski, 1977, "Detoxification of Marine
Poisons By Ozone Gas", Presented at 3rd Intl. Symp. on Ozone
Technol., Paris, France, May. Intl. Ozone Assoc., Cleveland,
Ohio.
AQ-39 Stopka, K., 1975, "European and Canadian Experiences with Ozone in
Controlled Closed Circuit Fresh & Salt Water Systems", in Aquatic
Applications of Ozone, W.J. Blogoslawski & R.G. Rice, editors,
Intl. Ozone Assoc., Cleveland, Ohio, p. 170-176.
AQ-40 Tchakhotine, S., 1937, "The Destructive Action of Ozone on Sperm",
Compt. rend, de Soc. de Biologie 126:1154-1156.
AQ-41 Thompson, G.E., 1976, "Ozone Applications in Manitoba, Canada", in
Proc. Sec. Intl. Symp. on Ozone Technology, R.G. Rice, P. Pichet &
M.-A. Vincent, editors, Intl. Ozone Assoc., Cleveland, Ohio, p.
682-693.
AQ-42 Thurberg, P.P., 1.975, "Inactivation of Red-Tide Toxins by Ozone
Treatment", in Aquatic Applications of Ozone. W.J. Blogoslawski &
R.G. Rice, editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 50-58.
AQ-43* Violle, H., 1929, "Sterilization of Seawater with Ozone: Appli-
cation of this Method to the Purification of Contaminated Shell-
fish", Rev. Hyg. et de Med. Preventive 51:42-46.
52
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BIOFOULING CONTROL
The largest non-consumptive user of both fresh and saline water is the
electric power industry. Large quantities of water are used for cooling
purposes. Typically, raw water is passed through a steam condenser, heated
to a temperature of approximately 8°C above its ambient temperature while
performing its cooling function, then is returned to the river, estuary or
the sea. Most of this large volume of cooling water is treated chemically
to prevent biofouling. Not only can the rapid, undesireable growth of
aquatic flora and fauna physically plug the condenser tubing, which can
cause failure and plant shutdown, but even thin layers of biogrowth will
rapidly decrease the heat transfer efficiencies of the cooling surfaces.
Presently, most power plants add chlorine, either as the gas or as
aqueous solutions of hypochlorite, to disinfect or reduce the biofouling
which occurs in cooling water systems. The acute and chronic effects of
chlorinated compounds on aquatic life are well documented (Brungs, 1973) and
residual chlorine levels in cooling water discharges now are subject to the
EPA National Pollutant Discharge Elimination System (NPDES) regulation
(Chase, 1975).
EPA guidelines have been established requiring that the maximum free
available chlorine in once-through condenser and cooling tower blowdown
waters cannot exceed 0.5 mg/1 for more than 2 hrs/day, without a special
state NPDES exemption (Blogoslawski & Stewart, 1976). This has encouraged
the electric power industry to search for environmentally and economically
acceptable biocides as alternatives to chlorination. One of the biocides
under active consideration is ozone.
Toner & Brooks (1975) reported that ozone is an effective biocide at
residual concentrations of 0.08 to 1.0 mg/1 in seawater for marine plankton,
arthropods and fish. They concluded that treatment of cooling water with
ozone is just as effective as treatment with chlorine for the indigenous
flora and fauna found near the marine intake waters of the Brayton Point
Power Station, Massachusetts. Toner & Brooks (1975) also concluded that
both oxidants provided equivalent long term toxicity to aquatic life.
On the other hand, Mangum & Mcllhenny (1975) compared the use of ozone
versus chlorine to prevent the biofouling of influent waters at the Freeport,
Texas seawater distillation facilities. These investigators found that
chlorine was effective when applied during only 50% of the water flow time
at a 1 mg/1 concentration. However, to attain the same level of efficiency,
ozone had to be applied BB% of the time of water flow at an average dosage
of 1.0 mg/1. In addition, both oxidants produced a relatively long-lived
oxidant level.
Sengupta e_t al_. (1975) estimated the costs involved in using ozone
versus chlorine for power plant biofouling control. They concluded that
ozone applied continuously at levels commonly used to disinfect drinking
water (2 to 3 mg/1), the costs of ozonation for biofouling control would be
53
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considerably higher than those for chlorination. However, if lower levels
(1.0 mg/1 or less) could be effective, the economics would be more favorable
(Sengupta & Chakravorti, 1975).
Siegrist, Tuttle & Majumdar (1976) reviewed the technical and economic
factors of biocide system options for cooling water systems. They concluded
that for ozonation to replace chlorination on an economic basis alone, the
economics of ozone production first must be substantially improved. These
authors considered continuous dosing of ozone at 0.75 mg/1 as well as inter-
mittent dosing at 2.0 mg/1. Although continuous dosing at the lower level
would require less capital investment in ozone generation equipment than
would intermittent dosing at a higher level, the operating costs would be
higher. Overall, the total costs of ozonation compared with chlorine gas or
hypochlorite were estimated to be 10 to 20 times higher. Pertinent data are
given in Table 9.
Yu, Richardson & Medley (1977) have discussed alternatives to chlori-
nation for control of condenser tube biofouling under contract to the U.S.
Environmental Protection Agency. They concluded that the high cost of
ozonation, poor ozone transfer efficiency, lack of residual protection
against downstream contamination for the cooling tower, and lack of field
demonstration probably are reasons why ozonation has not been practiced in
powerplant cooling water systems in the past.
These authors stated:
"In view of the more rigorous criteria proposed for residual chlorine
content in discharging waters in the future, now is an opportune time
for field testing of ozonation for treatment of cooling water. A
breakthrough in ozone production technology is required, however,
before ozonation can compete economically with other methods Although
ozone is quite efficient in the disinfection of water, the applicability
of ozone for the biofouling control of power plants is yet to be field
demonstrated".
Finally, Yu, Richardson & Hedley (1977) stated that if ozone could be
generated for lOtf/lb, its use could be feasible for use in full-scale power
plant cooling water treatment systems in the future, but that at present,
"ozone is simply too new, and too untried in the control of biofouling of
the powerplant condensers".
The Electric Power Research Institute recently has funded a demon-
stration contract (No. RP-733-1) to Public Service Electric & Gas Company of
New Jersey to compare chlorination with ozonation for biofouling control at
an operating power plant (Guerra, 1978). The program began in early 1977
and is scheduled to be completed in early 1979. A mobile trailer has been
fitted with three cooling water condensers (connected in parallel) and
associated instrumentation and is able to process cooling water flows of 100
gal/min. Each condenser is 9 ft long, contains 9 identical tubes, and is
activated by electrical heaters. Instrumentation is available to measure
temperatures, pressures and flow rates.
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TABLE 9. COMPARISON.OF VARIOUS BIOCIDE.SYSTEM ALTERNATIVES
System
Capital Cost
Annual
Operating Cost
Chlorine Gas
Hypochlorite
Generators
Purchased NaOCl
Soln. (15%)
Ozonation
Continuous
Intermittent
Amertap System
(mechanical)
Copper Sulfate
$
$
201,000
230,000
$4,306,000
$ 5,803,000
$ 920,000
$ 123,000
$ 144,000
$ 223,000
$1,445,000
$ 53,000
$ 57,000
$ 127,000
Bases:
1) Costs estimated based on a 2-unit, 1,220 MWe (each) nuclear power
station
2) 1974 price index
3) Interest rate -- 10%
4) Plant life — 40 years
5) Power cost — 30 mils/kwhr, 1981 basis
6) Capacity replacement factor for life of plant ignored
7) Chlorine or hypochlorite required -- 1,900 Ibs/day
8) Dechlorination with S02 included to produce 0.2 mg/1 free chlorine
residual
9) Continuous ozone dosage -- 0.75 mg/1
10) Intermittent ozone dosage -- 2 mg/1 for two 10-minute periods/day
11) CuSO. dosage -- 4 mg/1 for two 10-minute periods/day.
Source: Siegrist, Tuttle & Majumdar (1976)
55
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In the first phase of this demonstration program, the base line perfor-
mance of the condensers will be assessed using chlorine. Heat balances and
the response of the instrumentation under varying simulated power plant
operating conditions will be determined, then chlorine will be employed as
the biofoulant control and the performances of the "model" condensers, on-
site, will be compared with those of the full-scale plant condensers using
chlorine.
In early summer, 1978, the program plan is to shift to the use of
ozone. The on-site performance of ozone in the model condensers then will
be extrapolated to plant-scale performance using as criteria the performances
determined using chlorine.
In a parallel program which will be funded by the Department of Energy,
bioassays are to be performed on the treated waters to determine the effects
of the chlorinated and of the ozonized cooling waters upon selected aquatic
species.
Two cooling waters, brackish and fresh, are to be tested by PSEG/NJ
under this program, but not full-strength seawater (Guerra, 1978).
A decision as to the applicability of ozonation for control of biofouling
of power plant cooling waters thus should be available about mid-1979.
Conclusions
1) Ozone has been shown to be an effective biocide in seawater at residual
concentrations of 0.08 to 1.0 mg/1 for marine plankton, arthropods and
fish in Massachusetts waters.
2) In Gulf of Mexico waters (Freeport, Texas), ozone has been shown to be
an effective biocide at a dosage of 1.0 mg/1, but was required to be
applied 85% of the water flow time to be as effective as 1.0 mg/1 of
chlorine applied 50% of the time.
3) Both ozone and chlorine, used as biocides in seawater, produce a
relatively long lived oxidant residual and a long-lived toxicity to
aquatic life. This toxicity probably is caused by oxidation of bromide
ion to higher oxidation states (see Section 5 -- Aquaculture).
4) Total capital and operating costs of ozonation for biofouling control
at a continuous dosage level of 0.75 mg/1 have been estimated to be 10
to 20 times higher than those for chlorination using chlorine gas or
hypochlorite.
5) A definitive demonstration study comparing ozonation with chlorination
under actual power plant operating conditions began in early 1977 with
results expected in 1979. Effects of the ozonized and chlorinated
cooling waters upon selected aquatic species and operating costs are to
be determined as part of this program.
56
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LITERATURE CITED -- BIOFOULING CONTROL (BF)*
BF-01 Blogoslawski, W.J. & M.E. Stewart, 1976, "Marine Applications of
Ozone Water Treatment", in Forum on Ozone Disinfection, E.G.
Fochtman, R.G. Rice & M.E. Browning, editors, Intl. Ozone Assoc.,
Cleveland, Ohio, p. 266-276.
Brungs, W.A., 1973, "Effect of Residual Chlorine on Aquatic Life",
J. Poll. Control Fed. 45:2180-2193.
BF-02 Chase, R.E., 1975, "The Federal Water Pollution Control Act Amend-
ments of 1972 — PL 92-500 — As It Relates to the Steam Electric
Power Generating Industry", in Aquatic Applications of Ozone, W.J.
Blogoslawski & R.G. Rice, editors, Intl. Ozone Assoc., Cleveland,
Ohio, p. 177-186.
BF-03 Garey, J., 1977, "Ozone For Anti-Fouling Control", presented at
Workshop on Assessment of Technology and Ecological Effects of
Biofouling Control Procedures at Thermal Power Plant Cooling Water
Systems, Baltimore, Md., June 16-17. Electric Power Research
Inst., Palo Alto, Calif.
BF-04 Garey, J., 1977, "A Comparison of the Effectiveness of Ozone and
Chlorine in Reducing Slime Growth Within the Condensers of an
Electric Generating Station Using Seawater as a Coolant", in Forum
on Ozone Disinfection, E.G. Fochtman, R.G. Rice & M.E. Browning,
editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 277-283.
Guerra, C.J., 1978, Public Service Gas & Electric Co. of New
Jersey, Private Communication.
BF-05 Helz, G.R., R.Y. Hsu & R.M. Block, 1978, "Bromoform Production by
Oxidative Biocides in Marine Waters", in Ozone/Chlorine Dioxide
Oxidation Products of Organic Materials, R.G. Rice & J.A. Cotruvo,
editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 68-76.
BF-06 Mangum, D.C. & W.F. Mcllhenny, 1975, "Control of Marine Fouling in
Intake Systems - A Comparison of Ozone and Chlorine", in Aquatic
Applications of Ozone. W.J. Blogoslawski and R.G. Rice, editors,
Intl. Ozone Assoc., Cleveland, Ohio, p. 138-153.
BF-07 Manning, G.B. & A.A. Bacher, 1975, "Ozone and the Steam Electric
Power Industry", in Aqua-tic Applications of Ozone, W.J. Blogo-
slawski and R.G. Rice, editors, Intl. Ozone Assoc., Cleveland,
Ohio, p. 161-176.
* Abstracts of asterisked articles will be found in EPA 600/2-79- -b.
57
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BF-08 Senguta, C., G. Levine, E.G. Wackenhuth & C.R. Guerra, 1975,
"Power Plant Cooling Water Treatment With Ozone", in Aquatic
Applications of Ozone, W.J. Blogoslawski & R.G Rice, editors,
Intl. Ozone Assoc., Cleveland, Ohio, p. 119-137.
BF-09 Senguta, C. & R. Chakravorti, 1975, "Power Plants and Biofouling",
Discussion, Workshop No. 4, in Aquatic Applications of Ozone, W.J.
Blogoslawski & R.G. Rice, editors, Intl. Ozone AssbcTT Cleveland,
Ohio, p. 215-226.
BF-10 Siegrist, H.W., D.G. Tuttle & S.B. Majumdar, 1975, "Technical and
Economic Considerations of Biocide System Options for Cooling
Water Systems: A Review", in Proc. Sec. Intl. Symp. on Ozone
Techno 1.. R.G. Rice, P. Pichet & M.-A~TVincent, editors~,~7ntT.
Ozone Assoc., Cleveland, Ohio, p. 632-649.
BF-11 Toner, R.C. & B. Brooks, 1975, "The Effects of Ozone on Four
Species of Phytoplankton, Crab Zoea and Megalops and the Atlantic
Silverside, Menidia Menidia." in Aquatic Applications of Ozone.
W.J. Blogoslawski & R.G. Rice, editors, Intl. Ozone Assoc., Cleve-
land, Ohio, p. 154-160.
BF-12* Yu, H.H.S., G.A. Richardson & W.H. Hedley, 1977, "Alternatives to
Chlorination for Control of Condenser Tube Bio-Fouling", EPA
Report No. EPA-600/7-77-030, March. U.S. Environmental Protection
Agency, Industrial Environmental Research Lab., Research Triangle
Park, North Carolina 27711. NTIS No. PB-266,269.
58
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CYANIDES AND CYANATES
Cyanides
The first waste cyanide solutions of any significance were produced in
the gold and silver mining industries, where cyanides were used to dissolve
these metals from their ores. Since that time, the use of cyanides has
expanded significantly into the electroplating industry and photographic
bleaches. Cyanides also are found in iron and steel manufacturing (coke
oven wastewaters. In addition, certain types of organic chemicals (nitriles
and cyanohydrins) contain the cyanide grouping in their structure and some
of these compounds can find their way into wastewater discharges.
The known uses of ozonation in each of these major industrial categories
will be discussed in the appropriate sections of this report. However, in
this section the known chemistries of the basic reactions of ozone with
aqueous cyanide and cyanate solutions will be discussed.
The first published account of ozone oxidation of cyanides was by
Neuwirth (1933) who treated KCN solutions batchwise with ozonized air and
obtained substantial reductions in cyanide concentrations when iron and
manganese "catalysts" were present. It is speculated by Sondak & Dodge
(1961), however, that the amount of cyanide reported as "lost" by Neuwirth
might merely have formed stable (to ozonation) metallic complexes with the
catalysts used. That this is highly probable, at least with respect to
iron, is indicated by the high degree of stability of iron cyanide complexes
to simple ozonation (see Section 4, dealing with Ozone/UV Radiation).
Khandelwal, Barduhn & Grove (1959) investigated the kinetics of ozonation
of aqueous cyanide solutions. Using gas phase concentrations of 70 to 90
mg/1 of ozone in oxygen and an application rate of 20 to 25 mg of ozone per
minute through a 1,500 ml sparged ozone reactor at ambient temperatures,
ozonation reaction rates were determined under a variety of conditions for
the, destruction of cyanide according to the following equation:
(CN~) + 03 + HOH—>(CNO") + 02 + HOH
The rate of cyanide disappearance was shown to follow the equation:
d(CN"]/dt = K[CN~]1/3
where: [CN~] = concentration of cyanide ^/
i -C>$5$
t = reaction time f
K = reaction rate constant
The apparent order of the reaction was 1/3. When copper ions were
added the reaction rate more than doubled, but higher copper ion concen-
trations did not further increasxeJhe reaction rate. The rate constant for
59
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ozonation of cyanide ion increased in the following order with the sulfate
salts of the cations added as catalysts: Cd(II), Mn(II), Ni(II) and Cu(II).
The rate constant for Cd(II) was practically the same as for the uncatalyzed
reaction; the rates were unaffected by the choice of anion, specifically
when sulfate, nitrate, acetate or chloride was added as copper salts, over
the temperature range 13 to 30°C.
Sondak & Dodge (1961) conducted a detailed investigation of (1) pure
aqueous cyanide solutions, (2) synthetic and actual zinc, cadmium and copper
plating solutions, and (3) pure aqueous cyanate solutions to examine the
kinetics of ozonation reactions.
Ozone was prepared from dried air (compressor, silica gel, dry ice-
acetone trap), then passed through dilute sodium hydroxide solution to
remove nitrogen oxides. Contacting was conducted in a 4 ft tall by 2.375
inch I.D. glass column containing a porous frit, and usually operated at 2/3
capacity. Ozone in the reactor inlet and outlet gases was measured so that
mass balances could be determined.
Experimentation with pure aqueous cyanide solutions showed that 1.84 g
of ozone was required to oxidize 1 g of cyanide ion to cyanate:
(CN~) + 03— ^(CNO~) + 02 (1.84 Ib (yib CN~)
In addition, it was shown that:
(1) The rate of ozone absorption was constant at a constant inlet ozone
concentration above a limiting ozone concentration,
(2) The rate of ozone absorption increased linearly with inlet ozone
concentration,
(3) Because the rate of ozone transfer from the gas film was rate controlling
in the region of cyanide concentrations studied (up to 80 mg/1 and in
the pH range of 10.3 to 12.4), increasing temperature or addition of
metal ion catalysts had no effect upon the rate of ozone absorption,
(4) Below a critical value of cyanide ion concentration (about 4 mg/1), the
rate of ozone absorption dropped off rapidly and the reaction became
rate controlled instead of mass transfer controlled.
Essentially the same results were obtained with synthetic and actual
plating solutions, except that the rate constant for copper plating solution
was about 15% lower than that for pure aqueous cyanide solutions. In addition,
the plot of rate data for cadmium solutions showed a slight curvature,
rather than being a straight line.
Bahensky & Zika (1966) studied the effect of copper ion and pH on the
ozone oxidation of aqueous cyanide and determined that copper concentrations
of 5 to 15 mg/1 at pH 10 to 11 are optimum for ozonizing solutions containing
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at least 100 mg/1 of cyanide. At pH values below 7, HCN can be liberated
from the reaction mixtures.
Cyanates
Although ozonation of cyanide proceeds rapidly to form cyanate, the
oxidative/hydrolytic destruction of cyanate ion proceeds much more slowly
upon continued treatment with ozone. Cyanate ion is known to decompose at
high or low pH. Kolthoff & Stenger (1947) recommended hydrolysis in strong
alkali as a method for determining the concentration of cyanate ion:
(CNO~) + (OH") + HOH—*C03~2 + NH3
Resnick, Moore & Ettinger (1958) studied the acid hydrolysis of cyanate
at pH 4 and found a half-life for cyanate ion destruction of about 38 minutes.
At temperatures of 30 to 50°C (Sondak & Dodge 1961), the rate of
oxidation of cyanate ion was about one-fifth that of cyanide under the same
ozonation conditions. At pH 11.0, the rate of cyanate oxidation was fastest,
and the ozone demand was 3.06 g/g of cyanate. No hydrolysis of cyanate to
free ammonia was observed.
Additional Reactions
Balyanskii, Selin & Kolychev (1972) ozonized 38 to 40 mg/1 potassium
cyanide solutions under strongly alkaline conditions (pH 12), and identified
nitrate as a reaction product. These authors proposed that hydrolysis of
cyanate ion first forms ammonia, which then oxidizes quickly at this pH upon
ozonation. About 70% of the nitrogen content of the original cyanide was
accounted for as nitrate; the remainder was assumed to have been lost as
nitrogen gas via direct ozonation of cyanate according to the reaction:
2(CNO") + 303 + HOH—>N2 + 2HC03" + 302
The apparent stoichiometry under the experimental conditions (20°C) could be
represented as follows:
(CN") +1.30, - {°H") > (CNO")
O
(CNO") + 4.503 —(OH") >-0.7(N03)" + 0.15N2 + (HC03~)
Balyanakii et_ajk (1972) reported that mass transfer of ozone across
the gas/liquid interface was the rate controlling step in both cyanide and
cyanate oxidations at 20°C and pH 12.
In reviewing methods for purification of wastewaters containing cyanide
ion, Zumbrunn (1971) concluded that using small quantities of ozone produces
cyanate, but that with excess ozone, cyanide forms nitrogen and carbonate:
61
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2(CN~) + 503 + 2NaOH-=>2(NaC03~) + N2 + 502 + HOH
For this reaction to proceed, the pH must be "very alkaline".
Mathieu (1973) describes the ozonation of sodium cyanide solutions,
some of which were mixtures with cuprous cyanide. Tests were conducted in
a pilot installation capable of treating 2 to 7 gal /mi n of solution. The
ozone contactor system was the sprayer type, in which tiny droplets of
solution are sprayed into an atmosphere of ozone in air. Contact time in
this type of contactor is about 12 seconds per contacting chamber. The
process was more effective at cyanide concentrations of 100 mg/1 than at 10
mg/1, removing 91 to 97% of the cyanide. Costs for treating solutions
containing concentrations of 50 mg/1 of cyanide were estimated to be 5 to
7<£/l,000 gal.
In a more detailed discussion of these tests, Mathieu (1975) states
that 98% of the cyanide was eliminated upon optimization of the process.
The solution was electro-coagulated to remove suspended solids, then ozonized
in three spray contactor chambers (total contact time, about 30 seconds).
No cyanate could be detected in the solutions after ozonation.
Fujisawa et aj_. (1973) ozonized solutions of pure KCN and KCNO at
various pH values. Cyanate ion was oxidized by ozone to nitrogen gas.
Ishizaki, Dobbs & Cohen (1978) ozonized aqueous solutions of acetone
cyanohydrin at pH 4, 7, 9 and 11 . At pH 4, the compound was only slightly
oxidized, but at the other values, organic nitrogen content decreased
readily, and ammonia and nitrogen were produced, indicating an increase in
oxi dative decomposition.
acetone cyanohydrin
Ikehata (1975) showed that although the destruction of sodium cyanide
with ozone is very rapid, ferricyanide and ferrocyanide compounds are very
stable to ozone destruction at pH 9 and 25°C. Potassium ferricyanide is a
major component in commercial photographic bleaches.
Ozone/UV Radi a t_1 on
Using synthetic cyanide-containing wastewaters, scientists at Houston
Research Inc. (Garrison, Mauk & Prengle, 1974) confirmed that:
(1) Ozonation at pH 11.0 converted all cyanide to cyanate,
(2) Acidification to pH 4 after ozonation immediately hydrolyzed
cyanate,
62
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(3) Three Ibs of ozone are required to destroy each pound of free cyanide,
except when copper ion is present, in which case the ratio is 2.5/1,
(4) Destruction of concentrated cyanide solutions (100,000 mg/1 or
higher) by -ozone is mass transfer limited, whereas ozonation of
solutions containing less than 1 mg/1 of cyanide is reaction rate
limited.
These Houston Research Inc. scientists also discovered the catalytic
effect of UV radiation and/or heat upon the rate of ozone oxidation of
cyanides and oxidatively refractory organic compounds. Iron cyanide complexes,
present in photoprocessing bleach solutions as well as some electroplating
wastewaters, normally are quite stable to ozonation. However, by applying
both ozone and UV radiation simultaneously, the cyanide concentration can be
reduced rapidly to below the limit of analytical detectability.
When employing an actual photoprocessing bleach solution containing
4,000 mg/1 of cyanide complexed with iron, and a 6-ozone contacting system
(the last 2 with added UV radiation), and using 5.9% ozone in oxygen, the
cyanide concentration leaving the last reactor was below 0.3 mg/1. Cyanate
ion also was destroyed by this system.
Conclusions
• Ozone reacts rapidly with free cyanide ion and many stable metal
cyanide complexes to produce cyanate ions. Iron cyanide complexes are
stable to ozonation. Copper ions catalyze the rate of oxidation of
cyanide to cyanate.
• The rate of ozone oxidation of cyanate ion is about 20% of the rate of
cyanide oxidation under the same conditions. Oxidation of cyanate is
fastest at high pH (11.0). Hydrolysis of cyanate proceeds rapidly at
acidic pH conditions.
• At pH 12, ozonation of cyanide produces nitrate and (apparently)
nitrogen gas from oxidation of the cyanate intermediate.
t Ozonation at pH below 10 to 11 (certainly below 7) might result in HCN
gas being stripped out of the reaction mixture and into the reactor
off-gases.
• Ozonation of cyanide solutions using a series of 3 spray-tower contactors
destroyed all cyanide and all cyanate in about 30 seconds of contact
time.
• Ozonation of acetone cyanohydrin solutions at pH 4 is quite slow, but
at pH 7, 9 and 11, oxidative decomposition is rapid. Organic nitrogen
content decreases rapidly, and ammonia and nitrogen are produced.
63
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» Metal cyanide complexes otherwise stable to ozone oxidation (ferro-,
ferri-, etc.) can be decomposed and the cyanide converted to some
oxidation stage past the cyanate stage by simultaneous treatment with
ozone and UV radiation.
LITERATURE CITED — CYANIDES AND CYANATES (CY)*
CY-01 Anonymous, 1974, Mitsui Shipbuilding Tech. Review 85:42-48 (Jan).
CY-02* Bahensky, V. & Z. Zika, 1966, "Treating Cyanide Wastes by Oxida-
tion with Ozone." Koroze Ochrana Materialu 10(1):19-21. Chem.
Abstr. 65:6907c (1966).
CY-03* Balyanskii, G.V., M.E. Selin & V.B. Kolychev, 1972, "Ozonation of
Simple Cyanides in Water." Zhurnal Prikladnoi Khimii (J. Applied
Chem.) 45(10):2152-56.
CY-04* Besselievre, E.H., 1957, "The Economical and Practical Use and
Handling of Chemicals Used in Industrial Waste Treatment", in
Proc. 12th Indl. Waste Conf., 342-363 (publ. 1958), Purdue Univ.,
Engrg. Bull. Ext. Serv. No. 94.
CY-05 Des Rosiers, P.E. & H.S. Skovronek, 1975, "The EPA Program and
Industrial Advanced Wastewater Treatment Needs—Ozone", in Prgc.
First Intl. Symp. £n Ozone for Water &^ Wastewater Treatment'T'Oi.
Rice & M.E. Browning, editors, Intl. Ozone Assoc., Cleveland,
Ohio, p. 500-521.
CY-06 Diaper, E.W.J., 1972, "Ozone Moves to the Fore", Water & Wastes
Engrg., May, p. 65-69.
CY-07 Eiring, L.V., 1969, "Kinetics and Mechanism of Ozone Oxidation of
Cyanide-Containing Waste Water." Tstel Metal (USSR), 73-76.
CY-08* Fabjan, C. & R. Davies, 1976, "Decontamination with Ozone of
Sewage Containing Cyanide", Wasser, Luft & Betrieb 20(4):175-178.
Chem. Abstr. 85:148426u.
CY-09 Fabjan, C. & R. Davies, 1970-1977, "Die Reinigung Galvanischer und
Anderer Abwasser nach dem Ozonizieren Verfahren", U.S. Dept. of
Commerce, NTIS Report No. PS-77/0749.
CY-10* Fujisawa, T., Y. Matsuda, Y. Takasu, Y. Tanaka & H. Imagawa, 1973,
"On the Ozone-Oxidation Treatment of Sewage Containing Cyanide or
Cyanate." XXXI. Semi-Annual Autumn Mtg. of the Japanese Chemical
Soc., Lecture 131, Oct.
CY-11 Guillerd, J. & C. Valin, 1961, "Traitment par 1'Ozone", TEau,
May.
Abstracts of asterisked articles will be found in EPA 600/2-79- b.
64
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CY-12 Garrison, R.L., C.E. Mauk & H.W. Prengle, Jr., 1974, "Cyanide Dis-
posal by Ozone Oxidation". Final Report, U.S. Air Force Weapons
Lab., Kirtland Air Force Base, New Mexico, Feb., Report No. AFWL-
TR-73-212, U.S. Dept. of Commerce, NTIS Report No. AD-775.152/2WP.
CY-13 Ikehata, A., 1975, "Treatment of Municipal Wastewater by the Use
of Ozone to Yield High Quality Water", in Proc. 1st Intl. Symp. on_
Ozone for Water & Wastewater Treatment., R.G. Rice & M.E. Browning,
editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 227-231.
CY-14 Ishizaki, K., R.A. Dobbs & J.M. Cohen, 1978, "Ozonation of Hazar-
dous and Toxic Organic Compounds in Aqueous Solution", in Ozone/-
Chlorine Dioxide Oxidation Products of Organic Materials, R.G.
Rice & J.A. Cotruvo, editors. Intl. Ozone Assoc., Cleveland,
Ohio, p. 210-226.
CY-15 Kandzas, P.F. & A.A. Mokina, 1968, "Use of Ozone for Purifying
Industrial Wastewaters." Trudy Vses. Nauchno-Issled. in-ta Vodos-
nabzh., Kanaliz., Gidrotekh. Soouzhenii Imzh. Gidrogeol, 20:40-
45. Chem. Abstr. 71:6388v (1969).
CY-16* Khandelwal, K.H., A.J. Barduhn & C.S. Grove, Jr., 1959, "Kinetics
of Ozonation of Cyanides", in Ozone Chem..& Techno!., Adv. in
Chem. Series No. 21, Am. Chem. Soc., Washington, D.C., p. 78-86.
CY-17 Kolthoff, I.M. & V. Stenger, 1947, Volumetric Analysis, Vol. II,
Interscience Publishers, New York, N.Y., p. 267.
CY-18 Kubo, A. & M. Nagata, 1974, "Highly Advanced Treatment of Water
Treated by Activated Sludge Process Effluent of Gas Liquor."
(Journal unknown), Jan.
CY-19* Mathieu, G.I., 1973, "The Film Layer Purifying Process for Cyanide
Destruction", Canadian Mining J., June, p. 3-4.
CY-20 Mathieu, G.I., 1975, "Application of Film Layer Purifying Chamber
Process to Cyanide Destruction—A Progress Report," in Ozone for
Water & Wastewater Treatment, R.G. Rice & M.E. Browning, editors,
Intl. Ozone Assoc., Cleveland, Ohio, p. 533-550.
CY-21 Mathieu, G.I., 1977, "Ozonation for Destruction of Cyanide in
Canadian Effluents - A Preliminary Evaluation", Canada Centre for
Mineral and Energy Tech., Ottawa, Canada, CANMET Report 77-11.
Presented at Symp. on Advanced Ozone Technology, Toronto, Ontario,
Canada, Nov. 1977. Intl. Ozone Assoc., Cleveland, Ohio.
CY-22 Matsuoka, H., 1973, "On the Ozone Treatment of Industrial Sewage."
PPM 4(10):57-59.
65
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CY-23 Neuwirth, F., 1933, Berg-u HUttenmann. Jahrb. Montan. Hochschule
Loeben, 81:126-131.
CY-24 Reznick, J.D., W.A. Moore & M.B. Ettinger, 1958, "Behavior of
Cyanates in Polluted Water", Indl. Engrg. Chem. 50(l):71-72.
CY-25 Sondak, N.E. & B.F. Dodge, 1961, "The Oxidation of Cyanide-Bearing
Plating Wastes by Ozone, Part 1", Plating, 173-180.
CY-26 Sondak, N.E. & B.F. Dodge, 1961, "The Oxidation of Cyanide-Bearing
Plating Wastes by Ozone, Part 2", Plating, 280-284.
CY-27* Zumbrunn, J.P., 1971, "Produits et Proc&des—Epuration des Eaux
Residuaires Cyanurges." Chimie et Industrie. Genie Chimique
104(20):2573-84.
66
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ELECTROPLATING
The earliest application of ozonation to an actual plating waste was
reported by Tyler e_t al. (1951) who treated cadmium plating solutions with
ozone and observed oxTcTation of cyanide to cyanate, then oxidation of cyanate
to bicarbonate and nitrogen:
2KCN
2KCNO
2KCN
Walker & Zabban (1953) studied the use of several oxidants, including
ozone, with dilute electroplating wastewater solutions. Samples containing
from 200 to 400 mg/1 of total cyanide were prepared from the following
stocks:
Copper Plating Bath: Cuprous cyanide 45 g/1; NaCN 68 g/1; sodium
carbonate 30 g/1
Zinc Plating Bath: Zinc cyanide 60 g/1; NaCN 41 g/1; NaOH 79
g/1.
Ozone was generated in a glass tube apparatus with tin foil electrodes,
from air which had been dried by passing it through concentrated sulfuric
acid and anhydrous calcium sulfate. At the steady state, the concentration
of ozone produced was about 1.2% by volume. A 500 ml bottle, with a porous
frit, served as the reaction vessel.
In the initial reaction, cyanide ion was oxidized to cyanate, requiring
0.6 to 0.85 mole of ozone per mole of cyanide. The reaction was catalyzed
with 10 to 20 mg/1 of copper or manganese ions. Without metal ion catalyst,
the zinc plating solution absorbed only 50% of the ozone applied; the balance
passed through the contactor unreacted. Cyanate ion was not oxidized appre-
ciably under these conditions (initial pH 10 to 12; duration of ozonation 2
to 10 minutes).
For disposal of cyanide-containing plating wastewaters, the alkaline
chlorination process is the standard treatment process. However, Selm
(1959) points out several disadvantages of alkaline chlorination:
(1) Chlorine must be used in considerable excess — about 8 Ibs/lb of
cyanide to be treated. Destruction of 100 mg/1 of cyanides results in
chloride ion concentrations of 800 mg/1.
(2) Excess chlorine is toxic to aquatic life in rivers, lakes, streams,
etc., which may receive the treated wastewaters.
67
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Finally, Selm (1959) suggested that it might be acceptable to stop the
reaction of cyanide destruction at the cyanate stage, rather than proceeding
to complete destruction, because of the lesser toxicity of cyanate compared
with cyanide ion. Recently promulgated U.S. EPA effluent discharge regula-
tions for the electroplating category have supported this concept. EPA has
promulgated a cyanide standard, but has not promulgated a discharge standard
for cyanate ion in electroplating wastewaters.
The work of Selm (1959) led to the installation of an ozone treatment
system for cyanide-containing electroplating wastewaters at the Boeing
Aircraft Company, Wichita, Kansas. This wastewater treatment plant was put
into operation in 1957 using ozonation, and has been operating satisfactorily
ever since (Klingsick, 1975).
The Boeing, Wichita wastewater treatment plant originally installed two
60 Ib/day ozone (from air) generators and two cylindical contacting towers
packed with Intalox saddles (Klingsick, 1975). These contact towers are 30
ft tall by 4 ft in diameter. Each column contains 18 ft of 2-inch Intalox
saddles. Cyanide content is 0.0 to 0.25 mg/1 in the wastewater, which first
undergoes oil separation, sulfur dioxide reduction of chromates, alkaline
precipitation of heavy metals, then clarification. The treated wastes at pH
9 are sent to the first ozonation tower at a flow rate of 20,000 Ibs/sq
ft/hr. Effluent from the first tower is acidified to pH 7 by carbonation,
clarified, then passed through the second tower countercurrent to the flow
of gas effluent from the first tower. This technique removes excess sulfur
dioxide and disposes of excess ozone in the off-gases from the first tower.
Capital cost for this plant was $70,000, and the ozone production costs
are 14 to 15<£/lb (1958 prices). Ozonation is cost-effective over chlorination
when the accessories needed to support chlorination (large detention basins,
facilities for storing and handling chlorine, railroad spurs and chlorinating
equipment) are considered (Anonymous, 1958).
In laboratory studies leading up to the installation of the Boeing
plant, Selm (1959) found that 1.75 to 2.00 Ibs of ozone were consumed per
Ib of cyanide oxidized. The initial wastewater solution contained 44.5 mg/1
of cyanide at pH 8.8 and at temperatures of 28 to 30°C. The extent of
cyanide oxidation with ozone was followed by measuring the oxidation potential
of the ozonized solution. While the cyanide was reacting no residual ozone
was present, and the redox potential of the solution was low. However, when
all cyanide had oxidized, and dissolved ozone was present, the redox potential
of the solution rose quickly to a high level.
Klingsick (1975) reviewed the experiences at the Boeing, Wichita plant
since its inception. Spot data were taken on an average of 20 daily composite
samples in October-November, 1971. The average influent cyanide concentration
to the ozone treatment process step was 0.17 mg/1 and the average effluent
cyanide concentration was 0.06 mg/1; the wastewater flow averaged 175,000
gal/day in 1971 (Klingsick, 1975 - Private Communication).
68
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Serota (1958) reviewed the published literature of the time and noted
that cyanide groups in ferricyanide compounds are.not attacked by ozone. An
appreciable drop in pH occurs during ozonation of cyanide-containing solutions,
thus a pH above 10 was recommended for ozonizing electroplating solutions,
to avoid the possibility of HCN volatilizing. Lowering the solution pH to
about 3 after ozonation allows hydrolysis of cyanate to ammonium ion.
Serota concluded that ozonation is a satisfactory treatment technique for
large volumes of solutions containing less than 5 mg/1 of cyanide, since the
cyanate formed will be present in concentrations below 10 mg/1, "which is
below the toxic concentration".
Costs for ozonation were estimated by Sondak & Dodge (1961) and compared
with those for chlorination for a 100,000 gal/8 hr day wastewater stream
containing 200 mg/1 total cyanide, 8 mg/1 cadmium, 58 mg/1 copper and 63
mg/1 zinc. Treated effluent would contain less than 0.5 mg/1 of cyanide,
less than 20 mg/1 cyanate and pH of 6 to 8. Equipment for hydrolysis of
cyanate was included in the ozonation estimates. Ozonation costs were
estimated on the basis of batch or continuous processing and compared with
batch processing by chlorination (Table 10).
Ozonation system capital costs were about 67% ($172,000) of the total
batch system equipment costs ($250,900), but continuous ozonation capital
costs ($194,500) were about 15% lower. Batch chlorination system costs were
much lower ($38,400). Operating costs for batch ozonation were $230.40/day,
mainly because of the high amortization cost ($126.00/day — 12 years deprecia-
tion at 8%) compared with $120.85/day for chlorination (1956 dollars).
Ikehata e_t al_. (1972) ran batch and continuous tests on silver and
copper plating wastewaters with ozone generated from oxygen. Contacting was
effected by means of spargers (porous diffusers). For the continuous run
studies, contacting was conducted using 3 and 4 stages, so as to allow for
complete decomposition of cyanate, which began to decompose rapidly when the
total cyanide concentration was lowered to about 60 mg/1 (copper plating
wastewater) and to about 5 mg/1 (silver plating wastewater). Ferrous cyanide
complex was the most difficult to be decomposed, whereas nickel and copper
cyanide complexes were decomposed rapidly upon ozonation.
Ozone consumption increased considerably as the cyanide concentration
decreased. The rate of cyanide decomposition with ozone was zero order
between pH 6 and 8, first order with respect to cyanide ion and 0.5 order
with respect to hydroxide ion.
Off-gas ozone was recycled to the contactors, thus increasing ozone
utilization to 95%. Excess ozone was destroyed by feeding the off-gases
into the plant boiler combustion chamber, or by passage through GAC.
Although 6.82 moles of ozone theoretically are required to completely
destroy 1 mole of cyanide (past the cyanate stage), in practice, large
excesses of ozone are required, and the pH must be kept at 9 or above. The
pH for optimum decomposition of cyanic acid by hydrolysis is 6.5 to 7. Thus
in destroying cyanides by alkaline chlorination, 2-stage pH control is
69
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TABLE 10. COMPARISON OF INVESTMENT COSTS AND OPERATING EXPENSES
FOR A 100,000 GALLON PER DAY PLATING WASTE DISPOSAL
PLANT USING OZONE OR CHLORINE (a.e)
Reactant
System
Equipment
Storage
Reacti on
Hydrolyzer
Ozonator System (b)
Tanks for Chemicals (e)
Pumps & Mixers
Piping (c)
Total
Operations
Power
Ozone
Pumping
Chemicals
Amortization (d)
Ozone
Batch
Cost, $
2,200
20,600
25,400
172,000
900
3,000
7,000
250,900
Cost,
$/Day
71.20
0.60
32.60
126.00
230.40
Continuous
Cost, $
9,600
6,000
172,000
900
2,000
3,000
194,500
Cost,
$/Day
71.20
0.60
32.60
Chlorine
Batch
Cost, $
16,000
10,000
900
6,500
5,000
38,400
Cost,
$/Day
5.00
94.50
21.35
120.85
(a) Costs all reduced to a Dec 1956 basis.
(b) Costs from "Ozone Generation for Industrial
Application," The Welsbach Corp., 1956, page 9,
figure 4.
(c) Fifteen per cent of equipment costs used for
this charge.
(d) Twelve year depreciation with money valued at
8 per cent was used.
(e) Cost of sludge handling not included.
Source: Sondak & Dodqe,
1961.
70
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required. On the other hand, ozonation of cyanide or cyanate can be conducted
under nearly neutral conditions. The CN/ozone mass ratio for first stage
oxidation (to cyanate) is 0.542 and for second stage decomposition (of
cyanate) is 0.217. In acidic solution, the CN/ozone mass ratio for second
stage decomposition of cyanate is 0.361.
Ikehata ejt aJL (1972) concluded that even though the major drawback of
ozonation for treatment of electroplating wastewaters is high ozone generator
cost, the ozonation of cyanide wastewaters still is somewhat less costly
than alkaline chlorination.
Upon reviewing the economics of treating cyanide-containing wastes,
Goldstein (1973) concluded that ozonation is economically practical for
partial destruction (to cyanate) of 20 Ibs/day of cyanide, or for total
destruction of 10 Ibs/day. Capital costs for ozonation equipment would be
$30,000 with $l,200/year annual operating (power) costs. These costs for
ozonation compare with $6,000 to $10,000/year annual operating (chemical)
costs for alkaline chlorination. Very little capital investment is required
for alkaline chlorination, but only 40% as much ozone is required as chlorine
to oxidize each Ib of cyanide.
Trejtnar (1974) conducted laboratory, then plant ozonation experiments
on metal finishing wastewaters in Czechoslovakia and confirmed the two step
reaction between ozone and cyanides:
2KCN + 203
2KCNO + HOH +303
About 1.1 to 1.6 volumes of ozone are required for each volume of cyanide
oxidized to cyanate. However, because of the presence of other oxidizable
materials, the practical dosage is 3 g of ozone per g of cyanide. Oxidation
with ozone is independent of pH over the range 7 to 12.5, but even at pH 3,
the rate is nearly as fast. No sludges or precipitates are formed. The
treated wastewater could be used as "service water" (for washing equipment).
Fabjan (1975) concluded that ozone will convert cyanide to cyanate
efficiently at alkaline pH, and that cyanate is hydrolyzed to carbon dioxide
and ammonium ion at low pH values. At an ozone production cost of 16<£/kg
(from air) or 7<£/kg (from oxygen), ozonation is less costly than chlorination.
Capital costs for ozonation equipment should be in the range of $1,000 to
$2,000/kg/day of ozone generation capacity. Power costs for the generation
of ozone represent 75% of the total operating costs. The use of oxygen to
generate ozone is recommended for treatment of concentrated cyanide solutions.
Bollyky (1977) describes a 9-month full scale electroplating wastewater
plant demonstration project which was conducted for the U.S. Environmental
Protection Agency at the Sealectro Corporation, Mamaroneck, New York. This
plant discharges 2 wastewaters: an acid wastewater, containing nickel, tin
and lead, and an alkaline wastewater containing up to 60 mg/1 of cyanide,
71
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with copper and silver. The combined plant wastewater flows average 34
gal/min, with peak surges up to 50 gpm.
Sealectro's new wastewater treatment process involves ozonation of the
alkaline wastewater without any pH adjustment in the range of 7 to 11,
combining the ozone treated alkaline waste with the acid wastewater in a
flash mixer, adjustment of the pH with caustic, settling, then discharge to
the local sewer. Installed ozonation capacity is 20 Ibs/day (from air).
Contacting is conducted in a two-compartment, cylindrical chamber, 18.5 ft
tall by 30 inches in diameter (total volume 600 gal). The lower compartment
contains porous diffusers for treating alkaline wastewaters preozonized in
the upper chamber. In the smaller, upper chamber, off-gases from the lower
compartment are reintroduced either through a packed column or diffused
through the incoming alkaline wastewater. Vent gases from the ozone contactor
consistently contain less than 0.05 mg/1 (by volume) of waste ozone.
To meet the current EPA/NPDES and New York state discharge standards
for BPTCA (0.1 mg/1 cyanide oxidizable by chlorine; 1.0 mg/1 total cyanide)
requires 1.85 to 2.8 mg/1 of ozone per mg/1 of cyanide at an initial pH of
7.0 to 9.5. The effluent wastewater consistently contains below 0.1 mg/1 of
cyanide and 6 mg/1 of cyanate.
The amount of ozone required depends upon the initial cyanide concentra-
tion. At concentrations below 20 mg/1 of cyanide, the mole ratio of ozone/-
cyanide required to reduce the concentration of cyanide to below 0.1 mg/1 is
1:1. At 20 to 40 mg/1 cyanide concentrations, the mole ratio required is
2:1 to obtain less than 1 mg/1 cyanide, and 3.6 to attain less than 0.1
mg/1.
Plant-scale studies on ozonation of aqueous sodium cyanide showed that
ozone/cyanide mole ratios of 2.65 destroyed 97.6% of the cyanide, ratios of
4.3 destroyed 44.8% of the cyanate. and ratios of 14.0 destroyed 97% of the
cyanate. For copper cyanide solutions, 1 to 1.5 moles of ozone/mole of
cyanide reduced the cyanide concentration to below 0.1 mg/1 at initial
cyanide concentrations of up to 20 mg/1. As the cyanide concentration rises
to 75 mg/1, the mole ratio of ozone/cyanide required to meet the discharge
standard increases to 3.0.
Capital plus operating costs at the Sealectro Corporation plant (operated
24 hr/day, 1975 prices, 15 year amortization) are estimated to be $1.31/1,000
gal of combined plant wastewater. Capital investment for the optimized
treatment system is $51,200 (Table 11).
The ozone treatment system at Sealectro Corporation began operating in
late 1973 and has been treating these electroplating wastewaters satisfac-
torily since then (Bollyky, 1978). Finally, Bollyky (1977) suggests that
with increased ozone dosages (up to 2 moles of ozone/mole of cyanide), plus
the addition of flocculant or settling tubes in the settling tank, the
treated wastewater could be used to cool the ozone generator or air condi-
tioning equipment.
72
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TABLE 11. SEALECTRO CORPORATION. COST DATA SUMMARY
combined cyanide
+ heavy metal waste
cyanide waste alone
operating
cost
$1.03/1,000 gal
$1.43/1,000 gal
total
cost
$1.31/1,000 gal
$2.35/1,000 gal
$10.34/kg of CN
$4. 70/1 b of CN
• combined cyanide + heavy metals waste flow = 49,000 gal/day
• capital investment for optimized ozonation system = $51,200
(1975 prices)
Ozone/UV Radiation
The ozone/UV wastewater treatment process was initially developed for
destruction of cyanides in wastewaters from electroplating and color photo-
graphic processes (Prengle, 1977). Cyanides vary in resistance to oxidation
from very low (KCN) to very high (complexed ferricyanide). Free cyanide ion
is destroyed by ozone essentially as fast as ozone can be added to the
solution, and does not require UV input. The reaction rate of free cyanide
ion with ozone, therefore, is mass transfer limited, being limited only by
the rate at which ozone can be transferred from the gas into the liquid
phase.
On the other hand, complexed cyanides of iron, copper and nickel are
very difficult to oxidize with ozone alone, but are readily oxidized by the
combination of ozone with UV radiation, as shown in Figure 9 for iron' complexed
cyanide wastewater. Coupling ozone with UV radiation and raising the reaction
temperature to 66°C results in the fastest rate of iron cyanide destruction.
The beneficial effect of multistage reactors upon the destruction of
complexed cyanides is indicated in Table 12. Iron, copper and nickel complexed
cyanide solutions containing 4,000 mg/1 of total cyanide treated in 3 to 6
reactor stages to final cyanide concentrations of less than 0.3 mg/1 cyanide
theoretically should produce 6,500 mg/1 of cyanate, if the ozonation proceeds
only to the cyanate stage. The fact that much lower concentrations of
cyanate actually were found indicates that the ozone/UV process also destroys
cyanate ion.
Employing the two-staged reactor system shown in Figure 6, designed to
treat an industrial wastewater containing 150 mg/1 of free and metal complexed
cyanides and 90 mg/1 of refractory organics, Prengle & Mauk (1977) were able
to reduce total cyanide to below 0.1 mg/1 and TOC to below 1 mg/1. The
process involves chemical coagulation, sedimentation, clarification, equali-
zation, pH adjustment, followed by a single stage ozonation reactor (for
easily oxidized materials) then a multistaged reactor for difficult to
73
-------
<:
8 •
7 •
6 .
5
^ 4
E
2 ••
25°C, Zero UV,
1% ozone in gas
1% ozone in gas
25°C, 1.2 w/1 UV,
1% ozone in gas
°C, 1.2 w/1 UV,
5% ozone in gas
66°C,
1.2 w/1 UV,
5% ozone in gas
t
10 20 30 40
TIME, minutes
50
Figure 9. Ozonation of iron complexed cyanide waste.
Source: Garrison, Mauk & Prengle (1975)
60
74
-------
oxidize species. The capital costs to treat 100 gal/min of this wastewater
are $662,700, and are described in Table 13 (Prengle, 1977).
TABLE 12. TYPICAL CYANIDE OXIDATIONS WITH OZONE AND OZONE/UV
Influent
Parameters
Cu Complexed
CN, mg/1
Cyanate, mg/1
Temperature, °C
PH
UV, watts/1
Ni Complexed
CN, mg/1
Cyanate, mg/1
Temperature, °C
pH
UV, watts/1
Fe Complexed
CN, mg/1
Cyanate, mg/1
Temperature, °C
PH
UV, watts/1
4,000
0
20
11.5
--
4,000
0
20
11.8
--
Effluent from Reactor Staqes:
1
17
20
0
110
20
0
4,000 2,680
0
20
--
66
0
2
0.5
20
0
0.6
20
0
1,630
66
0
3
<0.1
no
66
7.7
1.2
<0.1
470
66
8.5
1.2
710
66
0
4
105
66
0
5
13
66
0
6
<0.3
47
66
8.9
1.2
Source: Prengle (1977)
As of late 1977 (Prengle, 1977) Houston Research Inc. has installed
ozone/UV (the OXYPHOTOLYSIS Process) wastewater treatment systems for metal
finishing wastewaters at the U.S. Air Force/Tinker Air Force Base, Oklahoma
(metal complexed cyanides), at the French facility of a large American
chemical company (cyanide and refractory organics), a similar design for the
same company at an American installation, and at Hughes Tool Co., Houston,
Texas. This last system has been in full-scale operation since November,
1976, treating metal finishing wastewaters.
Conclusions
1) Ozone treatment of metal finishing, cyanide-containing wastewaters has
been in use at the Boeing Company, Wichita, Kansas since 1957. This is
the longest known use of ozone for treating these types of wastewaters.
The facility treats 175,000 gal/day of wastewaters and ozone reduces
the concentration of cyanide from an average of 0.17 mg/1 to below 0.06
mg/1.
2) Since 1973, Sealectro Corporation, Mamaroneck, New York has been using
ozone treatment to lower cyanide levels in copper and silver plating
wastewaters from 60 g/1 to below 0.1 mg/1 at the rate of 34 gal/min.
75
-------
The effluent consistently contains less than 6 mg/1 of cyanate and meets
current discharge standards with respect to other water quality parameters,
TABLE 13. CAPITAL COST ESTIMATE — OZONE/UV TREATMENT OF AN
INDUSTRIAL WASTEWATER
(100 gpm stream containing cyanides and biorefractory organics;
e.g., Figure 6)
Item
Wastewater Evaluation & Treatability Study
Equipment
Chemical Coagulation Unit
Sedimentation-Equalization Unit
Ozone Generation Unit, with Air Processing
Ozone Reaction Unit
Ozone/UV Reaction Unit
Pumps & Control Valves
Instrumentation
Total Equipment
Skids, Piping & Installation
Design, Engineering & Fee
TOTAL COST
Source: Prengle, 1977
Amount
$ 17,500
10,500
45,300
210,000
95,600
144,300
7,500
18,500
($531,700)
55,000
58,500
$662,700
3) Cyanide ion at concentrations of 100 mg/1 or less may be oxidized
rapidly to cyanate in the presence of copper ions in the pH range of 7
to 12. In this range, pH adjustment is not necessary.
4) Non-transition metal cyanides (Zn, Sn, Cd, Na, K, etc.) are oxidized
rapidly in the presence of copper catalyst at room temperature.
5) Iron cyanide complexes are oxidized very slowly by ozone at room
temperature. However, these complexes are oxidized rapidly by the
combination of ozone with UV radiation and/or coupled with heating to
150°F.
6) Combinations of ozone with UV radiation and/or with elevated temperature
have been used to treat metal finishing wastewaters containing iron
cyanide complexes since late 1976 at an industrial metal finishing
plant, a U.S. Air Force base and at a French affiliate of a large U.S.
chemical company. Ozone/UV combinations in multiple staged reactors
lower total cyanide concentrations from 4,000 mg/1 to below 0.3 mg/1
and also destroy cyanate ion.
7) The literature often does not distinguish between mass transfer rate,
kinetic oxidation rate and combinations of these. Therefore, the
published data often appear contradictory and may not be directly
usable for purposes of designing wastewater treatment systems.
76
-------
LITERATURE CITED -- ELECTROPLATING (EP)*
EP-01* Anonymous, 1958, "Ozone Counters Waste Cyanides Lethal Punch",
Chem. Engr., March 24, p. 63-64.
EP-02 Anonymous, 1974, "Ozonation: Another Way to Treat Plating Wastes",
Prod. Finish 38:10, 98; Engrg. Index Monthly 12:049085 (1975).
EP-03 Anonymous, 1975, French Patent, 2,265,691 (Nov. 28). Derwent
French Patent Abstracts x(3):D5, Feb. 1976.
EP-04 Bollyky, L.J., 1975, "Ozone Treatment of Cyanide and Plating
Waste." In Proc. First Intl. Syrup. on_ Ozone for Water & Wastewater
Treatment, R.G. Rice & M.E. Browning, editorsTTntl. Ozone Assoc.,
Cleveland, Ohio, p. 587-590.
EP-05 Bollyky, L.J., C. Balint & B. Siege!, 1976, "Ozone Treatment of
Cyanide and Plating Waste on a Plant Scale", in Proc. Sec. Intl.
Symp. on Ozone Techno]., R.G. Rice, P. Pichet & M.-A. Vincent,
editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 393-420.
EP-06* Bollyky, L.J., 1977, "Ozone Treatment of Cyanide-Bearing Plating
Waste", EPA Report No. EPA-600/2-77-104, .June 1977. U.S. Environ-
mental Protection Agency, Industrial Environmental Research Lab.,
Cincinnati, Ohio 45268.
EP-07* Browning, M.E., 1976, "Wastewater Treatment in the U.S.A", Gal-
vanotechnik 67(6):465-470.
EP-08 Cheremisinoff, P.N., A.J. Perna & J. Ciancia, 1977, "Treating
Metal Finishing Wastes, Part 2", Indl. Wastes Jan/Feb, p. 32-34.
EP-09* Ciancia, J., 1973, "New Waste Treatment Technology in the Metal
Finishing Industry." Plating 60:1037.
EP-10 Ellerbusch, F. & H.S. Skovronek, 1977, "Oxidation Treatment of
Industrial Wastewater", Indl. Water Engrg., Sept., p. 20-29.
EP-11* Fabjan, C., 1975, "Purification of Electroplating and Other
Effluent Waters by the Ozone Process." Galvanotechnik 66(2):100-
107.
EP-12 Fabjan, C., R. Davies & K. Marschall, 1970-1977, "Destruction of
Complex!ng Agents in Electroplating and Other Effluents by Ozone",
U.S. Dept. of Commerce, NTIS Report No. PS-77/0749, p. 643-645.
* Abstracts of asterisked articles appear in EPA 600/2-79- b.
77
-------
EP-13* Garrison, R.L., C.E. Mauk & H.W. Prengle, Jr., 1974, "Cyanide
Disposal by Ozone Oxidation." Final Report, U.S. Air Force Weapons
Lab., Kirtland Air Force Base, New Mex., Feb. #AFWL-TR-73-212,
U.S. Dept. of Commerce, NTIS Report No. AD-775J52/2WP.
EP-14 Garrison, R.L., C.E. Mauk & H.W. Prengle, Jr., 1975, "Advanced
Ozone Oxidation System for Complexed Cyanides." In Proc. 1st Intl.
Symp. on Ozone for Water & Wastewater Treatment, R.G. Rice & M7ET
Browning, editors, Intl. Ozone Assoc., Cleveland, Ohio, p. 551-
577.
EP-15* Garrison, R.L., H.W. Prengle, Jr. & C.E. Mauk, 1975, "Ozone-based
System Treats Plating Effluent." Metal Progress 108(6):61-62.
EP-16* Goldstein, M., 1976, "Economics of Treating Cyanide Wastes",
Pollution Engineering, March, p. 36-38.
EP-17* Ikehata, A., K. Ishizaki, N. Tabata & R. Hashimoto, 1972, "Oxidation
of Cyanides in Plating Wastes by Use of Ozone." J. Japan Soc. for
Safety Engr. II (2):74-84.
EP-18 Klingsick, G., 1975, "Application of Ozone at the Boeing Co.,
Wichita, Kansas. In Proc. First Intl. Symp. on Ozone for Water &
Wastewater Treatment, R.G. Rice & M.E. Browning, editors, Intl.
Ozone Assoc., Cleveland, Ohio, p. 587-590.
EP-19 Kubala, F., 1964, "Regeneration of Chromium Bath with Ozone."
Korose A Ochrana Materialu.
EP-20 Morguardt, K., 1974, "Treatment of Wastewater in the Metal Working
Industry." Belg. Ned. Tijdschr. Oppervlakte Tech. Metal 16:306.
Chem. Abstr. 81:63529 (1974).
EP-21 Pinner, W.L., 1972, "Progress Report of Am. Electroplaters Soc.
.Research Projects on Plating Room Waste", in Proc. 7th I_ndJ_. Waste
Conf., Purdue Univ. Engr. Ser. 79:518-540.
EP-22 Prengle, H.W., Jr., 1977, "Evolution of the Ozone/UV Process for
Wastewater Treatment", Presented at Seminar on Wastewater Treatment
& Disinfection with Ozone, Cincinnati, Ohio, Sept. 15. Intl.
Ozone Assoc., Cleveland, Ohio.
Prengle, H.W., Jr. & C.E. Mauk, 1977, "Ozone/UV Chemical Oxidation
Wastewater Process for Metal Complexes, Organic Species and
Disinfection", presented at 83rd Natl. Meeting of AIChE, Houston,
Texas, Mar. 20-24. Am. Soc. Chem. Engrs., New York, N.Y.
EP-23* Selm, R.P., 1957, "Ozone Oxidation of Aqueous Cyanide Waste Solu-
tions in Stirred Batch Reactors and Packed Towers." In Ozone Chem.
& Technol., Am. Chem. Soc., Adv. in Chem. Series, Vol. 2Tf6"6-6Y. "
78
-------
EP-24* Serota, L., 1958, "Science for Electroplaters 33. Cyanide Waste
Treatment--0zonation and Electrolysis." Metal Finishing, Feb. p.
71-74.
EP-25* Sondak, N.E'. & B.F. Dodge, 1961, "The Oxidation of Cyanide-Bearing
Plating Wastes by Ozone, Part 1," Plating, p. 173-80.
EP-26 Sondak, N.E. & B.F. Dodge, 1961, "The Oxidation of Cyanide-Bearing
Plating Wastes by Ozone. Part 2", Plating, p. 280-84.
EP-27* Trejtnar, J., 1974, "Ozonization as a Means of Wastev/ater Purifi-
cation." Czechoslovak Heavy Industry 10:34-35.
EP-28 Tyler, R.G., W. Maske, M.J. Westing & W. Mathews, 1951, Sewage &
Indl. Wastes 23:1150-1153.
EP-29* Walker, C.A. & W. Zabban, 1953, "Disposal of Plating Room Wastes
VI. Treatment of Plating Room Waste Solutions with Ozone", Plating,
p. 777-780.
79
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FOOD AND KINDRED PRODUCTS
With the exception of publications dealing with the use of ozone to
treat brewery waters, the published uses of ozone in the food and kindred
products category have been restricted to sterilization of bottle washing
waters in the preparation of baby foods, treatment of sauerkraut brines to
reduce COD, treatment of bakery wastes, aiding the extraction of tea solubles
from spent tea leaves by oxidation, the artificial aging of wine and the
disinfection of poultry processing wastewaters.
Bottle Washing Hater
Leayitt & Ziemba (1969) and Leavitt (1972) describe the use of ozonation
to sterilize waters on a commercial scale which are used for washing bottles
in the preparation of baby foods at Gerber Products Co. In the 1969 article,
these authors discuss the reuse of water after ozonation, but also the
reclamation of the heating and cooling potentials of the water to be reused.
Water is first sterilized by ozonation in a 25,000 gal tank, after
which the ozonized water is pumped through a vertical filter and heat exchan-
ger, then into three water use loops. One of these is 190°F water for
bottle washing, a second loop supplies 190°F water for retorting, and the
third loop collects water at temperatures below 150°F from the retorts for
cleaning floors and flushing gutters.
In the 1972 article, Leayitt discusses the Gerber water treatment
system in more detail, emphasizing the instrumentation aspects. Ozone is
generated from oxygen feed gas and diffused into water in a 7,500 gal stain-
less steel tank, 16 ft deep. The entire water treatment system, including
ozonation, was purchased for $80,000 in 1968, to which another 30% should be
added for installation costs, making a total capital cost of $135,000. The
savings in water reuse, steam and sewer charges amounts to $125,000 annually,
equating to an 82% return on investment and a payoff period of 1.9 years.
Sauerkraut Brines
This laboratory work has been conducted by Walter & Sherman (1974,
1976) using samples from lactic acid fermentation of cabbage to produce
sauerkr"aut. BOD of this type of effluent can reach 41,000 mg/1, with
lactic acid contents ranging between 14,000 and 16,800 mg/1. Ozonation was
conducted in a small, fritted dispersion cylinder (120 mm high and 24 mm
diameter which contained 40 ml brine samples. Ozone was generated from
oxygen and its concentration was measured both in the inlet and outlet
gases, so as to determine accurately the amount of ozone actually used. The
contactor off-gases were bubbled through barium hydroxide solution (to form
barium carbonate, indicating the presence of carbon dioxide) then through
piperazine-nitroprusside reagent, indicating the presence of acetaldehyde.
The steady state concentration of ozone being bubbled through the reactor
was between 400 and 500 mg/1 at 25°. Ozonation was conducted for 24 hr
periods, under these conditions for a total of 72 hours (1974 paper) and 5
days (1976 paper).
80
-------
The initial filtered brine solution before ozonation contained 1.30
g/ml of lactic acid, 0 mg/1 of pyruvic acid, 0.04 g/ml of sugar, total
acidity of 0.17 milliequivalents (meq)/20 ml, was at a pH of 3.3 and gave
negative tests for C02 and acetaldehyde. As ozonation progressed, the sugar
concentration fell to 0 g/ml in 24 hrs, lactic acid concentration was
reduced, pyruvic acid concentration rose to 0.28 g/ml (280 mg/1) in 24
hours, then decreased, and the mixture also gave positive tests for acetalde-
hyde and C02. Pertinent data are presented in Table 14.
During the first 48 hrs of ozonation, the COD dropped 48% from an
initial value of nearly 15,000 mg/1, and a 78% reduction in COD concen-
tration was obtained after 3 days (about 3,500 mg/1). Thereafter, the
relatively higher stability of the remaining organic constituents to ozone
oxidation slowed the rate of carbon loss. Upon lime neutralization of the
ozonized brines, colloidally dispersed cabbage constituents that were unaffec-
ted by ozonation precipitated, resulting in a further reduction in COD
content of 1,200 mg/1. The ratio of ozone consumed to COD reduction obtained
over the 72 hour period was 2.0.
These authors conclude that where ozone generators already are installed
in food processing facilities, and where small batches of refractory effluents
are not amenable to biological stabilization, ozonation may be applied as a
chemical alternative to lower the concentrations of COD in wastewaters.
Walter & Sherman project the probable chemistry involved in these
studies to be represented by the following equations:
Ozone
CH--CH-COOH + 0, >CH.-C-COOH > CH.CHO + C09
6 OH d J 0
lactic acid pyruvic acid acetaldehyde
and:
sugar + 03 ^ C02 + H20
Because of the low boiling point of acetaldehyde (21°C) and because the
ozonations were carried out at 25°C, much of the acetaldehyde produced was
physically stripped from the reaction mixture by the aeration action in the
ozonation reactor. This would explain why oxidation did not continue to
produce acetic acid.
In the later paper (Walter &.Sherman, 1976), ozonations were conducted
over 5 days using sauerkraut brines having two different COD concentrations
(35.1 g/1 and 17.25 g/1). After 5 days of continuous ozonation, the COD of
the higher concentration brine had dropped to 17.5 g/1 and that of the lower
concentration brine had dropped to 6.75 g/1. However, the efficiency of
ozone use over this period of time was higher with the higher concentration
brine. This indicates that if ozonation is to be used to treat high COD
wastewaters, dilution should occur after, not before, ozonation.
81
-------
00
I\D
TABLE 14. ANALYTICAL DATA FOR OZONIZED AND NON-OZONIZED
SAUERKRAUT BRINE
PH
Total acidity
(meq/20 ml)
Lactic acid
(g/mi)
Pyruvic acid
(g/mi)
Sugar
(g/mi)
Total Volatiles
(g/mi)
Fixed residues
(g/ml)
Test for*
Acetaldehyde
co2
Filtered
Brine
3.3
0.17
1.30
0.00
0.04
2.0
1.9
-
+
-
Oxygenated
Brine
3.5
0.17
1.30
0.00
0.04
-
+
-
Ozonated
Brine (24 hr)
0.70
0.28
0.00
+
+
Ozonated
Brine (48 hr)
0.20
0.03
Ozonated
Brine (72 hr)
1.7
0.20
0.05
0.01
0.9
2.2
*
*
* + indicates positive
- indicates negative
Source: Walter & Sherman (1974)
-------
Bakery Wastewaters
Yim £t aj_. (1975) conducted treatability studies on bakery wastewaters
in Hawaii by four methods: chemical coagulation, pressure flotation,
chlorine dioxide oxidation and ozonation, and the efficiencies of the
treatment methods were determined by the amounts of BOD-5, SS and grease
removed by each process.
The ferric sulfate and alum coagulants worked best at pH 8.0, at
dosages of 1,300 mg/1 and was the only treatment which allowed the high
strength wastewaters to meet the local sewer ordinances, with ho additional
sewer use charges to the bakery (300 BOD-5, 300 SS, 100 mg/1 grease; pH 5.5
to 10.0). Poor removal rates were obtained with the pressure flotation
unit, which worked best at 50 psig after acidification to pH 1.0.
At the highest chlorine dioxide dosage (200 mg/1) over a 15 minute
contact time, only 62.2% removal efficiency was obtained for BOD-5; however,
a residual of 9.5 mg/1 was present which was considered to be potentially
harmful to the receiving sewer stream.
At the maximum applied ozone dosage possible with the ozonation system
employed, only 21.2% reduction in BOD-5, 61.5% reduction in SS and 36.8%
reduction in grease was obtained using an ozone contact time of 5 minutes.
The ozonation system was not described, other than to mention that contacting
was accomplished by diffusion, and costs were not discussed. These authors
state that increasing the ozone contact time to 15 to 30 minutes, and using .
a finer air diffuser for contacting, probably would have achieved the desired
results. Both chlorine dioxide and ozonation systems had the advantages of
minimum space requirements and no sludge disposal.
Pertinent pollutant removal data for the 4 processes studied are given
in Table 15.
Extraction Of Tea
Rivkowich e_t aj_. (1974) were issued a patent claiming, but not demonstra-
ting by example, the improved extraction of tea leaves to yield soluble
solids for instant tea production by oxidation of extracted or spent tea
leaves with a solution of ozone in water. Other suitable oxidants are
oxygen and hydrogen peroxide, and an example of the process employing hydrogen
peroxide is given.
Tea leaves (8 Ibs) and 202 Ibs of water at 88eC are charged to an
atmospheric extractor. After 20 minutes, 175 Ibs of liquid extract containing
2.8 Ibs of soluble solids are withdrawn. Moist tea leaves (27 Ibs) containing
5.2 Ibs of soluble solids are fed to a pressure reactor with 4.6 Ibs of 30%
aqueous hydrogen peroxide solution. The mixture is heated at 240°F and 40
psig pressure for about 50 minutes, producing 74 Ibs of liquid extract
containing 1.4 Ibs of soluble solids. Thus, treatment of spent tea leaves
with an aqueous solution of oxidant produces about a 50% improvement in
yields of soluble solids.
83
-------
CO
TABLE 15. COMPARISON OF TREATMENT METHODS ON CAKE SHOP WASTEWATERS
Pollutant
BOD- 5
(mg/1)
Suspended
Solids
(mg/1)
Grease
(mg/1)
Optimum
pH
Dosage
(mg/1) (
Optimum
Pressure
Chemical Coagulation
Ferric Su
before
2780
2310
1450
8.0
1300
optimum
after
810(1)
960(2)
128(1)
173(2)
96(1)
84(2)
4.3(1)
5.4(2)
)
(1) data obtained at opt
(2) data obtained at opt
Source: Yim et al. (197
fate
%
Redn.
70.9
65.5
94.4
92.5
93.4
94.2
I
Alum
before
2780
2310
1450
8.0
1300
optimum
after
870(1)
110(2)
96(1)
26(2)
47(1)
52(2)
5.2(1)
6.1(2)
)
%
Redn.
68.7
60.1
95.8
98.9
96.8
96.4
imum pH of ferric sulfate
imum dosage of alum
5)
Pressure Flotation
before
2780
2310
1450
1.0
50 ps
after
2030
1470
493
ig
%
Redn.
27
36.4
66
Chlorine Dioxide
before
3840
960
2360
8.4
200
for
(ma
after
1450
410
1070
4.7
mg/1
15 min.
ximum)
%
Redn.
62.2
57.3
54.7
Ozonation
before
4940
3040
1260
8.4
after
3990
1140
796
384 mg/1
(maximum)
(5 min.
contact)
%
Redn.
21.1
61.5
36.8
-------
Disinfection Of Poultry Processing Wastewaters
Netzer e_t al_. (1977) compared the relative merits of ozonation against
those of chlorination for treatment of poultry processing effluents at two
plants in Canada, with particular emphasis on the control of salmonella.
Both laboratory and pilot scale field evaluations of the two alternative
disinfection methods were conducted and the economic implications of using
ozone in this application were assessed.
Laboratory ozonation studies were conducted using porous-diffuser
contacting in a 12-ft high, 4-inch I.D. contact column. This provided a 13
minute contact time at the wastewater flow rates chosen. Diffusers were
located at the base of the column and halfway up, so that ozone could be
applied to either diffuser or to both simultaneously. Although only the
applied ozone dosages were measured, at least 90% utilization of the ozone
added at the base of the column can be expected to be mass transferred into
solution to react with the wastewater components. This is because of the
height of the column (12 ft).
In laboratory studies, ozone dosages of 20 to 50 mg/1 reduced salmonella
contents in a biologically treated poultry processing wastewater to below
the limit of detection. Standard plate counts were reduced from 6,500 MPN
to a range of 265 to 103,fecal coliforms/100 ml were reduced from 220 MPN to
a range of 16 to 2,and adenosine triphosphate concentration was reduced from
8.0 nanograms (ng)/ml to 0.37 to 0.17 ng/ml (the higher numbers were obtained
at 20 mg/1 ozone dosage and the lower numbers at 50 mg/1 ozone dosage).
In other laboratory tests using a wastewater significantly more contami-
nated (BOD 92 mg/1, SS 80 mg/1 and bacterial counts 630,000), even 50 mg/1
applied ozone dosages were not effective in reducing the salmonella contents,
although fecal coliform counts were reduced 99% (from 88,000 to a range of
500 to 600/100 ml). It was concluded that the effectiveness of ozonation
for control of salmonella is significantly affected by the chemical and
bacteriological quality of the secondary effluent.
Pilot field studies were conducted using ozone generated from oxygen
and applied to the base of 2 consecutive 18-ft high contactor columns eauipped
with cone type diffusers. Liquid flow was countercurrent in column #1 (9.5
Igal volume) and cocurrent in column #2 (21.4 Igal volume). Liquid flow
rates were varied from 2.5 to 0.5 Igpm (Imperial gal/min) (equivalent to 15
to 60 minutes hydraulic retention times) and 75% of the ozone was applied to
column #2. A high degree of ozone dispersion was confirmed in this system
by tracer studies with Rhodamine B and oxygen in process water.
In a parallel chlorination system, NaOCl solution was dosed to a
stirred 45-gal contact tank by means of a metering pump.
Ozone efficiency was evaluated at 2 Ontario, Canada poultry processing
plants under winter and summer conditions over 2-month periods. At one
plant processing 2,500 birds/hr, process waste flows were about 100,000
Igpd. Effluent was screened to remove feathers, grease and gross solids
85
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prior to biological treatment. Secondary effluent was dosed with lime and
alum to precipitate phosphorus and coagulate residual solids, and this
secondary effluent was used to feed the pilot plant studies. Under normal
(summer) conditions the secondary effluent contained 20 mg/1 BOD and 30 mg/1
OO •
Initial pilot studies confirmed the laboratory results, i.e., effective
control of salmonella with ozonation is not directly related to disinfection
efficiency as measured by other microbiological parameters. Salmonella were
detected in some cases where fecal coliform reductions were above 99%.
However in other runs, salmonella were not detected, despite low disinfection
efficiencies in terms of the other parameters.
Based on these preliminary results, 30 mg/1 of applied ozone dosage and
60-minute contact time was chosen for further testing over a 5-day period
under winter conditions at this plant. Salmonella were not detected in any
of the ozonated secondary effluent samples. Reductions in fecal coliforms
approached 3 powers of 10 (99.9%). During all runs under these conditions,
salmonella were detected in only 1 of 7 ozonized effluent samples.
These conditions were repeated during the summer at the same plant.
Chemical quality of the secondary effluents was somewhat higher. Ozonation
efficiency was comparable, with salmonella being detected in only 1 of 5
ozonized samples.
The pilot equipment then was moved to a second poultry processing plant
which handles 6,000 chickens and turkeys per hour and process waste flows
were about 500,000 Igpd. The effluent was screened, then treated in parallel
aeration tanks (5 days retention time). Clarified effluent normally is
discharged to a polishing lagoon prior to chlorination and discharge.
However, a poor settling, filamentous sludge in the biological reactor
resulted in excessive SS carryover from the secondary clarifier, severely
limiting the pilot plant ozonation efficiency. In 2 cases, ozonation resulted
in negligible reductions in fecal coliform counts. The quality of effluent
improved significantly prior to the final 2 runs; in 1 of these runs, salmon-
ella were not present after ozonation.
Comparison of winter and summer runs at this second plant (30 mg/1
ozone dosage -- 60 minute contact time) showed 80 to 96% salmonella control
efficiency, 98.5 to 99.6% fecal coliform reduction and 55% (winter) to 73%
(summer) reduction efficiency of standard plate count numbers. No significant
difference related to seasonal effluent variation was observed at this
plant.
In fish toxicity tests (96-hr static bioassay procedures), ozonation
did not affect the toxicity of secondary effluents. No introduction of
toxicity to non-toxic secondary effluents was noted, however, ozonation did
not reduce the toxicity in cases where fish mortality was noted in secondary
effluents before ozonation.
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Economic evaluations were based on disinfecting 1.0 mlgd (million
Imperial gal/day) of biologically treated poultry processing plant effluent
using ozone prepared from dry air (-40°F dew point). Two types of contacting
equipment were costed: (1) columns similar to those used in the pilot
studies- and (2) a covered baffled tank with gas diffusers. Capital costs of
the 2 contactor systems were found to be comparable. Power requirements
were estimated to be 10 kwhr/lb of ozone generated. Cost estimates are
summarized in Table 16.
TABLE 16. ESTIMATED CAPITAL AND OPERATING COSTS FOR OZONE TREATMENT OF
POULTRY PROCESSING WASTEWATERS
1977 Costs -- Capital:
Air Preparation
Ozone Generation (300 Ibs/day)
Contacting System (6700 cu ft)
-- Operating:
Power (3,000 kwhr/day @ $0.02)
Amortization (15%/yr)
Total Operating Cost
$ 70,000
140,000
50,000
$260,000
$ 60.00/day
106.85/day
$166.85/day =
$0.17/1000 Igal
Source: Netzer et al., 1977
Netzer ejt aJL (1977) concluded the following from this study:
(1) Disinfection efficiency with ozone depends on chemical and bacterial
quality of the effluent, the higher quality effluents giving better
results,
(2) Ozone at 30 mg/1 dosages over 60 minutes of contacting was successful
in controlling salmonella 80% of the time in summer and winter,
(3) Disinfection requirements are site-specific and should be ascertained
at each site.
Breweries
Ozone has been used in various brewery applications for many years,
and particularly in German, French, American and Canadian installations.
Du Jardin (1924) reviewed the then current uses of ozonation in breweries,
citing the germicidal capabilities of ozone and its property of not
leaving an undesirable residue as its primary features. Van Laer (1928)
determined that for sterilizing brewing water, 2.25 g of ozone is required
per cu m of water provided that oxidizable organic materials are removed
first. This author also pointed out that ozonized water is more effective
for sterilizing vats and piping than is ozonized air.
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Mayrhofer and Steinhart (1955) describe the use of ozonized water in
yeast manufacture for the brewing process. Bacteria and coliform counts were
reduced to zero, color was diminished and there were no observed detrimental
effects on the yeast fermentation ability. Stability of the yeast, baking
properties and appearance of the yeast were better than in the preceding year
when ozonized water was not used.
Schauble and Gillardin (1958) determined that 0.5 g/cu m of ozone was
sufficient to sterilize waters containing added amounts of various forms of
yeasts, rhodotorulae, cocci, short rod bacteria, mold hyphae and spores.
Foreign taste and odor problems also were decreased, even though the mechanical
ozone contacting system used was inefficient. These authors suggested that
the "many advantages" of ozonation should be excellently suited to the fruit
juice industry, even though ozonation costs are "slightly greater" than those
for chlorination.
Fergason, Harding & Smith (1973) describe a portable ozone test unit
assembled at the University of Idaho for field testing of the ozonation unit
process. One such test was conducted by a major brewery to eliminate tastes
and odors from its brewery waters. As a result of successful testing with
this unit, the brewer was reported to be installing a full-scale ozonation
plant to treat a portion of the brewery water. Preliminary estimates for the
cost of ozonation at a full-scale plant based on tests with this portable
test unit were 30<£/1,000 gal for decolorization and deodorization. The
portable test unit contained a 2 gallon reactor capable of varying contact
times from 1 to 20 minutes. The contactor was a Venturi nozzle (injector).
Ozone production capability of the unit was 12 g/hr and the treatment rate
was 1.5 gal/minute.
Tenney (1973a) points out several barriers to broader acceptance of
ozonation in breweries. In the early days of useage, ozone often was asked
to perform oxidation functions that could be accomplished more economically
by first removing reactive materials using less expensive procedures, such as
filtration, GAC, etc. Ozone certainly is too expensive an oxidant to be
considered for the total treatment of heavily contaminated waters, even
though it can perform many oxidations that other oxidants cannot accomplish
alone.
Ozone has several applications in treating brewery waters, even though
in solution ozone has a short half-life. Tenney (1973a) recommends that a
brewery considering the use of ozone for multiple applications should plan to
install several small ozone generators, one at each point of use, rather than
to install a single unit in some central location. Once ozone has been
contacted with water, the water should not be pumped to some distant point in
the plant, but should be used immediately after ozone addition, so as not to
lose any ozone by decomposition.
Tenney (1973a) also points out that one of the early designs of
ozone generators used in breweries had a fan blowing air across electri-
cally charged plates spaced so as to create a corona discharge. However,
88
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as dust built up on the plates during prolonged use, short circuiting
occurred, causing malfunction of the equipment. -This particular design
of ozone generator also incorporated a heater to dry the incoming air
(rather than a compressor and/or desiccant tower). The efficiency of
such units diminished quickly and most of them were soon inactivated.
Unfortunately, a number of these devices were sold to American breweries
during the late 1940s. Their ineffectiveness has contributed to distrust
of other, more reliable types of ozone generators.
Tenney (1973a) concludes that with electricity costs of 1.5<£/kwhr
and at ozone generation rates of 10 g/hr, costs for ozone generation
should be less than 30<£/kg. Capital costs for ozone generators capable
of generating 5 to 10 g/hr from air range from $2,000 to $3,000.
In a second review article, Tenney (1973b) discusses the existing
and potential uses of ozonation in breweries. In brewery water treatment,
yeast washing is conducted with freshly ozonized water containing 1 to 3
mg/1 of ozone for destruction of the easily oxidizable substances in the
yeast mass, including melanoidins which create color in the beer residue.
Bacteria also are destroyed with minimal damage to the yeast.
Final rinsing of bottles or cans by means of water containing
dissolved ozone will remove trace materials and eliminate beer-spoiling
organisms. The maximum amount of oxygen introduced to the beer by using
this technique is 0.000009 g/bottle, which will have negligible influence
on the product. Normal variations in air content provide more oxygen
variation than this small amount caused by ozonation.
Beer fillers and process equipment such as filters, tanks, pipelines,
etc., are sterilized before use by circulating hot solutions through
the equipment. The cooling water which follows must be sterile, and water con-
taining 1 mg/1 of ozone is effective for this application. Final rinsing
of brewery filter mass with ozonized water just before packing new pads
will assure sterility at this point in the process for plants still
using this type of equipment (Tenney, 1973b).
Brewers have used ozone to purify air in rooms used by taste panels
and for controlling mold growth and odors in brewery cellars. Ozone
also can be used for purifying air in yeast handling areas, in wort
cooling and aeration, and might replace chemical scrubbing of C0?, such
as with permanganate (Tenney, 1973b).
Geminn (1974) describes the processing of concentrated wort as
practiced at the Genessee Brewing-Co., Rochester, New York, which involves
the use of ozonation in the preparation of dilution water. Municipal
tap water is filtered at the rate of 63 gal/min through a combined
sand and gravel filter, then through activated carbon. Ozone then is
diffused through the filtered water at 2 mg/1 over 3 to 5 minutes contact
time to sterilize and remove tastes, odors and possible entrained
bacteria. The 0.2 mg/1 ozone residual decays in about 6 minutes.
89
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Ozonized water is deaerated by spraying, passing through a packed
column, then is recarbonated and stored under C02 for blending with the
concentrated wort. Power requirements for the 3-electric cell ozone generator,
equipped with air filter, motor compressor set and dual tower desiccator are
"about the same as burning a 200 watt bulb, plus an additional cost of about
15 gal/hr of tap water to cool the electrodes".
A survey of available literature from various ozonation equipment
vendors located in Europe shows that ozonation systems are installed in the
breweries listed in Table 17.
TABLE 17. EUROPEAN BREWERIES USING OZONE
Installation
Bayerische Bierbrauerei
Aschaffenburg, Germany
Stadtbrauerei , Gtitti ngen ,
Germany
Brauerei Bock, Finland
Oy Kaukas, Finland
M.M. Braun, Belgium
(plant in Katanga)
Process Flow
40 cu m/hr
35 cu m/hr
Amt. of Ozone
40 g/hr
25 g/hr
100 g/hr
500 g/hr
150 g/hr
Year Installed
1959
1962
In addition, it is known from private communications that Brauerei Beck
(Bremen, Germany), Molson's (Canada), Schlitz, Coors and Genessee Breweries
in the United States have incorporated ozone into their beer manufacturing
processes.
Wine Making
An English patent (Coffre, 1931) describes the ozonation of oak chips,
which then are soaked with fermenting wines. By alternately soaking and
aging ozonized oak chips 15 to 20 times at 24-hour intervals and then
reozonizing, the aging wine acquires the same characteristics in three weeks
as wines aged 10 to 15 years. However this process has been banned in
France, because of the importance of the wine-making industry there and its
dependence upon vending of naturally aged wines (Bechaux, 1977; Le Pauloue1,
1977).
Yeast Production
Very recently, Jurgensen & Patton (1977) at Michigan Technological
University, have reported studies on the growth of yeast in ozonized spent
sulfite liquors from the pulp and paper industrial category (see Section 5,
under Pulp & Paper). Short term ozonation (10 minutes) of spent sulfite
liquors converts biorefractory organic materials into more readily biodegrad-
able organic materials by partial oxidation. Early in this project, yeast
production yields of 0.5 to 5.0 g of dry yeast per liter of ozonized effluent
were obtained in laboratory scale studies.
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This program is being conducted under contract to the U.S. Department
of Energy, Division of Industrial Conservation. The primary objective of
this work was to generate methane from spent sulfite liquors, but the yeast-
producing potentials are believed to be economically feasible now (Jurgensen,
1978) and pilot plant-scale studies to prove engineering feasibility are
being planned.
Conclusions
(1) Ozonation is in commercial scale use for treating bottle washing waters
at Gerber Products Co. and in several breweries for treating bottle
washing and process waters (Genessee Brewing, Rochester, N.Y.; Coors,
Golden, Colorado; several in Germany, Canada, Katanga and Finland).
(2) Capital costs for the ozonation system at Gerber Products ($135,000)
were repaid in 1.9 yrs by the savings obtained from water reuse and
lower steam and sewer charges ($125,000/yr).
(3) Ozonation has been described for treating brewery atmospheres to control
mold growths and odors in brewery cellars and in yeast handling areas.
Ozonized water is more effective for sterilizing brewing vats and
piping than is ozonized air.
(4) Laboratory and pilot plant studies have been conducted recently on the
use of ozonation for treating sauerkraut brines (to reduce levels of
COD), bakery wastewaters and to disinfect poultry processing wastewaters.
Estimated costs of salmonella control in Canadian poultry processing
secondary effluents upon ozonation are $0.17/1,000 Igal.
(5) Ozonation of spent sulfite liquors from pulp and paper mills provides
an oxygenated medium conducive to the growth of yeast. This potential
application for ozonation appears to be economically feasible on a
laboratory scale and currently is being pilot plant tested on larger
scale.
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LITERATURE CITED -- FOOD & KINDRED PRODUCTS (FO) & BREWING (BR)*
FOOD & KINDRED PRODUCTS (FO)
FO-01 Barrett, F., 1970, "Minimizing the Waste Disposal Problem in
Vegetable Processing." Proc. Symp. Farm Wastes. The Institute of
Water Pollution Control & the Univ. of Newcastle-upon-Tyne (8):57-
65.
Bechaux, J., 1977, Degremont, Malmaison, France. Private Communi-
cation.
FO-02* Coffre, R., 1931, "Process for Ozonization of Fermented Liquids."
English Patent 340,647, January 8. Abstracted in J. Inst. Brewing,
London, p. 449.
Jurgensen, M.F., Michigan Technical Univ., Houghton, Michigan,
Private Communication.
Jurgensen, M.F. & J.T. Patton, 1977, "Energy and Protein Pro-
duction From Pulp Mill Wastes", Annual Report, 6/15/76-6/15/77
under U.S. ERDA Contract E(ll-l)-2983. See also Progress Reports
for the periods 6/15/77-9/15/77 and 9/15/77-12/15/77 under the
same contract.
FO-03 Leavitt P. & J.V. Ziemba, 1969, "At Gerber Water Does Triple
Duty," Food Engrg. 41:90-91.
FO-04* Leavitt, P, 1972, "Water Reuse Through Ozone Sterilization". ISA
FID-726,408, 19-24.
Le Pauloue1, J., 1977, Trailigaz, Garges-les-Gonesse, France.
Private Communication.
FO-05 Netzer, A., M.J. Riddle, I.J. Marvan & S.G. Nutt, 1977, "Use of
Ozone for Disinfection of Salmonella in Poultry Plant Effluent",
presented at Symp. on Advanced Ozone Technology, Toronto, Ontario,
Canada, Nov. Intl. Ozone Assoc., Cleveland, Ohio.
FO-06 Rivkowich, H., W.C. Rehman, W. Knapp & B. Borders, 1974, "Method
of Extracting Tea", U.S. Patent 3,809,769, 3 May 1974. Chem.
Abstr. 81:90130 (1974).
FO-07* Walter, R.H. & R.M. Sherman, 1974, "Ozonation of Lactic Acid
Fermentation Effluent." J. Water Poll. Control Fed. 46(7):1800-
1803.
* Abstracts of asterisked articles will be found in EPA 600/2-79- -b
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FO-08* Walter, R.H. & R.M. Sherman, 1976, "Efficiency of Oxygen Demand
Reduction of Sauerkraut Brine by Ozone." In Proc. Second Intl.
Symp. on Ozone Technology, R.G. Rice, P. Pichet & M.-A. Vincent,
Eds., Intl. Ozone Assocr, Cleveland, Ohio, p. 694-698.
FO-09 Yim, B., R.H.F. Young, N.C. Burbank, Jr. & G.L. Dugan, 1975,
"Bakery Waste: Its Characteristics & Treatability. Part I", Indl.
Wastes, March/April, p. 24-25. Part II, Ibid. Sept/Oct., p. 41-
44.
BREWING
BR-01 Coffre, R., 1931, "Process for Ozonisation of Fermented Liquids",
British Patent 340,647, Jan. 8, 1931. Abstracted in J. Inst.
Brewing (London), p. 449 (1931).
BR-02* Du Jardin, E., 1924, "The Application of Ozone in the Brewery",
Ann. Brass, et Dist. 23:122. Abstracted in J. Inst. Brewing,
London (1925), p. 88.
BR-03* Fergason, R.R., H.L. Harding & M.A. Smith, 1973, "Ozone Treatment
of Waste Effluent", Research Technical Completion Report, OWRR
Project No. A-037-1 DA, Water Resources Research Inst., Univ. of
Idaho, April. U.S. Dept. of Commerce, NTIS Report No. PB 220,008.
BR-04* Geminn, C.C., 1974, "Concentrated Wort Processing Method", Master
Brewers Assoc. of America, Tech. Quarterly ll(l):21-25.
BR-05* Mayrhofer, K.G, & H. Steinhardt, 1955, "Use of Ozonized Water in
Yeast Manufacture) Brauwelt, 857-859. Abstracted in J. Inst.
Brewing, London 61:530 (1955).
BR-06* SchSuble, R. & M. Gillardin, 1958, "Ozonized Water in the Brewing
and Mineral Water Industries", Brauerei, Wissenschaft Beil. 11:75-
86. Abstracted in J. Inst. Brewing, London 64:515 (1958).
BR-07* Tenney, R.I., 1973, "Ozone Generation and Use in the Brewery",
Brewer's Digest 48(6):64-66.
BR-08* Tenney, R.I., 1973, "Ozone, the Add-Nothing Sterilant", Master
Brewers Assoc. of America, Technical Quarterly 10(1):35-41.
BR-09* Van Laer, M., 1928, "The Use of Ozone in Brewing", Petit J. Brass.
36:854-856. Abstracted in J. Inst. Brewing, London, p.497 (1928).
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HOSPITAL WASTEWATERS
Although there are no reported applications of ozonation for treating
actual hospital wastewaters, a very comprehensive research & development
program was conducted by the U.S. Army Medical Bioengineering R&D Labora-
tories, Ft. Detrick, Maryland, from the early 1970s until late 1977. This
program developed a large volume of fundamental information which is of
great significance to all wastewater treatment applications involving
ozonation. In particular, the combination of ozone with UV light was opti-
mized for oxidation of refractory organics under this program (McCarthy,
Lambert & Reuter, 1977).
The objective of this Army program was to develop a wastewater treatment
system for a mobile field hospital, named MUST (Medical Unit, Self-Contained,
Transportable). MUST wastewaters from the hospital X-ray laboratory, -clinical
laboratory, kitchen, operating room, shower and laundry facilities (all non-
sanitary wastewaters) were to be treated to such a high quality that the
waters could be reused for non-consumptive human purposes. Therefore, the
Army defined the COD of such reuse water to be 10 mg/1 and TOC to be 5 mg/1,
with no toxicity to humans.
In conducting research to define a candidate wastewater treatment
process for pilot testing and prototype development, considerable effort was
expended on the characterization of these wastewaters. Sufficient quantities
of actual field hospital wastewaters were not available for extended treat-
ability studies, so that realistic wastewater recipes had to be developed to
allow representative wastewaters from any hospital activity to be synthesized
as needed (Lambert & Reuter, 1976).
MUST hospital composite wastewater has the following composition:
Shower
Operating Room
Kitchen
Clinical Lab
X-Ray Lab
and the following characteristics:
51% (by volume)
26%
12%
8%
3%
TDS
SS
pH
COD
TOC
1240 mg/1
70 mg/1
6.6
870 mg/1
229 mg/1
MUST laundry composite wastewaters have the following characteristics:
94
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IDS 1630 mg/1
SS 194 mg/1
pH 10.5
COD 1740 mg/1
TOO 457 mg/1
As stated earlier, the wastewater treatment objectives were to attain
waters having a COD of 10 mg/1 and a TOC of 5 mg/1, which are the maximum
allowable concentrations of these parameters in the 1962 U.S. Public Health
Service drinking water standards. The Army's Water Processing Element (WPE)
was designed to treat 4,200 gal/day, and to recover 85% of the wastewater
for reuse. Initially, reuse was for non-consumptive purposes (showers,
laundries, washing, toilet flushing), but eventually the process could allow
for potable reuse as well.
Unit processes for the WPE treatment train are, in sequence: hydraulic
equalization, 40-mesh screening, ultrafiltration, reverse osmosis, UV-
ozonation followed by hypochlorination. Much of the remainder of this
discussion will center on R&D efforts directed toward design of the UV-
ozonation unit operation.
Army R&D efforts were concentrated in 4 areas:
• characterization of wastewaters before, during and after treatment,
• understanding of ozone oxidation mechanisms and kinetics of reaction
with wastewater consituents,
• design and scaleup of a UV-ozonation reactor which optimized mass
transfer and reaction of ozone in a multi-component liquid,
• development and evaluation of control and monitoring instrumentation
for the ozonation unit operation.
The combined UV-ozonation step was chosen because many of the wastewater
components are refractory organic compounds which are only slowly oxidized
by ozone, and the necessity to convert contained COD and TOC into C02 and
water in order to meet the stated objectives of 10 and 5 mg/1, respectively.
Much emphasis was placed by the Army on development of automatic control and
monitoring capability for process parameters, detecting component failures,
sequencing actuators for mode transitions and reducing operator errors to
assure trouble-free operation in the field.
Initial studies aimed at selection of treatment process steps consisted
of comparison of ozonation, activated carbon, ion exchange and biological
oxidation as potential candidates alone or in combination. Ozonation proved
to be the only unit operation which satisfactorily treated all wastewaters
tested (Bryce et_ al., 1973; Sierka, 1975; Reuter, 1975; Chian, Kuo & Chang,
1977). Next, development of suitable analytical methods and techniques for
wastewater characterization were initiated, including the identification of
intermediate and final oxidation products to allow the study of mechanisms
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of the ozonation process and to identify potentially toxic products. Methanol
and acetone were found to comprise a large fraction of the reverse osmosis
(RO) permeates from hospital laboratories. o-Toluidine and N,N-diethyl-m-
toluamide (DEET) were present in most other RO permeates (Chian, Kuo &
Chang, 1977; Mix & Scharen, 1975).
Ozone oxidation kinetics were monitored in the various wastewaters to
gain insight into how to enhance removal of the organic compounds. Wastewater
oxidations exhibited initial periods of rapid TOC removal and low dissolved
ozone values, indicating that initial removal was principally mass transfer
controlled. There was a subsequent period of slower TOC removal and stable
dissolved ozone values, indicating that the reaction rates of the organics
with the dissolved ozone were controlling the TOC removal rates (Figure 10).
It was noted that, depending on the wastewater, gas stripping of components
was significant in various degrees during mass transfer controlled oxidations.
The pH of the wastewater was significant in the reaction rate controlled
cases. Oxidation increased with increasing pH, supporting an hypothesis of
free radical mechanisms (Sierka, 1975; Reuter, 1975; Chian, Kuo & Chang,
1977; Gollan ejt al., 1976).
A portion of the wastewaters, and especially RO permeates from clinical
laboratory wastes, remained refractory to ozone oxidation. UV radiation was
investigated extensively in response to indications that aqueous ozone
oxidation kinetics are accelerated by addition of UV (Chian, Kuo & Chang,
1977; Hewes e£ al_., 1974; Zef f et_ aj_., 1976).
Treatability studies also allowed identification and quantification of
variables affecting the ozonation process. These included temperature, pH,
ozone concentration, mixing speed, gas flow, contact time and organic
composition. It became difficult to compare results obtained by each of the
investigators who, in addition to using different reactors, employed different
experimental conditions in their approach to the problem. Nevertheless,
general trends were recognized and served as bases for further work closer
to optimum ozone oxidation conditions (Lambert & McCarthy, 1977).
During the next phase (1975-1976), ozonation of Army field hospital
wastewaters was investigated on laboratory and pilot scales. Most attention
was focused on 2 wastewaters studied as RO permeates. One was called compo-
site waste, a time-averaged composite of all the non-sanitary field hospital
wastewaters which reasonably could be expected in an actual field situation.
The composite waste represented the "average" wastewater. The second was
the hospital laboratory wastewater which represented the worst case because
of large concentrations of organics refractory to UV/ozone oxidation.
Analytical techniques were refined to measure selected compounds at low
concentrations and to identify unknown compounds. Additional compounds
identified in composite or laboratory RO permeates included phenolic compounds,
chloroform, diethyl ether, methyl ethyl ketone and propanol (Chian, Kuo &
Chang, 1977; Cowen, Cooper & Highfill, 1975).
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TOC
TOC,
II
III
Time
I Initial period (Mass transfer control)
- Fast reaction with large TOC
III Tail end (Reaction rate control)
- Slow reaction with small TOC
II Major reaction (Both important)
Source: Lee & See (1977)
Figure 10. UV/ozone oxidation of hospital composite wastewater.
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As analytical techniques became more precise and "routine", additional
studies on ozonating or UV-ozonating single model compounds in aqueous
solution were better able to follow the intermediate and final oxidation
products with minimum interferences. Compounds at significant concentra-
tions in the wastewater were studied, including those listed above as well
as important intermediate oxidation products. Major ozonation end products
were found to include formic, glyoxylic, oxalic, and acetic acids (Chian,
Kuo & Chang, 1977; Cowen & Cooper, 1975).
HCOOH HOOC-CHO HOOC-COOH CH3COOH
formic acid glyoxylic acid oxalic acid acetic acid
Advantages or disadvantages of adding UV light in the oxidation reaction
also were studied. Within the conditions studied, methanol and urea showed
little or no improvement to ozonation when UV was added, and are among the
most ozone-refractory organic compounds. o-Toluidine and DEET were easily
oxidized whether UV was present or not. Methyl ethyl ketone and acetic acid
showed distinct increases in the rates of oxidation when UV light was added.
Although the benefit of UV addition varied among compounds, its overall
effect on the composite and laboratory wastewaters was a positive one,
especially during the latter stages of ozonation. UV intensity was shown to
attenuate rapidly (reduced 95% within 5 inches from the bulb) however,
underscoring the need for good mixing (Chian, Kuo & Chang, 1977; Gollan et
al_., 1976; Zeff et a]_., 1976; See, Yang & Kacholia, 1976). ~
Measurement of ozone oxidation kinetics and comparison of data obtained
under mass transfer controlled conditions versus reaction rate controlled
conditions suggested that mass transfer conditions dominated, unless ozone
dose concentrations were approximately 2% or more by weight. Hospital
laboratory wastes continued to be those most refractory to ozone oxidation.
Shower wastes were easiest to treat. For most cases, COD was shown to be
the limiting factor in meeting the water quality specifications, rather than
TOC removal. This underscored the industrial nature of the wastewater
(Chian, Kuo & Chang, 1977; Gollan et a^., 1976; See, Yang & Kacholia, 1976).
Further refinements were made to study the effects of different variables.
The most rapid TOC removal was found to occur between a pH of 8 and 10 and
was hypothesized to be related to free radical production. Rapid TOC removal
also occurred between 45e and 60°C, but fell off on either side in the 30*
to 809C range for most wastewaters. This variation in removal rate is
believed to be a result of the combination of an increase in the oxidation
reaction rate with temperature and a simultaneous decrease in ozone solubility
(Gollan et. al_., 1976).
During this time period 3 pilot scale contactors were developed and
constructed. One was a stirred, 2-chamber contactor with multiple UV lamps.
A second used only gas sparging for mixing and had multiple compartments and
multiple UV lamps. A third was also gas sparged and utilized completely
mixed columns in series, each with a UV lamp down the middle. All contactors
were tested and evaluated to varying degrees (Gollan et al., 1976; Zeff et
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aj_., 1976; See, Yang & Kacholia, 1976). A comparison of the efficiency of
ozone/UV oxidation by the three reactors is given in Table 18 (Lee & See,
1977).
The third or last contactor (preceeding paragraph) was selected for
extended testing prior to full scale pilot evaluation (Figure IT shows a
schematic), using the synthetic hospital composite wastewater shown in Table
19 (Lee & See, 1977). Six reactor columns are arranged in series through
which wastewater alternately flows concurrently then countercurrently to
ozone-laden gas. The gas containing ozone is bubbled up through each column
via a sparger in the bottom and a UV lamp extends down the middle of each
column. The columns operate at about 15 psig pressure (aiding mass transfer)
because all off-gases are collected and routed to a precontactor or scrubber.
The precontactor aids in transferring remaining ozone into the fresh incoming
wastewater while stripping out volatile organics from solutions (See, Yang &
Kacholia, 1976). Figure 12 is a photograph of the pilot scale ozone/UV
contactor built for this program.
TABLE 19. ORGANIC CHEMICAL COMPOSITION OF SYNTHETIC MUST HOSPITAL
COMPOSITE WASTEWATER
Kodak X-Omat Developer
Kodak X-Omat Fixer
Methanol
Acetone
Urea
Acetic Acid
Phenol
Ethanol
N,N-Diethyl-m-toluamide (DEET)
Oleic Acid
Di ethyl Ether
TOTAL
Source: Lee & See, 1977.
RO
Permeate
283 yl/1
283 ill /I
16 yl/1
5 yl/1
12.0 mg/1
2.8 yl/1
0.4 mg/1
0.5 yl/1
0.2 mg/1
0.1 yl/1
0.1 yl/1
TOC,
mg/1
18.42
4.76
2.50
2.40
1.15
0.31
0.20
0.15
0.06
0.05
30.0
COD,
mg/1
64.80
19.05
8.70
9.60
3.15
0.95
0.82
0.52
0.23
0.18
108.0
In parallel with this Torn celli-type contactor design, considerable
planning and effort was devoted to control and monitoring instrumentation.
A proposed control and monitor panel connected to a computer which activates
an ozone oxidation unit process simulation panel was built (See, Yang &
Kacholia, 1976).
During the summer of 1976 an investigation of the feasibility of
combining ultrasound with ozone was begun. Within its small scale, generally
favorable results were noted, especially for the more refractory laboratory
RO permeate. Urea, however, still resisted ozone oxidation with or without
99
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TABLE 18. COMPARISON OF OZONE/UV OXIDATION OF ETHANOL BY VARIOUS TYPES OF REACTORS
Test
Condition
Performance
Efficiency
Source:
Parameter
• Reactor Volume, liters
• Initial TOC, mg/1
• 0, Concn. , wt %
• UV Intensity, Watts/1
• 02 Flow Rate, 1/min/l Water
• Half-life of Reaction (tn c)
Min °'b
• Ozone Dosage, mg 0-,/mg
TOC Oxidized J
• Energy Consumption,
kW-hr/g TOC Oxidized
• Ozone Eff., mg TOC Oxidized/g
0, Dosed
• Energy Eff., g TOC Oxidized/
kW-hr
Lee & See, 1977.
gas sparged, completely
mixed columns, each with
a UV lamp down the middle
35
57.7
1.4
1.52
0.18
92
12.8
0.40
78.1
2.5
gas sparged, multiple
compartments, multiple
UV lamps
12
65
2.6
2.69
0.11
214
22.0
0.83
45.5
1.2
stirred, 2-chamber,
with multiple UV
lamps
10
67
3.0
1.50
0.10
175
22.8
0.97
43.9
1.0
o
o
-------
V
1
1
ozone '
generator
1
1
T
1
vastewater
feed ven
I t
* 1 precontactor
• — r -i
1 ^
, k, ,,,tr ~H stage no. 1 > T
ti
'-^ 1 stage no. 2 1 £ J
1
__,fc_ . I staae no. ^ f" P
i
Ti
1
^" , ^| ctagp nn. d 1 kj, (
i
ki 1 <;tanp no R I
T
t ^ . — , , i
^ J st.agp no. 6 1 .
1
t
I
,
1
i
L
L
T
product
Figure 11. Modified Torricelli ozone contactor for U.S. Army MUST
hospital wastewater treatment
Source: McCarthy, Lambert & Reuter (1977)
101
-------
o
ro
Figure 12, Pilot scale ozone/UV contactor used in U.S. Army MUST
wastewater treatment program.
-------
ultrasound. When ultrasound was used, ozone mass transfer rates into solution
were found to be faster. Increasing TOC and COD removal rates indicated
that ozone oxidation rates were enhanced for laboratory and composite waste-
waters (Sierka, 1976, 1977; Sierka & Skaggs, 1977).
In this 1976 to 1977 period, efforts were focused on ozonating laboratory
and composite RO permeate wastewaters using the pilot scale Torricelli
contactor or contact chambers of similar dimensions. Detailed information
needed for scale up to full pilot size was obtained and studies were made on
the stripability of the wastewater components.
Composite and laboratory wastewaters were subjected to extended strip-
ability tests. It was believed that maximizing the amounts of contaminants
removed by the stripping operation would minimize the more costly ozonation
operation. However, tests on composite wastewater showed little tendency to
strip volatiles from solution within the range of conditions studied. Tests
with hospital laboratory wastewaters were more encouraging. At 50°C and
relatively high gas flows, 11% of the TOC was stripped the first hour and
about 6% during the second hour. A model was developed which predicts the
amount of stripping experienced by the laboratory wastewater at 50°C as a
function of the oxygen transfer coefficient, k,a, in any gas sparged reactor
(McCarthy et al_., 1977).
The Torricelli pilot contactor was characterized extensively using
worst case hospital laboratory wastewaters. Variables explored were UV
intensity, ozone concentrations, gas flow, mass transfer, hydraulic mixing,
and prestripping. At 1% by weight ozone concentration in air, about 10 hrs
were required to reduce the TOC level of 138 mg/1 and COD level of 535 mg/1
to 5 mg/1 and 10 mg/1 respectively. Time to attain these same results was
cut to about 6 hrs when 1.5% weight concentration of ozone in air was used
(McCarthy et al_., 1977).
Development of analytical methods and techniques continued, and glyoxal,
methyl glyoxal and dimethyl glyoxal were identified as major end products of
ozonation. Oxalic acid, an important oxidation end product, showed an
improved rate of oxidation to C02 when UV light was added. Surprisingly,
its most rapid removal came under acidic and not alkaline conditions. It
was postulated that the accumulation of inorganic carbon in solution at high
pH retards the oxidation of oxalic acid to C02- When the pH of the solution
was lowered to less than the pK value, most of the bicarbonate remained in
the unstable carbonic acid state, resulting in a substantial improvement in
the reaction rate (Chian, Kuo & Chang, 1977).
Mixtures of compounds in aqueous solution were ozonized. Methanol and
acetone were investigated because these were the 2 most abundant compounds
in laboratory RO permeates. Methanol was removed rather rapidly but acetone
was difficult to remove. Within the conditions studied, the refractory
nature of the acetone apparently was a result of competition for ozone among
the methanol, methanol oxidation products, and acetone. It apparently was
not a result of interactions among the organic compounds (Chain, Kuo &
Chang, 1977).
103
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There have been suggestions in the literature that once generated,
ozone can decompose catalytically in diffusers made from different porous
materials before it has a chance to contact the aqueous stream to be ozonized.
To determine the validity of these suggestions, several different diffuser
materials were evaluated with respect to ozone decomposition. They were
fritted glass, stainless steel, fused aluminum, and Teflon. All materials
used resulted in negligible gas phase decomposition of ozone (Chian, Kuo &
Chang, 1977).
Design equations and criteria necessary for scale-up to a full size
pilot contactor were determined using composite wastewater and subsequent
construction of the reactor has been accomplished. Contactor configuration
is basically the Torricelli type configuration shown in Figure 11. In
design, it was recognized that there are 3, not 2, mass transfer states to
consider. These are the first phase where the rate of reaction (oxidation)
is mass transfer controlled, a long second phase where both mass transfer
and reaction rate are important, and finally a third phase which is princi-
pally reaction rate controlled (Lee & See, 1977, Figure 10).
The full-scale pilot ozone contactor was delivered to the Army Medical
Bioengineering R&D Laboratories at Ft. Detrick, Maryland in September, 1977.
Information from strategically placed probes and sensors can be transferred
onto computer tape or a print-out recorder. The pilot contactor has UV
lights in all reactor chambers and an ultrasound horn in the first. It has
provisions for temperature, pH, and gas flow monitoring and control, and can
be operated manually or in an automatic mode. Variable ozone concentrations
(within flow and pressure limits) are available from the attached 26 Ib/day
ozone generator (Figure 13).
A mathematical model simulating a sparged ozone contactor for the
removal of low concentrations of organics in aqueous solution has been
developed. Given a fixed residence time and well mixed conditions, expected
variables of the model are ozone partial pressure and superficial gas velocity.
The model is designed to be independent of contactor geometry or size. When
completed, it can be tested against empirical results from the full size
pilot contactor and can be an aid to prototype unit design (McCarthy, 1977).
Further investigation of ultrasound with ozonation was conducted.
Unlike the first feasibility effort which was bench-scale (Sierka, 1976)
later work was conducted in a Torricelli chamber geometrically similar to
one in the quarter scale contactor which preceeded full scale-up. Laboratory
and composite RO permeates were ozonated in combination with ultrasound.
Special attention was paid to the effects of column length to diameter ratio
(Sierka & Skaggs, 1977).
A feasibility study of ozonation under high pressure also was completed
and is to be reported in the near future. Pressures to 100 psig were explored.
Ozone losses due to heat of compression and gas "blow-up" were monitored.
High pressure ozonation is looked upon as an alternative (or supplement) to
higher ozone gas feed concentrations. Larger amounts of ozone are expected
104
-------
o
en
nUU I*
Figure 13.
Ozone generator (26 "Ibs/day from air)
and control panel used in U.S. Army
MUST program pilot wastewater testing
unit.
-------
to dissolve into solution according to Henry's law. Heat transfer problems
(for the small-scale studies) were minimal. Verification of the feasibility
of the process would come with treatability studies which show increased
rates of oxidation under high pressure conditions (Hill & Howell, 1977).
Contractor and in-house reports which have emanated from the Army's
MUST program provide some of the most complete information available on
ozonation, UV/ozonation and UV/ultrasonics systems for oxidation of refractory
organic compounds, identification of oxidation products of organic compounds
and oxidation reaction kinectics. Considerable advances strides also were
made in the development of monitoring and control instrumentation for small
scale ozonation systems.
In late 1977 the Army terminated its program pointed at developing
field operational and deployable MUST hospital units. This has resulted in
a change in the wastewater treatment R&D program being conducted by the Army
Medical Bioengineering R&D Laboratories at Ft. Detrick, Maryland.
Current priorities of the Army involve studies pointed at wastewater
reuse, as can be made applicable to the total needs of the Army, rather than
being restricted to hospital wastewaters alone. Medical-specific wastewaters
(X-ray lab, clinical lab and operating room) from Army installations are of
insufficient volumes to consider treatment for reuse as being practicable.
Discharges of these wastewaters to the environment are regulated satisfac-
torily under PL 92-500 and the Clean Water Act of 1977.
On an Army-wide basis, the Army Medical Bioengineering R&D Laboratories
currently are characterizing laundry and shower wastewaters for the ability
to be treated for reuse. Standards and criteria for these raw and treated
wastewaters are being developed and toxicological parameters are being
determined (Peterman, 1978).
Conclusions
1) The Army Medical Bioengineering R&D Laboratories MUST program was
unique in that techniques were being developed to treat hospital
wastewaters for at least non-consumptive human reuse.
2) Results of this program generally are applicable to hospital wastewater
components which are classified as "toxic to receiving bodies of water
or sewer systems".
3) Major ozonation products of organic wastewater components are formic
acid, glyoxylic acid, oxalic acid and acetic acid. All of these are
biodegradable.
4) Increasing the concentration of ozone in air from 1% to 1.5% reduces
the time necessary to attain the target TOC and COD concentrations (of
5 and 10 mg/1, respectively) by 40%.
106
-------
5) Three pilot ozone/UV reactors were tested and one design was scaled up
for extended pilot scale evaluation. This reactor consists of 6 columns,
each having a UV bulb extending the length of the column and each
having a porous diffuser for ozone at its base. Water flow is alter-
nately cocurrent then countercurrent to the gas flow. The unit operates
under 15 psi pressure of ozone-containing gas, and off-gases from the 6
columns are sent to a preozonation contactor where ozone demand is
highest. The precontactor also allows volatile organics to be air-
stripped from solution.
6) Porous ozone diffusers made from glass, stainless steel, fused aluminum
and Teflon gave the same performances. No gas phase decomposition of
ozone was observed with any of these diffuser materials.
7) Studies conducted at gas pressures of ozone in air up to 100 psi show
promise as an alternative means of increasing the concentration of
dissolved ozone, thus reducing required reaction times.
LITERATURE CITED — HOSPITAL WASTEWATERS (HE)*
HE-01 Bryce, C.A., J.A. Heist, R. Leon, R.J. Daley & R.D. Holyer Black,
1973, "MUST Waste Water Treatment System", US Army Medical Research
& Development Command, Contract DADA 17-71-C-1090, Final Report.
HE-02 Chian, E.S.K. & P.P.K. Kuo, 1975, "Fundamental Study .on the Post
Treatment of RO Permeates From Army Wastewaters", First Annual
Summary Rept., U.S. Army Medical R & D Command, Washington, D.C.,
Contract No. DAMD 17-75-C-5006. UILU-ENG-75-2026. NTIS Rept. No.
AD-AD-A021 476/7WP.
HE-03* Chain, E.S.K. & P.P.K. Kuo, 1976, "Fundamental Study on the Post-
Treatment of RO Permeates from Army Wastewater", Sec. Annual
Summary Rept. U.S. Army Med. R & D Command, Washington, D.C.
Contract DAMD 17-75-C-5006. Rept. No. UILU-ENG 76-2019. NTIS No.
AD-A035, 912/5WP.
HE-04 Chian, E.S.K., P.P.K Kuo & B.J. Chang, 1978, "Fundamental Study
on the Post Treatment of RO Permeates from Army Waste-waters,"
U.S. Army Medical Research & Development Command, Ft. Detrick,
Md., Contract DAMD 17-75-C-5006, Final Report 1974-1977 (to be
published 1978).
HE-05 Cowen, W.F., W.J. Cooper & J.W. Highfill, 1975, "Evacuated Gas
Sampling Value for Quantitative Head Space Analysis of Volatile
Organic Compounds in Water by Gas Chromatography," Analytical
Chemistry 47(14):2483.
Abstracts of asterisked articles will be found in EPA 600/2-79- -b.
107
-------
HE-06 Cowen, W.F. & W.J. Cooper, 1975, "Analysis of Volatile Organic
Compounds in Wai den Research MUST Integrated Test Samples and in
a Laboratory Waste Reverse Osmosis Permeate," Memorandum For
Record, Environmental Protection Research Division, U.S. Army
Bioengineering Research & Development Laboratory, Ft. Detrick, Md.
HE-07 Gollan, A.K., K.J. McNulty, R.L. Goldsmith, M.H. Kleper & D.C.
Grant, 1976, "Evaluation of Membrane Separation Processes, Carbon
Adsorption and Ozonation for Treatment of MUST Hospital Wastes,"
U.S. Army Medical Research and Development Command, Contract DAMD
17-74-C-4066, Final Report.
HE-08 Hewes, C.G., H.W. Prengle, C.E. Mauk & O.D. Sparkman, 1974,
"Oxidation of Refractory Organic Materials by Ozone and UV Light,"
U.S. Army Mobility Equipment Research & Development Center, Ft.
Belvoir, Va. Contract DAAK 02-74-C-0239, Final Report.
HE-09 Hill, A.G. & J.B. Howell, 1977, "Compression of 03/02 and 03/Air
Mixtures", presented at Symp. on Advanced Ozone Techno!., Toronto,
Ontario, Canada, Nov. Intl. Ozone Assoc., Cleveland, Ohio.
HE-10 Hill, A.G. & J. Howell, 1978, "Feasibility of Treating MUST
Reverse Osmosis Permeates by High Pressure Ozonation", U.S. Army
Medical Bioengineering R&D Command, Ft. Detrick, Md., Contract
DAMD 17-77-C-7030, Final Report (to be published 1978).
HE-11 Lambert, W.P. & L.H. Reuter, 1976, "Wastewater Reuse Within An
Army Field Hospital", Proc. Third Natl. Conf. on Complete Water
Reuse, Cincinnati, Ohio. Am. Inst. Chem. Engrs., New York, NYY.
HE-12 Lambert, W.P. & J.J. McCarthy, 1977, "Ozone Oxidation for Reuse
of Army Field Hospital Wastewaters", in Forum on Ozone Disinfection,
E.G. Fochtman, R.G. Rice & M.E. Browning, editors, Intl. Ozone
Assoc., Cleveland, Ohio, p. 108-124.
HE-13 Lee, M. & G. See, 1977a, "Ozone Technology Presentation", Life
Systems, Inc., Engineering Report 314-35, Cleveland, Ohio.
HE-14 Lee, M.K., G.G. See & R.A. Wynveen, 1977, "Reaction Kinetics of
UV-Ozone with Organic Compounds in Hospital Wastewater", presented
at Symp. on Advanced Ozone Technol., Toronto, Ontario, Canada,
Nov. Intl. Ozone Assoc., Cleveland, Ohio.
HE-15 McCarthy, J.J., W.F. Cowen, E.S.K. Chian & B.W. Peterman, 1977,
"Evaluation of an Air Stripping-Ozone Contactor System", Technical
Report 7707, U.S. Army Medical Bioengineering R&D Laboratory, Ft.
Detrick, Md.
108
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HE-16 McCarthy, J.J., W.P. Lambert & L.H. Reuter, 1977, "Research and
Development Efforts Concerning Ozonatian of Army Field Hospital
Wastewaters", presented at Seminar on the Current Status of
Ozonation for Wastewater Treatment and Disinfection, Cincinnati,
Ohio, Sept. 15. Intl. Ozone Assoc., Cleveland, Ohio.
HE-17 Mix, T.W. & H. Scharen, 1974, "Organic Solute Dectection", NTIS
Rept. No. PS-770,749, U.S. Dept. of Commerce, Springfield, Va.
HE-18 Mix, T.W. & H. Scharen, 1975, "Development of Techniques for
Detection of Low Molecular Weight Contaminants in Product Water
from Water Purification of Water Reuse Systems", U.S. Army Medical
R&D Command, Washington, D.C., Contract DADA 17-72-C-2169, Final
Report.
Peterman, B.W., 1978, U.S". Army Medical Bioengrg, R&D Lab, Ft.
Detrick, Md., Private Communication.
HE-19 Reuter, L.H., 1975, "Ozone Research Supported by the U.S. Army
Medical Research and Development Command," in Proc. First Intl.
Symposium ojx Ozone for Water and Wastewater Treatment, R.G. Rice &
M.'E. Browning, editors, Intl. Ozone Assoc., Cleveland, Ohio, p.
476-482.
HE-20 See, G.G., K.K. Kacholia & R.A. Wynveen, 1975, "Control and
Monitor Instrumentation for MUST Water Processing Element", U.S.
Army Medical R&D Command, Washington, D.C., Final Report, Contract
No. DADA 17-73-C-3163.
HE-21 See., G.6., P.Y. Yang & K.K. Kacholia, 1976, "Research and
Development of an Ozone Contactor System," US Army Medical Bioengi-
neering R&D Command, Ft. Detrick, Md., Contract DAMD 17-76-C-
6041, Final Report.
HE-22* Sierka, R.A., 1975, "Activated Carbon Treatment and Ozonation of
MUST Hospital Composite and Individual Component Waste-waters,"
Technical Report 7502, US Army Medical Bioengi-neering R&D
Laboratory, Ft. Detrick, Md. Final Report.
HE-23 Sierka, R.A., 1976, "Mass Transfer and Reaction Rate Studies of
Ozonated MUST Wastewaters in the Presence of Sound Waves," U.S.
Army Medical Research and Development Command, Contract DAMD 17-
76-C-6057, Final Report.
HE-24 Sierka, R.A., 1977, "The Effects of Sonic and Ultrasonic Waves on
the Mass Transfer of Ozone and the Oxidation of Organic Substances
in Aqueous Solution", Presented at Third Intl. Symp. on Ozone
Technol., Paris, France, May, 1977. Intl. Ozone Assoc., Cleveland,
Ohio.
109
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HE-25 Sierka R.A. & R.L. Skaggs, 1978, "Effects of Ultrasound on MUST
Hospital Composite Wastewater," US Army Medical Bio-engineering R
& D Command, Ft. Detrick, Md. Contract DAMD 17-77-C-7031, Final
Report.
HE-26* Tencza, S.J. & R.A. Sierka, 1975, "Ozonation of Low Molecular
Weight Compounds", Presented at Sec. Natl. Conf. on Water Reuse,
May 4-8. Am. Inst. Chem. Engrs., New York, N.Y.
HE-27 Vlahakis, J.G., 1975, "Renovation of a Hospital-Type Wastewater
for Recycle", Presented at the Second National Conference on
Complete WateReuse, Waters Interface With Energy, Air, and Solids,
May, Am. Inst. Chem. Engrs., New York, N.Y.
HE-28* Zeff, J.R., R.R. Barton, B. Smiley & E. Alhadeff, 1974, "UV-Ozone
Water Oxidation/Sterilization Process". Final Report #1401 to
U.S. Army Medical R & D Command, Contract DADA 17-73C-3138, Sept.
HE-29 Zeff, J.D., R. Shuman & E.S. Alhadeff, 1975, "UV-Ozone Water
Oxidation/Sterilization Process", U.S. Army Medical R & D Command,
Washington, D.C., Contract DAMD 17-75-C-5013, Annual Report.
HE-30 Zeff, J.D., R. Shuman, E.S. Alhadeff, J. Wark, F.C. Farrell, D.T.
Boylan & A. Forsythe, 1976, "UV-Ozone Water Oxidation/ Sterili-
zation Process," U.S. Army Medical Bioengineering R & D Command,
Ft. Detrick, Md., Contract DAMD 17-75-C-5013, Final Report 1973-
1976.
110
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INORGANICS
All easily oxidized inorganic anions and cations can be oxidized by
ozone under aqueous conditions. Specific ions which have been ozonized
under wastewater treatment conditions include cyanides, cyanates, thio-
cyanates, nitrites, sulfides, sulfites, thiosulfates, cations of Mn(II),
iron(II), Hg(I), arsenic, aluminum, lead, nickel, chromium, copper, cobalt,
barium, zinc, cadmium and organic complexes of some of these metals.
Details of the ozone oxidation of cyanide, cyanate and thiocyanate ions
already have been discussed under Cyanides and Cyanates. Sulfides will be
discussed to some extent under Leather Tanneries and under Petroleum Refiner-
ies, iron and manganese oxidation will be discussed to some extent under
Mining and sulfites and thiosulfates in sections dealing with Photoprocessing
and Textiles. Other literature dealing with oxidation of these inorganic
materials will be discussed in this section, along with the ozonation of
aqueous solutions of ammonia.
Some drinking water supplies contain small amounts of sulfides (ground-
waters which contain sulfate and anaerobic bacteria), cyanides and iron and
manganese. There are many operating drinking water treatment plants through-
out the world using ozone for coping with these specific problems. The
recently started (Spring, 1978) 13 mgd drinking water treatment plant at
Monroe, Michigan installed ozonation mainly for tastes and odors, but also
for cyanide oxidation (Le Page, 1976).
Iron and Manganese
German water treatment plants along the lower Rhine River in the
DUsseldorf area draw well waters which have been filtered through the sand
banks located along the Rhine. During this process of river sand bank
filtration, levels of iron and manganese in the raw waters rise considerably,
and ozonation was installed in the early 1950s to oxidize these cations from
the divalent to the trivalent (iron) and tetravalent (manganese) states. In
the trivalent state ferric ion now hydrolyzes, forming insoluble ferric
hydroxide. As this material coagulates it serves as a flocculating agent
for dissolved organic materials which are polar in nature:
Fe(OH)3
Ozonation of manganous ion produces insoluble manganese dioxide, which
precipitates much more rapidly than does ferric hydroxide. Continued
ozonation of manganese-containing solutions can form the septavalent perman-
ganate ion, which is quite soluble and which imparts a pink color to the
solution:
°3
Mn02 >• Mn04"
111
-------
If a pink color is obtained during drinking water treatment, indicating
over-ozonation of manganese-containing solutions, the ozonized waters are
held about 30 minutes, during which time the permanganate slowly oxidizes
extraneous dissolved organic materials, being reduced back to manganese
dioxide, and the pink color disappears. Alternatively, the slightly pink
solution can be passed through GAC, which reduces permanganate ions to
manganese dioxide.
Details of the use of ozonation for iron and manganese oxidation in
drinking water treatment can be found in Miller et al. (1978). Other
references on this subject include Whitson (194777 Sergeev (1964), Marcy &
Metthes (1967), Sengaki & Ikehata (1968) and Rohner (1969).
Other Heavy Metals
Lizunov, Leontovich & Skripnik (1972) ozonized wastewaters from chlor-
alkali production containing mercury. An air mixture containing 22 to 24
mg/1 of ozone was passed through a 50 mm x 2 mm column containing 0.124 mg/1
Hg for 6 to 32 minutes. The oxidation rate of mercury increased with decreas-
ing pH and "was complete" at pH 4. No metallic mercury vapor was produced.
No further details were given in the English abstract of this work.
Yakobi, Galstyan & Galstyan (1975) studied the oxidation of Cr(III)
solutions with ozone. In the absence of transition metals, Cr(OH)3 was not
appreciably oxidized by ozone-air mixtures. Addition of manganese compounds
to the solutions, however, allowed the oxidation to proceed smoothly, giving
a quantitative yield of Cr(VI). The mechanism proposed by these authors for
the accelerating effect of manganese is that ozone first reacts with bivalent
manganese ions, producing trivalent manganese and hydroxyl radicals. Both
the trivalent manganese and the hydroxyl radicals then are postulated to
oxidize Cr(III) to Cr(IV), which then disproportionates to Cr(VI) (33%) and
Cr(III) (67%).
Netzer, Bowers & Norman (1972) described a bench scale system for
removing trace metals from solution by treatment with lime and ozone. Stock
solutions of metals were prepared at 100 rng/1 concentrations. Lime was
added to adjust pH to 7 to 9, then ozonation was conducted to saturation in
a 120 x 6.5 cm column. Metals removed from solution were above 99.5% for
Al, As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni and Zn. Removal of mercury "was
lower". This preliminary work showed that these metal cations precipitate
in aqueous solutions as a result of the formation of insoluble hydroxides
and oxides.
In a more detailed report, Netzer & Bowers (1975) showed that a large
percentage of these metals are removed by lime adjustment to pH 7.0, 8.0 and
9.0, and that the remaining dissolved metals are precipitated by ozone at
these pH levels. Stock solutions containing 100 mg/1 of the metal cations
were treated with lime in a rapid mix reactor, from which the mixture was
passed into a flocculation/sedimentation tank with a residence time of about
one hour, then to a clearwell holding tank prior to ozonation.
112
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Ozone was produced from dry oxygen, then passed through a porous stone
in a 120 x 6.5 cm perspex column with solution being pumped cocurrently to
the ozone flow. Ozone was analyzed in the inlet gases and in solution, but
not in the contactor off-gases. Ozonatidn was carried to saturation and
only the effect of pH was examined experimentally. To show that removal of
metals was due to ozonation, duplicate experiments were conducted with
nitrogen, air and pure oxygen under conditions identical to those involving
ozone. No removal of metals was found unless ozone was present.
Greater than 99.5% removal was achieved for all the metals studied,
except mercury which was removed only to the extent of 2% at pH 7 and 8, and
1% at pH 9. Furthermore, the pH for complete removal of all metals except
cadmium and iron was lower by this process than the pH necessary for complete
removal by lime treatment alone. Lime treatment alone would require recarbona-
tion to lower the pH of an effluent prior to discharge. Costs for the
lime/ozonation process are estimated to be H/1,000 gal at pH 8 and 1.4<£ at
pH 9. By comparison, lime treatment alone at pH 10 is estimated to cost 1.7
to 3.6(^/1,000 gal (cost estimates are based on a 10 mgd wastewater flow
containing 25 mg/1 heavy metal content).
Weber & Waters (1973) showed that ozonation (ozone generated from
oxygen) of aqueous solutions of dimethylmercury "destroyed" the mercurial
compound from its solubility of 0.0005M to below its limits of detection
(0.00005M) and that at least 90% of the material originally present reacted
in 10 minutes. The ozonation reaction was too fast to allow calculation of
a rate constant.
Shambaugh & Melnyk (1978) studied the removal of heavy metals from
solution by means of ozonation. Aqueous solutions of lead, manganese,
cobalt, nickel, barium and zinc were studied, as were aqueous solutions of
EDTA complexes of manganese, cadmium, nickel and lead.
Ozone was generated from oxygen and applied to the solutions through a
sintered glass sparger contained in a 1-liter glass reactor 21 cm high.
Solutions of the metals (100 mg/1) were buffered with 6.6 x 10~4M sodium
tetraborate. Following ozonation, the pH was raised with NaOH and any
material which precipitated was filtered. Concentration levels of solutions
of uncomplexed Mn, Co and Ni then were too low to be measured by flame
atomic absorption spectroscopy, but no lowering in concentrations of Ba and
Zn was observed. These last two metals have only one known oxidation state
in solution, which is incapable of being changed by ozonation.
The concentrations of lead were lowered very rapidly upon ozonation at
pH 8, 9, 10 and 11. At the 3 higher pH values, lead concentrations decreased
to less'than 0.1 mg/1 within 3 minutes after ozonation began. During the
course of these runs, the pH changed by no more than 0.2 pH unit. At pH 8
(borate buffered), however, the pH dropped to 3.6 during the course of
ozonation over 10 minutes, after which the concentration of lead was 0.1
mg/1. This behavior at pH 8 is explained on the basis of maintenance of pH
by the buffer for the first few minutes of ozonation, after which it decom-
poses and the pH then drops slowly.
113
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Shambaugh & Melnyk (1978) concluded that ozonation times on the order
of 1 minute will suffice for lowering the concentrations of uncomplexed
metals (which can be oxidized to higher valence states by ozone) to levels
below the current EPA maximum allowable discharge concentrations. For EDTA
complexes of Mn, Cd, Ni and Pb, ozonation times of 10 minutes are required
to reach the same levels.
For ozonation of the EDTA-metal complexes, a simple second order rate
expression describes the disappearance of metal complexes. It was also
shown that ozone decomposes at least 50 times faster than it reacts with
EDTA and that the rate of destruction of EDTA-metal complexes is an order of
magnitude faster than that of the simple attack of ozone on EDTA alone.
Ammonia
Singer & Zilli (1975) studied the effects of ozonation on the ammonia
content of municipal wastewater and evaluated the effects of pH and concentra-
tions of ammonia, ozone and residual COD on ammonia removal with ozone.
Ozone was generated from oxygen and the contactor was a plexiglass column 43
cm high and 9.5 cm in diameter, which contained a porous diffuser stone.
Concentrations of ozone were measured in the influent gas from the generator
and in the contactor off-gases so that the amount of ozone actually consumed
(or decomposed) could be determined.
In the first phase of this program, buffered solutions of ammonium
chloride (NfyCl) were ozonized to determine the products of the ammonia-
ozone reaction and to establish the kinetics of the reaction. Solutions
buffered at pH 9 (boric acid-borate) containing 10 to 50 mg/1 of NH4C1 were
ozonized for 30 minutes (the gas stream contained 5.7 to 5.8 weight % ozone)
and samples were collected periodically and analyzed for ammonia, nitrite
and nitrate. No nitrite was found and the rate of increase of nitrate ion
paralleled the rate of decrease of ammonia concentration on a 1:1 basis.
To confirm that the disappearance of ammonia could not be attributed to
air stripping or to oxidation by oxygen, one of the experimental runs was
conducted under the same ozonation conditions, but with the power to the
ozone generator turned off. Thus only oxygen gas was being passed into the
solution. No changes in concentration of ammonia were observed at pH 9
under these conditions.
The rate of disappearance of ammonia during ozonation decreased as the
ammonia concentration decreased. The half-life for ammonia at an initial
concentration of either 10 or 50 mg/1 was about 12 minutes, indicating that
the reaction is first order with respect to ammonia over the pH range 7 to
9. However, the rate of oxidation is pH dependent, being 10 to 20 times
faster at pH 9 than at pH 7. The buffered test solutions never decreased
more than 0.2 pH unit during ozonation.
Ozonation of solutions of ammonium sulfate gave the same results,
indicating that with NH4C1 there was no oxidation of chloride ion to chlorine
(by ozone) followed by chlorine oxidation of ammonium ion.
114
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In the second phase of the study, secondary sewage treatment plant
effluent was spiked with NH4C1 to produce ammonia levels of 30 mg/1. The
spiked effluent was treated with lime to the pH test level(s), SS were
allowed to settle and the clarified liquid was drawn off and ozonized in the
same manner as were the samples of Nh^Cl. Ozonized samples were analyzed
for ammonia, nitrate and COD. When no buffering was employed and no adjust-
ment of the pH was made, ozonation lowered the COD 34% (from 66.1 to 43.9
mg/1). However, only a slight decrease in ammonia concentration-was observed
after 60 minutes of ozonation, during which time the pH fell from 7.55 to
7.20.
When the pH was raised by addition of lime or NaOH, ozonation caused a
depression of pH which limited effective ammonia oxidation. The pH dropped
from an initial value of 9.2 to 8.3 within the first 15 minutes of ozonation,
after which subsequent oxidation of ammonia was negligible. After 60 minutes
of ozonation, the pH had dropped to 7.4.
When secondary effluent was buffered at pH 9 with boric acid-borate,
ammonia removal was appreciable (70% being oxidized in 60 minutes), although
the COD remained unchanged. Measurements of the rate of nitrate ion increase
confirmed that nitrate was the only oxidation product of ammonia, and that
for each mole of ammonia which disappeared, one mole of nitrate was produced.
However, the rate of oxidation of ammonia in wastewaters containing 66 mg/1
of COD was slower than in simple NH^l solutions.
In one experiment, a large lime dose was added to the wastewater to
elevate the pH to 11.6 and the settling step was omitted. Despite the drop
in pH to 7.7 upon ozonation, the ammonia concentration decreased 89% to 3.3
mg/1 and the COD concentration also decreased by 69%.
Stoichiometrically, the oxidation of 1 equivalent of ammonium ion to
produce 1 equivalent of nitrate ion requires 4 equivalents of ozone, according
to the following equation:
NH4+ + 403 * N03~ + 402 + H20 + 2H+
In actuality, a slightly greater amount of ozone was required because some
of the ozone added decomposed before it could react with the ammonium ions.
Singer & Zilli (1975) concluded that ozone oxidation of ammonia in
wastewaters can be attractive when the wastewaters are pretreated with lime
to produce high pH values.
Somiya, Yamada & Goda (1977) studied the ozonation of aqueous solutions
of ammonia, nitrite and several organo-nitrogen compounds. Ozone was genera-
ted from oxygen and the contactor was an acrylic column 100 cm high and 5 cm
in diameter, one end of which contained a fritted glass plate. Then 1.2-
liter samples of 0.5 mM (millimolar) nitrogenous compounds were adjusted to
alkalinities of 100 mg/1 of bicarbonate and to test pH values with 0.1N
sulfuric acid or NaOH. Solutions were ozonized 30 to 60 minutes and the
samples were analyzed for ammonia, nitrite, nitrate, pH, alkalinity and TOC.
115
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During the ozonation of ammonia solution starting at pH 11.58, nitrite
ion concentration increased rapidly to a peak concentration in 2 minutes,
then decreased to zero during the next eight minutes. Nitrate was formed
stoichiometrically with decrease in ammonia concentration, indicating that
none of the ammonia was physically stripped out of solution during ozonation.
The rate of formation of nitrite from solutions containing 7 mg/1 of ammonia-N
is about 0.02 mg/1/min at pH 7, increasing to about 0.95 at pH of 11.58;
1.0 mg of ammonia-N consumed 7.14 mg of alkalinity.
Nitrite
Ozonation of potassium nitrite solutions containing 7 mg/1 of nitrite-N
at initial pH values of 5.0, 7.0 and 10.0 oxidized all nitrite ion to nitrate
ion within two minutes. The rate of formation of nitrate increased at the
same rate as the concentration of nitrite decreased. A decrease in alkalinity
was not observed and the pH of the solutions was not changed upon ozonation.
To confirm that the disappearance of nitrite was not caused by oxygen
oxidation (as opposed to ozone oxidation), an "ozonation" experiment was
conducted at pH 7 without power being supplied to the ozone generator. No
change in nitrite concentration was observed after 30 minutes of passing
oxygen through the solution (Somiya, Yamada & Goda, 1977).
Conclusions
1) Sulfide, cyanide, thiocyanate and nitrite ions are oxidized rapidly by
ozone.
2) Ozonation of water supplies to remove iron and manganese has been a
common practice in many European drinking water treatment plants for
many years.
3) Pure solutions of Cr(III) are not appreciably oxidized by ozone, but
addition of manganese compounds allows the oxidation to Cr(VI) to
proceed smoothly.
4) Metals which can exist in more than one oxidation state in aqueous
solution (Cd, Co, Cr, As, Cu, Fe, Pb, Mn and Ni) can be removed from
solution by ozonation with or without prior treatment with lime.
Greater than 99.5% removal of these metals can be achieved starting
with concentrations of 100 mg/1 by lime treatment followed by ozonation,
and at a lower pH (9) than that required for removal using lime treatment
alone. Mercury cannot be removed from solution effectively by the
lime/ozonation procedure.
5) Concentrations of uncomplexed Pb, Mn, Co and Ni at initial pH values of
9, 10 or 11 can be lowered from 100 mg/1 to less than 0.1 mg/1 within 3
minutes of the start of ozonation. EDTA complexes of these same metals
react more slowly, requiring 10 minutes of ozonation to reach concentra-
tions below 0.1 mg/1.
116
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6) Aqueous pure solutions of ammonia at initial pH values of 7 to 11.58
react with ozone to produce nitrite ion as an intermediate, which
rapidly oxidizes to nitrate. Even at pH values above 9 (where ammonium
ion exists as free ammonia), one equivalent of nitrate is formed for
each equivalent of ammonia-N removed from solution by ozonation. Thus,
no gas stripping of ammonia occurs during ozonation.
7) Ozonation of ammonia in secondary sewage treatment plant effluents
produces nitrate stoichiometrically. The rate of oxidation with ozone
is very slow at an initial pH of 7.55 but more rapid at higher pH
values. However, the presence of COD levels of 66 mg/1 apparently
lowered the ammonia oxidation rates considerably over those observed
with pure solutions of ammonium compounds.
LITERATURE CITED — INORGANICS (1C)*
IC-01* Geisel, R., H. Krause, & W. Kluger, 1972, "Decontamination of
Radioactive Waters", Ger. Patent 2,120,754, Nov. 9, Addn. to Ger.
Patent 1,517,664 (Chem. Abstr. 75:40130x for 1,517,664).
LePage, W.L., 1976, "Ozone Treatment at Monroe, Michigan", in
Proc. Sec. .Intl. Symp. on Ozone techno1., R.G. Rice, P. Pichet &
M.-A. Vincent, editors. Intl. Ozone Assoc. Cleveland, Ohio, p.
198-210.
IC-02* Lizunoy, V.V., E.V. Leontovich, & V.A. Skripnik, 1972, "Ozone
Oxidation of Mercury in Waste Waters from Chlorine and Alkali
Production", Vodopodgotovka Ochistka Prom. Stokov 9:19-22 (Russ).
From Ref. Zh., Khim, 1972, Abstr. No. 171412.
IC-03 Marcy 0. & F. Matthes, 1967, "The Reaction of Manganese (II) Salt
Solution with Ozone", Chem. Tech. 19:430.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, W. Kuhn & H.
Wolf, 1978, "An Assessment of Ozone and Chlorine Dioxide Technolo-
gies for Treatment of Municipal Water Supplies", U.S. EPA Report
EPA 600/2-78-147. U.S. Environmental Protection Agency, Municipal
Environmental Research Laboratory, Cincinnati, Ohio.
IC-04* Netzer, A., A. Bowers & J.D. Norman, 1972, "Removal of Trace
Metals from Waste Water by Lime and Ozonation", Pollut. Eng. Sci.
Solutions, Proc. Intl. Meet. Soc. Eng. Sci., 1st 1972 (Pub.
1973), 380-6.
IC-05 Netzer, A. & A. Bowers, 1975, "Removal of Trace Metals from Waste-
water by Lime and Ozonation", in Proc. First Intl. Syjnp. on Ozone
for Water & Wastewater Treatment, TT."G". RTce~~& MYE. Browning,
editors. Intl. Ozone Assoc., Cleveland, Ohio, p. 731-747.
* Abstracts of asterisked articles will be found in EPA 600/2-79- -b.
117
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IC-06 Rohner, E., 1969, "Removal of Manganese in Water with Ozone",
Swiss Patent 481,020, December 31.
IC-07 Senzaki T. & A. Ikehata, 1968, "Oxidation of Manganese (II) in
Aqueous Solutions by Ozone", Kogyo Yosui, 116:46. Chem. Abstr.
69:100209t (1968).
IC-08 Sergeev, Y.S., 1964, "Iron Removal and Quality Improvement of
Alluvial water", Kommun Khoz. sb., 2:72. Chem. Abstr. 65:5218g
(1966).
IC-09* Shambaugh, R.L. & P.B. Melnyk, 1978, "Removal of Heavy Metals via
Ozonation", J. Water Poll. Control Fed. 50:113.
IC-10 Singer, P.C. & W.B. Zilli, 1975, "Ozonation of Ammonia in Municipal
Wastewater", in Proc. First Intl. Symp. on Ozone for Water &
Wastewater Treatment. RYGYttTce~& M7E7 Browning;, eBTtors. Tntl.
Ozone Assoc., Cleveland, Ohio, p. 269-287.
IC-11 Somiya, I., H. Yamada & T. Goda, 1977, "The Ozonation of Nitro-
genous Compounds in Water", presented at Symp. on Advanced Ozone
Technol., Toronto, Ontario, Canada, Nov. Intl. Ozone Assoc.,
Cleveland, Ohio.
IC-12* Weber, P. & W.L. Waters, 1973, "Ozonation of Aqueous Dimethyl-
mercury", Proc. Montana Acad. Sci., 32:66-69.
IC-13 Whitson, J.T.B., 1947, "The Effect of Ozone on Waters Containing
Manganese", J. Inst. Water Engrs. 1:464.
IC-14 Yakobi, V.A., G.A. Galstyan & T.M. Galstyan, 1975, "Oxidation of
Compounds of Trivalent Chromium by Ozone", Zhurnal Prikladnoi
Khimii 48(1):16-19.
118
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IRON AND STEEL
In this category, wastewater pollutants which have been treated by
ozonation include:
Cyanide
Thiocyanate
Phenols
Thiosulfates
Sulfide
In addition, it is possible to consider ozonation for the removal of
manganese and ammonia. Manganous and ferrous ions are easily oxidized by a
number of strong oxidizing agents, including ozone, and the use of ozonation
for this specific purpose in many European drinking water treatment plants
(Miller et aj_., 1978) since the mid-1950s attests to its efficacy.
Preozonation of GAC columns and beds has been incorporated into some
German and French drinking water treatment plants specifically to promote
biological growth in the carbon adsorbent. Nitrifying bacteria develop in
the carbon adsorbent, and thus the preozonized carbon now is capable of
converting ammonia to nitrate biologically. Whether or not this technique
can be transferred from the rather dilute ammonia concentrations found in
drinking water supplies (up to 8 mg/1) to iron and steel wastewater effluents
(up to 2,400 mg/1) is not known at th'is time.'"Nevertheless, the applicability
of Biological Activated Carbon (BAG) (Rice, 1978) to iron & steel and other
industrial categories whose wastewaters are likely to contain ammonia should
be determined by experimentation and pilot studies. A more detailed discus-
sion of the status of BAC is given in Section 7.
Ozonation of wastewater containing phenols will be discussed in detail
in this section, but ozonation of specific iron and steel industry wastewaters
will be discussed at this point. The chemistries involved upon ozonation of
cyanides have been discussed under Cyanides and Cyanates.
Thiocyanate ion, (NCS)~, also is oxidized upon treatment with ozone,
producing cyanide ion first, which then further oxidizes to cyanate, then to
COp and nitrogen:
(NCS)~ + 03 MCN)~ + (S04)~2 >(CNO)
The oxidation of thiocyanate to cyanide by means of ozone is faster than the
oxidation of cyanide to cyanate.
Phenols in Coke Plant Effluents
The total amount of phenols in coke plant discharges (ahead of dephenoli-
zing) usually is between 0.25 and 0.50 Ib/ton of coal carbonized, and the
total amount of waters containing phenols to be discharged may be on the
order of 35 to 50 gal/ton of coal processed. Approximately one-half of this
is condensate from the gas coolers. Representative concentrations of phenol
119
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in this effluent may range from 1,000 to 2,000 mg/1. In the discharges from
light oil decanters, phenol concentrations may be 50 to 150 mg/1 and 10 to
50 mg/1 in the effluents from miscellaneous plant sources. If it is assumed
that most coke plants employ efficient dephenolizers which will remove 95 to
99% of the phenol in the gas cooling condensate, and then add the discharge
from the light oil decanters (without passing it through the dephenolizer),
the combined effluent from the coke plant that will have to be treated will
have an average concentration of phenol of about 100 mg/1 (Nebolsine, 1957).
Marechal (1905) was the first to patent the use of ozone for oxidation
of phenols in iron & steel industry wastes. Later, Leggett (1920) obtained
a U.S. patent for the same purpose. Although the use of ozonation for
phenol oxidation was well known, the first detailed study of its use in the
iron & steel industry was not published until 1951, when a consortium of
companies and agencies participated in a program directed by the Ohio River
Valley Water Sanitation Commission (ORSANCO) and later described by several
authors (Anonymous, 1951a, 1951b; Cleary & Kinney, 1951; Murdock, 1951).
In the ORSANCO study, phenol wastewaters originating as the effluents
from a dephenolized ammonia still in the Armco Steel Co. (Hamilton, Ohio)
coke plant were tested first in laboratory experiments, then in an on-site
pilot plant. Three treatment processes were studied: chlorination, chlorine
dioxide and ozonation. Phenols present in the wastewater stream included
phenol, cresols and xylenols, and the characteristics of the dephenolizer
effluents are given in Table 20.
TABLE 20. ANALYSES OF PHENOL-CONTAINING WASTEWATERS
Pneno I
TyanTdes" aTuT cyanates
Sulfides
Chlorides
Oxygen Consumed (OCj
BOD f
~~A"mmonia
Temperature"
_ 28_to__332_mg/J
„ in. lQW_coji£enJi]ratiojj _
Jess thanJOOjTig/1
between 7.000 and JL70HjngZ]
1,400 to 1,800 mg/1 (about one-half
the OC as measured by the dichromate
reflux method was djue to chlorides!
_300_to 400 rmj/J
10 to 2,390 mg/1 (variation due to "
_dropin_fixed_ leg of ajnmonia, s_ti]J)
fTxecT leg of ammonia still ordinarily
operated above 11.0 for maximum
Ammonia recovery .
from the still at IQQ^C ~
Source: Cleary & Kinney, 1951
Laboratory investigations showed the following:
(1) Complete destruction of phenols in ammonia still wastewaters could be
achieved by oxidation with chlorine, chlorine dioxide or ozone.
120
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(2) No pretreatment was required for oxidation with ozone or chlorine
dioxide, but for chlorination, the pH had to be adjusted to 7.0 to 10.0
and the temperature reduced to 45*C.
(3) Under-oxidation with ozone or with chlorine dioxide did not result in
the formation of chlorophenols; chlorination required complete oxidation
to prevent the formation of such end products, requiring an excess of
several hundred mg/1 of chlorine. This excess chlorine then could be
removed easily with GAC.
(4) Ozonation caused no increase in chloride content; chlorine dioxide
caused about 1.50% increase; chlorination caused an increase equivalent
to the amount dosed for complete oxidation.
Based on these laboratory experiments, a pilot plant was constructed at
Armco Steel which was capable of handling 2 gal/min continuous wastewater
flows, or 350 gal in batch operations. A 1,000 gal holding tank provided
uniform wastewater for a 1-day run, and the water was heated by means of a
steam coil. A reaction tower 2 ft in diameter and 18 ft high allowed varia-
tion in liquid depth at 2 ft intervals. Wastewater was pumped to the top of
the tower, and ozone was added through stainless steel diffusers at the
bottom of the tower. Chlorine dioxide was added in-line at the top of the
tower. Caustic could be added at any level for pH control. Two 55-gal
drums served as chlorination reactors, after which the chlorinated wastewater
was pumped to the tower.
In general, the laboratory results were confirmed in this pilot plant.
Chlorine added during continuous flow did not provide complete phenol removal
in 18 minutes. The initial chlorine dosage first had to satisfy the ammonia
demand, after which there was a significant decrease in phenol concentration
with small increases in chlorine dosage. Chlorine destroyed phenols over a
wide pH range (1.8 to 11.0). The recommended pH was above 7.0 (to avoid
formation of chlorophenols and nitrogen trichloride) and under 10.0 for
economic reasons. It was found that the temperature should be reduced to
45"C before chlorine is added, to avoid the formation of chlorates.
Ozonation was effective at the ambient pH level of 11.8, so that no pH
adjustment was required. As Ozonation proceeded the pH dropped, but the
final pH was on the alkaline side. Variation in temperature had no effect
upon the dosage of ozone required, and because ozone does not react rapidly
with ammonia, the concentration of ammonia had no effect on the ozone dosage.
Substantial reduction in phenol concentration was obtained with small dosages
of ozone, but increasingly higher dosages were required as phenol concentra-
tion was further reduced.
Best results were obtained from chlorine dioxide starting at pH above
11.5 when it was not controlled. The pH fell to the acid side during treat-
ment. No temperature adjustment was necessary. A 2:1 chlorine:chlorine
dioxide ratio resulted in the best efficiency in less than 15 minutes of
treatment. Ammonia content also had no effect on the dosage of chlorine
dioxide required.
121
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During these ORSANCO studies, the distilled amtnonantipyrine (DAAP)
method for measuring phenol with a sensitivity of 0.1 to 0.5 mg/1 was
developed (Cleary & Kinney, 1951).
In reporting results of the ORSANCO work (Anonymous, 1951b) the following
performance data were cited:
(1) Only 600 mg/1 of ozone reduced phenol concentration to less than 1 ppm;
however 1,000 mg/1 of ozone or more were required to attain 5 ppb, the
taste-producing limit for drinking water supplies.
(2) Pure phenol required less ozone for complete oxidation, probably
because of the presence of other oxidizable materials (thiosulfate,
cyanide, thiocyanate) in the actual wastewaters. The average reduction
in COD concentration was 0.7 part/part of ozone.
(3) Foaming occurred during ozonation if the wastewater was allowed to cool
to ambient temperature. However no serious foaming developed at 43°C.
In this same article (Anonymous, 1951b), costs for ozonation are
discussed. Capital installations for chlorine and chlorine dioxide are much
less than those for ozonation, but operating costs for chlorination are 2 to
3 times those for ozonation and 6 to 8 times higher for chlorine dioxide.
The low operating costs for ozonation should offset the first cost differen-
tial in 2 to 5 years. It is estimated that coke plant phenolic wastes can
be treated with ozone for about $1.00/gal (1951 costs) generating ozone from
air, and $0.35/gal if oxygen is used as the feed gas.
Murdock (1951) in reporting results of the ORSANCO study showed that
ammonia still wastewaters containing 118 mg/1 of phenol required 6,000 mg/1
of chlorine to reduce the phenol concentration to 3 mg/1. Costs for ozonation
of ammonia still wastewaters in a 100-oven coke plant would be about 3<£/ton
of coal carbonized, which would drop to 2<£/ton of coal carbonized for a 300-
oven plant. If low cost oxygen were available, this 2<£/ton figure would
drop further to 1.25<£/ton of coal carbonized. The capital equipment was
amortized over 12 years in these costs calculations. Murdock concludes that
where quick write-offs are allowable in new facilities, a large plant could
expect a cost of lit/ton of coal carbonized after a 5-year amortization
period.
In reviewing the ORSANCO work, Nebolsine (1957) concluded that chemical
costs to reduce phenol concentrations to 20 to 50 mg/1 from raw wastewaters
are not large, although the equipment required to generate chlorine dioxide
or ozone is "extensive and costly". To reduce phenol concentrations much
below the concentrations just mentioned would require more elaborate facili-
ties and disproportionately larger dosages of chemicals, "and no new designs
have been reported that have overcome this difficulty". "Getting rid of the
last trace of phenols is like trying to squeeze the last drop out of a
toothpaste tube -- there always seems to be a little more".
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Hall (1958) reported the results of detailed laboratory investigations
on the effects of ozonation of ammoniacal waste Liquors from 15 coke oven
effluents in Britain. In addition to phenols, these effluents also contained
thiosulfates, thiocyanates and sulfides. In ozonation experiments, the
amounts of ozone in the influent gas stream and in the contactor off-gases
were measured so that the amount of ozone actually used could be determined.
Ozonation was conducted using a sintered glass frit, and gas flow was counter-
current to the flow of effluent being treated. Ozone dosages employed were
200 to 300 mg/1, and confirmed that the amount of ozone required to destroy
one part of phenol becomes greater at the lower phenol concentrations.
For 13 raw wastewaters tested at the Durham coke plant, an average of
17 Ibs of ozone was required per 1,000 gal of wastewater. Maintaining the
pH at about 10 caused a 25% increase in the efficiency of ozone useage, thus
lowering treatment cost. During these tests, thiosulfates, even at 4,000
mg/1 initial concentrations, were 98% converted to sulfuric acid (or sulfate)
during the early stages of ozonation.
Oxidation of thiocyanate by ozone was found to occur in three steps,
going first to cyanide, then to cyanate, then to C0? and nitrogen. Monitoring
the cyanide content of effluents being treated showed that cyanide concentra-
tion passed through a maximum of 25 to 50 mg/1, which appeared at the point
of thiocyanate disappearance. However, although th.iocyanate was converted
rapidly to cyanide during the early stages of ozonation, once it had formed,
cyanate remained "stable" to further ozone additions until the phenol concen-
tration dropped to low values. Only then did ozonation of cyanide become
rapid.
When the pH was increased to above 8.0, reaction of ozone with thio-
cyanate became slower, and at an initial effluent pH of 11.5, the time
required for thiocyanate destruction in cokeworks spent liquor was nearly 10
times longer than when conducted below pH 8.0. It was shown experimentally
that there was practically no accumulation of cyanide as long as the pH was
maintained above 9.0.
«
Sulfides were easily oxidized to sulfuric acid, but ferrocyanides were
little affected. Oxalic acid was found in ozonized solutions of catechol
and of coke works spent liquor, in concentrations up to 800 mg/1.
Pretreatment by froth flotation reduced the phenol concentrations to 30
to 100 mg/1, and the amount of ozone now required to destroy all phenols
dropped to less than 1 Ib of ozone/1,000 gal. When pretreated by an activated
sludge process, the effluent now contained about 10 mg/1 of phenol, and even
less ozone was required to destroy these quantities of phenol. However,
ozonation of the contained thiocyanate again produced cyanide, which would
be removed more economically by final treatment with ferrous sulfate or
chlorine than by ozone.
Using an assumed cost of tonnage quantities of ozone of 10 to 15<£/lb
(1958 USA prices), Hall (1958) considered the costs for ozonation in Britain
to be 42<£/lb for a plant producing 10 Ibs/hr. This is comprised as follows:
123
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Depreciation & Interest 14
-------
The following conclusions were reached from ozonation studies using
this apparatus and air containing 6 mg/1 of ozone:
(1) It should be possible to produce an effluent with a residual perman-
ganate value of about 30 mg/1 from a coke works spent liquor previously
treated by a biological process. The ozone consumption should not
exceed 1.5 Ib/lb of permanganate value destroyed.
(2) Assuming ozone costs at 42
-------
Carbon Adsorption: Capital cost $9 million
Operating cost $l,100/year
Ozonation: Generation & contacting $80,000-$125,000
Power cost $4,000 - $9,000/year
@ 2<£/kwhr
Conclusions
1) Coke plant wastewaters contain phenols (phenol, cresols) thiocyanate,
thiosulfate, cyanide, sulfide and ammonia at pH above 11. All of these
except ammonia are readily oxidized by ozone.
2) Upon ozonation, thiosulfates and sulfides are oxidized rapidly to
sulfuric acid, which is partially responsible for causing the pH to be
lowered.
3) Thiocyanate then oxidizes to cyanide, which remains "stable" to further
ozonation while phenols are oxidized. Once phenols are destroyed,
ozonation of cyanide to cyanate, then to C0? and nitrogen proceeds
rapidly.
-------
11) Ferro- and fern cyanides are stable to ozonation, but the combination
of ozone with UV radiation destroys these complexes. On the other
hand, ozone consumption to accomplish this appears to be high (5 to 80
times greater than the stoichiometric amounts).
12) To date, ozonation has not been utilized to oxidize manganese and other
heavy metals in iron and steel wastewaters, nor has BAG been tested for
ammonia removal.
LITERATURE CITED — IRON & STEEL (IS)*
IS-01 Anonymous, 1951a, "Ozone Kills Phenols in Waste", Chem. Engineering
225-228, Sept. 1951.
IS-02 Anonymous, 1951b, "Phenol Wastes, Treatment by Chemical Oxidation",
Cooperative Study, Ohio River Valley Water Sanitation Commission,
Cincinnati, Ohio, 15 June 1951.
IS-03 Cleary, E.J. & J.E. Kinney, 1951, "Findings from a Cooperative
Study of Phenol Waste Treatment", Engineering Bull., Purdue Univ.
Engr. Ext. Serv. 76:158-170.
IS-04* Hall, D.A., 1958, "The Treatment of Coke Works Effluent with
Ozone", Gas World 147(3829): Coking Sect: 52(539):7-13.
IS-05* Hall, D.A. & G.R. Nellist, 1959, "Treatment of Phenolic Effluents",
J. Appl. Chem. 9:565-576.
IS-06* Hall, D.A. & G.R. Nellist, 1965, "Phenolic Effluents Treatment",
Chem. Trade. J. & Chem. Engineer 156(4072):786.
IS-07* Kucharski, O.K., E. Ladouceur & B.P. Le Clair, 1976, "Treatment
of Blast Furnace Scrubber Water", Presented at llth Canadian Symp.
on Water Pollution Research, Burlington, Ontario, 5 Feb.
IS-08 Leggett, 1920, U.S. Patent 1,341,913.
IS-09 Marechal, 1905, French Patent 350,679.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, H. Wolf & W.
KUhn, 1978, "An Assessment of Ozone and Chlorine Dioxide Technolo-
gies for Treatment of Municipal Water Supplies", U.S. EPA Report
No. 600/2-78-147. U.S. Environmental Protection Agency, Municipal
Environmental Research Lab., Cincinnati, Ohio.
IS-10* Murdock, H.R., 1951, "Ozone Provides an Economical Means for
Oxidizing Phenolic Compounds in Coke Oven Wastes", Indl. Engr.
Chem. 43(11):125A, 126A, 128A.
Abstracts of asterisked articles will be found in EPA 600/2-79- b.
127
-------
IS-11 Niegowski, S.J., 1953, "Destruction of Phenols by Oxidation with
Ozone", Indl. Engrg. Chem. 45:632.
IS-12* Nebolsine, R., 1957, "The Treatment of Waterborne Wastes from
Steel Plants", Iron & Steel Engr., Dec., 125-150.
IS-13* Prober, R., P.B. Melnyk & L.A. Mansfield, 1977, "Ozone-Ultraviolet
Treatment of Coke Oven and Blast Furnace Effluents for Destruction
of Ferricyanides", Presented at 32nd Annual Indl. Waste Conf.,
Purdue Univ., Lafayette, Indiana, May.
Rice, R.G., 6.W. Miller & C.M. Robson, 1978, "Potentials of Biolo-
gical Activated Carbon for the Treatment of Industrial Waste-
waters", presented at 6th Annual Indl. Pollution Control Conf.,
St. Louis, Mo., April. Water & Wastewater Equipment Mfgrs;
Assoc., McLean, Va.
IS-14 Rozhnyatovskii, 1.1., D.P. Dubrovaskaya & F.A. Melamed, 1959,
"The Purification of Waste Waters from Coke Plants by Ozonation."
Koks i Khim, 7:63-66.
Throop, W.M., 1977, "Alternative Methods of Phenol Wastewater
Control", J. Hazardous Materials 1:319-329.
128
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LEATHER TANNERIES
Only a few attempts have been made to study the use of ozone for
treating tannery wastes, and investigators so far have concluded that
ozonation is more cos-tly than other methods available. Eye (1956) suggested
the use of ozone for color reduction in spent vegetable liquor. However,
Eye concluded that the applicability of any oxidant to color removal is
limited because of the large amounts required.
Eye & Clement (1972) studied the oxidation of sulfide in lime-sodium
sulfide unhairing wastewaters using direct chemical oxidation-with ammonium
persulfate or ozone, precipitation with ferrous sulfate and the use of air
oxidation catalyzed by manganous sulfate, chromium(III) and potassium perman-
ganate. Ozone, as well as air oxidation with manganous sulfate or perman-
ganate, rapidly oxidized sulfide, while the other techniques were unsuccessful.
The permanganate reaction then was applied to a hair-burning wastewater
containing about 5,000 mg/1 of sulfide. At a total permanganate concentration
of 500 mg/1, complete oxidation of the sulfide was obtained in 90 minutes in
a 2-stage treatment system. Pertinent data regarding these experiments are
listed in Table 22. The purpose of removing sulfide from this wastewater is
as a pretreatment to biological treatment, with which high concentrations of
sulfide are known to interfere.
TABLE 22. COMPARISON OF SULFIDE OXIDATION SYSTEMS
Treatment
Method*
KMn04 + air
MnS04 + air
03 - 3.0 1/min
03 - 6.4 1/min
Initial
[S]
(mg/1 )
100
100
100
100
Final
[S]
(mg/1)
0
0
0
0
Contact
Time (sec)
290
1800
220
180
* 100 mg/1 reagent concentration, except ozone which was of unknown
concentration
Source: Eye
& Clement, 1972
Eye & Clement (1972) reported that the concentration of ozone used was
not measured, but was present "in excess, as evidenced by the odor of ozone
at the surface of the reaction solution". These authors concluded the
following:
"Ozone is only very slightly soluble in water and technical problems in
efficiently applying this oxidant prevented further study. An efficient
contact device might make ozone a feasible means for sulfide elimination,
especially in applications where treatment space is limited. Ozone
generation equipment currently is expensive and its use must be evaluated
carefully".
129
-------
This kind of statement made without reporting how the ozone was generated
(from air or oxygen), what type of contacting was used, a description of the
contactor nor determining the ozone dosage and amount of ozone in the contac-
tor off-gases, makes evaluation of this work very difficult. The statement
technical problems in efficiently applying this oxidant prevented further
study implies that these authors did not have access to technical assistance
in the proper application of ozone.
The wastewaters from an actual hair-burning operation have the character-
istics as shown in Table 23. The waste typically smells strongly of ammonia
and decaying organic matter, is of a brown-black color and contains large
quantities of short, stiff pieces of hair about 0.25 inch long. Compositions
listed for Effluents #1 and #2 are those obtained by the 2-stage permanganate/-
air oxidation process.
TABLE 23. CHARACTERISTICS OF TANNERY HAIR BURNING WASTEWATERS*
BOD-5
COD
TS
TVS
SS
VSS
PH
TKN
[S-2]
Raw Water
78,000
123,000
43,600
39,300
20,500
11.7
6,200
5,000
Coarse Screened
130,000
83,000
11.7
4,800
Effluent #1**
73,000
25,500
11.7
500-800
Effluent #2***
10,560
42,400
7,800
11. 7-12. 2
0
* all concentrations in mg/1
** after KMn04 aeration and clarification
*** after a second KMn04/aeration, clarification step
Source: Eye & Clement, 1972
Costs for the successful permanganate treatment were estimated to be
$4.20/gal of wastewater treated, based on 1971 prices.
One can develop an estimated cost for ozonation, assuming efficient
contacting and that sulfide is oxidized to sulfur trioxide which then
hydrolyzes to sulfate by the following reactions:
H20
0,
-> so
-2
4
If the reaction proceeds in this fashion, then for each mole of sulfide
(molecular weight of 32), 1 mole of ozone (molecular weight of 48) will be
required. Therefore, stoichiometrically 5,000 mg of sulfide will require
7,500 mg of ozone. At an ozone cost even as high as $1.00/lb (most ozonation
equipment purveyors cite 25 to 50<£/lb generation and contacting costs) the
amount of ozone required to oxidize 5 g of sulfide to sulfate ion would be
7.5 g and would cost about 0.65£/liter, or 2.6£/gal.
130
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On the other hand, some of the applied ozone will be consumed in
oxidizing other components of the wastewater, particularly BOD and COD, even
though sulfide ion should be the most readily oxidized component. If it is
assumed that 90% of the ozone added would react with components other than
sulfide, then the total amount of ozone for sulfide oxidation would increase
900% to about 742 g, which would raise the ozonation cost to $1.60/gal of
wastewater treated. This is considerably less than the permanganate costs
and indicates that ozonation still should be considered as a viable candidate
to be further evaluated.
Successful use of ozone for sulfide oxidation in this wastewater would
show other advantages in:
(1) partially reducing BOD and/or COD levels and
(2) not forming manganous sludges (which form with permanganate
oxidation), therefore reducing sludge disposal costs.
Conclusions
1) Ozonation has been studied once for oxidation of sulfides in hair-
burning wastewaters and without reporting the key parameters sufficient
for proper evaluation of the work. The investigators rejected further
evaluation of ozonation due to "technical problems" of contacting.
Instead, potassium permanganate was shown to be successful in removing
sulfide at levels of 5,000 mg/1 in the raw water, but at a cost of
$4.20/gal of wastewater treated.
2) With contact efficiencies equivalent to those obtained in ozonation
plants for disinfection of sewage, estimates of costs for ozonation of
sulfides are well under $2.00/gal of wastewater treated and should
produce no manganous sludges. Therefore the use of ozonation should be
reconsidered.
LITERATURE CITED -- LEATHER TANNERIES (LT)*
LT-01 Dye, J.D., 1956, "The Treatment and Disposal of Tannery Wastes",
in The Chemistry and Technology of Leather, F. 0'Flaherty e_t aJL,
editors, "Rein hold Publ. Corp., New York, R.Y.
LT-02* Eye, J.D. & D.P. Clement, 1972, "Oxidation of Sulfides in Tannery
Wastewaters," J. Am. Leather Chem. Assoc., 67:256-267.
LT-03* Shevchenko, M.A. & R.N. Kas'yanchuk, 1964, "Adsorption of Tanning
Substances from Water and Their Stability to Destructive Oxidation",
Ukr. Khim. Zh., 30(10) :1'103-07.
*" Abstracts of articles asterisked will be found in EPA 600/2-79- b.
131
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MINING
There are two types of mining wastewaters which have been treated by
ozonation,
(1) acid mine discharges from coal mines
(2) cyanide discharges from gold mining operations
Actual acid coal mine drainage wastewaters have been ozonized but only
synthetic cyanide-containing solutions in the gold mining category have been
ozonized.
Acid Coal Mine Wastewaters
Mine drainages from coal mines, are characterized by high levels of
dissolved iron and manganese at low pH values. This type of pollution is a
result of bacterial oxidation of pyrites (iron sulfides) in the mines by
oxygen in the mine water. Acid is produced by the oxidation of sulfide to
sulfate, and much of the soluble iron remains in the ferrous state. Manganous
compounds are leached into the mine waters and rise to fairly high levels,
sometimes 20 to 100 mg/1. Such discharges can contaminate downstream water
supplies. Compositions of typical discharges from a Pennsylvania anthracite
field are given in Table 24, along with analysis of a typical culm runoff
from either anthracite or bituminous regions of Pennsylvania.
TABLE 24. ANALYSES OF MINE WATERS IN WYOMING VALLEY p
Mine Water
Discharge I
Discharge II
Culm Bank Runoff
PH
3.4
5.8
2.5
Fe(mg/l)
29§
153
1044
Mn(mq/l)
22
10.6
83.2
PENNSYLVANIA
Source: Rozelle & Swain, 1975
Ozone is stable at low pH and is used for removal of iron and manganese
in many European drinking water treatment plants (Miller et aJL (1978). In
the process, soluble ferrous and manganous ions are oxidized to the ferric
and manganic states, respectively, at which they hydrolyze to insoluble
products which are readily removed by filtration:
Mn+2 + 0
Mn0
2H20
Rozelle e^t aj_. (1968) first compared the use of oxygen and of ozone for
the oxidation of ferrous to ferric iron in mine wastewaters. For complete
hydrolysis using oxygen, the pH must be raised to a value of 10; however,
ozonation was found to be effective at pH 3, and this would require sufficient
neutralizing agent to raise the pH only to between 5 and 7 after ozone
132
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treatment, to allow coagulation and precipitation of insoluble iron hydroxide.
Thus, limestone requirements would be less as would the amount of sludge
produced.
Under an EPA funded program, Bellar, Waide & Steinberg (1970) conducted
an engineering design and economic study to evaluate the feasibility of
ozone oxidation followed by limestone neutralization of acid mine drainage
(AMD). No experimental studies were performed. AMD flows which were con-
sidered ranged from 0.25 to 6 mgd and contained ferrous iron concentrations
varying from 50 to 1,000 mg/1. Treatment cost values developed are given in
Table 25.
In this table the lowest cost values applv to the highest flow rates.
These data also assume ozone production of 200 tons/day by a chemonuclear
process and ozone packaging (compressed and stored in Freon F-ll) and shipment
from a centrally located point in the coal fields.
TABLE 25. OZONE/LIMESTONE TREATMENT COSTS FOR ACID MINE DRAINAGES
ferrous
iron, mg/1
§6
300
1.000
* flow variation
Source: Bellar, Waide
<£/l,000
gallons
9-13
18-34
40-78
from 250,000 gpd to
& Steinberg, 1970
6 mgd
For a specific case of an AMD containing 150 mg/1 of ferrous iron, the
conventional aeration/limestone process would cost $0.17/1,000 gal at an
investment cost of $350,000. The ozone/limestone process would cost $0.13
to $0.16/1,000 gal and require $280,000 for an on-site ozone/limestone
treatment system. The investment cost using ozone produced in a central
plant, and including on-site ozone storage equipment would be $184,000.
The investment cost to treat the entire AMD of southwestern Pennsyl-
vania (estimated at 486 mgd) would be $182 million, based on the use of a
200 ton/day central chemonuclear plant generating ozone.
Also under EPA funding Swain & Rozelle (1974, 1975) and Rozelle & Swain
(1975) conducted laboratory studies on ozonation of actual acid mine drainage
waters. The aeration/lime neutralization method had been found by Rozelle
et. aJL (1968) to be more cost-effective than ozone for removing iron, but
ineffective for removing manganese. In order to remove Mn(II) effectively
by aeration and lime, one would have to overtreat considerably with lime
(Swain & Rozelle, 1975) to precipitate manganous hydroxide.
Ozone was generated from oxygen and the effects of variables on the
oxidation rate of Mn(II) with ozone were studied (Swain & Rozelle, 1975) at
ozone gas phase concentrations of about 2 mg/1. At pH 7 to 8 the oxidation
was about twice as fast as at 3 to 4, but was temperature independent. At
the higher pH values, Mn concentrations below 0.1 mg/1 were obtained, but
133
-------
only 0.5 mg/1 Mn concentrations could be achieved at pH 3 to 4. A minimum
concentration was reached, indicating that upon continued oxidation the
Mn(IV) was being converted to higher oxidation states which are more soluble.
It is well known in European drinking water treatment plants using ozone for
iron and manganese oxidation that overdosage with ozone forms soluble perman-
ganate. The European practice is to allow ozonized water to stand 15 to 30
minutes to allow hydrolyzed Fe(III) and Mn(IV) oxides to coagulate and
precipitate as well as to allow Mn(VII) to decay back to Mn(IV) by oxidizing
dissolved organics (Miller et al_., 1978). Filtration through GAC completes
the process of reducing permanganate to MnO?.
Swain & Rozelle (1975) also showed that at pH 1.4 to 2.0, oxidation of
Mn(II) to Mn(IV) by ozonation occurred only after all Fe(II) had been
ozidized to Fe(III). They also found that chlorine gas will not oxidize
Mn(II) at pH 1, 3, 5 or 7. On the other hand, ozone use efficiencies were
only 10% in the work described, indicating the necessity for better ozone
contactor design.
In later work, Rozelle & Swain (1975) compared ozone, hypochlorite and
chlorine gas for oxidation of Mn(II) in acid mine drainage to Mn(IV).
Reverse osmosis was shown not to reduce the Mn levels to below 0.05 mg/1
(the potable water limit). Chlorine gas at pH 2, 4, 6 and 7.9 showed no
significant oxidation of Mn(II).
The experimental ozonation setup included a 500 ml suction flask which
contained a bubbler and the sample to be ozonized. The amounts of ozone in
the feed gas and in the out-gases from the suction flask were measured, so
that the efficiency of ozone use could be determined. Using a single reactor,
the ozone use efficiency was found to be only 2 to 3%. Using 5 such reactors
in series, the ozone use efficiency rose to 10%. Since ozone use efficiencies
greater than 90% are obtained in full-scale ozonation systems for oxidizing
iron and manganese in drinking water treatment (Miller e£ al., 1978), it is
apparent that the ozone contacting reported during this worE* was quite
inefficient.
Reaction rates of ozone with Mn(II) at pH 7 to 8 were found to be about
2 to 3 times faster than at pH 3 to 5. In addition, the ozonation reaction
was temperature independent over the range 2* to 56*C. There was little
difficulty in lowering total Mn levels to below 1 mg/1 with ozone at pH 3 to
8, but levels below 0.05 mg/1 were obtained only in the more neutral solutions
(pH about 7). This is because in the more acid solutions, secondary oxidation
of Mn(IV) occurs upon ozonation, probably forming permanganate, Mn(VII).
On the other hand, hypochlorite was not found to cause secondary
oxidation of Mn(IV), and thus can be used to reduce Mn concentrations to
very low values. The hypochlorite oxidation of manganous ion occurs by the
following equation:
Mn+2 + 2(OC1)~- >C12 + Mn02
134
-------
Two equations were developed for determining the amounts of ozone
required to oxidize Mn in acid mine drainage, as .a function of ozone contact-
ing efficiency. Both are based on the following oxidation reaction:
Mn+2 + 03 + 2(OH)~ > Mn02 + 02 + Fy)
To oxidize 1 mg/1 of Mn(II) would require 7.2 x 10~6 Ibs of ozone, or
8.6 x 10-4 g. Thus the two equations for calculating costs become:
(7.2 x 10~6)(gal of AMD)[mg/1 of Mn(II)])/(Eff1dency) = Ibs of ozone
(8.6 x 10"4)(liters of AMD)[mg/l of Mn(II)])/(Efficiency) = g of ozone
NaOCl oxidation requires 2,2 x Iff5 Ib or 2.6 x 10"3 g per mg/1 of
Mn(II), and similar equations are developed. In the Rozelle & Swain (1975)
work, the efficiency of use of hypochlorite was at least 60% when 45 mg/1 of
NaOCl was used, which was much more efficient than the ozonation experiments
conducted. Even with these differences in use efficiencies, however, it was
concluded that when the acid mine drainages contain more than 2 mg/1 of
manganese, the ozonation process is less costly than is hypochlorite, depend-
ing upon the total volume of discharge to be treated. At manganese concentra-
tions below 2 mg/1, the hypochlorite process is less costly.
Gold Mining
Mathieu (1977) has compiled an excellent summation of the published
literature on cyanide oxidation with ozone and has evaluated the potentials
of applying ozone to the treatment of Canadian gold mill effluents. A
private communication is cited by Mathieu which reports the destruction of
one part of cyanide with one part of ozone in treating a sample of bled
solution from Giant Yellowknife Mines Ltd. which contained 450 mg/1 of
cyanide, of which about 220 mg/1 were metal-cyanide complexes. Only 2 mg/1,
probably in the form of ferricyanide, was left in solution after 20 minutes
of ozonation by bubbling, for a decomposition rate of more than 22 mg/1/minute.
This value indicates that the ozonation reaction probably is autocatalytic,
meaning that reaction of cyanide with ozone catalyzes the reaction of cyanide
or cyanate with the oxygen present.
In 1973, the Sumitomo Metal & Mining Co. of Japan reported studies on
cyanide-containing wastewaters at their Konomai gold mine. Filtrate from
the Merrill press operation was diluted to about 110 mg/1 cyanide concentra-
tion, and the filtrate also contained Cu = 7.7, Zn = 41.4, Fe = 0.14 and Mn=
<0.1 mg/1. The data from 6 ozonation tests on this filtrate are reported in
Table 26.
135
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TABLE 26. OZONE TREATMENT OF KONAMAI MINE MERRILL PRESS LIQUID (DILUTED)
Imti
pH
T.9
11.9
11.9
11.9
11.9
11.9
Final
1.5
11.1
9.9
9.0
8.7
8.6
Source
CN (mg/1)
Initial
109"
109
109
109
109
109
Final
65.3
34.9
9.6
0.5
0.3
0.3
Time
(min)
3
5
7
10
12
15
CN destruction
rate (mg/min)
Average
14.5
14.8
14.2
10.8
9.1
7.2
Increment
14.S
15.2
12.1
3.6
0.1
0.0
03 (mg/1)
Added
130
215
300
430
515
645
Absorbed
130
215
300
349
365
400
: Sumitomo Metal & Mining Co. (1973)
Mathieu (1977) considers the 99.5% cyanide decomposition obtained in 10
minutes to be particularly encouraging in view of the shortcomings and
adverse conditions of ozonation during the tests, namely:
(1) use of a low frequency ozone generator delivering only 1% ozone in air,
(2) use of a conventional ozone diffuser contactor, rather than a spray
drier contacting system (see Mathieu, 1975),
(3) lack of pH adjustment to prevent its decrease during reaction to a
level at which the reaction rate becomes slow,
(4) lack of UV light to destroy the residual 0.3 mg/1 CN present as iron-
cyano complexes.
The same is said by Mathieu (1977) about published Russian studies to
date. The Russians claim good success in ozone oxidation of cyanide complexes
of zinc, copper, nickel and iron in the wastewater from Lemnogorskii,
Zodskii and Zyryanovskii dressing plants, but give practically no informa-
tion on the cost projections and economics of a full-scale application under
optimum conditions. For instance, Chernovbrov and Rozinoer (1975) have only
this to say about test work on cyanide removal by ozone in the pilot plant
at Zodskii:
"Wastewater from the processing of mixed ore from the Zodskii deposit
gave the following analysis (mg/1): Cu - 20, Zn - 40, Ni - 15, Fe - 4
to 8.5, As <0.4, Sb <1.5, Pb - 16 to 20, SCN - 9 to 10, and CN - 70 to
100 (free and bound in complexes). An ozone-oxygen mixture with a pH
of 11 to 12 was used for the ozonization (37 to 56 mg/1 of ozone).
After 10 to 20 minutes there was a complete removal of simple and
complex cyanides from the wastewater. By the time 100% dissociation of
cyanides was achieved, 90 to 98% of heavy metals (Cu, Zn, Ni, Pb) were
removed. Pilot plant experiments at the Zodskii plant have shown that
cyanide-containing wastewater treated with ozone can be used for
recycling".
136
-------
The main features of the tests in the USSR appear to be the use of
oxygen as the carrying gas, the high concentration of ozone, the presence of
transition metal ions (catalyst), and a favorable pH. These conditions
probably are responsible for the rapid and complete destruction of all the
cyanides. Recent papers by Kvyastkovskii et^aK (1975) on the use of cata-
lysts for purification of cyanide-containing wastewaters with ozone and by
Bespamyatov et^aJL (1975) on decomposition of cyanides from wastewaters of a
concentration plant by ozonation (with separate use of non-ferrous metals)
may go further on optimization and practicability of the ozonation method
for purifying mill cyanide-barren effluents. As of this writing, however,
translations of these articles had not become available.
Mathieu (1975) described ozonation experiments on synthetic solutions
of sodium cyanide and of copper complexed sodium cyanide solutions using the
spray drier type of contactor system. In this contacting system, fine
bubbles of solution are sprayed into an atmosphere of ozone in air or oxygen.
A portable pilot plant capable of treating 2 to 7 gal/minute was employed,
which had a series of 3 spray drier contacting units. Contact time in each
chamber was about 12 seconds. Two levels of cyanide concentration were
tested: 10 mg/1 and 100 mg/1. The lower concentration is representative of
gold mill tailing pond overflows and the higher concentration is representa-
tive of those found in solutions bled from the same type of mill. Cyanide
solutions were fed through the pilot unit at 2 gal/min. Ozone was generated
in oxygen at the rate of 0.4 g/min.
It was found that 91 to 97% of the cyanide was decomposed in less than
2 minutes of contact with ozone in this type of contacting apparatus,
irrespective of the starting cyanide concentration. Additionally, analysis
of the ozonates for cyanate showed this material to be absent; therefore,
Mathieu (1975) concluded that ozonation converts cyanide past the cyanate
stage in the spray type contactor.
Incorporation of an electrocoagulation step prior to ozonation decreased
the time required to attain 98% cyanide destruction from 2 to 3 minutes to
less than 1 minute. On the other hand, about 4 parts of ozone were required
to destroy 1 part of cyanide at initial cyanide concentrations of 10 mg/1.
Therefore, several experiments were conducted with electrocoagulation and
addition of copper ion as catalyst in attempts to reduce this high ozone/CN
ratio required at the lower cyanide concentrations.
Pretreatment by electrocoagulation allowed 98% of the initial cyanide
to be decomposed within 36 seconds (on passing through three contact chambers)
with or without the presence of copper ions as catalysts. However, cupric
ions favored elimination of some cyanide during the electrocoagulation
stage, 34.7% of the cyanide being removed in the presence of copper sulfate
(1:1 by weight with NaCN) and only 8.1% being removed in its absence. In
the first contact stage, ozone was completely utilized and nearly all the
cyanide present was destroyed.
137
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Mathieu (1977) also compared the costs for ozonation of cyanide today
with the analysis made by Sondak & Dodge (1961). These 1961 authors concluded
that the cost for treating 100,000 gpd of copper plating wastewaters (200
mg/1 CN) would be nearly twice that of chlorine treatment ($1.27 to $1.38/lb
of CN for ozone, versus $0.72/lb of CN for chlorine). Bollyky (1975) deter-
mined ozonation costs to be $0.94/lb of CN in 100,000 gpd plating wastes
containing 100 mg/1 CN. Mathieu (1977) extrapolated cost data developed for
ozonation systems by Bowers, Netzer & Norman (1973). Assuming that (1)
oxidation with oxygen is cheaper than oxidation with ozone, (2) maximum
oxygen losses would be 5% and (3) a conservative ratio of 2.5:1 (ozone/CN)
would be required to destroy cyanides, the total cost for ozonation would be
lower than $0.80/lb of cyanide decomposed using a 200 Ibs/day ozone generation
(from oxygen) plant. By using air instead of oxygen, the operating cost
would drop to $0.60/lb, but the capital costs would increase from $28,200 to
$46,600.
Goldstein (1976) analyzed costs for destruction of 140 Ibs of cyanide
per day by ozonation and by chlorination. Capital costs for ozonation were
$100,000 and were $30,000 for chlorination. Operating costs were $0.74/lb
for ozonation (including amortization, interest at 20%, no labor and electri-
city at H/kwhr), versus $1.94/lb for chlorination (chlorine at 10.25<£/lb
and caustic at 6
-------
5) Synthetic cyanide-containing gold mining wastewaters ozonized using a
spray drying type of contactor system showed 91% to 97% cyanide destruc-
tion past the cyanate stage in less than 2 minutes of ozonation.
Incorporating a prior electrocoagulation step decreased the ozonation
time necessary to attain 98% cyanide destruction to 36 seconds in this
contacting system.
6) Operating costs for ozonation of cyanide-containing wastewaters to
destroy 140 Ibs/day of cyanide are lower than for treatment by alkaline
chlorination ($0.74/lb of cyanide removed by ozonation vs $1.94/lb by
chlorination). However, capital costs for ozonation are higher ($100,000
vs $30,000).
LITERATURE CITED -- MINING (MI)*
MI-01* Seller, M., C. Waide & M. Steinberg, 1970, "Treatment of Acid Mine
Drainage by Ozone Oxidation", U.S. EPA Report No. EPA-WQO-
14010-FMH-12/70, 99 pages. U.S. EPA, Washington, D.C.,
NTIS No. PB-198,225.
MI-02 Bespamyatov, O.K., A.N. Kvyatkovskii, E.K. Rochin & L.F. Atyaksheva,
1975, "Decomposition of Cyanide - Containing Wastewaters of Concen-
tration Plants by Ozonation with Separate Use of Non-Ferrous
Metals", Ref. Zh. Metal!.
Bollyky, L.J., 1975, "Ozone Treatment of Cyanide and Plating
Waste", In Proc. 1st Intl. Symp. on Ozone for Water & Wastewater
Treatment, RVGV Rice & MYE. Browning, editors, Tn'tT. Ozone Assoc.,
Cleveland, Ohio, p. 587-590.
Bowers, A., A. Netzer & J.D. Norman, 1973, "Ozonation of Waste-
water -Some Technical and Economic Aspects", Can. Journ. of Chem.
Eng., 51:332.
MI-03 Chernobrov, S.M. & S.M. Rozinoer, 1975, "Ozone Purification of
Waste Water from Dressing Plants", Obogashchenie Rud, 20(1).
MI-04 Eiring, L.V., 1967, "Detoxification of Industrial Wastewaters of
Gold Mines by Ozonation. I. Behavior of Simple and Complex Anions
During Ozonation", Uch. Zap., Erevan, Gos. Univ., 2:49-64.
MI-05 Eiring, L.V., 1969, "Kinetics and Mechanism of Ozone Oxidation of
Cyanide - Containing Waste Water", Tsvet, Metal, Nov. 42.
MI-06 Fridman, I.D., L.E. Ponchkina, N.N. Khavskii, LA. Yakubovich &
B.A. Agranat, 1969, "Removal of Toxic Cyanides from Wastewaters of
Gold Extracting Mills." Sh. Mosk. Inst. Stali Splavov Sbornik,
3:106.
* Abstracts of articles asterisked will be found in EPA 600/2-79- b.
139
-------
Goldstein, M.> 1976, "Economics of Treating Cyanide Wastes",
Pollution Engineering, March, p. 36-38.
MI-07 Kvyatkovskii, A.M., L.G. Konchina & E.K. Roshchin, 1975, "Possibility
of the Use of Catalysts for Purification of Cyanide-Containing
Wastewaters with Ozone", Ref. Zh. Metall.
MI-08 Mathieu, G.I., 1975, "Application of the Film Layer Purifying
Chamber Ozonation Process to Cyanide Destruction," in Proc. First
Int'l. Symp. cm Ozone for Water .& Wastewater Treatment, R.G. Rice
& M.E. Browning (eds.), Intl. Ozone Assoc., Cleveland, Ohio, p.
533-550.
MI-09 Mathieu, G.I., 1977, "Ozonation for Destruction of Cyanide in
Canadian Gold Mill Effluents — A Preliminary Evaluation", Presented
at Symposium on Advanced Ozone Technology, Toronto, Canada, Nov.,
Intl. Ozone Assoc., Cleveland, Ohio.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, W. Ktlhn & H.
Wolf, 1978, "An Assessment of Ozone and Chlorine Dioxide Technolo-
gies for Treatment of Municipal Water Supplies". U.S. EPA Report
600/2-78-147. U.S. Environmental Protection Agency, Municipal
Environmental Research Laboratory, Cincinnati, Ohio.
MI-10 Rozelle, R.B., ejt a]_., 1968, "Studies on the Removal of Iron from
Acid Mine Drainage Water", Wilkes College Research & Graduate
Center, Wilkes-Barre Penn., Submitted to Coal Research Board,
Commonwealth of Pennsylvania.
MI-11 Rozelle, R.B., & H.A. Swain, 1975, "Removal of Manganese from Mine
Drainage by Ozone and Chlorine", EPA Report EPA/670/2-75/006, U.S.
EPA, Washington, D.C. NTIS Report No. PB-241,143/7WP.
Sondak, N.E. & B.F. Dodge, 1961, "The Oxidation of Cyanide-Bearing
Plating Wastes by Ozone, Part 1", Plating, 173-180.
Sondak, N.E. & B.F. Dodge, "The Oxidation of Cyanide-Bearing
Plating Wastes by Ozone, Part 2", Plating, 280-284.
MI-12 Sumitomo Metal and Mining Co., Central Research Dressing Group,
1973, "Wastewater Treatment With Ozone at the Konomai Mine", Feb.
12.
MI-13 Swain, H.A., Jr. & R.B. Rozelle, 1974, "Removal of Manganese from
Mine Waters", Proc. Fifth Symp. Coal Mine Drainage Research
Preprints, p. 357.
MI-14* Swain, H.A. & R.B. Rozelle, 1975, "Use of Ozone for Treatment of
Mine Drainage Discharges", in Proc. First Int'l. Symp. on Ozone
for Water & Wastewater Treatment, R.G. Rice & M.E. Browning Ozone
Assoc., Cleveland, Ohio, p. 748-753.
140
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ORGANIC CHEMICALS
Although there are many published articles dealing with the ozonation
of aqueous solutions containing specific organic chemicals, there are very
few published accounts of ozonation of actual wastewaters from plants manufac-
turing organic chemicals. Nevertheless, the chemistries involved in ozonizing
pure solutions of specific organic compounds are reasonably similar to those
which can be expected when actual wastewaters are ozonized, and so the
subject will be reviewed here.
For more details on the chemistry of oxidation of organic materials
with ozone, the reader is referred to the proceedings of a workshop on
Ozone/Chlorine Dioxide Oxidation Products of_ Organic Materials, recently
published (1978) by the International Ozone Association. The subject of
this workshop was identification of organic oxidation products formed upon
ozonation and determination of their toxicities (or potential toxicities).
In an early presentation at this workshop, Oehlschlaeger (1978) reviewed the
known chemistries involved in oxidizing organic compounds with ozone. Most
of the published literature on the subject deals with ozonation in non-
aqueous solvents, and water and wastewater treatment engineers need to know
that non-aqueous chemistry is or is not applicable to reactions which occur
in dilute aqueous solution.
By the end of this workshop, it had become quite clear that when
organic compounds are ozonized in aqueous solution, their reaction products
generally are the same as when the ozonation reactions are carried out in
non-aqueous solvents. The same oxidation products have been identified,
although in lower concentrations, from ozonations in dilute aqueous solution
as from ozonizing more concentrated non-aqueous solutions of the same organic
compounds, then quenching the solutions in water. There are exceptions to
this general statement, but the conclusion is generally applicable.
For a more detailed discussion of the organic oxidation products
formed upon ozonation, the reader is also referred to Section 6 of this
report, to Section 12 in "An Assessment of Ozone and Chlorine Dioxide
Technologies for the Treatment of Municipal Water Supplies", a Final Report
by Miller et ajk (1978) to the EPA Water Supply Research Laboratory, EPA
600/2-78-147. Also, Rice & Miller (1977) have discussed the types of organic
materials formed when drinking water supplies containing organic materials
ape ozonized.
A later part of this section, Phenols, contains a detailed discussion
of the organic oxidation products obtained upon ozonizing aqueous solutions
containing specific phenolic compounds.
Actual Organic Wastewaters
Gregersen (1971) studied color reduction by ozonation of 4 unidentified
chemical plant wastewater streams which included (1) a combined wastewater,
(2) a process wastewater, (3) an arsenic wastewater and (4) a low pH nitrifi-
141
-------
cation process wastewater containing primarily a salicylic acid derivative.
In addition, a number of nitro-aromatic compounds in water were ozonized.
The first 2 wastewaters lost considerable color after 10 minutes of
ozonation, but the last 2 wastewaters seemed to be unaffected. Some organic
carbon was eliminated. Activated carbon was recommended for treating these
wastewaters, primarily because the technology needed to design treatment
systems already existed. Ozonation followed by biological treatment was
selected second, but it was not known to what degree the ozonized organic
compounds truly are biodegradable. The process of ozonation followed by
biological treatment potentially is less expensive to operate than a GAC
column (Gregersen, 1971).
Livke, Velushchak & Plysynk (1972) describe ozonation of wastewaters
from caprolactam synthesis at two different Russian chemical plants.
Ozonation was applied after biological treatment, both for chemical oxidation
and disinfection, then the ozonized effluents were stored in biological
ponds prior to reuse as cooling water.
Tables 28 and 29 show the results of ozonation of caprolactam wastewaters
at the 2 Russian plants which had received secondary biological treatment.
At ozone consumptions of 10 mg/1, "complete clarification" of the wastewaters
was obtained. Increasing ozone consumptions to 15 to 25 mg/1 provided
"complete removal of resins" from the wastewaters as a result of oxidative
degradation of the resins to simpler compounds. This is indicated by the
fact that during ozonation, the BOD values increased as the COD values
declined, and the ratios of BOD:COD changed from 0.1 to 0.5.
TABLE 28. OZONE TREATMENT OF SERVERODONETSK CAPROLACTAM WORKS,
BIOLOGICALLY TREATED CAPROLACTAM WASTEWATERS
parameter
COD (mg Oo/l)
BOD (mg/1)
BOD-5 (mg 09/1)
DO (mg/1) i
NH3 (mg/1)
nitrites (mg/1)
nitrates (mg/1)
microbe no.
1 03 os/ml
Col i form titer
n.d. = not c
after
secondary
treatment
92
11
78
5.2
0.25
4.5
24
6.2
0.004
after ozone treatment
ozone consumption (mq/1 )
16
82
13
30
5.0
0.05
4.6
13
5.0
0.04
15
74
16
30
4.5
traces
4.8
9
3.0
0.43
20
68
24
25
4
n.d.
5.1
traces
2.4
0.43
etected
Source: Livke, Velushchak & Plysynk (1972)
142
-------
TABLE 29. OZONE TREATMENT OF SHCHEKINO CHEMICAL WORKS,
BIOLOGICALLY TREATED CAPROLACTAM WASTEWATERS
parameter
COD (ing 02/1 J
BOD- 5 (mg 0?/1)
DO, mg/1
NH3, mg/1
nitrite, mg/1
nitrates, mg/1
urea, mg/1
caprolactam, mg/1
after
secondary
treatment
120
9.7
3.5
15.9
0.5
14.7
7.3
2.8
hydroxylamine, mg/1 0.9
cyclohexanol , mg/1 0.7
Microbe no,
1 03 os/ml
Col i form titer
30
0.004
after ozone treatment
ozone consumption (mg/1
£
106
13
12.8
15.9
0.2
14.8
6.2
1.2
0.1
0.5
22
0.004
10
96
16
25.8
15.4
0.11
15.3
4.9
0.9
none
none
4
0.04
15
92
17
26.4
14.7
0.1
16.0
none
0.5
none
none
1.5
0.43
)
20
56
22
27.0
14.3
none
16.8
none
none
none
none
none
4.3
25
42
43
29.1
13.5
none
17.4
none
none
none
none
none
4.3
Source: Livke, Velushchak & Plysynk, 1972
These authors concluded that the cost of ozonizing biologically treated
caprolactam wastewaters, producing water that can be reused in place of
river or well waters for plant purposes, is about 15% of the cost of the
biological treatment. The ozone contactor off-gases should be recirculated
to provide these results, as should used oxygen (if ozone is generated from
oxygen).
Kanebo Ltd. and the Japan Organo Co. announced on March 22, 1973 the
joint development of a treatment process for colored wastewater using ozona-
tion followed by powdered activated carbon. The process is installed at a
chemical plant of Kanebo in the Nagahama factory (Shiga Prefecture). Waste-
water is treated to an almost colorless clean water, containing less than 50
mg/1 of BOD and COD. The process is reported to have the advantages of :
(1) excellent decolorization and no foaming during treatment due to quick
decomposition of surfactants, (2) decomposition of phenols, (3) no sludge
production, (4) less installation space, (5) automatic operation and (6)
lower running costs. No published technical account of this plant has been
found as yet, however, to be able to evaluate performance and cost data.
Lapidot (1975) describes pilot studies on the ozonation of wastewaters
from a major chemical plant manufacturing si 11 cones. Ozone was generated
from oxygen, and contactor off-gases were passed through a catalytic burner
to prevent the buildup of flammables, then through 2-stage drying prior to
recycling to the ozone generator. A value of 3.75 Ibs of ozone was found to
remove each Ib of total oxygen demand (TOD) of the wastewater (with 25%
losses), and an engineering estimate was made of the costs for utilizing
ozonation to remove 1,000 Ibs/day of TOD at this plant at the rate of 2,000
gal/minute. This would require 3,750 Ibs/day of ozone generation capacity.
143
-------
Assuming 10-yrs amortization, 1.8<£/lb for oxygen, U/kwhr for power and
100% ozone use efficiency, the total costs for ozonation were determined to
be $253,000/yr, or $0.72 to remove each Ib of TOD by ozonation ($0.25/1,000
gal treated). This cost was considered excessive, and the project was
abandoned.
Prengle, Mauk, Legan & Hewes (1975) reported the use of ozone in
combination with UV light at an unidentified plant which treats wastewater
first by secondary biological treatment, then by activated carbon adsorption.
A 1 mgd wastewater stream contains 10 mg/1 TOC which must be lowered to less
than 0.1 mg/1. The organics in the wastewater are not identified, but are
referred to as "potentially toxic, refractory organic compounds remaining
after secondary treatment and carbon adsorption". The influent stream from
the previous treatment units is flow controlled to a multistage ozone/UV
reaction unit (described in Section 4) where the organic compounds undergo
oxidation to COp and water. Ozone is generated from dried air, its concentra-
tion is adjusted automatically by an effluent monitor, and'the installed
cost of the entire ozone/UV facility was $505,000.
Davis, Magee, Stein & Adams (1976) ozonized wastewaters from the
production of several alkyl amines using a submerged turbine contactor.
Pertinent data are given in Table 30. Parameters of primary interest were
the COD and TOC concentrations. Residual COD of the isobutyl amine wastewater
increased during the first two hours of ozonation, indicating structural
alteration of some of the wastewater components, but then dropped to about
33% of the original content after an additional two hours of ozonation.
Thus a relatively high ozone utilization rate will be required to substan-
tially reduce the organic content of these wastewaters.
These authors also ozonized a wastewater generated from a synthetic
organic chemicals plant manufacturing chelating agents. Ozonation was
tested for removing COD, nitrogen and cyanide compounds after biological
pretreatment. A net increase in ammonia-N was observed under acid conditions,
probably due to degradation of organic nitrogen compounds to ammonia. At a
pH of 8.8, removal of ammonia by ozonation was very low. Ozonation appeared
to increase the free cyanide content, and this behavior was ascribed to
ozone decomposition of complexing agents containing cyanide moieties.
Finally, ozonation had little effect on the COD of the wastewater before
biological treatment, but significantly decreased the COD of biologically
treated wastewater (Table 31).
Finally, Davis e£ ajL (1976) ozonized a wastewater generated in an
organic chemicals plant producing organic dyes and resins. The purpose of
ozonation was to remove color. For the raw wastewater, ozonation generally
decreased the total and soluble TOC and BOD, but increased the volatile
suspended solids concentration. This means that ozonation precipitated and
coagulated soluble wastewater constituents.
144
-------
TABLE 30. SUMMARY OF BATCH OZONATION RESULTS FOR ORGANIC CHEMICALS
INTERMEDIATE NASTEMATERS
Wastewater
Isobutyl
Amine
Isopropyl
Amine
Isopropyl
Ami ne
(Pretreated)(b)
Influent Reaction
Ozone Time
(mg/1-minj
39.0
39.0
39.0
39.0
39.0
39.0
39.0
39.0
39.0
39.0
39.0
39.0
39.5
39.5
39.5
39.5
39.5
39.5
(min)
0
15
30
60
120
240
0
15
30
60
120
240
0
15
30
60
120
420
Effluent
PH
7.6(a
7.6
7.6
7.6
7.6
7.6
8.8
6.6
5.8
3.8
2.8
2.5
8.0
7.0
5.5
5.2
4.6
4.3
Adj
PH
\
—
--
—
--
—
—
--
—
--
--
—
--
—
9.5
10.7
9.5
—
Ozone
(mg/l-min)
2.0
0.8
0.8
0.5
3.8
14.1
0.6
,6.0
8.6
16.6
—
32.1
1.3
3.2
6.7
7.3
12.3
16.6
COD
(mg/1 )
1,000
1,300
1,500
1,600
1,180
360
9,250
9,290
9,210
8,050
7,760
6,080
6,820
8,370
7,830
6,940
5,780
4,800
TOC
(tug/I )
800
770
740
690
420
180
—
—
—
—
—
—
1,920
1,920
1,890
1,820
1,610
1,320
Ca) pH maintained at 7.6
(b) Activated sludge pretreatment.
Source: Davis et al
. (1976)
145
-------
TABLE 31. SUMMARY OF COD REMOVAL FROM A CHELATING COMPOUND PLANT
WASTEWATER
Time
(min)
0
15
30
60
120
240
Run No. 1 (b)
Raw
8,340
8,650
8,340
7,930
--
7,680
Biological
Pretreate
_ _
3,500
--
3, ,140
--
1,800
(a) Values shown
ly
>d
Run No. 2
Raw
8,340
--
8,200
8,270
--
—
c
Biologically
Pretreated
4,620
3,630
3,670
3,580
1
_
,680
Run No. 3 (d
Raw
8,340
8,740
8,900
8,820
8,670
Biologically
Pretreated
4,340
4,030
3,950
--
are total COD concentration in mq/1 .
(b) pH adjusted to 6.0.
(c) pH not adjusted - 8.0.
(d) pH adjusted to 11.0.
Source: Davis et
al. (1976)
Biologically treated wastewater from the dye and resin plant was
ozonized with dosages up to 626 mg/1 (Table 32). Only marginal changes in
TOC content were observed, but approximately linear increases in BOD (up to
2,900%) were found with ozone doses of up to 200 mg/1.
Laboratory Studies
Polynuclear Aromatic Hydrocarbons (PAH)~
Il'nitsky, Khesina, Cherkinsky & Shabad (1968) ozonized water solutions
of 3,4-benzpyrene, 1,2-benzanthracene, 1,2,5,6-dibenzanthracene, pyrene and
9,10-dimethyl-l,2-benzanthracene and showed that all these compounds were
destroyed. 3,4-Benzpyrene was the most ozone-resistant, and the last named
compound showed the least ozone resistance.
Il'nitsky (1969) showed that the concentration of 3,4-benzpyrene was
reduced about 200 times after 5 minutes of ozonation, and that it could no
longer be detected after 7.5 minutes of ozonation. The starting concentra-
tions of BP in water were 0.038 to 1.2 mg/1, and ozonation conditions were
those generally used in treating drinking water (1 to 3 mg/1 dosage; contact
time 5 to 10 minutes).
Reichert (1969) and ITnitsky & Khesina (1969) showed that 3,4-benzpyrene
concentrations of 1 to 100 yg/1 in double distilled water are more than 99%
decomposed in 30 minutes ozonation time with ozone dosages of 0.5 to 1.5
mg/1. However, incorporation of natural materials, which can adsorb the
3,4-benzpyrene, into the waters will lengthen the required ozonation time to
achieve the same degree of decomposition.
Sforzolini e_t aj_. (1974a; 1974b) studied the chlorination and ozonation
of pyrene, 1,2-benzanthracene, 3,4-benzpyrene, 3,4-benzofluoroanthene and
146
-------
TABLE 32. OZONATION RESULTS FOR TREATMENT OF A FILTERED, BIOLOGICALLY PRETREATED WASTEWATER FROM
A RESIN AND DYE PLANT
Ozone
Applied
(ing 03/1)
40
88
98
106
187
154
166
303
295
356
626
TOC (mg/1)
•Inf
Tot
134
136
146
139
129
137
138
129
128
139
141
Sol
137
126
144
134
119
120
126
120
122
131
123
Eff
Tot
154
129
169
140
149
137
152
146
132
139
93
Sol
144
120
147
131
116
135
142
136
128
129
93
Change in TOC (a)
%
Tot
14.9
5.1
-15.8
-0.7
-15.5
0.0
-10.1
13.2
-3.1
0.0
34.0
Sol
-5.1
4.8
-2.1
2.2
2.5
-12.5
-12.7
13.3
-4.9
1.5
24.4
BOD (mg/1) C
Inf
Tot
13
13
7
11
12
7
6
11
13
10
7
Sol
6
7
2
5
5
1
4
5
6
4
2
Eff
Tot
23
30
27
26
34
30
32
41
44
42
39
Sol
17
23
23
25
27
30
30
38
38
38'
36
hange in BOD
%
Tot
-76.9
^131
-286 -
-136
-183
-329 -
-433
-273
-238
-320
-457 -
Sol
-183
-229
1,050
-400
-440
2,900
-650
-660
-533
-850
1,700
Solids (mg/1)
Inf
SS
41
75
39
27
46
25
45
41
42
24
29
VSS
16
26
36
11
25
~
27
20
20
19
12
Eff
SS
45
48
40
20
26
36
44
53
33
53
50
VSS
23
25
32
10
13
27
29
33
17
35
24
Dhange in Solids (a)
%
SS
-9.8
36.0
2.6
25.9
43.5
44.0
2.2
-29.3
21.4
-121
-72.4
VSS
-43.8
3.8
11.1
9.1
48.0
—
-7.4
-65.0
15.0
-84.2
-100
(a) Negative sign designates an increase upon ozonation
Source:
Davis et al., 1976
-------
11,12-benzofluoroanthene. Chlorination produced new peaks observed spectro-
photometrically, but ozonation produced no new peaks. Ozonation destroyed
100% of the 3,4-benzopyrene and 11,12-benzofluoranthene, but only major
proportions of the other compounds. Variability of results was high in
river water samples spiked with the PAH compounds, probably because of
adsorption of these compounds onto naturally contained colloidal materials.
Pesticides--
Buescher, Dougherty & Skrinde (1964) studied the ozonation of aqueous
solutions of lindane, aldrin and dieldrin. Ozonation markedly affected the
lindane concentration, but did not remove it completely. Aldrin was complete-
ly removed by ozonation. Dieldrin was 90% removed by a combination of air
stripping and ozonation.
Robeck, Dostal, Cohen & Kreissl (1965) ozonized aqueous solutions of
lindane, dieldrin, DDT and parathion and found that dosages of 10 to '38 mg/1
of ozone were required to destroy these pesticides to levels acceptable for
drinking water. These dosages were considered to be too high to be practical.
These authors also concluded that the more usual drinking water treatment
plant ozone dosages of 1 to 2 mg/1 probably would oxidize parathion to
paraoxon, a compound which is more toxic than is parathion.
Gabovich & Kurinnyi (1966) showed that ozone actively oxidizes such
organophosphorus pesticides as carbophos, methaphos, M-81 and trichloro-
methaphos-3. Using 26 mg/1 doses of ozone, it was possible to completely
disintegrate ICTmg/1 concentrations of carbophos, and with net 8 to 10 mg/1
doses of ozone,'initial 10 mg/1 concentrations of trichloromethaphos-3,
methaphos and M-81 were reduced in value to 0.7, 0.1 and 0.0 mg/1, respectively
Richard & Brenner (1978) confirmed that ozonation of parathion with 3
mg/1 ozone dosage does form paraoxon, a more toxic material than parathion
itself. The reaction proceeds fastest in acid medium. Continued ozonation
of paraoxon (5'mg/l ozone dosage) proceeds slower, with destruction of
paraoxon and formation of 2,4-dinitrophenol, picric acid, H2S04 and H3P04:
40// \^
^ x / 2 3 mg/1
(CH3CH2or \=/ (acid)
parathion
(continued on next page)
148
-------
N0
H2S04
HP0
Similarly, Richard & Brener (1978) ozonized malathion and isolated
malaoxon as the first stage intermediate. Continued ozonation destroyed the
malathion, producing H3P04 and unidentified, degraded organic compounds.
CH-0
»
P-S-CH-
COOC2H5
CH2COOC2H5
malathion
CH~0.II
J ^P-S-CH-COOC2H5
CH30
malaoxon
,
+ degraded oxidation products
It is apparent, therefore, that under-ozonation of some organic materials
can produce other organic materials that are toxic. It is therefore critical
to know the chemical content of waters to be treated with ozone (or any
other oxidant) so that sufficient oxidant dosages can be provided.
Hoffmann & EichelsdSrfer (1971) dissolved various pesticides in hexane
or acetone, then diluted with water to make aqueous solutions as high as 2
mg/1 in pesticide concentrations. These were ozonized over 45 minutes with
total ozone dosages of up to 240 mg/1. At these dosages, aldrirr and hepta-
chlor were "quantitatively" destroyed, but oxidation products were not
identified. On the other hand, solutions of dieldrin, heptachlorepoxide,
chlordane, lindane, DDT and endosulfan were hardly affected by ozonation at
all. This raises the question as to whether the ozonation of heptachlor
produces heptachlor epoxide. If so, the epoxide will be stable to further
ozonation and is a toxic material. Neal (1978) has advised that experiments
conducted in his laboratories have confirmed that ozonation of aqueous
solutions of heptachlor produced heptachlorepoxide.
149
-------
c
Cl H Cl
Cl H Cl
heptachlor
heptachlorepoxi de
Mallevialle, Laval, LeFebvre & Rousseau (1978) ozonized aqueous solutions
of aldrin, and found this compound to be easily degraded by ozone. On the
other hand, when aldrin was added to aqueous solutions containing humic
acids, 0.45 yg/1 of aldrin was detected even after 10 minutes of ozonation.
These researchers concluded that ozonation studies on organic compounds
conducted in pure solutions can be misleading. It is necessary to know the
humics or soils content of water to be ozonized, since these materials can
adsorb dissolved organics and thereby "protect" them from the oxidizing
action of ozone.
Prengle & Mauk (1978) showed that ozonation of DDT in water proceeds
very slowly, but the oxidation rate is accelerated by combining UV radiation
with ozonation.
Weil, Struif & Quentin (1977) ozonized 0.0001M solutions of 2,4,5-T
with 0.048 mole/hr of ozone and identified oxalic acid, glycolic acid,
dichloromaleic acid, chloride ion and CO? as oxidation products. No ozonides
or polymeric peroxides could be found. The concentration of dichloromaleic
acid peaked after 8,to 9 minutes, that of glycolic acid peaked after 12
minutes and that of oxalic acid peaked after 20 minutes of ozonation, after
which the concentrations of all three intermediate products decreased with
time of ozonation. The concentration of dichloromaleic acid became zero in
25 minutes:
0-CH2COOH
HOOC-CH-CH-COOH
Cl Cl
+ HOOC-CH2OH
+ HOOC-COOH
+ Cl" + C00
peaked in 8 to 9 minutes
peaked in 12 minutes
peaked in 20 minutes
150
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Miscellaneous Organic Chemicals--
Rogozhkin (1970) ozonized wastewaters containing dimethyl amine in an
alkaline medium and concluded that this amine is oxidized to formaldehyde,
formic acid, C^, nitrites and nitrates.
Kandzas et_ aJL (1970) ozonized 50 mg/1 concentrations of cyclohexane in
water for 90 minutes of ozonation at pH 11.5 to 12.5. The COD value was
reduced from 120 mg/1 to 5.95 mg/1 (in the case of pH 11.5) and to 13 mg/1
(in the case of pH 12.5), and almost complete oxidation to C02 was attained
with 5 to 7 mg of ozone/mg of cyclohexane.
Krasnov, Pakul & Kirillova (1974) studied the ozonation of aliphatic
alcohols, using ethanol as the model compound. Ozonized air was cleansed of
nitrogen oxides by passing through a dilute alkali absorber before entering
the ozone contact chamber. Ethanol, butanol and octanol gave acids (through
aldehyde intermediates), the rate of oxidation increasing with increasing
pH. Secondary alcohols produced acids, forming ketones as intermediates.
Hydrogen peroxide was produced as a by-product of the decomposition of the
intermediates. Formation of acids upon ozonation was considered to be more
environmentally acceptable than discharge of alcohols, since acids are more
readily biodegradable.
Tencza & Sierka (1975) studied the ozonation of aqueous solutions of
butyric acid, which was easier to oxidize than butyl or isobutyl alcohols,
methyl ethyl ketone or butyraldehyde. Oxidation was faster with increasing
ozone concentrations in oxygen (fastest at 5.67 wt %), with increasing
temperature and with increasing pH (fastest at 12.0).
Organo-Nitrogen Compounds—
Somiya, Yamada & Goda (1977) studied the ozonation of aqueous solutions
of organo-nitrogen compounds such as ami no acids, proteins, ethylamine and
urea. Ozone was generated from oxygen and applied at 20*C through a porous
diffuser contactor chamber 100 cm high and 5 cm in diameter. Off-gases were
analyzed for excess ozone. Solutions 0.05 mM in nitrogen compound (1 liter)
and buffered with 1/30M phosphate or 0.02M carbonate were ozonized 30 to 60
minutes. Samples were analyzed periodically for the starting compound,
nitrite, nitrate, pH, TOC and alkalinity.
Ozonation of 0.2, 0.5, 1 and 2 mM/1 solutions of glycine (H2NCH2COOH)
at pH 5 produced ammonia, nitrite (in very small amounts and as an inter-
mediate only) and nitrate. The concentrations of ammonia and nitrate increa-
sed during ozonation, and it was concluded that both are formed initially
and simultaneously during ozonation, then the ammonia is oxidized to nitrate,
but only above pH 7. No hydroxylamine (HONHg) was detected during these
ozonation studies. At the higher concentrations, most of the applied ozone
was utilized for oxidizing the carbonaceous chain, rather than for oxidation
of ammonia.
During ozonation of the aliphatic amino acids glycine, leucine, isoleu-
cine and glutamic acid, increasing the pH from 5 to 10 linearly increased
151
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the rate of formation of ammonia. About 90% of the nitrogen in the starting
aliphatic ami no acids was detected as ammonia and nitrite ion after 40
minutes of ozonation. With aromatic ami no acids, the rate of ammonia forma-
tion was independent of pH, and only 50% of the nitrogen was detected as
ammonia and nitrite after 40 minutes of ozonation.
Solutions of aromatic amino acids containing side chains gave varied
rates of TOC concentration decreases. With tryptophan and glutamic acid,
the carbon was easily oxidized by ozone and the rate was independent of pH.
With aromatic amino acids, only 50% decreases in TOC were observed during
the ozonation period. Aliphatic amino acids decomposed rapidly during the
initial stages of ozonation with increasing pH, but these rates slowed
drastically during the later stages of ozonation, even at high pH. In
general, TOC levels were lowered the most in neutral solutions after 40
minutes of ozonation.
Oxidative decomposition rates of ethylamine upon ozonation were one-
half those of glycine (which contains the same number of carbon atoms) and
these rates increased with increasing pH.
Ozonation of an aqueous solution containing 50 mg of a protein, bovine
serum albumin, was found to be independent of pH. Nitrate was detected in
the ozonate, but only 10% of the starting nitrogen was found as nitrate ion
after 40 minutes of ozonation.
Urea was not appreciably oxidized with ozone at pH 6.1, 7.8 or 9.6.
Ozone/UV Studies
A general discussion of this technology already has been given in
Section 4. Specific applications also were discussed earlier in this section
under Hospitals. Others will be discussed at this point and later in this
section under Photoprocessing.
Prengle, Hewes & Mauk (1976) discuss the treatment of refractory
organic compounds, such as ethanol, acetic acid, glycine, glycerol and
palmitic acid, with ozone/UV in a multistage reactor. The addition of UV
radiation during ozonation increased oxidation rates for these compounds 100
to 1,000 fold. Ethanol was oxidized to acetaldehyde, then to acetic acid,
then to C02.
Fochtman & Huff (1976) ozonized wastewaters containing small amounts of
trinitrotoluene (TNT) in the presence of UV light. About 85% of the carbon
lost from solution was isolated as C0p» and the ozone utilization was 12
Ibs/lb of carbon removed. The initial TOC of 63 mg/1 decreased to 56 mg/1
using ozonation alone for 3.5 hrs. With concurrently applied UV, the TOC
decreased to 17 mg/1 in 2 hrs.
Farrell et aJL (1977) reported studies leading to the design of a 5,000
gpd pink-water pilot plant using ozone/UV treatment technology. Pink water
152
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is a wastewater from TNT manufacturing, and contains TNT plus dinitrotoluenes
as its major contaminants. This 5,000 gpd pilot plant is said to be capable
of being scaled up to a 100,000 gpd plant simply by adding modules.
Engineering data-were gathered by Farrell et^ al_. (1977) using a 1,000
gpd pilot test unit after bench-scale tests using a 5-stage, 25 gal reactor
in which water flow alternated cocurrently, then countercurrently/to the
direction of the rising ozone bubbles. Each of the 6 ozonation stages also
contained five 40-watt UV lamps and ozone was introduced in equal amounts to
each reactor chamber through two spargers per stage. Wastewater could be
exposed to ozone and to UV radiation simultaneously. This pilot test unit
was 15 inches x 15 inches x 30 inches high.
Levels of 54 mg/1 TNT in tap water (analyzing 20 mg/1 TOC) could be
lowered to below 1 mg/1 TOC at a 16/1 ratio of ozone/TOC in 95 minutes of
ozone/UV treatment using 2 reactor stages which contained 3 UV lamps in the
first stage and one in the second; the ozone concentration was 1.4% in
oxygen. The initial pH was 7.6 and the operating temperature was 319C.
Repeating this experiment with actual pink water (10 mg/1 initial TOC, pH 9,
operating temperature 25"C) gave less than 1 mg/1 of TOC in 86 minutes of
treatment at an applied ozone/TOC ratio of 18.8/1 and using 1.3% ozone in
oxygen.
The 1,000 gpd pilot test unit was 28 inches wide, 45 inches long and 45
inches high and contained 6 chambers, which held up to 30, SL36G low pressure
UV lamps and porous diffusers to allow introduction of ozone into each
chamber. Water flow also alternated cocurrently then countercurrently.
Pink water flow rates were varied between 0.2 and 2 gpm, allowing retention
times to be varied from 37 to 375 minutes in the reactor. The pink water to
be tested contained 140 mg/1 of TNT, 72 mg/1 of RDX (a reaction product of
hexamethylenetetramine and fuming nitric acid, also called "cyclonite"), 10
mg/1 of wax and 68 mg/1 of TOC. Therefore, for initial screening a synthetic
TNT solution was prepared at 140 mg/1 concentration. At this high level,
undissolved TNT was present in the mixture, but this dissolved and reacted
as oxidation progressed.
This synthetic TNT mixture was treated using 2% ozone in oxygen at a
feed rate of 1 g of ozone/minute and 29 UV lamps were turned on in the
reactor. A TOC value of 4 mg/1 was obtained after a residence time of 140
minutes. Further testing of 140 mg/1 TNT solutions showed that TOC levels
of 5 to 10 mg/1 could be obtained in the first 3 reactor stages using 9 to
13 UV lamps and residence times of 118 minutes. In order to lower the TOC
level further (to 1 to 3 mg/1), 9 to 14 UV lamps were necessary in the last
3 stages and an additional 118 minutes of residence time also was required.
Actual pink waters showed greater resistances to oxidation in the 1,000
gpd test unit than did solutions of TNT in water. The TOC of pink water was
lowered only to 17 mg/1 after 240 minutes of residence time and the number
of UV lamps used had to be increased.
153
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Results obtained in the 1,000 gpd reactor on actual pink waters are
summarized in Table 33. Less than 1 mg/1 each of TNT and RDX remained in
all effluent samples analyzed. On a volume basis and starting with a TOC
level of 70 mg/1, the ozone requirement to obtain these results is 910 mg/1
and the UV requirement is 770 watts/1. Theoretically, assuming no reaction
of the oxygen carrier gas with the organic components, the amount of ozone
required to oxidize all organic carbon to C02 and water is 813 mg/1. Thus,
the stoichiometric requirement of ozone/TOC was 1.12/1, or, the ozone use
efficiency was 89.3%.
Engineering analyses of the data obtained in the 1,000 gpd pilot test
unit were performed to derive design and operating parameters for a 5,000
gpd (18.9 cu m/day) larger pilot test unit. These parameters are listed in
Table 34. Estimated installed capital costs ($97,255) for this size ozone/UV
reactor system are detailed in Table 35. Operating costs will include 600
kwhrs of electrical power/24 hrs of operation plus 2 hrs of supervisory and
6 to 8 hrs of technician time for each 8-hr shift.
For a 100,000 gpd ozone/UV system based on the results of Parrel 1 e_t
al_. (1977) and for pink water assuming an optimum ozone requirement of 800
mg/1, the total ozone generating capacity required will be 660 Ibs (302
kg)/day. An ozone/UV unit using this amount of ozone is said to be capable
of being constructed from 15 modules, each 5,000 gpd in size, if the optimum
residence time is 150 minutes. This size system will require 1,080 UV lamps
and will involve $962,500 installed capital cost and an annual operating
cost of $91,300 ($2.61/gal), based on 350 days of operation/yr. The operating
expenses are comprised of $48,200 power cost for ozone generation (@ $0.02/-
kwhr), $12,400 UV light power cost plus $30,700 maintenance, of which 70% is
for UV lamp replacement.
Polychlorinated Biphenyls (PCBs)
The combination of ozone with UV radiation has been specified by EPA as
BPTCA for treating wastewaters which contain PCBs. Based upon work performed
for EPA by Versar, Inc. (1976) at Houston Research and at Westgate Research,
EPA has adopted the use of ozone/UV for treating wastewaters containing
PCBs. At Houston Research, a 1,000 mg/1 solution of Arachlor 1254 in methanol
was employed to prepare a 514 ppb aqueous solution. Ozone (2% in oxygen)
was sparged into 21 liters of this solution at 3 1/min. At the same time, a
high pressure, 650-watt mercury UV bulb generating 253,7 nm radiation was
present in the reaction flask. In 1 hr, about 67% of the PCBs had been
decomposed; in 3 hrs, only 7% of the PCBs remained; in 4 to 5 hrs, nearly
complete destruction to C02 and water had occurred.
At Westgate Research, a 3-liter reactor was used with the same UV
energy, and ozone was fed into the 200 ppb PCB solution at the rate of 3.4
1/min of 1.4% ozone in oxygen. More than 99% of the PCBs was destroyed in 4
hrs of exposure to ozone/UV, and the final PCB concentration in solution was
about 1 ppb. Both Arochlor 1254 and 1016 were destroyed satisfactorily in
this manner. With the more reactive Arochlor 1016, the initial concentration
154
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TABLE 33. UV/OZONATION OF PINK WATER*
Parameters
Residence time (min)
Stages 1, 2 & 3
Stages 4, 5 & 6
Weight % ozone
Ozone mass flow (mg/min)
Stages 1, 2 & 3
Stages 4, 5 & 6
TOA at steady state (mg/1)
Influent
After 3 reaction stages
After 6 reaction stages
No. of UV lamps/stage
Stage 1
2
3
4
5
6
Average pH value
Influent
Effluent
Average effluent temperature (*F)
Ozone/TOC mass ratio (mg/mg)
Stages 1, 2 & 3
Stages 4, 5 & 6
UV/TOC input, watts/mg
Stages 1, 2 & 3
Stages 4, 5 & 6
* containing 140 mg/1 TNT, 72 mg/1 RD,
Source: Parrel! et al., 19'
Te
1
118
118
2.2
850
850
68
22
17
5
5
3
3
3
3
6.2
3.8
85
10
32
6
14
< and 10 mg
77
st Number
2
177
177
2.1
942
942
67
6.5
5
5
5
5
4
4
3
6.2
3.8
86
18
181
11
85
/I wax
3
177
177
1.8
721
721
70
5
3
5
5
5
4
5
5
6.2
3.8
86
13
180
11
140
155
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TABLE 34. DESIGN & OPERATING PARAMETERS OF PROPOSED 5,000 GPD
UV/OZONE REACTOR FOR PINK WATER (TO OBTAIN <1 mg/1 TNT + RDX)
Volume : 675 gal (2.6 cu m)
Flow rate : 5,000 gal/day (18.9 cu m/day)
Retention time : 180 minutes
Dimensions : 3 x 6 x 5 ft (0.9 x 1.8 x 1.5 m)
UV lamp specs : G64T6, 64" long, 0.75" diam.
Draws 65 watts. Av UV power output
25.5 watts. Lamp life 7,500 hours
No. of UV lamps : 144
Ozone requirements : 37.5 Ibs/day (17 kg/day) at 1 wt % from air
No. of reactor stages: 3 minimum, up to 6
containing 140 mg/1 TNT, 72 mg/1 RDX and 10 mg/1 wax
Source: Farrell et al. 1977
TABLE 35. ESTIMATED INSTALLED COSTS FOR 5,000 GPD UV/OZONE REACTOR FOR
PINK WATER
Engineering
Supervision $ 1,120
Engineering 3,000
Technicians 3,900
Materials 16,000
Outside Services 2,500
Packing & Shipping 2,000
Travel 2.000
Sub-total 30,520
G & A @ 75% 22,890
Fee @ 7.2% 3,845
Ozone Generator (40 Ibs/day from 02 40,000
TOTAL COST $ 97,255
Source: Farrell et al. 1977
156
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was 237 ppb. Within 45 minutes of exposure to ozone/UV, the PCB level had
dropped to 1 to 2 ppb (99+ % destruction); after 2 hrs the PCB concentration
was less than 100 parts per trillion.
Based upon these'results, EPA adopted ozone/UV treatment as BPTCA for
PCBs for both existing and new sources in February, 1977.
Conclusions
1) Oxidation products of organic materials subjected to ozonation generally
are the same whether they are synthesized in aqueous or non-aqueous
solvents. The major exception to this statement are those compounds
produced when water participates in the reaction itself, such as in
hydrolysis of intermediates. This conclusion is important because
there is a great deal of published literature regarding the reaction of
organic materials with ozone either neat, in non-aqueous solvents or in
the gas phase, much more than is available in dilute aqueous solutions.
2) Oxidation of pure organic materials in clean water usually proceeds at
faster rates than in wastewaters. Even small amounts of suspended
solids can adsorb dissolved organics and increase their apparent
resistance to oxidation by ozone.
3) At 2 Russian chemical plants manufacturing caprolactam, ozonation has
been applied to the effluents from biological treatment on full scale
since 1972. Ozone is used both for chemical oxidation and disinfection,
and the ozonized effluents are stored in biological treatment ponds
prior to reuse as cooling waters. Complete clarification of the second-
ary effluents is obtained with ozone consumptions of 10 mg/1. Complete
destruction of remaining resins (by converting them to simpler compounds)
is obtained with ozone consumptions of 15 to 25 mg/1. Ratios of BOD/COD
increase from 0.1 to 0.5 after ozonation at these plants. Costs for
ozonizing these biologically treated caprolactam wastewaters are about
15% of the costs for the biological treatments themselves.
4) A Japanese chemical plant installed ozonation followed by powdered
activated carbon in 1973. The wastewater is unidentified, but contains
surfactants and phenols; ozone is used for decolorizing. The ozonized
wastewater is colorless and contains about 50 mg/1 of BOD and COD.
5) Ozonation of wastewaters from the manufacture of alkylamines showed an
increase of COD content during the first 2 hrs of treatment, followed
by a drop to about 33% of the initial value after an additional 2 hrs
of ozonation.
6) Ozonation of biologically treated wastewaters from a synthetic organics
plant manufacturing chelating agents produced an initial increase in
cyanide content -- probably by destruction of the chelating compound.
Ozonation of the wastewater before biological treatment had little
effect upon COD levels, but ozonation after biological treatment lowered
157
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the COD to about 20% of its initial value after 4 hrs of treatment.
The COD level was reduced about 60% during the first 15 minutes of
ozonation.
7) Ozonation of wastewaters from an organic dyes and resins manufacturing
plant for color removal decreased total soluble BOD and COD, but
increased volatile suspended solids. This confirms that ozonation can
produce a flocculation effect, and indicates that a filtration step
should be considered after ozonation in such cases.
8) Biologically treated effluent from a dye and resin manufacturing plant
treated with up to 626 mg/1 dosages of ozone showed only marginal
changes in TOC levels. However with ozone doses of up to 200 mg/1, BOD
levels increased as much as 2,900%. This confirms that ozonation of
biorefractory organic materials forms oxidized materials which can be
much more biodegradable.
9) In wastewaters, methylamine produces formaldehyde, formic acid, nitrite
and nitrate ions and C02 upon ozonation. Amino acids produce ammonia,
nitrite and nitrate ions. Glycine oxidizes faster with ozone than does
ethylamine. Acetic and oxalic acids are quite stable to oxidation with
ozone. Cyclohexene oxidizes completely to C00 with ozone doses of 5 to
7 mg/1. 2
10) 3,4-benzopyrene, 1,2-benzanthracene, 1,2,5,6-dibenzanthracene, pyrene
and 9,10-dimethyl-l ,2-benzanthracene all are destroyed rapidly upon
ozonation, with the last compound being the most reactive and the first
being the least.
11) The pesticides aldrin, carbophos, M-81, methaphos and heptachlor are
completely oxidized to other products upon ozonation. Dieldrin,
lindane, trichloromethaphos and 2,4,5-T are about 90% oxidized with
ozone. On the other hand, dieldrin, heptachlorepoxide, chlordane,
lindane, DDT and endosulfan are hardly affected by ozonation. Combina-
tions of ozone with UV radiation will oxidize these refractory compounds
at faster rates.
12) Ozonation of the pesticides parathion and malathion proceeds through
the corresponding oxons as intermediates. These are more toxic than
the starting thions. Continued ozonation decomposes the oxon inter-
mediates. Thus it is important in designing ozonation systems for
chemical oxidation to know as much as possible about the chemistries of
the materials to be oxidized.
13) Combining ozone with UV radiation increases the oxidation rates for
refractory materials such as ethanol, acetic acid, glycine, glycerol
and palmitic acid by 100 to 1,000 times. Oxidation rates of many
refractory pesticides and halogenated organic compounds also can be
increased by this combination. Ozone/UV has been specified as BPTCA by
EPA for PCBs.
158
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14) Ozone/UV treatment systems for pink waters from TNT maunfacturing are
being developed under sponsorship of the U.S. Army Armament R&D Command.
LITERATURE CITED -- ORGANIC CHEMICALS (OC)*
OC-01 Anonymous, 1973, "New Process for Colored Wastewater Treatment",
Source Unknown, March 22.
Anonymous, 1974, "Ozone-Carbon Dye-Waste Treatment", Textile Ind.
138(10):43, 45.
OC-02 Akimova, N.A. & R.A. Karvatskaya, 1968, "Purification of Waste
from Organosilicon Production by Ozonation", (Inst.
Titan. Zaporozhe, USSR) Khim. PromUgr. 5:48-50.
OC-03 Bauch, H. & H. Burchard, 1970, "Investigations Concerning the
Influence of Ozone on Water with Few Impurities", Wasser Luft u.
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OC-04 Besselievre, E.H., 1957, "The Economical and Practical Use and
Handling of Chemicals Used in Industrial Waste Treatment", Proc.
12th Indl. Waste Conf. 342-63. Purdue Univ. Engr. Bull., Ext.
Serv., No. 94, Lafayette, Indiana.
OC-05 Brower, G.R., 1967, "Ozonation Reactions of Selected Pesticides
for Water Pollution Abatement", Wash. Univ., St. Louis,
Mo., Ph.D. Diss. #67-9384, 211 pp.
OC-06* Buescher, C.A., J.H. Dougherty & R.T. Skrinde, 1964, "Chemical
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OC-07* Cheremisinoff, P.N., A.J. Pema & E.R. Swaszek, 1975, "Controlling
Organic Pollutants in Industrial Wastewaters", Indl. Wastes,
Sept./Oct., 26-35.
OC-08 Collier, H.E., Jr., 1967, "Recovery of Alkyl Lead Compounds from
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Patent #3,308,061, March 7.
OC-09 Davis, G.M., C.D. Magee, R.M. Stein & C.E. Adams, Jr., 1976,
"Ozonation of Wastewaters from Organic Chemicals Manufacture", in
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OC-10 Farrell, F.C., J.D. Zeff, T.C. Crase & D.T. Boyland, 1977,
"Development Effort to Design and Describe Pink Water Abatement
Processes", Final Technol. Report No. 1701 to U.S. Army Armament
R&D Command, Dover, N.J., August.
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159
-------
OC-11 Fochtman, E.G. & J.E. Huff, 1976, "Ozone-Ultraviolet Light Treat-
ment of TNT Wastewaters", in Proc. Sec. Intl. Symp. on Ozone
Techno!.. R.6. Rice, P. Pichet & M.-A. Vincent, editors. Intl.
Ozone Assoc., Cleveland, Ohio, p. 211-223.
OC-12 Foshko, L.S. & D.M. Maryanchuk, 1974, "Possibility of Utilization
of Sewage Waters at Water Treatment Plants of Power Stations",
Terploinergetica (USSR), Jan., p. 72.
OC-13* Gabovich, R.D., J.L. Kurinnyi & Z.P. Fedorenko, 1969, "The Effect
of Ozone and Chlorine on 3,4-Benzopyrene During Water Treatment".
Gtg. Naselennkh Mest., p. 88.
OC-14 Gabovich, R.D. & I.L. Kurinnyi, 1966, in Voprosy KommunaTnoy
Gigreny (Questions of Community Hygiene), Kiev, p. 11.
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Petroleum Products, Aromatic Hydrocarbons, Nitro Compounds and
Organochlorine Pesticides", U.S. Army Medical Intelligence &
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V.Ya. Storozhenko & A.A. Chumachenk, 1970, "Use of Ozone to Purify
Industrial Discharge", Isv. Vyssh. Uckeb. Zared., Khim. Tekhanol.
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Secondary Treatment Liquid", J. Japan Sewage Works Assoc. 10(112):
14-24.
OC-18* Gorbenko-Germanov, D.S., N.M. Vodop'yanova, N.M Kharina, M.M.
Gorodnov, V.A. Zaitsev, A.K. Koldashov & Ya. M. Murav'ev, 1974,
"Oxidation of Acetone by Ozone in Aqueous media, as Applicable to
the Treatment of Wastewater Containing Ozone", The Soviet
Chemical Industry 6(12):756-57.
OC-19* Gregersen, J.K., 1971, "Evaluation of an Ozonation-Activated
Carbon Treatment for a Colored Industrial Waste", Thesis, Iowa
State Univ., Ames, Iowa.
OC-20 Hoffman, J. & D. Eichelsdttrfer, 1971, "Zur Ozone Einwirkung auf
Pestizide der Chlorkohlenwasserstoffegruppe im Wasser", Vom
Wasser 38:197-206.
OC-21 Hoigne, J., 1975, "Comparison of the Chemical Effects of Ozone
and of Irradiation on Organic Impurities in Water", Radiation for
a Clean Environment, Intl. Atomic Energy Agency, Vienna, p. 297-
305.
OC-22* Il'nitskii, A.P., 1969, "Experimental Investigation of the Elimi-
nation of Carcinogenic Hydrocarbons from Water During Clarifi-
cation and Disinfection", Gig. y Sanit. 9:26-29.
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OC-23 Il'nitskii, A.P. & A.Ya. Khesina, 1969, Gig. i Sanit. 6:116.
OC-24 ITnitskii, A.P., A. Ya. Khesina, S.N. Cherkinskii & L.M.
Shabad, 1968, "Vliyanie Ozonirovaniya na Aromatisheskie, v Chast-
nosti Kantserogennye, Uglevodorody" ("Effect of Ozonization on
Aromatic, in Particular Carcinogenic, Carbohydrates"), Gig. y
Sanit. 33(3):8-ll. Chem. Abstr. 69:5026X (1968).
OC-25 Ishizaki, K, R.A. Dobbs & J.M. Cohen, 1978, "Oxidation of Hazar-
dous and Toxic Organic Compounds in Aqueous Solution", in Ozone/-
Chlorine Dioxide Oxidation Products of Organic Materials, R.G.
Rice & J.A. Cotruvo, editors. Intl. Ozone Assoc., Cleveland,
Ohio, p. 210-226.
OC-26 Kalnins, A., e£ aJL, (year unknown), "Removal of Organic Sub-
stances from Industrial Wastewater" Izobret., Prom. Obraztsy,
Tovarnye Znaki, 45(24):153.
OC-27 Kandzas, P.P., A.A. Mokina, R.F. Marchenko & L.A. Savina, 1970,
"Oxidation of Cyclohexane in an Aqueous Solution Under the Action
of Ozone", Tr. Vses. Nauch-Issled. Inst. Vodosnabzh., Kanaliz.,
Gidrotekh. Scoruzhenii Inzh. Gidrogeol. 28:18-23.
OC-28* Korolov, A.A., 1972, "Ozonation as a Method of Decontaminating
Water Contaminated by Chemical Compounds", Gig. y Sanit. 37:78-82.
OC-29* Krasnov, B.P., D.L. Pakul & T.V. Kirillova, 1974, "Use of Ozone
for the Treatment of Industrial Wastewaters." Intl. Chem. Engr.,
14(4):747-750. Transl. from Khim. Promy. 1:28-30 (1974).
OC-30 Lapidot, H. 1975, "Estimated Cost of Ozone Treatment of an
Industrial Wastewater," in Proc. 1st Intl. Symp. on Ozone for
Water & Wastewater Treatment, R.GTTice & M.E. Browning, EdTT,
Intl. Ozone Assoc., Cleveland, Ohio, p. 712-730.
OC-31 LaPlanche, A., G. Martin & Y. Richard, 1974, "Etude de la
Degradation des Pesticides par TOzone: Cas du Parathion", Ctre.
Beige d1Etude et de Documentation des Eaux 362:22-26.
OC-32 LaPlanche, A., G. Martin & Y. Richard, 1974, "L'Etude de la
Degradation par TOzone de Quelques Insecticides du Groupe des
Organo-Phosphores", T.S.M.-l'Eau 7:407-413.
OC-33 Livke, V.A. & S.I. Velushchak, 1971, "Supplementary Ozone
Treatment of Wastewaters from Acetylene Production", Khim. Tekhanol
1:58-60.
OC-34* Livke, V.A., S.I. Velushchak & A.A. Plysynk, 1972, "Ozonation
as a Method of Final Purification and Disinfection of Wastewaters
That Have Undergone Biological Treatment", The Soviet Chemical
Industry 3:156-158.
161
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OC-35 Mallevialle, J., Y. Laval, M. Lefebvre & C. Rousseau, 1978. "The
Degradation of Humic Substances in Water by Various Oxidation
Agents (Ozone, Chlorine, Chlorine Dioxide) in Ozone/Chlorine
Dioxide Oxidation Products of Organic Materials. R.6. Rice & J.A.
Cotruvo, editors. Intl. Ozone Assoc., Cleveland, Ohio, p. 189-
OC-36* Mauk, C.E. & H.W. Prengle, Jr., 1976, "Ozone with Ultraviolet
Light Provides Improved Chemical Oxidation of Refractory Organics",
Pollution Engineering, Jan., 42-43.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, W. KUhn &
H.W. Wolf, "An Assessment of Ozone and Chlorine Dioxide Technologies
for Treatment of Municipal Water Supplies", EPA 600/2-78-147, U.S.
EPA, Municipal Environmental Research Laboratory, Cincinnati,
Ohio.
OC-37 Moldavskii, B.L. & V.K. Tsyskovskii, 1971, "Oxidation of Hydro-
carbons-- An Economical Way to Produce Petrochemical Products",
Khim. I Tech. Top. I Masel 7(5-6):409-413.
Neal, R., 1978, Vanderbilt Univ. Private Communication.
OC-38 Oehlschlaeger, H.F., 1978, "Reactions of Ozone with Organic
Compounds", in Ozone/Chlorine Dioxide Oxidation Products of
Organic Materials, R.G. Rice & J.A. Cotruvo, editors. Intl. Ozone
Assoc., Cleveland, Ohio, p. 302-320.
OC-39* Pakul, D.L., A.M Sazhina & B.P. Krasnov, 1974, "Oxidation of
Alcohols in Dilute Aqueous Solutions By Ozone", J. Appl. Chem.
USSR 47(l):34-37.
OC-40* Prengle, H.W., Jr., C.E. Mauk, R.W. Legan & C.G. Hewes, III, 1975,
"Ozone/UV Process Effective for Wastewater Treatment", Hydrocarbon
Processing 54(10):82-87.
OC-41* Prengle, H.W., Jr., C.G. Hewes & C.E. Mauk, 1976, "Oxidation of
Refractory Materials by Ozone With Ultraviolet Radiation", in
Proc. Sec. Intl. Symp. on Ozone Techno!., R.G. Rice, P. Pichet &
M.-A. Vincent, editors. Intl. Ozone Assoc., Cleveland, Ohio, p.
224-252.
OC-42 Prengle, H.W., Jr. & C.E. Mauk, 1978, "Ozone/UV Oxidation of
Pesticides in Aqueous Solution", in Ozone/Chlorine Dioxide
Oxidation Products of Organic Materials. R.G. Rice & J.A. Cotruvo,
editors. Intl. Ozone Assoc., Cleveland, Ohio, p. 302-320.
OC-43 Reichert, J., 1969, "Examination for the Elimination of Carcino-
genic, Aromatic Polycyclics in the Treatment of Drinking Water,
with Special Consideration of Ozone." Wasser u. Abwasser 110(18):477-
82.
162
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Rice, R.G. & J.A. Cotruvo, Editors, 1978, Ozone/Chlorine Dioxide
Products of Organic Materials, Intl. Ozone Assoc., Cleveland,
Ohio, 480+ pages.
OC-44 Rice, R.G. & G.W. Miller, 1977, "Reaction Products of Organic
Materials with Ozone & with Chlorine Dioxide in Water", Presented
at Symp. on Advanced Ozone Technology, Toronto, Ontario, Canada,
Nov. Intl. Ozone Assoc., Cleveland, Ohio.
OC-45 Richard, Y. & L. Brener, 1978, "Organic Materials Produced Upon
Ozonization of Water", in Ozone/Chlorine Dioxide Oxidation
Products of Organic Materials, R.G. Rice & J.A. Cotruvo, editors.
Intl. Ozone Assoc., Cleveland, Ohio, p. 169-188.
OC-46 Robeck, G., K. Dostal, J.M. Cohen & J.F. Kreissl, 1965, "Effec-
tiveness of Water Treatment Processes in Pesticide Removal", J.
Am. Water Works Assoc. 57(2):181-99.
OC-47 Rogozhkin, G.I., 1970, Trudy Vsesoyuzn Nauchno - Issled. Inta
Vodosnabzheniya, Kanalizatsii, Gidrotekhnicheskikh Sooruzheniy i
Gidrogeologii (Works of the All-Union Sci. Rsch. Inst. of Water
Supply, Sewerage, Hydraulic Structures & Hydrogeology) 27:45.
OC-48 Sforzolini, G.S., A. Savino & S. Monarca, 1974a, "Decontamination
of Water Contaminated with Polycyclic Aromatic Hydrocarbons (PAH)
I. Action of Chlorine and Ozone on PAH Dissolved in Doubly Distilled
and in Deionized Water", Igiene Moderna 66(3):309-335.
OC-49 Sforzolini, G.S., A. Savino & S. Monarca, 1974b, "Decontamination
of Water Contaminated With Polycyclic Aromatic Hydrocarbons
(PAH). II. Action of Chlorine and Ozone on PAH Dissolved in
Drinking and River Water", Igiene Moderna 66(6):595-619.
OC-50 Sharifov, R.R., L.A. Mamediarova & E.V. Shul'ts, 1973, "Treatment
of Wastewaters Containing Petroleum Product", Azer. Neft. Khoz.
53(4):36-38. Chem. Abstr. 70:107925P (1973).
OC-51 Sharonova, N.F., N.A. Kuzmina & Yu.A. Kuhbabin, 1968, "Ozoniza-
tion of Wastewaters of the Isoprene Industry", Prom. Sin. Kauch.
OC-52 Shevchenko, M.A. & P.N. Taran, 1966, "Products of Ozonization of
Humus Materials", Ukr. Khim. Zh. 32(5):532-36. Chem. Abstr.
65:5393h (1966).
OC-53 Shevchenko, M.A., 1965, "Kinetics of Ozonization of Organic
Impurities in Natural Waters", Ozonirov. Vody i Vybor Rats. Tipa.
Ozonatorn. St., Sb. 37-42.
163
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OC-54 Shkolich, P.M.., M.P. Gracheva & E.O. Pen'Kov, 1972, "Carcinogen-
removing Effectiveness of Biological Methods of Purification of
Wastewaters from Organic Synthesis Plants", Ref. Zh. Khim. Abstr.
No. 231387.
OC-55* Sigworth, E.A., 1965, "Identification & Removal of Herbicides and
Pesticides." J. Am. Water Works Assoc., 57(8):1016-1022.
OC-56 Somiya, I., H. Yamoda & T. Goda, 1977, "The Ozonation of Nitro-
genous Compounds in Water", Presented at Symp. on Advanced Ozone
Technology, Toronto, Ontario, Canada, Nov. Intl. Ozone Inst.,
Cleveland, Ohio.
OC-57 Stepanyan, I.S., I.A. Vinokur & C.M. Padaryan, 1973, "Liquid-
phase Oxidation of Phenol, Methanol and Formaldehyde as Applied to
Wastewater Purification." Intl. Chem. Engr. 12(14):649-50.
OC-58 Stoveken, J. & T. Sproston, 1974, "Ozone & Chlorine Degradation of
Wastewater Pollutants." U.S. Dept. Interior, OWRR Rpt. A-017-
VT(1), NTIS Rpt. #PB 238,365/lWP, June. U.S. Dept. of Commerce,
Natl. Tech. Info. Service, Springfield, Va.
OC-59 Strackenbrock, K.H., 1958, "Chromatographic Separation of Uro-
chromes and Removal from Water by Ozone", Gesundheits Ingenieur
79:54-55.
OC-60 Tencza, S.J. & R.A. Sierka, 1975, "Ozonation of Low Molecular
Weight Compounds". Proc. Second Natl. Conf. on Water Reuse, May
4-8. Am. Inst. Chem. Engrs., New York, N.Y.
OC-61 Tyutyunnikoy, B.N., A.A. Drozdov, Z.V. Didenko & S.S. Potatueva,
1968, "Initiation of the Oxidation of a Paraffin by Ozonized Air",
Khim. Tekhanol, Topi. Masel 13(2):22-25.
OC-62 Vagobi, V.A., M.S. Gavrilov, V.L. Plakidin, G.F. Siezko & B.A.
Ponomarev, "Ozone Oxidation of Industrial Waste Streams", Vodosnabek.
Sanit. Tekh. 4:23-26.
OC-63 Versar, Inc., 1976, "Assessment of Wastewater Management, Treat-
ment Technology and Associated Costs for Abatement of PCB Concentra-
tions in Industrial Effluents", Feb. 1976; "Refinement of Alterna-
tive Technologies and Estimated Costs for Reduction of PCBs in
Industrial Wastewaters from the Capacitor and Transformer Manufac-
turing Categories", Jan. 1977; "PCBs in the United States: Indus-
trial Use and Distribution", Feb. 1976. Natl. Tech. Info. Service,
Springfield, Va., Rept. No. PB-252,402/3WP.
OC-64 Weil, L., B. Struif & K.E. Quentin, 1978, "Reaktionsmechanismen
beim Abbau Organischer Suktanzen 1m Wasser mit Ozon", Wasser
Berlin 1977. Prgc. Intl. Symp. —Ozon und Wasser. AMK Berlin,
Germany, p. 294-307.
164
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OC-65 Wingard, L.B., Jr. & R.K. Finn, 1969, "Oxidation of Catechol to
cis, cis-Muconic Acid with Ozone", Indl. Engrg. Chem., Prod.
R & D 8(l):65-69.
OC-66 Yocum, F.H., 1978, "Oxidation of Styrerte with Ozone in Aqueous
Solution", in Ozone/Chlorine Dioxide Oxidation Products of
Organic Maten'aIs, R.G. Rice & J.A. Cotruvo, editors. Intl. Ozone
Assoc., Cleveland, Ohio, p. 243-263.
165
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PAINTS AND VARNISHES
Only. 4 published papers have been found in this category. Two of these
discuss treatment of paint and varnish plant wastewaters with ozone and two
deal with treatment of aircraft paint stripping wastewaters (which contain
phenols) with ozone.
Paint and Varnish Plant Wastewaters
Ballnus and Leiss (1968) describe a treatment scheme involving ozonation
of a paint plant wastewater at pH 12 to 13, which was highly colored and
contained 1,100 to 10,400 mg/1 BOD-5, 10 to 40 mg/1 of phenols, 1,300 to
14,200 mg/1 permanganate number and divalent Zn, Pb and Cu ions. The BOD
consisted of melamine and aerylate polymers. The raw wastewater was acidified
to pH 5.0 with HC1, flocculated with FeS04 for 1 hr, then treated with lime
to pH 10.5, filtered, then then ozonized. This produced a clear, colorless
wastewater with the permanganate number now less than 80 mg/1 and which
could be discharged to the local receiving canal. Chemical costs for this
treatment process totalled 0.40 Dettsch Marks (DM)/cu m (20<£/cu m at an
exchange rate of 2 DM/$1.00), of which ozonation cost (77 g/cu m) was 0.31
DM, HC1 cost (0.7 1/cu m) was 0.06 DM and lime cost (7.4 1/cu m Time water)
was 0.03 DM.
Bauch & Burchard (1970) reported rather extensive studies of treatment
of a varnish plant wastewater in Wuppertal, Germany (on the Rhine, near
DOsseldorf). Wastewaters were preclarified with FeClo and/or Al2(S04)3,
then neutralized and ozonized. Pertinent data are presented in Table 36.
The residue on evaporation was reduced by 210 mg/1 (from 2,400), but the
residue on ignition remained the same, indicating that ozonation converted
about 10% of the organic content to 062. In addition, the permanganate
oxidizability was lowered significantly (from 1,940 to 340 mg/1), BOD-5 was
lowered from 1,400 to 190 mg/1), and concentrations of volatile hydrocarbons,
volatile phenols, non-volatile phenols and fats and oils also were reduced
significantly by 30 minutes of ozonation (20 mg of ozone/1 of air) at 19'C.
Even better results were obtained by Bauch & Burchard (1970) when they
pretreated the wastewaters with chlorine, then ozonized. The KMnO* number
was lowered to 120 mg/1 and BOD-5 to 80. In Table 37 are presented data
showing the same varnish plant wastewaters treated by several techniques.
Table 38 shows similar data obtained by treating canal water near the dis-
charge outlet of this paint & varnish plant. Hot and cold aeration without
ozonation provided some improvement, but not nearly as much as did ozonation.
Bauch & Burchard (1970) reported that flocculation followed by filtration
through activated carbon is acceptable for treating small volumes of paint &
varnish wastewaters, but that activated carbon costs were too high for
consideration when treating large volumes of these wastewaters. In addition,
they stated that the carbon cannot be regenerated, implying that it becomes
too fouled. They also stated that treatment with chlorine was not acceptable,
due to formation of chlorinated organic materials which interfered with
166
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TABLE 36. TREATMENT OF WASTEWATER FROM A VARNISH PLANT BY GASSING
WITH OZONE (20 mg/1) FOR 30 MINUTES AT 19°C
Analytical Parameters
Capable of settling after 2 hrs
Appearance after settling
Odor
Odor threshold
)H value
Conductivity in microsec
Residue on evapn
Residue on ignition
Chlorides as Cl~
_2
Sulfate as SO,
Sulfide as H^S
Overall hardness in ° dH
Calcium as CaO
Iron II
Iron III
Zinc as Zn
Lead as Pb
Copper as Cu
Volatile hydrocarbons
Volatile phenols
Nonvolatile phenols
Fats and Oils
Oxidizability (KMnO^ consumption)
BOD-5
Before treatment
6 ml/1
slightly turbid,
yellow
intensively of
varnish
1:600
6.0
4,900
2,400 mg/1
1,010 mg/1
150 mg/1
320.0 mg/1
8.0 mg/1
15.6 mg/1
128.0 mg/1
20.0 mg/1
11.0 mg/1
131.0 mg/1
18.0 mg/1
3.5 mg/1
140.0 mg/1
24.0 mg/1
14.0 mg/1
62.0 mg/1
1,940.0 mg/1
1,400.0 mg/1
After treatment
6.3 ml/1
slightly turbid,
almost colorless
stale, faintly of
varnish
1:16
5.3
4,950
2,190 mg/1
1,040 mg/1
155 mg/1
335 mg/1
not traceable
14.2 mg/1
130.0 mg/1
not traceable
36.0 Mg/1
135.0 mg/1
16.0 mg/1
3.0 mg/1
20.0 mg/1
4.0 mg/1
not traceable
32.0 mg/1
340.0 mg/1
190.0 mg/1
Source: Bauch & Burchard, 1970
167
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CO
TABLE 37. WASTEWATER DISCHARGE OF A PAINT & VARNISH PLANT TREATED 25 MINUTES WITH OZONIZED AIR*
Untreated sewage
after 24 hrs
settling
Sewage acidified
with sulfuric acid
(pH 3.6) addition:
0.05 g iron as Fed,
+0.05 aluminum as
Al2(S04)3, neutral-
ized milk of lime
up to pH 8.1
Clarified sewage
gassed cold with
air
Clarified sewage
gassed hot with
air
Clarified sewage
treated with ozone
Clarified sewage
pretreated with Cl?,
then treated with
ozone
Appearance
milky turbid,
brownish
clear
yellowish
clear
yellowish
clear
yellowish
clear
yellowish
clear,
strongly
yellowish
* 20 mg ozone/liter of air
Odor
Intensively
of varnish
and esters
intensively
of varnish
and esters
intensively
of varnish
and ester
intensively
of varnish,
faintly of
ester
faintly of
varnish
stale,
somewhat of
benzene
Odor
Thresh-
old
1:1,000
1:900
1:500
1:150
1:18
1:8
KMn04
Con-
sumption
2,850
2,800
2,400
1,400
no
120
BOD-5
mg/1
1,860
1,900
1,600
1,050
180
80
Lead
mq/1
40.0
--
--
—
Zinc
mq/1
200
—
--
—
Volatile
Components
mq/1
80
80
30
15
—
—
Fats &
Oils
mq/1
98
15
14
16
16
12
Source: Bauch & Burchard, 1970
-------
TABLE 38. WASTEWATER FROM THE CANAL NEAR THE OUTLET OF A PAINT & VARNISH MANUFACTURING PLANT,
PRETREATED BY PRECIPITATION AND TREATED WITH OZONE* (30 MINUTES) AND CHLORINE
Untreated sewage
after 24 hrs
settling
Sewage acidified to
pH 5.0 with sulfuric
acid addition:
0.1 g/1 iron as
Fed 3, precipitated
with milk of lime at
pH 7.6
Clarified sewage
gassed cold with
air
Clarified sewage
gassed hot with
air
Clarified sewage
gassed cold with
ozonized air
Clarified sewage
pretreated cold
with excess Cl2,
then ozonized air
Appearance
milky, turbid
clear
yellowish
clear
yellowish
clear
yellowish
clear, almost
colorless
clear, almost
colorless
* 20 mg ozone/ liter of air
Source: Bai
Odor
intensively
of varnish
intensively
of varnish
intensively
of varnish
intensively
of varnish
faintly of
varnish
stale,
indefinable
Odor
Thresh-
old
1:800
1:700
1:500
1:240
1:20
1:4
KMn04 | BOD- 5
Consumption
mg/1
3,850
2,900
2,720
1,800
190
82
mg/1
1,800
2,600
2,100
1,400
260
150
Lead
& Zn
mg/1
114.3
trace;
trace;
trace;
traces
traces
ch & Burchard, 1970
Volatile
Portions
mg/1
110
70
60
10
Fats
and Oils
mg/1
80
18
16
19
16
5
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later clarification processes in municipal wastewaters treatment plants.
However, pretreatment with chlorine before ozonation was justified on the
basis that ozone will oxidize any residual chlorine to perchlorate, which
itself is a powerful oxidant capable of destroying organic compounds.
Phenolic Aircraft Paint Stripping Wastewaters
Kroop (1975) reported the removal of phenols by ozonation of aircraft
paint stripping wastewaters, which generally contain the following components:
Phenols 1,000-3,000 mg/1
Methylene Chloride 1,000-3,000 mg/1
COD 5,000-30,000 mg/1
Chromium 50-200 mg/1
Suspended Solids 100-1,000 mg/1
Oils 100-2,000 mg/1
pH 8.0-8.5'
Some 71.5% of the COD is contributed by the phenols.
In batch ozonation experiments on these wastewaters, it was found that
99.7% of the phenol could be destroyed by ozonation, but that COD values
were reduced only 57%. Formation of C02 was only 10% of that stoichio-
metrically expected on the basis of phenol being oxidized completely, thus
intermediate oxidation products- probably are formed which were not detected
by the analytical method (4-aminoantipyrine) used to determine phenol.
Controlling the initial pH at 11.0 lowered the amount of ozone required to
remove phenol to 3.46 moles/mole of phenol (or 1.77 g of ozone/g of phenol).
Ozone concentrations were measured in the inlet gas and in the contactor
off-gases. Lowering of the COD during the initial 30 minutes of ozonation
was shown to be a result of air stripping of the volatile methylene chloride
solvent.
Continuous flow ozonations then were conducted in a 2-stage diffuser
reactor system at an influent pH of 11.5. Wastewater flowed first to
Reactor #1, where it was treated with 40 mg/min of ozone (in air) and all
ozone was consumed. Effluent from Reactor #1 then flowed into Reactor #2
along with the off-gases from Reactor #1. An additional 17 mg/min of ozone
in air was added to Reactor #2.
Using this 2-stage reactor system, Kroop (1975) found that to attain
99% destruction of phenol (30 mg/1 residual phenol) required 200 minutes of
ozonation; to attain 3 mg/1 residual phenol (99.9% removal) required 300
minutes of ozonation. After 240 minutes of ozonation, even though the
residual phenol concentration was below 20 mg/1, the COD was 3,500 mg/1 (a
65% reduction in COD value). To attain 99% phenol removal by ozonation
required 5.2 moles of ozone/mole of phenol (2.66 g/g); to attain 99.9%
phenol removal required 8.0 moles of ozone/mole of phenol (4.50 g/g).
170
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Kroop (1973) reported the capital and operating costs to treat 29,000
gal/day of phenolic aircraft paint stripping wastewater to the two levels of
treatment (99% and 99.9%) as follows:
concn. of residual Phenol
20 mg/1 2.0 mg/1
Capital Cost $389,000 $505,000
Operating Cost $400/day $548/day
Conclusions
1) Ozonation of a colored paint and varnish wastewater having a perman-
ganate number of 1,300 to 14,200 and containing melamine and acrylate
polymers, phenols, Zn, Pb and Cu produced an effluent having a perman-
ganate number of 80 mg/1 and which could be discharged to the environ-
ment. Chemical treatment costs totalled 20<£/cu m, of which ozonation
costs were 15 to 16£/cu m.
2) Ozonation of varnish plant wastewaters which had been preclarified with
Fed., or Alo(S04)3 and neutralized, lowered permanganate numbers from
1,940 to 340 mg/1 and BOD-5 from 1,400 to 190 mg/1 in 30 minutes.
Pretreatment of this wastewater with chlorine allowed permanganate and
BOD-5 values of 120 and 80 mg/1, respectively, to be obtained upon
ozonation.
3) Aircraft paint stripping wastewaters containing 1,000 to 3,000 mg/1 of
phenol when ozonized in a 2-stage diffuser reactor produced 99% removal
of phenol (to below 30 mg/1) over 200 minutes and required 5.2 moles of
ozone per mole of phenol. To attain 99.9% phenol removal (to less than
3 mg/1) required 300 minutes of ozonation (8.0 moles of ozone/mole of
phenol).
4) Total capital and operating costs to treat 29,000 gal/day of phenolic
aircraft paint stripping wastewaters to phenol levels of 20 and 2.0
mg/1 have been estimated to be $400/day and $548/day, respectively.
REFERENCES CITED -- PAINT & VARNISH (PV)*
PV-01 Ballnus, W. & W. Leiss, 1968, "Verfahren zur Behandlung von Ab-
wa"ssern der Lackindustrie" (Procedures for Treating Wastewaters of
the Varnish Industry), Wasser, Luft und Betrieb 12(5):289, 292-
293.
PV-02* Bauch, H. & H. Burchard, 1970, "Experiments to Improve Highly
Odorous or Harmful Sewage with Ozone", Wasser, Luft & Betrieb,
12(5):289, 292-293.
Abstracts of asterisked articles will be found in EPA 600/2-79- b.
171
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PV-03 Kroop, R.H., 1973, "Treatment of Phenolic Aircraft Paint Stripping
Wastewater", USAFWL Rept. 72-181, Jan. 98 pp. U.S. Air Force
Weapons Laboratory, Kirtland Air Force Base, New Mexico.
PV-04* Kroop, R.H., 1975, "Ozonation of Phenolic Aircraft Paint Stripping
Wastewater", in Proc. First Intl. Symp. pji Ozone for Water &
Wastewater Treatment, R.G. Rice & M.E. Browning, Editors, Intl.
Ozone Assoc., Cleveland, Ohio, p. 660-673.
172
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PETROLEUM REFINERIES
Wastewater Characteristic s
Table 39 shows the wastewater characteristics from 10 specific petroleum
refinery processing steps, as listed by Carnes, Ford & Brady (1973). Typi-
cally, refinery BOD and COD is composed of oils, hydrocarbons (saturated and
unsaturated), nitrogen-containing organics, phenolics (comprised of phenols,
cresols and xylenols), plus sulfides and mercaptans. In addition, ammonia
also is present in many refinery wastewaters.
Ozonation Studies on Refinery Effluents
As early as 1951, Murdock studied the ozonation of phenolic and sulfide
components of refinery wastewaters containing 470 mg/1 of phenols. Treatment
with 1500 mg/1 of ozone reduced the phenols content to 0 mg/1 (at pH 12.0).
Prior aeration of this wastewater, followed by pH adjustment to 12.0, reduced
the ozone requirement to 1,200 mg/1 for the reduction of phenol content to
0 mg/1. The amount of sulfides present in this wastewater is not mentioned,
but oxidation of sulfides present will occur before the ozone demand of
phenol is satisfied. A detailed discussion of the chemistry observed during
the ozonation of phenols is given later in this section under Phenols.
Peppier & Fern (1959) conducted a laboratory ozonation study of refinery
wastewaters at the Sarnia, Ontario, Canada refinery of Imperial Oil Ltd.
Cat-cracker condensates containing sulfides, mercaptans and phenol were
ozonized and it was confirmed that sulfide oxidation proceeds initially to
the exclusion of phenol oxidation. Therefore, cat-cracker condensates
should be stripped prior to ozonation in order to remove the volatile sulfides.
This will reduce the amount of ozone required, since 1 g of ^S requires
about 1.33 g of ozone to be oxidized to sulfate.
Refinery effluent from a biological treatment unit containing 900 ppb
of phenols required 345 mg/1 of ozone-to--lower the phenols content to 60
ppb. This corresponds to an ozone consumption of about 400 g of ozone/g of
phenol removed. This very high ozone "requirement" can be explained on the
basis that the amount of ozone present in the contactor off-gases was not
measured. Therefore this was the amount of ozone dosed to the reaction
mixture, not the amount consumed.
Comparative costs for phenol removal from refinery effluents were
estimated by Peppier & Fern (1959). Costs for steam and flue gas stripping
are $0.91/lb of phenol removed, for biological oxidation, $0.24/lb (at the
rate of 800 Ibs/day of phenol removed) and for ozonation, $0.95 to 1.65/lb
of phenol removed. These cost projections are based on an initial cost of
27.3<£/lb for ozone and a phenol ozone demand of 3.6 to 6 Ibs of ozone/1 b of
phenol. The actual ozone demand of the Sarnia refinery sour waters was
shown to be in the range of 3.5 to 6 Ibs of ozone/Ib of phenol removed.
This range corresponds well to the range discussed later under Phenolics.
173
-------
TABLE 39. .TYPICAL WASTE LOADINGS FROM REFINERY PROCESSES
TYPICAL TECHNOLOGY
Fundamental Process
Crude Desalting
Crude Fractionation
Catalytic
Cracking
Thermal Cracking
Hydrocracking
Hydrotreating
Delayed Coking
Reforming
Sour Condensates
Alkylation
Wastewater Characteristics
Flow,
gal/bbl
2.1
26
15
2.0
2.0
1.0
1.0
6.0
3.0
60
1
pH 1
6.7-9.1
8.6
8.3-9.7
6.4
7.3
9.0
8.8-9.1
7.6
4.5-9.5
8.1-12
!OD
b/bbl
0.
0.
0.
0.
0.
0.
0.
0.
003
COD
Ib/bbl
0.032
0002 .005
015
001
002
010
—
—
100
001
0.018
0.003
0.045
0.050
0.032
0.040
0.200
0.010
Oil
1 b/bbl
0.012
0.017
0.100
0.001
--
--
0.006
0.050
0.100
--
H2S
1 b/bbl
0.008
0.001
0.036
0.001
0.002
0.002
--
0.001
1.00
0.010
NH3
1 b/bbl
0.009
--
0.040
--
--
0.030
--
--
0.75
0
TDS
1 b/bbl
0.250
0.035
0.090
—
0.002
0.035
0.030
0.125
--
0.300
Primary Effluent Quality From Refineries
REFINERY
CLASSIFICATION CONTAMINANTS, mq/1
A
B
C
D
gal/bbl
crude
BOD COD
throughput
13 113
17 326 956
50 112 332
90 148 391
Oil
76
64
34
46
TDS Sulfide
2,980
2,380
597
2,100
2
57
21
21
Ammonia-N
351
35
40
Source: Carnes, Ford & Brady (1973)
174
-------
Popov (1960) showed that 75 to 80% of the petroleum products present in
wastewater could be removed in 16 hrs using ozone generated in air. Aeration
alone removed only 60% of these materials during the same time. The remaining
materials imparted little odor to the treated wastewater, and 4 to 5-fold
dilution removed this completely.
Alekseeva & Karelin (1963) ozonized a refinery wastewater containing
soluble petroleum products which they judged to be amenable to treatment
only by oxidation. The wastewaters contained 180 to 259 mg/1 of BOD, 20 to
50 mg/1 of oil residues and 0 mg/1 of dissolved oxygen. Ozonation with 1540
g of ozone/hr (in air) produced an effluent containing 2 to 4 mg/1 of
petroleum residues having a BOD of 8 to 15 mg/1 and 1.8 to 2.7% dissolved
oxygen. The abstract of this article does not list the time of ozonation,
the type of contacting apparatus used, nor how much ozone actually was
consumed to give these results.
Malkina (1971) studied the ozone oxidation of demulsifiers present in
refinery wastewaters and evaluated the toxicities of the ozonized wastewaters
to Daphnia magna (water fleas). The Russian demulsifiers NChK, OP-10 and
disolvane-4411 present in the wastewaters at concentrations of up to 50 mg/1
were 92 to 99% oxidized upon ozonation. The ozonized wastewaters were not
toxic to Daphnia magna.
A 1975 article by the Tungfanghung Oil Refinery describes the use of
ozonation in the treatment of wastewaters from a refinery in the Peoples
Republic of China. After desulfurizing, removal of oil, flotation, biological
treatment and aeration, the wastewater now can be "purified to surface water
quality" by single stage or 3-stage ozonation. "Good results" also were
obtained by ozone treatment of the flotation tank effluent, showing the
feasibility of replacing the biological treatment by a chemical method.
loakimis e_t aJL (1975) studied ozom ti on«of,three,different,refinery
wastewater,.streams;.. (1) .admixed.waste-before,biological treatment, (2) a
contaminated storm^drain.effluent and (3),a desalter waste after mechanical
treatment. The most effective method of ozonation involved multi-stage
contacting, which produced a maximum 60% reduction in COD concentration.
When the wastewater streams were ozonized in a countercurrent flow column,
the COD and BOD concentrations were found to decrease during all stages of
contacting, but the original ratio of BOD/COD hardly changed at all. A
first order linear differential equation predicting the ozonation reaction
mechanism was tested on a Minsk-22 computer, and confirmed the hypothesis of
formation of oxidized intermediates.
Zaidi & Tollefson (1976) studied the physical-chemical .treatment of
sour gas plant wastewaters using activated carbon, chemical clarification,
incineration, steam stripping, chlorine/UV oxidation and ozonation. Treatment
by these last 2 techniques "did not appear to be capable of meeting the
current wastewater quality standards".
175
-------
The Trafalgar Plant (near Toronto, Ontario, Canada)--
Dabine (1959) describes the wastewater treatment system which was
installed in 1957 at the then Cities Service (now British Petroleum) refinery,
located on Lake Ontario, at the city of Trafalgar, which is between Hamilton
and Toronto. The initial plant treatment capacity was 20,000 bbls/day, and
ozonation was installed as a polishing step to remove phenols, or to reduce
their concentrations to a sufficiently low level (0.003 mg/1) so that the
city of Bronte, whose drinking water intake is close to the refinery waste-
water discharge, would develop no undesireable tastes and odors during
potable water treatment, which includes chlorination.
Dabine (1959) describes some of the initial studies on the Trafalgar
refinery wastewater treatment system, which includes ozonation as a polishing
step for phenol removal. Biological treatment first reduces the phenol
concentrations from 55 mg/1 to 0.38 mg/1, after which ozonation lowers this
level to 0.012 mg/1. At the time this article was written, the suggested
local wastewater discharge standard for refinery phenols was 0.015 mg/1.
Following ozonation, the original treatment process included addition of 2
mg/1 of powdered activated carbon, followed by sand filtration to remove the
activated carbon, before discharge to Lake Ontario.
The Trafalgar plant wastewater treatment system was designed to handle
300 gal/minute, but Dabine states that it has handled up to 600 gpm "sati-
sfactorily". Total ozone generating capacity initially installed was 190
Ibs/day. Ozonation was chosen over chlorine dioxide treatment for phenol
removal because of the lower operating costs for ozonation (although the
capital costs would be much higher for ozone generation and contacting than
for chlorine dioxide).
In 1962, McPhee & Smith reported on the first 2 years of operation of
the Trafalgar refinery wastewater treatment system. The effluent standards
set as objectives for the refinery wastewaters were:
Phenolics less than 20 ppb
Iron 17 mg/1
pH 5.5-10.6
Oil (Total) 15 mg/1
Floating Solids none
Settlable Solids none
The Trafalgar refinery installed a 10-step wastewater treatment consis-
ting of:
(1) Stripping of sulfides and ammonia
(2) Separation of oil and tank bottoms
(3) pH adjustment
(4) Temperature adjustment (required because of low temperatures
encountered during winter months)
(5) Chemical coagulation and precipitation
(6) 2-Stage biological oxidation
(7) Final settling
176
-------
8) Ozonation (for phenols)
9) Activated carbon adsorption
10) Filtration through sand
Data reported in "this paper by McPhee & Smith were gathered during the
summer of 1960, when the wastewater flows averaged 225 Igpm. The phenoTtc
design loading was 200 Ibs/day and averaged 56 mg/1 in the raw wastewater.
Trafalgar's oil separators operate at 85 to 94% removal efficiencies
and the aerated equalization basin converted the phenolic concentrations
from a range of 40 to 80 mg/1 to constant feeds of about 40 mg/1. Also, the
oil concentrations were lowered from a range of 270 to 400 mg/1 to 50 to 100
mg/1. Flocculator/clarifier units complete oil separation, lowering its
concentration to below 15 mg/1. This also reduces COD from a range of 1,200
to 2,350 mg/1 to 240 to 440 mg/1 and BOD from 1,600 mg/1 to 160 to 260 mg/1.
Activated sludge treatment further reduces BOD from an average of 200 mg/1
to about 50 mg/1, COD from 400 to 150 mg/1 and phenols from 40 to 1 mg/1 (in
10 hrs) and to 0.35 mg/1 in an additional 3 hrs of activated sludge treatment
(13 hrs total).
Wastewater streams fed to the ozonation step contained 0.16 to 0.39
mg/1 concentrations of phenols which are oxidized to concentrations of less
than 0.003 mg/1. Because the ozonation step meets the effluent discharge
standards for phenols, the use of the activated carbon step was discontinued
after the first few months of plant startup and after steady state operation
had been attained. Rapid sand filtration now is sufficient to remove any
turbidity that may be present after ozonation. The treated plant wastewater
is said to be "as good as the Lake Ontario raw water", except that the total
solids are higher (1,606 mg/1 versus 116 to 224 mg/1 for the raw lake water).
Ozone dosage rates to attain this amount of phenol oxidation are 20 to 40
mg/1, and the diffuser contactors provide a total detention time of 80
minutes.
Hoffman ejt aj_. (1973) describe a computerized simulation program for
the Trafalgar wastewater treatment process at steady state operation. Using
operational plant data obtained since 1960, zero or first order kinetics
were assumed and plug flow or continuous stirred reactor hypotheses were
assumed. A first order reaction combined with a plug flow reactor gave the
most consistent results.
In 1977, the Trafalgar plant was visited by EPA Effluent Guidelines
officials (Schafer, 1977). Because of a process upset, these visitors were
not allowed into the plant. The plant originally was a 20,000 bbls/day
refinery, but today is an 80,000 bbls/day plant. Plant officials confirmed
the discontinuance of powdered activated carbon after ozonation for phenols
oxidation, but also the discontinuance of the following sand filter as well.
This had been installed originally to filter activated carbon and prevent it
from being discharged into the lake.
177
-------
Current ozonation capacity at Trafalgar is 120 Ibs/day, provided by 4
individual ozone generating units. Ozone contactors are 14 ft x 20 ft,
epoxy-lined stainless steel vessels, normally fed 50% of the 550 to 650 Igpm
biologically treated effluent. The installed cost of ozonation in 1958 was
$150,000. The maintenance costs for ozonation today are $40/1b of phenol
removed by ozonation, and the normal operating cost is $12/lb of phenol
removed. These costs are based upon 550 Igpm being fed to ozonation step.
It should be realized that with an influent phenol concentration of 30
to 100 ppb and an ozonation effluent concentration of 10 to 20 ppb, no more
than 0.25 Ib/day of phenol is being removed by ozonation at this plant.
Therefore, 1 Ib of phenol requires 4 days of ozonation at Trafalgar. The
seemingly high operating cost of $12/lb is not unreasonable on this basis.
For comparison, see Eisenhauer (1971) later in this section under Phenols,
who estimates that at an ozone cost of 7tf/lb, the cost to obtain 98% removal
of phenol by ozonation is 18<£/1 b (1971 Canadian dollars).
Trafalgar plant personnel reported (Schafer, 1977) that reliable
operation of the ozone generators at this plant "is very difficult" and
depends upon obtaining uniform cooling of the stainless steel generator
tubes as well as upon absolute control of the inlet air (to the ozone
generator) at a -60° dewpoint. A nearby Texaco refinery studied the use of
ozone for removing phenols in 1976 or 1977 and chose activated carbon
instead, because of higher costs for ozonation.
Ozonation of Used Cutting Oils
Filtration and ozonation of lubricating oils containing microorganisms
at a rate of 50 g/hr allowed a French automobile manufacturer to recycle
cutting oil and obtain one year total use from the oil, which previously had
been changed up to seven times per year (Anonymous, 1973).
Another article (Anonymous, 1974) also discusses the rejuvenation of
used cutting oil by treatment with ozone. With an ozone consumption of 50 g
of ozone/cu m of used oil, filter pressing allows recovery of 5% fuel oil in
addition to regeneration of the cutting oil. When regeneration is not
possible, the used oil is refined by decantation and filtration to recover
fuel oil.
Effects on Drinking Water Supplies
Gabovich & Kurinnoi (1967) showed that ozonation of drinking water
supplies containing petroleum product contaminants can be used to eliminate
or greatly reduce the concentrations of these contaminants. About 45 mg of
ozone was required to break down 1 mg of petroleum at an original concentra-
tion of 10 mg/1 of petroleum. Ozone also eliminated gasoline from water at
an ozone consumption ratio of 0.023 mg ozone/mg of gasoline, although the
result probably is due to air stripping of the gasoline rather than by
chemical oxidation by means of ozone. Dosages of 5.1 mg/1 of ozone fully
deodorized the gasoline-containing water (50 mg/1) in 5 minutes.
178
-------
Diehl e_t aj_ (1971) reported on a study conducted in 1969 at the Baton
Rouge (Louisiana) Humble Oil Refinery to define the refinery's contribution
to taste and odor problems in drinking waters taken from the lower Mississippi
River. Laboratory treatability studies were conducted on particular waste-
water streams using several treatment techniques.
Although ozonation generally was responsible for some lowering of COD
and BOD levels, threshold odor levels decreased to a minimum value, then
increased again. The character of the odors changed upon ozonation from
hydrocarbon odors to a sweet/sour odor similar to that of acetic acid. No
quantitative information on the use of ozone is given in this article, but
formation of acetic acid as a stable end product of ozonation is entirely
reasonable in light of the known organic oxidation chemistries.
Diehl (1976) amplified on the earlier results, showing that ozone
dosages of 20 to 30 mg/1 over 30 minutes of diffuser contacting produced 90%
reduction in threshold odor number, from just over 1,000 to just over 100.
On the other hand, simple oxygen stripping provided about 85% removal.
Upon continued ozonation (1 to 1.5 hrs of contacting, the threshold
number of the samples again rose to 200 to 250 after 5 to 7 hrs of ozone
contacting time.
Conclusions
1) Ozonation has been used commercially to polish effluents from a refinery
in Sarnia, Ontario, Canada since the late 1950s. This is the only
refinery currently known to be using ozone for treating actual waste-
waters. The plant wastewater discharge is close to a water supply
intake, therefore the plant must produce a very high quality effluent,
and has a 3 ppb phenols discharge limitation.
2) Ozone demand of sour waters at the Sarnia refinery is in the range of
3.5 to 6 Ibs of ozone/1b of phenol destroyed. This corresponds to
ozonation costs of $0.95 to $1.65/lb of phenol destroyed (at 27.3<£/lb
ozone cost).
3) In cat-cracker condensates containing sulfides, mercaptans and phenol,
ozonation oxidizes sulfides initially to the exclusion of phenol oxida-
tion. Thus, stripping prior to ozonation will reduce the amount of
ozone required to treat this type of refinery wastewater.
4) Used cutting oils can be rejuvenated by treating with ozone to a
consumption of 50 g of ozone/cu m of used oil. This treatment, followed
by filter pressing, allows recovery of 5% fuel oil as well.
5) Pilot tests at Humble Oil's Baton Rouge refinery showed that threshold
odor numbers of various ozonized wastewaters decreased at first, then
increased. The character of the odors changed from those of hydrocarbons
to those of esters, acids, ketones, aldehydes, etc.
179
-------
LITERATURE CITED « PETROLEUM REFINERIES (RE)*
RE-01 Alekseeva, V.A., 1965, "Use of Ozone in Purification of Waste-
water," Khim Tekhnol, Topliv i Masel.
RE-02* Alekseeva, V.A. & Ya.A. Karelin, 1963, "The Purification of Petro-
leum Refinery Wastewaters with Ozone." Neftepererabotka i Neftekhim.,
Nauchno-Teknicheskii Sbornik, 5:19-21.
RE-03* Anonymous, 1973, "Ozone Cleans Bug-Ridden Oil", New Scientist,
March, p. 548.
RE-04* Anonymous, 1974, "Disposal, Regeneration and Recovery of Used
Industrial Oils", Machine Moderne, Nov. p. 38-45.
RE-05 Anonymous, 1957, "Removal of Phenols From Refinery Wastes", Oil in
Canada, June 24, p. 26.
Carnes, B.A., D.L. Ford & S.O. Brady, 1973, "Treatment of Refinery
Wastewater for Reuse", Complete Watereuse, Industry's Opportunity,
Am. Inst. Chem. Engrs., New York, N.Y., p. 407-419.
RE-06* Dabine, R.A., 1959, "Phenol Free Wastewater." Chem. Engrg., Aug.
24, 114-117.
RE-07* Diehl, D.S., R.T. Denbo, M.N. Bhatla & W.D. Sitman, 1971, "Effluent
Quality Control at a Large Oil Refinery." J. Water Poll. Control
Fed. 43:2254-2270.
RE-08 Diehl, D., 1976, "Ozone for Taste & Odor Control of a Refinery
Effluent", in Ozone: Analytical Aspects & Odor Control. R.G. Rice
& M.E. Browning, editors. Intl. Ozone Assoc., Cleveland, Ohio, p.
77-78.
RE-09 Filby, J., J. Hutcheon & R. Schutte, 1976, "Use of Ozone in the
Preparation of Industrial Boiler Feed Water", in Forum on Ozone
Disinfection, E.G. Fochtman, R.G. Rice & M.E. Browning, Eds.,
Intl. Ozone Assoc., Cleveland, Ohio, p. 337-343.
RE-10* Gabovich, R.D. & I.L. Kurinnoi, 1967, "Ozonization of Water
Containing Petroleum Products, Aromatic Hydrocarbons, Nitro
Compounds and Chloro-organic Pesticides." Gig. Naselennykh Mest.
(USSR) Izd. "Zdorov'ya", 31-35 (1967).
RE-11* Hoffman, T.W., D.R. Woods, K.L. Murphy & J.D. Norman, 1973, "Simu-
lation of a Petroleum Refinery Waste Treatment Process", J. Water
Poll. Control Fed. 45(ll):2321-2334.
Abstracts of asterisked articles will be found in EPA 600/2-79- b.
180
-------
RE-12* loakimis, E.G., A.E. Kulikov, V.I. Nazasov, N.M. Podgoretskaya &
S.O. Eigenson, 1975, "Use of Ozone in Treating Refinery Wastes",
Chem. Technol. Fuels Oils 11(3-4):188-192.
RE-13 Korolev, A.A., Yu.P. Tikhomirov &. P.E. Shkodich, 1972, "Use of
Ozone for Decontamination of Carcinogenic Waste Waters Containing
Petroleum Products." Vop. Profil Zagryazneniya Okruzhayushch.
Cheloveka Sredy Kantserogen. Veshchestvami p. 72-75.
RE-14* Malkina, 1.1., 1971, "Ozone Oxidation of Demulsifiers Present in
Wastewaters From Petroleum Refineries and an Evaluation of the
Toxicity of the Treated Water". Sb. Tr., Mosk. Inzh. Stroit.
Inst. 87:133-136. Chem. Abstr. 78:151232p.
RE-15* McPhee, W.T. & A.R. Smith, 1962, "From Refinery Wastes to Pure
Water." Engrg. Bull., Purdue Univ. Engrg. Ext. Ser. 109:311-326.
RE-16* Murdock, H.R., 1951, "Ozone Provides an Economical Means for
Oxidizing Phenolic Compounds in Coke Oven Wastes." Indl. Engrg.
Chem. 43(11):125A, 126A, 128A.
RE-17 Niegowski, S.J., 1956, "Ozone Method for Destruction of Phenols in
Petroleum Wastewaters." Sewage & Indl. Wastes, 28:1266-1272.
RE-18* Peppier, M.L. & G.R.H. Fern, 1959, "A Laboratory Study on Ozone
Treatment of Refinery Phenolic Wastes". Oil in Canada 11(27):84-
90.
RE-19 Popov, M.A., 1970, "Purification of Petroleum Wastewaters by
Ozonization." Trudy Vses. Nauchno-Issled Dovatel'skii Inst. Vodo
Snab Sehenii Kanalizatsii, Gidrogeologii 2:45-48.
RE-20* Popov, M.A., 1960, "Use of Ozone for the,Final Treatment of
Effluents From an Oil Refinery". Gig. y Sanit. 25(5):92-3.
RE-21 Schafer, C.J., 1977, U.S. EPA/Effluent Guidelines Div., "Petroleum
Refining and Organic Chemicals: Canada". Trip Report, March.
RE-22* Sease, W.S. & G.F. Connell, 1966, "Put Ozone to Work Treating
Plant Wastewater." Plant Engineering, Nov.,
RE-23 Sharifov, R.R., Sh.I. Ismailov, S.S. Korf & A.R. Mamedova, 1976,
"Purification of Petroleum-Containing Formation Waters by Ozoniza-
tion and Sorption". Tr. Vnii Vodosnabzh, Kanaliz, Gidrotekhn.
Sooruzh. I Inzh. Gidrogeol. Bakin. Fil., 12:18-22.
RE-24 Sharifov, R.R., L.A. Mamed'yarova & E.V. Shul'ts, 1973, "Treatment
of Wastewater Containing Petroleum Products". Azer. Neft. Khoz.
53(4):36-38.
181
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RE-25 Shevchenko, M.A., Yu.M. Kaliniichuk & R.S. Kas'yanchuk, 1954,
"Purification of Water from Phenols and Petroleum Products
by Ozonization." 'Kr Khim. Zh.
RE-26* Tungfanghung Oil Refinery; Tsinghua Univ. (Res. Group Treat.
Oil Refinery Wastewater, Peking Chem. Works, Peking, Peoples Rep.
China), 1975, "Use of Ozonation in the Treatment of Wastewater
From Oil Refineries". Ch'ing Hua Pei Ta Li Kung Hsuch Pao 2(3):69,
87. Chem. Abstr. 86:47053k.
RE-27* Zaidi, S.A. & F.L. Tollefson, 1976, "Physical-Chemical Treatment
of Sour Gas Plant Process Waste Waters". J. Can. Petrol. Technol.
15(2):39-47.
182
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PHARMACEUTICALS
Although the wastewaters from this industrial category are organic in
nature, remarkably little interest in the potentials for ozonation has been
shown, as indicated by the paucity of published literature. A study initiated
in 1972 by the Pharmaceutical Manufacturers Association compiled information
on the sources, volumes and characteristics of the industry's wastes, current
treatment processes and future treatment needs (Lederman et al_., 1975). In
the section dealing with "Future Treatment Needs", the PMApoints to the
need to understand and utilize carbon adsorption, reverse osmosis, ultrafiltra-
tion and ozonation.
A French patent issued in 1974 describes the bleaching and clarifi-
cation of wastewater from the synthesis of Vitamin B2. The decolorization/-
clarification is accomplished by injecting ozone (4 to 6% in air) into the
waste stream. Chlorine also may be added, but only to the extent of about
50% of the ozone added. Otherwise the ozone will be destroyed.
Conclusion
Ozonation has been used to bleach and clarify wastewater from the
synthesis of vitamin 62- The processing employed 4 to 6% ozone generated
in air.
LITERATURE CITED -- PHARMACEUTICALS (PC)
PC-01 Lederman, P.B., H.S. Skovronek & P.E. Des Rosiers, 1975, Chem.
Engrg. Progress, 71(4):93-97.
PC-02 French Patent 10128W/06, 1975, March 21.
183
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PHENOLS
Phenols are a class of organic compounds which contain an aromatic ring
upon which is substituted at least one hydroxyl group. The simplest phenol
is phenol itself:
phenol
Other phenols include those in which more than one hydroxyl group is substi-
tuted onto the single aromatic ring, or multiple and/or fused aromatic rings
which contain one or more hydroxyl groups:
resorcinol phloroglucinol
OH st^W ^f^Qtt HO
HO
hydroquinone OH catechol OH g-naphthol
Phenols as a class are present in the wastewaters from a number of
industrial categories, in particular:
Organic Chemicals
Plastics & Synthetics
Petroleum Refineries
Iron & Steel (Coke) plants
Soaps & Detergents
Photoprocessing (hydroquinone)
Pulp & Paper
Textiles
When treated with chlorine, phenol first forms chloro-substituted
phenols, which are known to impart disagreeable medicinal tastes and odors
to drinking waters. As a class, however, these compounds generally are
rather easily oxidized by strong oxidants, such as ozone, chlorine dioxide
and potassium permanganate. Even continued additions of chlorine itself
eventually will destroy the aromatic ring moiety.
It must be borne in mind, however, that even though phenols as a class
are readily oxidizable, this does not necessarily mean that they will be
easily oxidized completely to C02 and water. Phenol oxidation under water
and wastewater treatment conditions can stop at some stage after rupture of
the aromatic ring, far short of all of the organic carbon being converted to
C0p» particularly if insufficient oxidant is used.
184
-------
In much of the water and wastewater literature there are references to
the "destruction of phenol" by ozone oxidation and by other powerful oxidants.
The reader should note, however, that the "destruction of phenol" is followed
by an analytical procedure which usually is specific only for the phenolic
compound, or for an aromatic oxidation product, and is not necessarily
specific for any of the aliphatic, ring-ruptured oxidation products that
will be formed.
In this section, we will discuss the organic chemistry of ozone oxidation
of phenolic compounds in some detail so that the reader will gain a greater
appreciation of these points. Many of the experiments reported here were
performed with the objective of isolating and identifying intermediate
oxidation products, and not necessarily of optimizing ozonation conditions
for destruction of phenols. Details of ozonation of specific phenol-contain-
ing wastewaters will be discussed in the sections dealing with pertinent
industrial categories.
Reactions Of Ozone With Phenol
Niegowski (1953) ozonized aqueous solutions containing 100 mg/1 concen-
trations of phenol, o-cresol and m-cresol at pH 12. These compounds
o-cresol
OH
II m-cresol
required ozone dosages of 200 to 260 mg/1 to be 99+% destroyed. Niegowski
(1953) also ozonized phenolic-containing wastewaters from 8 iron and steel
coke plants, from 1 chemical plant (containing 2,4-dichlorophenol) and from
2 refineries. With the exception of 2 of the coke plant wastewaters, the
ratios of ozone to phenol required to lower the phenol concentrations from
a range of 100 to 11,600 mg/1 down to 2.5 mg/1 or below ranged from 1.0 to
8.8. For the 2 coke plant wastewaters containing 38 and 51 mg/1 of phenols,
dosages of 18 to 20 mg/1 of ozone were required/mg of phenol to attain
residual phenol concentrations of 0.4 and 0.1 mg/1, respectively.
Eisenhauer (1968) ozonized aqueous solutions of phenol for 30 minutes
(until phenol was "destroyed" by the analytical test used) and isolated
catechol, hydroquinone, p-quinone, cjhs_-muconic acid, oxalic acid and fumaric
acid as organic oxidation products:
185
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OH
°
3 y
~lo l") "! L.COOH
minutes . ,
catechol 0 mucomc acid
p-quinone
H
HOOC-C=CCOOH (fumaric acid) +
H'OOC-COOH (oxalic acid)
After 4 moles of ozone/mole of phenol had been consumed (up to 1 hr of
ozonation time), substantially all of the phenol originally present had
disappeared, but very little C02 had formed.
When ozonation was conducted for only 10 minutes, Eisenhauer (1968)
isolated a 20% yield of catechol, but only 70% of the phenol was destroyed.
This indicates that upon oxidation of phenol, other organic compounds (10%)
or C02 are produced along with the catechol.
Eisenhauer (1971 a) ozonized 50 to 300 mg/1 concentrations of phenol at
pH 3 to 9 a-nd 20°C. As the ozonation reactions proceeded, the TOC of the
solutions decreased, but no CO? formed until after 1.5 moles of ozone/mole
of phenol had been consumed. When 33% of the theoretical CO? had formed,
CO? production ceased. At 50°C, about 65% of the theoretical C02 was produced
under the same conditions.
Eisenhauer (1971a) concluded that if the first stage of phenol oxidation
(destruction of the aromatic ring) is sufficient to satisfy a pollution
control problem, then 98% of the phenol can be "destroyed" using 5 moles of
ozone/mole of phenol. The phenol was "destroyed" according to the analytical
test employed, but 67% of the original dissolved organic carbon still was
present in the form of other organic oxidation products. Eisenhauer (1971 a;
1971b) concluded that at an ozone cost of 7<£/lb, a treatment cost of 18<£/lb
of phenol "destroyed" is required.
In further studies of the ozonation of aqueous solutions of phenol,
Eisenhauer (1971b) showed that 1 mole of C02 is formed for 7.3 moles of
ozone consumed. Complete oxidation of phenolic effluents to C02 and water
cannot be achieved economically with ozonation alone. The maximum rate of
ozonation of phenol occurs at pH 11 and 50°C, but its oxidation products are
not as reactive under these conditions.
Bauch, Burchard & Arsovic (1970) found monobasic and polybasic (alipha-
tic) acids upon ozonation of water solutions of phenol. They concluded that
186
-------
oxidation of phenol by ozone proceeds via the ozonide and produces hydrogen
peroxide. Initial phenolic oxidation products themselves consume additional
ozone.
Bauch & Burchard (1970) ozonized aqueous solutions of phenol and
isolated and identified maleic acid, tartaric acid, glyoxylic acid, oxalic
acid and CO,,:
¥ «
;-c=c-c
HOOC-C=C-COOH
maleic acid
HOOC-CHO
glyoxylic
acid
OH OH
:-CH-CH-(
HOOC-CH-CH-COOH
tartaric acid
HOOC-COOH +
oxalic
acid
CO,
Mallevialle (1975) ozonized 100 to 200 mg/1 aqueous solutions of
phenol with 25 mg/1 ozone doses and identified catechol, o-quinone, hydro-
quinone and p-quinone as oxidation products:
catechol o-quinone
p-benzo-
hydroquinone quinone
Mallevialle (1975) also showed that ozonation of aqueous solutions
containing naturally occurring humic acids produces phenolic compounds as
intermediates (analyzed chromatographically), which then oxidize upon
further ozonation. Thus it is possible to increase the concentrations of
phenols in water by insufficient ozonation. Waters containing 525 mg of
humics required 100 mg of ozone to -destroy 95% of the color and 320 mg of
ozone to destroy 95% of the polyhydroxyaromatic compounds. Mallevialle
(1975) concluded that it is necessary, therefore, to add 380 and 500 mg of
ozone to lower the COD and TOC values, respectively, by 75%.
187
-------
Spanggord & McClurg (1978) were the first investigators to identify
resorcinol as an initial oxidation product, along with catechol, upon
ozonation of phenol in water:
catechol
Gould & Weber (1976) have made the most complete study to date on the
ozonation of phenol. They found that the early oxidation products (catechol
and hydroquinone) are further oxidized as ozonation continues, and faTl to
relatively insignificant concentrations as the reactions proceed. Glyoxal
is formed by ring rupture, but its concentration decreases to a low level as
the reactions proceed. Glyoxylic acid is the main oxidation product isolated
after 30 minutes of treatment with ozone, together with smaller amounts of
oxalic acid.
OHC-CHO
glyoxal
H
hydroquinone
HOOC-CHO
glyoxylic
acid
HOOC-COOH
oxalic
acid
'(major product after 30 minutes)
Ozonation of aqueous phosphate buffered solutions containing 1.4 to
1,106 mmoles/1 of phenol required ozone dose rates of 0.774 to 8.076 moles
of ozone/mole of phenol. During the early stages of reaction, the combined
concentrations of catechol plus hydroquinone reached a maximum of about 10%
of the initial phenol concentration, indicating that hydroxylation of phenol
is not the most important reaction of the ozone.
188
-------
Gould & Weber (1976) also showed that addition of 24 moles of ozone/mole
of phenol lowered the COD of the solution 77%. An additional 24 moles of
ozone were required to lower the COD an additional 3%. Therefore, to attain
90% reduction in COD values requires greater than 150 moles of ozone/mole of
phenol. These authors concluded that ozonation beyond the stage of aromatic
ring rupture is not economical. This point is quite acceptable, however,
since the oxidation products are considered to be "inoffensive" and are
biodegradable. Therefore, dosages of 4 to 6 moles of ozone/mole of phenol
will assure virtually complete removal of phenol and its aromatic oxidation
by-products, will leave about 33% of the initial organic carbon in the form
of glyoxal and glyoxylic acid (about equal amounts) and a 70 to 80% reduction
in COD levels will be attained. Gould & Weber (1976) recommend that the
aromatic breakpoint can be used as an indicator of the optimum ozone dosage,
and this can be followed by a COD or TOC monitor.
Throop (1977) showed that ozone dosages of 5.32 mg/1 produced non-
detectable quantities of phenol in 5 minutes of contact, starting with
concentrations of 110 ppb of phenol in a presettled and decanted foundry
wastewater. This dosage is equivalent to 48 parts ozone/part of phenol.
However, ozone dosages of 25.5 mg/1 (200 parts ozone/part phenol) were
required to produce a measureable (trace) amount of residual ozone in the
solution. This confirms the fact that although ozone rapidly destroys
phenol itself, significant amounts of ozone-demanding oxidation products are
formed.
Throop (1977) compared the costs for treatment of foundry wastewaters
to reduce phenol concentrations to 1.5 ppb at flow rates of 2.89, 1.3 and
2.4 mgd. In 1974 dollars, the costs estimated are as follows:
Ch1 orination: Chiorination contact tanks $125,000
annual chlorine cost 40,000
Permanganate: $65,000/yr
Peroxide: $75,000/yr
Carbon Adsorption: $9 million capital cost
$l,100/yr operating cost
Ozonation: $80,000 to $125,000 ozone generation and contacting cost
$4,000 to $9,000/yr power cost (@ 2<£/kwhr).
Reactions Of Ozone With Other Phenols
Bauch, Burchard & Arsovic (1970) compared the rates of ozonation of
phenol with cresols and xylenols, and also isolated and identified ring
ruptured oxidation products in all cases. The 3 cresol isomers decomposed
more rapidly than did phenol, and the m-cresol isomer decomposed faster than
did either the o- or p-isomers. Cresols reacted faster with ozone in acid
solution than in basic solution. A decomposition of 80% for cresols was
189
-------
attained with 2 moles of ozone/mole of cresol (85 g ozone/100 g cresol).
Chlorophenols gave HC1, indicating splitting of C-C1 bonds by ozonation.
Upon initial ozonation, the methyl group of each cresol isomer oxidized
to the corresponding carboxylic acid. For example, o-cresol produced sali-
cylic acid:
OH OH
COOH
salicylic acid
o-cresol
Continued ozonation of cresols ruptured the aromatic ring and produced
maleic acid (which further oxidized to mesotartaric acid), acetic acid,
propionic acid, glycolic acid, glyoxylic acid, oxalic acid and C02:
OH
HOOC-CH=CH-COOH
maleic acid
CH3CH2COOH
CH3COOH
HOOC-CH(OH)-CH(OH)-COOH
mesotartaric acid
HOCH2COOH + OHC-COOH +
HOOC-COOH
CO,
All 3 cresols (o~, m- and p-) formed the same oxidation products upon
ozonation. Only the rates of oxidation varied.
Xylenols with ortho or para hydroxy groups reacted fastest with ozone
and produced the same oxidation products as the cresols (Bauch, Burchard &
Arsovic, 1970). In addition, 1,2,3- and 1,2,4-xylenols produced diacetyl,
glyoxal (which disproportionates to glyoxylic acid), hydroxyphthalic acid
and ketoaldehydes:
and
CH,
0 0
CH3C-8-CH3 + OHC-CHO +
diacetyl /
COOH
COOH
HOOC-CHO
glyoxylic
acid
hydroxy-
phthalic
acid
190
-------
Gilbert (1978) ozonized 1 mmole/1 of 2-nitro-p-cresol with 10 mg of
ozone/minute until the cresol was destroyed. He .found that 90% of the
original nitrogen was converted to nitrate ion, indicating rupture of the
aromatic ring as well as cleavage of the C-N bond.
)H
. . i\in_ n
N03" (90%)
Finally, Hillis (1977) ozonized aqueous solutions containing 30 mg/1
concentrations of 14 phenols and found that with ozone concentrations of 22
g/cu m (in oxygen) and 10 minutes of dosage, the concentrations of these
phenols could be brought to below 0.5 mg/1 (in many cases to below 0.1
mg/1), except for pentachlorophenol. Some 2 to 3 g of ozone/g of phenol (4
to 6 moles/mole) is required, and the COD levels are reduced 50 to 67%, but
are not eliminated, indicating that organic compounds remain in the solution
after ozonation has been completed.
Reactions Of Ozone With Chlorinated Phenols
Shuval & Peleg (1975) followed the rate of formation of chloride ion
during ozonation of aqueous solutions of o-chlorophenol. In all experiments,
about 80% of the aromatic chlorine was converted to chloride ion upon ozona-
tion, indicating that covalent C-C1 bonds on the aromatic rings are broken
with ozone. There was an induction period during which the concentration of
o-chlorophenol decreased, but without formation of chloride ion. On the
other hand, after all o-chlorophenol had disappeared, chloride ion still was
being produced upon continued ozonation. This indicates that the active
oxidation species attacks the aromatic ring at a site or sites other than
the chlorine site, producing chlorinated aliphatic compounds as intermediates.
These then decompose upon continued ozonation.
Gilbert (1976) ozonized aqueous solutions of 2-chloro-, 4-chloro-, 2,3-
dichloro-, 3,5-dichloro- and 2,4,6-trichlorophenols until the phenols could
not be detected by gas chromatography and no phenolic functionality could be
detected by the 4-aminoantipyrine method. This required 3.2 to 5 mmoles of
ozone/mmole of phenol. The rate of oxidation increased from mono- to tri-
chlorophenol. After ozonation, 60 to 95% of the chlorine was found as
chloride ion. Ozonation of 4-chlorophenol produced chloride ion at the
start of ozonation; chloride ion was first detected only after 40% of the
2-chlorophenol had been degraded. The different rates of dechlorination are
explained by Gilbert (1976) in terms of different electron density distribu-
tions on the aromatic rings.
The compound 2,4-dichlorophenol produced formic and oxalic acids upon
ozonation, in addition to chloride ion:
191
-------
HCOOH + HOOC-COOH + CV
Biodegradability of the ozonized products became higher with increasing
degrees of oxidation and with decreasing chlorophenol concentration. After
total oxidation of the phenols, the COD level had been reduced from 200 to
100 mg/1 and TOC concentration had been reduced from 72 to 59 mg/1.
After chlorophenols had disappeared, thin layer chromatography techniques
indicated the presence of carbonyl or carbonyl/carboxylic acid functionalities.
In instances of incomplete dechlorination, chlorinated aliphatic moieties
were isolated but not identified.
Gilbert (1978) ozonized 4-chloro-o-cresol and identified 67% of its
oxidation products. After 80 minutes of treatment with ozone (800 mg of
ozone total dosage added to 1 mmole of chlorocresol) none of the starting
cresol was present and 100% of the chlorine was found as chloride ion. In
the ozonate, methylglyoxal, pyruvic acid, acetic acid, formic acid and
oxalic acid were isolated and identified, along with C09. The course of
reaction is as follows: L
80
min
0
OHC-C=0 + CHoC-COOH
I 3
CH3
methyl
glyoxal
pyruvic
acid
CH3COOH +
acetic
acid
HCOOH
formi c
acid
HOOC-COOH
oxalic
acid
CO,
Methylglyoxal was produced from the beginning of the reaction, its
concentration reaching a maximum after 60 minutes of reaction, then slowly
decreasing. This means that its rate of formation from the cresol is faster
than its rate of oxidation.
192
-------
Pyruvic acid and acetic acid concentrations increased steadily during
ozonation, even after complete elimination of the cresol, indicating that
these two acids are produced from the initial oxidation products of the
cresol. All TOC was accounted for by these organic compounds at various
times during ozonation. Therefore, the above compounds, plus CCL, water and
chloride ion are the only oxidation products of this cresol.
Figure 14 summarizes the known reactions of phenols with ozone to
produce organic oxidation products before complete conversion to C02 and
water.
Catalyzed Ozonation
Chen & Smith (1971) reported the first studies on coupling sonocatalysis
or Raney nickel catalysis with ozonation for the treatment of solutions
containing phenol and of o-chloronitrobenzene. Aqueous solutions of phenol
(500 mg/1) were ozonized for 3 hrs and samples were withdrawn every 0.5 hr
for analysis. Ozonation alone (65 mg/hr) decreased the phenol concentration
31% in 3 hrs. Ultrasonics alone caused a 60%, almost linear, decrease in
phenol concentration, and this decrease was unaffected by the addition of
160 g of Raney nickel. However, combined sono-ozonation decreased phenol
concentration by 95%.
In later studies, Smith, Chen & Seyffarth (1973) showed that Raney
nickel plus ultrasound caused a 60% decrease in phenol concentration in 3
hrs, which is about the same rate as for ultrasound alone. However, combining
Raney nickel with ozonation decreased the phenol concentration 68% in 3
compared with 28% for ozonation alone. The lowest phenol concentration
found after 3 hrs of treatment was obtained using the combination of ultra-
sonics, ozone and Raney nickel. The combination of ozone with Raney nickel
caused a substantial loss in dissolved carbon, suggesting that more of the
phenol is converted to C02, while the other treatments merely produce more
highly oxidized species.
Finally, Chen, Hui, Keller & Smith (1975) showed that catalytic ozonation
allows at least two oxygen atoms from each ozone molecule to be utilized in
the oxidation reaction with phenol. Steady state oxidation of aqueous
solutions of phenol was reached in 90 minutes using ozone alone, but was
reached in 60 minutes using catalytic ozonation (using a special Fe203
catalyst). At initial COD concentrations of up to 900 mg/1, total removal
of COD was obtained by catalytic ozonation, whereas in the same ozone contact
time only 65% (at 200 mg/1 initial COD concentration) and 30% (at 900 mg/1
initial COD) of the initial COD was removed by ozonation alone (0.2 1/min;
30 mg/1 ozone concentration).
Conclusions
1) Ozonation of phenol in aqueous solution proceeds rapidly, to produce
aliphatic, ring-cleaved, oxidation products at an ozone/phenol molar
ratio of 4 to 5. These ring-ruptured oxidation products are biodegrad-
193
-------
OH
OH
OH
OH
^N
ci i" tr ci
OH
plus CT
HOOC-C=C-COOH
H
HOOC-OC-COOH
A A
HOOC-CH-CH-COOH
OH OH
HOCH2-COOH
OHC-COOH + HCOOH
OHC-CHO
HOOC-COOH + CO-
(R -
etc.)
OH
COOH
Figure 14. Reactions of ozone with phenol.
plus:
CH3COOH + CH3CH2COOH
CH,-C-C-CH
CH,-C-COOH + 0=C-CHO
3 II I
0 CH
-------
able. About 33% of the theoretical amount of C02 is formed, and the
final TOC value is about 67% of the original.
2) Under-ozonation of phenol will produce intermediate oxidation products
which still contain the aromatic ring. These include: catechol,
resorcinol, hydroquinone, o-quinone and p-quinone. To avoid having
these compounds in the ozonized solution, sufficient ozone should be
provided to allow their oxidation to aliphatic materials.
3) Aliphatic oxidation products of the ozonation of phenol include:
muconic, fumaric, oxalic, formic, maleic, tartaric and glyoxylic acids
and glyoxal, in addition to CO^.
4) Cresols and xylenols oxidize faster than phenol to produce aromatic
ring-containing oxidation products initially (salicylic acid from o-
cresol, for example). Continued ozonation ruptures the aromatic ring
to form maleic, mesotartaric, acetic, propionic, glycolic, glyoxylic
and oxalic acids, plus CO,,.
5) Chlorinated phenols react slower with ozone, producing chloride ion
after ring rupture, and non-chlorinated aliphatic oxidation products.
6) Catalytic ozonation with ozone/ultrasonics/Raney nickel, ozone/Fe203,
ozone/ultrasonics or ozone/UV will increase the rate of oxidation of
phenols.
LITERATURE CITED — PHENOLS (PH)*
PH-01 Bauch, H. & H. Burchard, 1970, "Investigations Concerning the
Influence of Ozone on Water With Few Impurities", Wasser, Luft und
Betrieb 14(7):270-273.
PH-02* Bauch, H., H. Burchard & H.M. Arsovic, 1970, "Ozone as an Oxi-
dative Disintegrant for Phenols in Aqueous Solutions", Gesund-
heits-Ingenieur, 91(9):258-262.
PH-03 Bernatek, E. & C. Frengen, 1961, "Ozonolysis of Phenols. I. Ozo-
nolysis of Phenol in Ethyl Acetate", Acta Chem. Scand., 15:158-
170.
PH-04 Bernatek, E. & A. Vincze, 1962, "Ozonolysis of Phenols. Ill", Acta
Chem. Scand. 16(8):2054-2056.
PH-05 Bernatek, E. & A. Vincze, 1965, "Ozonolysis of Phenols. IV", Acta
Chem. Scand., 19(8):2007-2008.
PH-06* Chen, J.W. & G.V. Smith, 1971, "Feasibility Studies of Applications
of Catalytic Oxidation in Wastewater", EPA Report 17020 EC 1-11/71,
73 pages. U.S. Environmental Protection Agency, Washington, D.C.
* Abstracts of articles asterisked will be found in EPA 600/2-79- b.
195
-------
PH-07* Chen, J.W., C. Hul, T. Keller & G.V. Smith, 1975, "Catalytic
Ozonation in Aqueous Systems", presented at 68th Meeting of Am.
Inst. Chem. Engrs., Los Angeles, Calif., Nov., (27 pages). Am.
Inst. Chem. Engrs., New York, N.Y.
PH-08* Eisenhauer, H.R., 1968, "The Ozonation of Phenolic Wastes", J.
Water Poll. Control Fed. 40:1887-1899.
PH-09* Eisenhauer, H.R., 1971a, "Increased Rate and Efficiency of Pheno-
lic Waste Ozonization", J. Water Poll. Control Fed. 43(2):200-208.
PH-10* Eisenhauer, H.R., 1971b, "Dephenolization by Ozonolysis", Water
Rsch., 5:467-472.
PH-11 Gaboyich, R.D. & I.L. Kurennoi, 1966, "Ozonization of Water Con-
taining Humic Compounds, Phenols, and Pesticides", Vop. Kommunal
Gig., 6:11-19.
PH-12 Gilbert, E., 1976, "Ozonolysis of Chlorophenols and Maleic Acid in
Aqueous Solution", in Proc. Sec. Intl. Symp. Oni Ozone Techno!..
R.G. Rice, P. Pichet & M.-A. Vincent, editors, Intl. Ozone Assoc.,
Cleveland, Ohio, p. 253-261.
PH-13 Gilbert, E., 1978, "Reactions of Ozone With Organic Compounds in
Dilute Aqueous Solution: Identification of Their Oxidation Products",
in Ozone/Chlorine Dioxide Oxidation Products of Organic Materials,
R.G. Rice & J.A. Cotruvo, editors, Intl. Ozone Assoc., Cleveland,
Ohio, p. 227-242.
PH-14* Gould, J.P. & W.J. Weber, Jr., 1976, "Oxidation of Phenols by
Ozone", J. Water Poll. Control Fed. 48(1):47-60.
PH-15 Hann, V.A. & S.J. Niegowski, 1955, "Treatment of Phenolic Wastes
With Ozone", U.S. Patent #2,703,312, March 1.
PH-16 Hirota, D.I., 1970, "Physico-chemical Factors Affecting the
Oxidation of Phenolic Compounds by Ozone". Ph.D. Diss.,
Michigan Univ., Ann Arbor Accession #W-73-00170, 162 p.
PH-17* Hillis, R., 1977, "The Treatment of Phenolic Wastes by Ozone",
Presented at 3rd Intl. Symp. on Ozone Technology, Paris, France,
May. Intl. Ozone Assoc., Cleveland, Ohio.
PH-18 Keay, R.E. & G.A. Hamilton, 1975, "Epoxidation of Alkenes and the
Hydroxylation of Phenols by an Intermediate in the Reaction of
Ozone with Alkynes". J. Appl. Chem. & Biotechnol., 25(7).
PH-19 Leggett, 1920, U.S. Patent 1,341,913.
196
-------
PH-20 Loffi, I.E. & E.A. Pedace, 1966, "Residual Liquids Containing
Phenols". Saneamiento (Buenos Aires), 30:108-117.
PH-21* Mallevialle, J., 1975, "Action de TOzone dans la Degradation des
Composes Phenoliques Simples et Polymerises: Application aux
Matieres Humiques Contenues dans 1'Eaux". T.S.M.-l'Eau, 70(3):107-
113.
PH-22 Marechal, 1905, French Patent 350,679.
PH-23 Nebel, C., R.D. Gottschling, J.L. Holmes & P.C. Unangst, 1976,
"Ozone Oxidation of Phenolic Effluents", in Proc. Sec. Intl. Symp.
on Ozone Technology. R.G. Rice, P. Pichet & M.-A. Vincent, Eds.,
Intl. Assoc., Inst., Cleveland, Ohio, p. 374-392.
PH-24* Niegowski, S.J., 1953, "Destruction of Phenols by Oxidation with
Ozone". Indl. Engrg. Chem. 45(3):632-634.
PH-25 Pasynkiewicz, J. & A. Grossman, 1967, "The Use of Ozone for
Eliminating Phenols from Gas Works Effluents". Gas World, 166(9):-
4324.
PH-26* Rosfjord, R.E., R.B. Trattner & P.M. Cheremisinoff, 1976,
"Phenols: A Water Pollution Control Assessment". Water & Sewage
Works, March, p. 96-99.
PH-27 Sharonova, N.F. & N.A. Kuz'mina, 1968, "Ozonation of Shale Tar
Water". Khim. Tekhnol Goryuch Prod. IKH Pererab.
PH-28* Shuval, H. & M. Peleg, 1975, "Studies on Refractory Organic Matter
from Wastewater by Ozonation". Prog. Rpt. to Gesellschaft filr
Kernforschung, Karlsruhe, Germany and the National Council for
R&D, Jerusalem,, Israel, Dec. 1975, 23 pp.
PH-29* Smith, G.V., J.W. Chen & K. Seyffarth, 1972, "Catalytic Oxidations
of Aqueous Phenol". Proc. Fifth Intl. Congress on Catalysis,
August, p. 893-903.
PH-30 Spanggord, R.J. & V.J. McClurg, 1978, "Ozone Methods and Ozone
Chemistry of Selected Organics in Water. I. Basic Chemistry", in
Ozone/Chlorine Dioxide Oxidation Products of Organic Materials.
R.G. Rice & J.A. Cotruvo, editors, Intl. Ozone Assoc., Cleveland,
Ohio, p. 115-125.
PH-31 Throop, W.M., 1975, "Perplexing Phenols. Alternative Methods for
Removal". Proc. Third Annual Pollution Control Conference, Water
& Wastewater Equipment Mfgrs. Assoc., McLean, Va., p. 115-143.
PH-32* Throop, W.M., 1977, "Alternative Methods of Phenol Wastewater
Control", J. Hazardous Materials 1:319-329.
197
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PHOTOPROCESSING
Wastewater Composition
Wastewaters from photographic processing establishments contain a
complex variety of organic and inorganic pollutants. The wastewaters
generally are characterized by a pH between 7 and 9, numerous toxic organic
compounds and inorganic salts, heavy metals, phosphates and nitrates which
promote algae growth, and high biochemical and chemical oxygen demands.
Table 40 shows an analysis of EA-4 photographic wastewaters (including wash
waters). In addition to the materials listed in this table, organic compounds
such as ethylene glycol, benzyl alcohol, acetic acid, N.N-dimethyl-p-phenylene-
diamine, 2-anrino-5-diethylaminotoluene, 4-amino-N-ethyl-N-[3-hydroxyethyl]-
aniline, p-dimethylaminophenol, l-phenyl-3-pyrazoline, EDTA, hydroxylamine,
formaldehyde and methanol also can be present in color film developer
formulations. Some of these react readily with ozone; others (acetic acid
and methanol, for example) are refractory to ozone (see section on Hospitals).
The majority of photographic bleaches contain ferricyanide salts and
are used primarily in color reversal processing. In doing its bleaching
job, ferricyanide ion is reduced to ferrocyanide. Both iron cyanide complexes
are very stable to oxidative destruction, therefore the spent ferrocyanide
bleaching solution can be treated with an oxidizing agent so as to regenerate
the ferricyanide solution for recycle and reuse:
2[Fe(CN)6]"4 + H20 + QS >-2[Fe(CN)6]"3 + 2(OH)" + 02
There are commercially available ozonation systems which are designed
to regenerate ferricyanide bleaching solutions as well as to reduce the
concentrations of oxidizable organic and inorganic constituents. Thus the
major objective of treating photoprocessing wastewaters is to remove toxic
components. A second objective is to regenerate, recycle and reuse ferri-
cyanide bleaching agents, and a third is to reduce the pollutional load of
the wastewaters before being discharged to local community sewers. It has
been estimated (Dougherty ejt al_., 1976) that 95% of all photoprocessing
plants discharge wastewaters to municipal sewer systems, rather than to free
bodies of water.
Treatment of Bleach Solutions
Lotz (1972) conducted a questionnaire survey of wastes generated by
photographic processing at U.S. Air Force major civil engineering installa-
tions and Air National Guard units within the continental USA and abroad.
Because the survey was conducted from June, 1970 to June, 1971, several
operational air bases in Viet Nam were surveyed. At the time, it was concluded
that over 26 million gal/month of photographic wastewaters were discharged
by these 2 service branches. Over 70% of the installations responding in
the U.S.A. discharged 10,000 to 1,000,000 gal/month.
198
-------
TABLE 40. ANALYSIS OF WASTE DISCHARGED FROM EA-4 PHOTOGRAPHIC PROCESS,
SHAH AIR FORCE BASE
Constituent
COD
Dissolved Solids
Suspended Solids
Volatile & Fixed Suspended Solids
)ils & Greases (as Heptane)
Surfactants (as Linear Alkyl Sulfonate)
5henols
*Ji trates
3hosphates
Sul fates
Cyanides
Silver
[ron
Zinc
Copper
Manganese
Chromium
_ead
Cadmium
Source: Lotz, 1972
Concentration
(mq/1)
2,234
5,942
70
70
22
13
0
48
380
1,100
260
6.70
1.96
0.20
0.08
0.05
0.05
<0.05
<0.01
Lotz concluded that wastewaters should be desilvered before biological
treatment or discharge because of the toxic effects of silver, but there is
also the strong economic incentive to recover silver for reuse. Additionally,
Lotz found that only 3 of the 311 installations submitting completed question-
naires regenerated the ferricyanide bleaches for reuse. All 3 regenerating
installations used chemical oxidation, rather than ozone oxidation.
Hendrickson & Daignault (1973a, 1973b) conducted a detailed investi-
gation of the treatment of complex cyanide compounds at the Berkey Photo
film processing plant at Fitchburg, Massachusetts. The objective of this
investigation was to evaluate electrolytic and ozone oxidation techniques
for the regeneration of ferrocyanide for reuse of photoprocessing bleach
baths, and to evaluate ozonation, precipitation and chlorination for the
treatment of waste solutions containing complex cyanides from film processing
waste discharges. A maximum residual ferrocyanide concentration of 0.4 mg/1
was the goal established during this work for the treated wastewater.
These authors concluded that "ozonation is the best choice for control
of complex cyanide pollution". Both ozonation or electrolysis could be used
with similar process cost savings for the recovery and reuse of ferricyanide
bleaches, and the recovery is economically justifiable. Copper and zinc can
precipitate ferro- or ferricyanide from solution, and complex iron cyanide
destruction can be achieved by either ozone or chlorine oxidation in acid
solution.
199
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Hendrickson & Daignault (1973a, 19735) studied the regeneration of
spent ferrocyanide bleach solutions in bench-scale systems using electrolysis,
chlorination and ozonation, then in pilot-scale systems using ozonation,
before installing a full-scale ozonation system at Berkey Photo. For bench-
scale ozonation studies, 1 liter of 10 g/1 potassium ferrocyanide solution
was ozonized until the odor of ozone could be detected above the solution
surface. The reaction was followed by analyzing for pH and ferricyanide.
A second bench-scale study was conducted at constant pH, in which concen-
trated HC1 was added to the ozone reactor (a sparger column, 18.5 inches
high and 2.5 inches in diameter).
In these bench-scale regeneration experiments, the rate of oxidation of
ferro- to ferricyanide was found to be zero order with respect to ferrocyanide
concentration. The ozonation reaction was rapid, mass transfer controlled,
and pH independent. The stoichiometry is:
2K4Fe(CN)6.10H20
2K3Fe(CN)6 + 2NaOH
For each unit weight of ozone, 20.2 unit weights of ferrocyanide are regenera-
ted to form 11.7 unit weights of ferricyanide. The ozone oxidation efficiency
is 100% at ferrocyanide concentrations above 1 g/1. Below this concentration,
ozone escapes from solution and the ferricyanide complex begins to decompose.
Therefore, detection of ozone in the exhaust gases indicates the reaction
end point. Pertinent data are given in Table 41.
These bench-top ozonation studies were conducted using used Ektachrome
ME-4 and Kodachrome K-12 bleaches. No apparent decrease in ozone efficiency
was observed for simulated or actual photoprocessing bleaches. The authors
stated that in some commercial installations using ozone regeneration of
ferricyanide bleach, the solutions have been regenerated up to 40 times with
no adverse effects observed as to their bleaching capabilities.
TABLE 41. RESULTS OF BENCH TOP OZONATION OF USED PHOTOPROCESSING BLEACH
AT BERKEY PHOTO*
'rocess
K-12F
1E-4
4E-4
1E-4
Time of
Reaction
(min)
40
30
50
40
Ozone
Feed Rate
(g/hr)
0.665
2.36
1.40
2.00
Initial
Ferricyanide
Concn
(a/1)
115
101
104.2
97.7
Final |
Ferricyanide
Concn
(g/1)
123
128
131.6
126.0
Efficiency
of Ozone
Use
(%)
100%
98%
100%
91%
* All solution volumes are 0.5 liter
Source: Hendrickson & Daignault, 1973a
Bench top ferricyanide destruction experiments were conducted using 500
ml of 0.01M potassium ferrocyanide solutions in a 1 liter flask, and pH was
adjusted by adding HC1 or NaOH solution. Three treatment schemes were
studied: (1) ozonation without pH control, (2) addition of 20 ml of concen-
200
-------
trated HC1 and 5 g of steel wool (catalyst), then ozonation, (3) acidification
with 20 ml of HC1, heating to 70 to 90°C, then ozonation. At room temperature,
ozonation had little effect on the ferricyanide destruction rate. Under
alkaline conditions, ozonation produced a dark red color after the stoichio-
metric amount of ozone had been added. This red color disappeared when the
mixtures were acidified. Some ferricyanide decomposition occurred with the
steel wool catalyst. Below pH 3.0, the reaction proceeded rapidly to produce
iron hydroxide and cyanate. Above pH 3.0, the reaction ceased. Under hot,
acidic conditions at 70 to 90°C, there was only a small initial effect of
ozonation, but as the reaction proceeded, the continued addition of ozone
promoted more rapid and complete destruction.
Chlorine destruction of ferricyanide was studied by adding 500 ml of
Chlorox to 500 ml of 10 g/1 potassium ferricyanide, and adjusting the pH to
11.0. At room temperature, little destruction was observed. However at
90°C, destruction was complete in 4 hrs. In a second technique, chlorine
gas was bubbled into 1 liter of a 10 g/1 ferricyanide solution with and
without the addition of NaOH to maintain the pH at 11.0. Sodium sulfite was
added to quench the reaction whenever the reaction mixture was sampled.
This process destroyed 85% of the ferricyanide. When the mixture then was
made alkaline again and filtered, an additional 85% of the remaining ferri-
cyanide could be destroyed. This second method (2) was found to be the best
chlorination method for ferricyanide destruction.
Pilot studies of ferrocyanide ozonation for bleach regeneration were
conducted in a continuous flow apparatus (see Figure 15). Ozone (2% in
oxygen) was sparged into the bottom of a column 52 inches high and 3.5
inches in diameter. A 50-gal synthetic bleach solution containing 30 g/1
potassium ferrocyanide was pumped through this ozonation reactor at the rate
of 50 to 150 ml/minute. Samples were analyzed periodically for ferrocyanide,
ferricyanide and pH. Results obtained in the pilot unit confirmed those
obtained in bench top studies. At a constant flow of ozone into the reactor,
the rate of conversion of ferrocyanide to ferricyanide was found to be
inversely proportional to the flow rate of solution.
Pilot ferricyanide destruction experiments also were conducted in a
continuous flow apparatus. Waste ferrocyanide solution and HC1 were heated
and ozonized. The overflow was filtered, and the filtrate was neutralized
with NaOH and sewered. The precipitate was treated with NaOH to extract the
metal complexed cyanides; this slurry was filtered and the filtrate was
recirculated to the ozonation reactor. The final products from this destruct-
ion scheme are NaCl and iron hydroxide, at the rate of about 6 Ibs/day from
the average processing machine.
Costs were analyzed by considering the wastes from an hypothetical
photographic processing machine. The chosen machine was a "combined average"
of various processes which included: Kodacolor Color Negative (process C-
22), Ektacolor Color Paper (process Ektaprint C), Ektachrome Reversal Film
(process E-4) and Ektachrome Paper (process Ektaprint-R). Table 42 shows
the flow rate, concentration of sodium ferricyanide and approximate costs
201
-------
HBr Tank
pH Controller
Splenoid Valve
Bleach Feed
Air
Compressor
Ozone
Generator
Sparger System
Source: Hendrickson & Daignault (1973a)
Figure 15. Flow schematic of a photographic bleach regeneration system
using ozone.
202
-------
for the individual bleaches and the "combined average". During film process-
ing, about one-sixth of the replenisher ferricyanide was assumed to be
reduced to ferrocyanide. An average year was taken as 260 days (8 hrs/day),
and a "combined average" machine was assumed to handle 800 rolls of film per
day.
TABLE 42. COSTS FOR THE "COMBINED AVERAGE" HYPOTHETICAL PROCESSING MACHINE
Process
Kodacolor (t-ZZ)
Ektacolor Paper
(Ektaprint-C)
Ektachrome Film (E-
Ektachrome Paper
(Ektaprint-R)
Combined Average*
* Assumed to
Replenisher
Flow Rate
(ml/min)
275
260
4) 115
150
200
Replenisher
Na3Fe(CN)6
Concn
(g/1)
25
25
120
30
50
Bleach
Cost
$/100 gal
$ 87.00
$ 48.00
$238.00
$ 72.00
$111.00
handle 800 rolls of film/8 hr day — 260 days/year
Source: Hendrickson & Daignault, 1973a
Costs for regeneration of bleach from the "combined average" processor
in the continuous flow mode were calculated to be $7,200 capital to recover
90% of the bleach used, saving $22.90/day, or 2.85
-------
TABLE 43. COSTS FOR BLEACH REGENERATION BY THE "COMBINED AVERAGE" PROCESSOR
Equipment
Ozone Generator (10 g/hr output, from air)
)ry Air Supply System
50 Gallon Polyester Tank
^lixer: 2 HP rubber-coated steel
Spargers & Acid Tank
Pumps
pH Controller with Automatic Probe,
Solenoid & Metering Valve
Labor & Maintenance (10% of cost)
TOTAL
Calculated present bleach cost/8 hr day
Cost of 03 equipment/day for 10 yr amortization
Savings at 90% bleach recovery
Daily savings = Daily bleach savings - Daily
equipment cost = $25.40 - $2.50 =
Savings/roll @ 800 rolls/day
Source'; Hendrickson & Daignault, 1973a
Tost
$2,000
$ 350
$ 100
$ 550
$ 300
$ 250
$3,000
$ 650
$7,200
$ 28.20
$ 2.50
$ 25.40
$
$
22.90
2.85/roll
TABLE 44. COSTS FOR OZONE DESTRUCTION OF COMPLEX CYANIDES
Equipment
teactor vessel; glass lined steel, 50 gal
fixing tanks, polyester, 50 gal
'ortable mixers, 2 HP rubber coated steel
teating coil, Teflon immersion coil
'umps, corrosion resistant
:ilter presses, plate & frame
)zone generation unit (200 g/hr)
.abor & maintenance (19% of cost)
Total
Cost/Unit
$ 2,000
200
550
1,000
250
1 ,200
14,000
2,480
$
$
$
$
$
$
$
$ 25,680
Daily Chemical Costs
f) Oxygen
2) HC1
3) NaOH
Quantity
200 cu ft
1 liter
1 Ib
Cost
$0.75
$0.30
Daily cost of destruction (equipment amortized 10 years)
increase in cost of processing per roll of film
Source:Hendrickson & Daignault, 1973a
$17.50
$ 0.02/roll
204
-------
TABLE 45. ESTIMATED SAVINGS ON TREATMENT OF FERROCYANIDE BLEACH.
"COMBINED AVERAGE" PROCESSOR
Method of Treatment
Electrolytic Regeneration
Ozone Regeneration
Ozone Destruction
Acid Chi ori nation
Alkali Chi ori nation
Daily Savings,
$/roll
0.029
0.0285
-0.022
-0.020
-0.075
)aily Saving = Daily Bleach Savings - Daily Costs of Equipment-
usinq 10 year amortization
Source: Hendrickson & Daignault, 1973b
The larger generator distributes ozone to 3 tanks which hold the over-
flows from the various photoprocessors, plus desilvered waste fixing solutions.
In these wastewaters, organic constituents plus easily oxidized inorganic
components (thiosulfate, sulfite, etc.) are destroyed before discharge of
the wastewaters to the local municipal sewer system.
Hendrickson (1975) has reviewed the applications of ozonation in the
treatment of photoprocessing wastewaters, and has cited case histories of
several operational photoprocessors who have installed ozonation equipment.
Ozone is used to regenerate ferricyanide bleach and to destroy complex
cyanides and other waste materials (organics, thiosulfate, sulfite).
In 1971, Photographic Corporation of America, Matthews, North Carolina,
installed a 100 g/hr ozonation system to lower the oxygen demand of its
wastewaters and/or to recover ferricyanide bleach for reuse. Ozone is
sparged through 100 micron ceramic diffusers and destroys the metal chelating
capability of EDTA present. The same ozonation system also is used to
regenerate bleach solutions. In 1973 the ozone generation capacity at this
plant was doubled so as to handle the increased volume of processing. Ozone
output can be varied from 20 to 200 g/hr at 0.75 to 1.5 weight % in dried
air. The total cost of this ozonation system at its current output capacity
of 200 g/hr is $42,000 — and this cost should be returned, through bleach
recovery, in about 5 years (Hendrickson, 1975).
The Berkey Photo system at Fitchburg, Massachusetts (Hendrickson &
Daignault, 1973a, 1973b), has been operational since mid-1971. As of
November, 1973, about 220 consecutive 100-gal batches of the same ferricyanide
bleaches had taken place, which amounted to an annual savings of about
$9,000. The 2 ozone generation units at Berkey Photo cost approximately
$41,000 (excluding installation), and the system should return its investment
in about 5 yrs, based upon recovery of ferricyanide bleach alone.
CBS Television News, New York, N.Y. processes between 100,000 and
200,000 ft of 16 mm film per week. In 1971 an automated ozonation system
was installed. When the photoprocessor is turned on, the ozone generator
205
-------
ro
o
cr>
SL A
Spent
Bleach
.Solutions
A A
A
Processor
Overflow
Wastes
(Cone. Only)
Mix Room
Waste
From T-4
(Overflow From Ag
Recovery Unit)
0-2
To Sanitary
Sewer
Key: 1-Black 5 White Paper Processor
2,4,5-Ektacolor Paper Processor
3-Ektachrome Paper Processor
6-Black $ White Film Processor
7-Ektachrome Film Processor
8,9-Kodacolor Film Processor
Regenerated Bleach *^
~ Recycle to
Mix Room
T-5 thru T-9 - 250 Gallon Holding Tank
T-10, T-ll - 55 Gallon Holding Tank
0-1, 0-2 - OiPAC Ozone Generators
Source: Hendrickson & Daignault (1973a)
Figure 16. Flow diagram of bleach regeneration system and concentrated waste oxidation system at
Berkey Photo, Fitchburg, Massachusetts.
-------
automatically pumps ozone to the waste treatment tank to destroy concentrated
waste overflows from the film processing machine. When the processing
machine is turned off, the ozonator operates automatically until the waste
is completely destroyed and then shuts down, unless the spent bleach tank is
full. In this instance, ozone is directed to that tank for bleach regenera-
tion, prior to automatic ozone generation shutdown. This equipment has paid
for itself in less than 2.5 yrs (Hendrickson, 1975).
JSOR-TV, Nagano City, Japan, processes 80,000 ft/month of 16 mm tele-
vision movie film. In late 1972 an ozonation system was installed to pretreat
photoprocessing wastewaters before discharge to a biological treatment
lagoon. Before the ozonation system was installed, effluent from the aerated
lagoon had a BOD-5 of 1500 mg/1. With ozonation installed, the effluent
BOD-5 now is about 12 mg/1, and all iron, cyanide, zinc, silver and cadmium
concentrations are within local discharge concentrations. The total invest-
ment for the ozonation system and biological lagoon was $34,000. Annual
savings generated are approximately $6,000/year, resulting in a total payoff
time for this installation of about 6 yrs.
Hendrickson (1975) concludes that for bleach regeneration only, a
properly designed ozonation system will return its entire investment in
approximately 24 months. For both chemical recovery and waste treatment,
the ozonation system will return its investment in .60 months (5 yrs).
Bober & Dagon (1974) compared ozone regeneration of spent ferricyanide
bleach with persulfate regeneration. Appreciable salt buildup, commonly
resulting from the traditional persulfate treatment process, is eliminated
by use of ozone. For a photoprocessing lab operating 5.5 days/week, a total
of 465 Ibs of sodium ferrocyanide would have to be regenerated. This would
require 224 Ibs of potassium persulfate or 39 Ibs of ozone, assuming 100%
efficiency in both cases.
Capital costs for ozonation were estimated at $18,700 (1970 prices,
exclusive of installation) and operating costs are $650/yr. Persulfate
operating costs are $4,070/yr, at 20<£/lb for persulfate. The cash flow rate
of return for the ozonation system was estimated to be 9%/yr.
These authors concluded that ozone can be used economically to regenerate
bleaches from Kodachrome film process K-12 and Ektachrome process CR1-1, but
that the high capital costs for ozonation equipment make it uneconomical for
treating other bleach baths. Malfunction of equipment was not found to be a
serious problem.
Some unidentified Japanese authors (Anonymous, 1975) studied the waste
bleaching solutions from 7 Japanese printing and 9 film developing plants.
Heat decomposition reduced cyanide concentrations to less than 0.5 mg/1.
Electrolytic oxidation of COD was unsatisfactory, removing only 11% of the
COD. Ozone oxidation attained 74% COD removal only if the COD content was
low, but removal efficiency decreased with increasing COD content. BOD and
COD could be removed at 100% efficiency by the combustion method, but this
forms sulfur oxides, and results in secondary pollution problems.
207
-------
Treatment of Organic Components
Bober & Dagon (1975) report a detailed study of the ozonation of
organic constituents of photoprocessing wastewaters. Although most of the
organic chemicals found in these wastewaters are biodegradable, certain
color developing agents are biorefractory, and conventional biological
treatment has little effect on their removal. The objectives of this study
were to determine if:
(1) ozonation can be used in place of biological treatment,
(2) the use of ozone as a tertiary treatment (disinfection after biological
treatment would be applicable,
(3) the use of ozone to selectively treat individual processing solutions
would be practical.
Bober & Dagon (1975) studied the ozonation, in detail, of solutions of
more than 25 individual processing chemicals and several photoprocessing
effluents. They concluded that ferro- or ferricyanides cannot be destroyed
effectively with ozone, but ozone can be used to regenerate ferricyanide
bleach solutions. Also, ozonation is not an effective substitute for
biological treatment. Thiosulfate, acetate, sulfite, hydroquinone and
benzyl alcohol respond well to biological treatment.
Ozonation of solutions of ethylene glycol produced 30 to 35% reduction
in COD content in 4 hrs, but had no effect thereafter during an additional
20 hrs. Hydroxylamine sulfate was easily attacked by ozone, 70% of the COD
being destroyed after 6 hrs of ozonation. The COD of a solution of benzyl
alcohol was 90% destroyed after 24 hrs of ozonation. No reduction in COD
content was observed after 24 hrs of ozonation of acetate. Thiosulfate
solutions (3 to 10 g/1) were 70% to 80% oxidized after 8 hrs of ozonation,
and 95% in 14 to 24 hrs. Sulfite was 100% oxidized in 1 hr of aeration,
without the need for ozone.
Color developing agents produced some spectacular color changes upon
ozonation. The material CD-3 (4-amino-N-ethyl-N-[3-methanesulfonamidoethyl]-
m-toluidine) turned from a pale pink to opaque purple, then scarlet within
15 minutes, then to a deep yellow, then orange, then lemon yellow, then to
creamy off-white, and then colorless. After 8 hrs of ozonation, the COD had
decreased 60% and then became stable to further ozonation.
The COD level of a 1 g/1 solution of CD-I (N,N-diethyl-p-phenylene-
diamine.HCl) was reduced 70% after 43 hrs of ozonation. Similarly, the COD
level of CD-2 (2-amino-5-diethylaminotoluene.HCl) was reduced 60% after 8 to
16 hrs of ozonation. The COD level of CD-4 (4-amino-3-methyl-N-ethyl-N-[3-
hydroxyethyl]aniline sulfate) was reduced 65% in 8 hrs of ozonation, after
which the COD content remained constant.
Glycine was unaffected by ozonation over 24 hrs. Hydroquinone was 60%
to 70% decomposed in 8 hrs and 95% decomposed in 16 to 24 hrs. The pH
dropped from 10 to 4 during the course of ozonation, probably because of
208
-------
the formation of organic acids (oxalic, formic, maleic, etc.). The COD of a
solution of Elon (p-dimethylaminophenol sulfate) was lowered 60% to 70%
after 8 hrs of ozonation, but remained constant thereafter.
The chemical pheriidine (l-phenyl-3-pyrazoline) exhibited an initial lag
period upon ozonation, after which there was a rapid decrease in COD concentra-
tions (to about 60%) in 4 to 8 hrs. COD removal then slowed, and 90% was
removed in 23 hrs.
EDTA was slowly decomposed initially (20% decrease in COD.after 14
hrs), then decomposition became rapid (70% COD decrease in 14 to 20 hrs of
total ozonation; 90% after 30 hrs total ozonation). The COD of sodium
formate was 90% removed in 4 hrs of ozonation. This material was not degraded
biologically. The COD of formalin (formaldehyde in water and methanol) was
decreased 50% in 4 to 6 hrs and 85% in 24 hrs. Methanol showed a 37% decrease
in 23 hrs, and KCNS showed greater than 90% decrease in COD in 2 hrs.
Ferrocyanide oxidized to ferricyanide very rapidly, but ferricyanide showed
no significant decomposition after 38 hrs of ozonation (9% in 20 hrs).
After 100 hrs of ozonation, only 30% of the ferricyanide had decomposed.
During ozonation studies with a sparger contacting system, foaming of
solutions caused serious mechanical problems. However, the authors believe
that the foaming can be designed around to minimize its disruptive effects
on the treatment system.
Bober & Dagon recommended regeneration of bleach, the use of squeegees,
silver recovery and installation of a ferrocyanide precipitation system
(using ferrous sulfate) to prevent ferrocyanide from being carried out with
the overflow fix and subsequent wash. Since acetate comprises 52% of the
BOD-5, is biodegradable, but is not readily oxidizable by ozone, biological
treatment should precede ozonation.
Simulated wastewater effluent from the standard ME-4 processor (motion
picture Ektachrome) using ammonium rather than sodium thiosulfate contains
4,700 m,g/l COD. Ozonation of this waste for 4 hrs provided 41% decrease in
COD concentrations (3 liters of ME-4 waste treated with 1.5 g/hr of ozone).
Finally, Bober & Dagon (1975) ozonized 3-liter samples of effluent from
an activated sludge system treating photoprocessing wastes solely. Samples
were ozonized 5, 10, 15, 30 and 60 minutes (1 liter/min gas flow; 1.5 mg/l/min
of ozone) and obtained complete disinfection in 30 minutes. At the same
time, the COD levels dropped from 50 to 30 mg/1. After 1 hr of ozonation,
the COD level of the effluent had dropped to 17 mg/1.
Treatment With Ozone/UV Light
Garrison, Mauk & Prengle (1974, 1975) first described the conjunctive
use of UV light with ozonation and heat for the destruction of complex
cyanides contained in photographic processing wastewaters. Under contract
to the U.S. Air Force Weapons Lab at Kirtland Air Force Base, New Mexico,
209
-------
these investigators at Houston Research Inc., Houston, Texas, studied the
destruction of both electroplating and photoprocessing wastewaters with the
ozone/UV/heat system. Treatment of electroplating wastewaters by these
techniques already has been discussed earlier in this section. Ozone/UV
treatment of pink waters from TNT manufacturing has been described earlier
in this section, under Organic Chemicals.
A laboratory-scale semi-batch reactor (Figure 17) was designed, fabrica-
ted and operated to obtain data from which ozone mass transfer constants,
ozone decomposition constants and reaction rate constants were obtained.
From these data, a continuous pilot-scale, multi-staged reactor was designed
(Figure 18) which was fabricated and used to treat actual photographic
bleach and photographic fixer wastewaters which contained high cyanide
concentrations. In all cases, the concentrations of cyanide in the final
effluents were below the limits of detection.
Preliminary oxidations using 3% ozone without added UV radiation lowered
the cyanide concentration in a diluted fixer bath from 5.8 mg/1 to 0.4 mg/1
in 4 hrs of ozonation (2.42 1/min of 3% by weight ozone — 103 mg/min), and
the initial pH dropped from 7.6 to 3.9, due to the formation of sulfurous
acid from oxidation of the thiosulfate. Ozonation of bleach (also 6 mg/1
initial cyanide concentration) under similar conditions lowered the cyanide
concentration to 1.3 mg/1 in 7 hrs of ozonation. However, conversion of
ferrocyanide to ferricyanide occurred during the first few seconds of this
run (by visual observation of color change).
At a higher cyanide concentration (665 mg/1), bleach waste was ozonized
using 1.3 weight % ozone (18 mg/min) and gave appreciable cyanide destruction
(about 300 mg/1 in 11 hrs of ozonation), but the weight of ozone required
per weight of cyanide destroyed was large. The fact that about one-half of
the cyanide was destroyed in 11 hrs using this high speed agitation ozone
reactor should be compared with the results obtained by Bober & Dagon (1975)
who used a sparger contactor and decomposed only 9% of the ferricyanide
after 20 hrs of ozonation with 1% ozone in air.
Addition of cupric ion to the 665 mg/1 cyanide bleach solution after 26
hrs of ozonation did not have any effect on the oxidation rate.
A full strength bleach waste, containing 73,000 mg/1 of cyanide was
ozonized at a rate of 1 liter/min with 1.2% by weight ozone (16 mg/min).
Cyanide concentration decreased by 40,000 mg/1 during the first 600 hrs of
ozonation. After 1,600 hours of ozonation, the cyanide concentration was
1.8 mg/1.
Maximum reaction rates of these cyanide-containing wastewaters occurred
at pH 7.0. The initial reaction rates were much faster when higher ozone
concentrations in air or oxygen were used. No improvement in reaction rate
was observed upon filtration during ozonation, upon addition of copper or
silver ions as catalysts, or whether the ozone was added in air or oxygen
(as long as it was at the same concentration in the gas phase and added at
210
-------
Variable
Speed
Mixer
Exhaus t
UV Light
Semi-Batch Reactor
(5.85 liter
capacity)
Gas
i t
Temperature
Control
pH Monitoring
Ozone
Meter
Vent
22 KI
Solution
Vent
Ozone
Generator
I
Source: Garrison, Mauk &
Prengle (1974)
Air
Oxygen
Figure 17. Schematic diagram of lab scale apparatus for mass transfer and
reaction kinetics tests ozone/UV.
211
-------
mixer (1/3 HP, 420 RPM)
Source:
Garrison, Mauk
& Prengle
(1974)
. •». ">. «^
Feed
Tank
r
First o
Stage^
Second
Stage
Exhaust
Cas
Third
Stage
i_i
i_i_
Temperature
Control
pH Monitoring
Temperature
Control
pH Monitoring
Temperature
Control
pH Monitoring
Ozone
Pump
15 gala/day
treated water
Ozone
Generator
Figure 18.
Schematic diagram of prototype cyanide disposal system based on
ozone/UV treatment.
212
-------
the same flow rate).
than those at 25°C.
However, reactions conducted at 65°C were much faster
A UV light shined on top of the liquid being ozonized caused some
increase in reaction rates, but substantially faster reactions occurred when
the UV bulb was totally immersed in the aqueous medium being ozonized. The
UV light source used drew 4 watts and produced 253.7 nm wavelength UV light.
Using this combination of UV with ozone at various concentrations (from 1%
to 5% by weight) in the carrier gas, substantial increases in cyanide destruc-
tion rates were obtained. For example, the initial reaction rate of 1%
ozone with UV light in a solution containing 53 mg/1 of bleach cyanide was
about equal to that obtained with 5% ozone without UV light, until a cyanide
concentration of about 16 mg/1 (70% conversion) was obtained, after which
the reaction rate with 1% ozone with UV was far superior to that of 5% ozone
without UV (Figure 19).
Studies then were conducted in the continuous flow, prototype reactor
(Figure 20) using dilute, 10 mg/1 cyanide concentrations in photo bleach and
photo fixer baths (Runs P-l and P-2, Table 46). The feed rate was 20 gal/24
hr day, which provided 18 hrs retention time equally divided over the 3
stages. Six 15 watt UV lights were used in each of the 3 stages, and the
electrical heaters were not used. Ozone was generated from oxygen, producing
1.4 Ibs/day of 3.2 wt % of ozone in oxygen. The prototype was operated
continuously on each wastewater for 32 hrs, to allow steady state concentra-
tions to be attained in each stage, before final cyanide sampling for analysis
was made. During the photo fixer runs, additions of small amounts of caustic
to the first stage were required to maintain the optimum pH level of 7. The
second and third stages had steady pH which did not require caustic for its
control. The photo bleach runs did not require pH control in any of the 3
stages.
TABLE 46. OZONE MATERIAL BALANCES IN PROTOTYPE UNIT RUNS
Run Type
No. of
Waste
P-l bleach
P-2 fixer
P-3 fixer
P-4 bleach
Ozone
Charged
(Ibs/day)
1.71
1.71
2.10
2.52
Ozone
Discharged
(Ibs/day)
0.40
0.43
0.54
0.16
Ozone
Consumed
(Ibs/day)
1.31
1.28
1.56
2.36
Original
CN concn
(mg/1)
10
10
700
4,000
Cyanide
Reacted
(Ibs/day)
0.00167
0.00167
0.088
0.501
Source: Garrison, Mauk & Prengle, 1974
Other prototype experiments were conducted using higher cyanide concentra-
tions, in which the gas feed contained 2.4 wt % ozone and was applied at the
rate of 2.1 Ibs/day. For fixer experiments, of the total ozone charged,
0.43 Ib/day was fed to stage 3, 0.43 Ib/day to stage 2, and 1.23 Ibs/day to
stage 1. Five 15-watt UV lamps were used in stage 3, and no UV lamps were
used in stages 1 or 2. The temperature in all 3 stages was maintained at
65°C. The liquid feed contained 700 mg/1 cyanide ion complexed with iron at
a pH of 8.4. The pH of stage 1 was controlled at 7 using NaOH solution (Run
P-3 of Table 46).
213
-------
60
0
O
S5
w
w
Q
JM
O
90
SO
70
60
50
P 40
30
20
10
O 1% Ozone
Q 5Z Ozone
A II Ozone, 12 Watts UV
o 51 Ozone, 12 Watts UV
Source: Garrison, Mauk &
Prengle (1974)
TIME (hours)
Figure 19. Effect of UV light and ozone concentration on ferricyanide at 77°F,
Starting bleach cyanide concentration: 53 mg/1.
214
-------
Nickel Strip
50,000 mg/1 CN~
5 gpm
Water
20 gpm
ro
tn
16,000
gal.
Mixer
160 HP
D
Mixer
160 HP
180 inR/1
2492 scfm
D
16,000
1994 scfm
Oxygen Recycle
0.6 mg/1
16,000
Mixer
/£
308 scfm
if"
-X
UV Lights
145 KW
Treated
Water
190 scfm
Ozone Generator
Dryers
7500 Ib/day
2 wt 2 ozone
1200 KW
Compressor
Makeup Oxygen 63 scfm
ft
125 HP
Source: Garrison, Mauk & Prengle (1974)
Figure 20. Full-size cyanide disposal system based on ozone/UV.
-------
The discharge from stage 3 of the experiment starting with fixer waste
containing 700 mg/1 of cyanide complexed with iron contained no detectable
cyanide (limit of detection: 0.2 mg/1). Cyanide concentration was reduced
to 550 mg/1 in stage 1 and to 70 mg/1 in stage 2. The treated water from
stage 3 contained 625 mg/1 SS, and the effluent was clear and colorless.
A photo bleach solution containing 4,000 mg/1 of cyanide complexed with
iron also was treated in the prototype reactor system. After three stages
of treatment, the level of complexed cyanide had dropped to 700 mg/1.
Therefore, the effluent was reprocessed through the same three stages, but
only after all wastewater had received 3-stage treatment. This gave the
effect of a 6-staged reactor system (Run P-4 of Table 46).
Ozone concentration in the feed gas was 5.9%, and 0.50 Ib/day was fed
to stages 1 and 4 and 0.38 Ib/day was fed to the other 4 stages. Five 15-
watt UV lamps were employed only in stages 5 and 6 and no UV was used in the
first 4 stages. The temperature in all 6 stages was controlled at 65°C.
The discharge from this prototype run contained no detectable cyanide
(limit of detection: 0.3 mg/1). The cyanide concentrations leaving stages
1, 2, 3, 4 and 5 were 2,680, 1,630, 710, 105 and 13 mg/1, respectively.
Approximately 1,900 mg/1 of SS were formed during this run; after filtering,
the resulting liquid was clear and colorless.
During these prototype runs, discharge gases from each run were collected
and the amount of ozone remaining was measured. The difference between the
ozone charged and the ozone discharged was taken to be the amount of ozone
consumed (see Table 46). For the dilute cyanide runs (P-l and P-2) the
amount of cyanide plus other oxidizable components was nearly negligible.
Thus, it appears that most of the ozone "consumed" can be attributed to
decomposition. For the concentrated runs, P-3 and P-4, it is less certain
how much ozone decomposed. For run P-3, fixer, considerable ozone reacted
with the thiosulfate present. But unless ozone also reacted with cyanate,
over one-half the ozone "consumed" might be attributed to decomposition.
More recent studies by Glaze e_t al_. (1977) on ozonizing dilute solutions
of humic acids in water in the presence of UV light have shown that UV
rapidly decomposes ozone. Passage of ozone through pure water develops a
measureable residual of ozone which has a certain stability. In the presence
of UV light, 0 mg/1 of zero residual ozone can be detected in solution. On
the other hand, the power to oxidize humic materials is higher in the solution
which has been treated with ozone and UV than in the solution containing the
residual ozone which was not also treated with UV radiation. Thus the
"decomposition of ozone", apparently without performing useful work, as
observed by Garrison, Mauk & Prengle (1974), might have been the other way
around, i.e., the ozone definitely was_ decomposed by the UV radiation, but
to some species which apparently is a more powerful oxidizing agent than is
ozone itself.
216
-------
Studies pointed at identifying the mechanisms of UV/ozone oxidations
are just beginning, and any further comments at this point would be merely
conjectural.
Garrison, Mauk &'Prengle (1974, 1975) developed the conceptual design
for full scale cyanide disposal systems based on their studies of Air Force
electroplating and photoprocessing wastewaters containing complexed cyanides.
Estimated equipment costs for a 5 gal/min treatment system are $2,481,700,
plus the cost of liquid oxygen storage for generating ozone from oxygen
(Table 47). The major operating cost is 1.35 megawatts of power (probably
per yr), with labor and makeup oxygen being in relatively minor proportion.
A reduced scale system capable of continuously processing 1,000 gal in
five 24-hr days/week, and in which ozone is generated from air, was estimated
to cost $217,000 capital (Table 48). The 3 reactors would each hold 450
gal. The first 2 mixers would have a 5 HP motor and the third would have a
2 HP motor. The third stage would require 4.1 kw for UV light. An 18 HP
air compressor would drive 350 scfm of ambient air through driers into the
ozone generator, which would require 34 kw to produce 210 Ibs/day of ozone.
The first reactor would receive 280 scfm of 1% ozone in air, the second
would receive 43 scfm and the third 27 scfm. The system requires only 2
ozone generators of 105 Ibs/day capacity, but a third generator is specified
as backup. Major operating costs would be 8 man hrs/week labor, 60 kw of
electrical power and $5000/year in replacement UV lights.
TABLE 47. COST ESTIMATE FOR 5 GPM CYANIDE TREATMENT BY UV/OZONE
Item $ OOP
Ozone generators, 9 ea., 840 Ibs/day units @ $120,000 $ 1,080
Gas drying units for recycle @ $40,000 ea. 360
UV lights (tubes only), 8,050 @ 35.35 280
125 HP compressor 30
160 HP mixer, 2 @ $1,700 3.4
64 HP mixer 1
Glass lined reactors, 3 @ $12,000 36
Pumps, 3 @ $500 ea. 1.5
Total Hardware $ 1,791.9
Engineering @ 10% of hardware 179.2
Ozone installation 180
Other installation @ 30% of hardware 105
TOTAL $ 2,256.1
Fee @ 10% of total 225.6
$ Z,481.7
plus cost of liquid oxygen storaoe
Source: Garrison, Mauk & Prengle, 1974
Mauk & Prengle (1976) discuss this same Air Force contract work, but
report data for UV/ozone destruction of ferricyanide bleach solution given
in Table 49.
217
-------
TABLE 48. COST ESTIMATE FOR 1.000 GAL/WEEK CYANIDE TREATMENT WITH OZONE/UV
Item
Ozone generators, 3 ea., 105 Ibs/day units @ $22,000
Gas drying units @ $15,000 ea.
UV lights (tubes only), 500 @ $9.70 ea.
Compressors, pumps, etc. (from 0.7 power rule)
Hardware
Engineering @ 10% of hardware
Ozone installation
Other installation @ 30% of other hardware
TOTAL
Fee @ 10% of total
Uses air, not oxygen
$ 000
66
45
5
6
$ 122
12
60
3.3
$ 197.3
19.7
$ 217.0
Source: Garrison, Mauk & Prengle, 1974
TABLE 49. CYANIDE BLEACH DESTRUCTION WITH OZONE/UV
FERRICYANIDE BLEACH SOLUTION
Item
Total CN, mg/1
CNO, mg/1
Temp., °C
pH
UV light, watts
Liquid flow, 1/hr
Ozone added, g/hr
Source:
Influent
Stage 1
4,000
0
20
—
2.36
--
Effluent From Stage
1
2,680
66
0
2.36
9.45
2
1,630
66
0
2.36
7.18
3
710
66
0
2.36
7.18
4
105
66
0
2.36
9.45
5
13
66
0
2.36
7.18
6
<0.3
47
66
8.9
75
2.36
7.18
Mauk & Prengle, 1976
218
-------
Dougherty et al. (1976) studied the photographic processing subcategory
of the photograpFic point source category for the purpose of developing
effluent limitations and guidelines for existing point sources and standards
of performance and pretreatment standards for existing sources and new
sources, to implement Sections 301(b), 301 (c), 304(b), 304(c), 306(b),
307(b) and 307(c) of the Federal Water Pollution Control Act, as amended.
This subcategory is defined to include commodities listed under Standard
Industrial Classifications (SIC) 7221, 7333, 7395 and 7819. An estimated
95% of all photoprocessing plants discharge their wastewaters to municipal
sewer systems. Regeneration of photoprocessing bleach solutions is recognized
and is specified by EPA as BPTCA for cyanide control in existing plants.
For the 1983 discharge standards requiring application of Best Available
Control Technology Economically Achievable (BATEA) and for New Source
Performance Standards, oxidation of BOD-5 and COD is specified, along with
filtration and ion exchange.
These investigators found 2 plants, one discharging 50,000 gal/day and
the other plant discharging an unknown quanity of wastewaters (out of 237
plants surveyed) which are currently using ozonation to recover and reuse
photographic bleach solutions. The EROS Data Center in Sioux Falls, S.D.
has installed an ozonation system to regenerate used bleach. In addition,
as the tenth of 11 wastewater treatment steps, ozonation in a series of
tanks reduces COD levels from an average of 25,000-mg/l to less than 5,000
mg/1. The ozonized water then is discharged to treatment ponds, which
subsequently reduce the COD to 30 mg/1, ferrocyanide to 0.05 mg/1 and total
silver to 0.006 mg/1.
In reviewing the literature, Dougherty e_t aJK (1976) concluded that the
photoprocessing chemicals could be grouped as shown in Table 50: those
treatable by ozonation, those marginally treatable, and those not treatable.
Only glycine and acetate ion are non-treatable, but both are biologically
susceptible.
Conclusions
1) Ozonation is a commercially practiced technique for regeneration of
spent photoprocessing bleaches, which are composed of iron cyanide
complexes. These complexes are so stable to oxidation by ozone that
spent ferrocyanide bleaches are oxidized upon ozonation only to the
fern*cyanide forms.
2) Savings of 2 to 3
-------
to $9,000 per yr, depending upon system size and amount of photographic
materials processed.
TABLE 50. TREATABILITY OF PHOTOPROCESSING CHEMICALS BY OZONATION
Treatable Chemicals
HAS
Benzyl Alcohol
Color Developing Agent
Thiosulfate
Sulfate
Hydroquinone
Kodak El on Developing Agent
Phenidone
EDTA
Ferric EDTA
Formate ion
Maleic Acid
Eastman Color Print Effluent
Ektaprint 3 Effluent
Flexicolor Effluent
Synthetic Effluent from Combined F
Non-treatable Chemicals
Glycine
Acetate ion
Marginally
Treatable Chemicals
Ethyl ene Glycol
Methanol
Ferri cyanide
Ethylenediamine
Ektachrome ME-4 Effluent
'rocess
Source: Dougherty et al, 1976
4) Hydroxylamine sulfate, benzyl alcohol, thiosulfate, sulfite, hydro-
quinone, phenidine, EDTA, sodium formate, formaldehyde and potassium
thiocyanate all are readily oxidized by ozone.
5) Organic developing agents CD-I, CD-2, CD-3 and CD-4 all are decolorized
upon ozonation, but COD levels are reduced only 60% to 70% over 8 hrs
of ozonation, after which COD levels become constant. This implies
that the original organic molecules are oxidized to simpler organic
materials, but which are more refractory to ozone oxidation.
6) Glycine and acetate ion are not treatable with ozone (for wastewater
discharges), but both of these can be treated biologically.
7) As the tenth in a sequence of 11 wastewater treatment steps in an
operating photoprocessing center, ozonation reduces COD levels from an
average of 25,000 mg/1 to less than 5,000 mg/1. The ozonized water
then is discharged to biological treatment ponds which subsequently
lower COD levels to 30 mg/1.
8) Immersion of UV light bulbs in ozonation reactors increases the rate of
oxidation of components of photoprocessing wastewaters. For example,
1% ozone with UV radiation gave about the same amount of oxidation of
bleach cyanide as did 5% ozone.
9) In a 6-stage ozone/UV reactor, a photographic bleach solution containing
4,000 mg/1 of iron-complexed cyanide, the level dropped to 700 mg/1
after passing through 3 treatment stages. After 6 treatment stages, no
220
-------
cyanide was detected (less than 0.3 mg/1).
10) Estimated equipment costs for a 5 gal/min ozone/UV system designed for
treating photoprocessing or electroplating wastewaters are $2.48 million.
LITERATURE CITED -- PHOTOPROCESSING (PF)*
PF-01 Anonymous, 1975, Kankocho Kogai Senmon Shiryo 10(4):63-74.
PF-02* Bober, T.W. & T.J. Dagon, 1974, "The Regeneration of Ferricyanide
Bleach Using Ozone", Image Technology, Aug/Sept., 19-24.
PF-03* Bober, T.W. & T.J. Dagon, 1975, "Ozonation of Photographic Process-
ing Wastes", J. Water Poll. Control Fed. 47(8):2114-2129.
PF-04* Dougherty, J.H., J.R. Ghia, W.D. Sitman & K.M. Peil, 1976, "Develop-
ment Document for Interim Final Effluent Limitations Guidelines
and Proposed New Source Performance Standards for the Photographic
Processing Subcategory of the Photographic Point Source Category",
Rept. No. EPA 440/1-76/060 1, Group II, July, 1976 U.S. EPA,
Effluent Guidelines Div. , Washington, D.C. 20460.
PF-05* Garrison, R.L., C.E. Mauk & H.W. Prengle, Jr., 1974, "Cyanide
Disposal by Ozone Oxidation", AFWL Report TR-73-212. Final Report
for Period April 1972 - Nov. 1973 (Feb. 1974). U.S. Air Force
Weapons Laboratory, Kirtland Air Force Base, N. Mexico 87117.
PF-06 Garrison, R.L., C.E. Mauk & H.W. Prengle, Jr., 1975, "Advanced
Ozone Oxidation System for Complexed Cyanides", in Proc 1st Int.1 .
Symp. on_ Ozone for Water &^ Wastewater Treatment, R.G. Rice & M.E.
Browning, editors. Tntl . Ozone Assoc . , CYevel and , Ohio, p. 551-
577.
Glaze, W.H., R. Rawley, F. Huang & S. Lin, 1977, "Ozone and Ozone/UV
Destruction of Trihalomethane Precursors and Other Refractory
Organic Compounds in Water", presented at Symp. on Advanced Ozone
Technology, Toronto, Ontario, Canada, Nov. 1977. Intl. Ozone
Assoc., Cleveland, Ohio.
PF-07* Gorbenko-Germanov, D.S., N.M. Vodop'yanova, N.M. Kharina, M.M.
Gorodnov, V.A. Zaitsev, A.N. Koldashov & Yu. M. Murav'ev, 1975,
"Ozonation of Silver-Containing Wastewaters From Enterprises
Producing Photographic Chemicals", Khim. Prom. 2:21-23.
PF-08* Hendrickson, T.N., 1975, "Economical Application of Ozone for
Chemical Recovery & Pollution Control in the Photographic Film
Processing Industry", in Proc. First Intl. Symp. on Ozone for
Water & Wastewater Treatment, R.G. Rice & M.E. Browning, Editors.
Intl. Ozone Assoc., Cleveland, Ohio, p. 578-586.
* Abstracts of asterisked articles will be found in EPA 600/2-79- b.
221
-------
PF-09* Hendrickson, T.N. & L.G. Daignault, 1973a, "Treatment of Complex
Cyanide Compounds for Reuse or Disposal." EPA Report No. EPA-R2-
73-269, June, 1973. U.S. EPA, Washington, D.C. 20460.
PF-10* Hendrickson, T.N. & L.G. Daignault, 1973b, "Treatment of Photo-
graphic Ferrocyanide-type Bleach Solutions for Reuse and Disposal",
J. Soc. Motion Picture & Television Engrs. 82(9):727-731.
PF-11 Lotz, R.E., 1972, "Chemical Wastes Generated by Air Force Photo-
graphic Operations", Air Force Weapons Lab Report No. AFWL-TR-72-
125, Sept. U.S. Air Force Weapons Lab, Kirtland Air Force Base,
N. Mexico.
PF-12 Mauk, C.E. & H.W. Prengle, 1976, Jr., "Ozone with Ultraviolet
Light Provides Improved Chemical Oxidation of Refractory Organics",
Pollution Engrg., Jan., p. 42-43.
222
-------
PLASTICS AND RESINS
Four pertinent publications have been found 'dealing with this category.
Wastewaters treated with include:
Phenol-formaldehyde manufacturing
Synthetic Polymers
Synthetic Leather
Synthetic Rubber
Phenol-formaldehyde Manufacturing
Linevich et al. (1972) discuss the ozonization of wastewaters containing
phenol and formalcTehyde. However, the original article could not be obtained
and the only information at hand in English is a short abstract which notes
that both the phenol and formaldehyde components were oxidized.
Synthetic Polymers
Kwie (1969) reported a laboratory study using wastewaters from an
unidentified synthetic polymer plant. Although the plant product was not
identified, the wastewaters contained unsaturated organics and some sodium
8-alkylnaphthalene sulfonate-2 (SANS) which is very resistant to biodegrada-
tion. Ozone was generated from oxygen and the ozone content of the oxygen
used was 101 to 106 mg/1. Ozone was determined in the inlet gas and in the
contactor off-gases. The contactor was a 100 ml bubbler vessel.
Ozonation just to the point of oxidizing all the unsaturated organics
(which react readily with ozone) lowered the COD content from 3,340 mg/1 to
910 mg/1 and 5,400 mg/1 of ozone was absorbed by the solution in an unspeci-
fied contact time.
An ozonized wastewater sample which had a COD of 1,380 immediately
after ozonation had a COD of 450 mg/1 after 7 days of storage. This is
attributed to the further reaction of aldehydes (initially formed upon
ozonation) with dissolved oxygen to form acids. Biological oxidation of
this ozonized sample is ruled out because of its very high salt content.
In all samples studied, foaming ability, color and odor levels were
reduced upon ozonation. Colloidal orange substances were converted upon
ozonation into an easily settleable sludge. One aromatic ring of SANS was
cleaved during ozonation, but the remaining ring-containing compound was
resistant to further ozonation. Ozonation of SANS did not increase its
biodegradability.
Synthetic Leather
Bauch & Burchard (1970) ozonized the wastewater from an artificial
leather plant in Wuppertal, Federal Republic of Germany. The wastewater
from the plant had been mixed with municipal sewage. Data of Table 51 show
223
-------
TABLE 51. WASTEWATER FROM AN ARTIFICIAL LEATHER PLANT, MIXED WITH SEWER WATER.
TREATMENT WITH OZONIZED AIR: 30 MINUTES. (20 MG OZONE/AIR)
ro
ro
Untreated sewage
after 24 hours of
settling
Sewage after pre-
cipitation by means
of iron chloride
and sodium hydrox-
ide (NaOH) at pH
8.0
Clarified sewage
gassed cold with
air
Clarified sewage
gassed hot with
air
Clarified sewage
treated with ozone
Clarified sewage,
after pretreatment
with C12 & treated
with ozone
Source: Bauch & Burc
Appearance
after pre-
liminary
clarifica-
tion
milky
turbid
clear
yellowish
clear
yellowish
clear
yellowish
clear
yellowish
clear
yellowish
Odor
strictly
of sol-
vent and
amyl
strictly
of sol-
vent and
amyl
strictly
of sol-
vent and
amyl
strictly
of sol-
vent and
amyl
faintly
of phenol
faintly
of ester
Odor
Thresh-
old
1:800
1:700
1:600
1:180
1:20
1:16
KMn04
Con-
sump-
tion
mg/1
950
910
800
620
250
180
BOD -5
mg/1
720
830
790
580
200
120
lleavy
Metals
Zn, Cu
Pb
mg/1
20 mg
Zn
—
—
Volatile
Hydro-
carbons
mg/1
90
80
60
20
not de- no
Phenols
Vola-
tile
Not
Vola-
tile
mg/1
25
28
29
8
t de-
tectable tectable
not de- no
t de-
tectable tectable
hard, 1970.
30
20
19
22
11
5
Petrol -
eum Ether
Soluble
70
32
34
30
24
18
-------
the results obtained. For comparison, data also are given after flocculation
with iron chloride and caustic at pH 8.0, after cold and hot aeration, after
treatment with ozone (30 minutes using 20 mg/1 of ozone in air) and after
pretreatment with chlorine, followed by ozonation.
Ozonation lowered the permanganate number from 950 to 250 mg/1 and the
BOD-5 from 720 to 200 mg/1. Pretreatment with chlorine followed by ozonation
lowered the permanganate number to 180 and the BOD-5 to 120 mg/1, and is
therefore the preferred treatment process.
Synthetic Rubber
Chen & Okey (1977) describe a 10 gpm pilot study using actual wastewaters
from emulsion polymerization of GRS rubber. These wastewaters contain
butadiene, styrene, K rosin soap, detergent, sodium phosphate, caustic,
Cerelose, ferrous sulfate, potassium pyrophosphate, cumene hydroperoxide,
tertiary mercaptans, hydroquinone and N-phenyl-2-naphthylamine. The BOD and
COD of the alum coagulated and settled wastewater from the latex filtering
step were 70 and 365 mg/1, respectively, and were only about 20% biodegradable.
Ozonation was conducted under undefined conditions, except that a
bubbler contactor was employed and flow rates of ozonized air were 1.0 or
1.5 scfm. At the higher ozone flow rate, COD concentration in the plant
effluent was lowered from 365 to 160 mg/1 in 40 minutes. Addition of 360
mg/1 NaHC03 under the same conditions lowered the COD to 85 mg/1 in the same
40 minutes of ozonation. At 1.0 scfm the COD concentration was lowered 47%
and 70% without and with added bicarbonate, respectively. The optimum pH
for ozonation of these wastewaters was 6.0 to 8.5.
Effluents treated with ozone exerted substantial influence on oxygen
uptake, whereas untreated effluents did not. This indicates that ozonation
of biorefractory organic materials followed by biological treatment would be
a better way to treat such organic materials.
Upon ozonation, the distinct odor of butadiene-styrene was replaced by
a milder scent. Turbid solutions became clear and suspended matter settled
within 10 to 20 minutes of ozonation.
Conclusions
1) Wastewaters from a synthetic polymer plant containing SANS and unsatura-
ted organics and ozonized just to the point of oxidizing all unsaturated
organics, lowered the COD content from 3,340 mg/1 to 910 mg/1. One
aromatic ring of the SANS molecule was cleaved during ozonation, but
the remaining ring-containing compound was resistant to further oxidation
by means of ozone.
2) Ozonation of wastewater from a synthetic leather plant, which had been
mixed with municipal sewage, lowered the permanganate number from 950
to 250 mg/1 and the BOD-5 from 720 to 200 mg/1. Prechlorination,
225
-------
followed by ozonation, further lowered the permanganate number to 180
mg/1 and the BOD-5 to 120 mg/1, and is a preferred treatment process
for this wastewater.
3) Ozonation of wastewaters from emulsion polymerization of GRS rubber for
40 minutes at pH 6.0 to 8.5 lowered the COD level from 365 to 160 mg/1
and to 85 mg/1 when bicarbonate was added. Ozonized effluents were
biodegradable, whereas the unozonized effluents were not.
LITERATURE CITED -PLASTICS & RESINS (PL)*
PL-01 Bauch, H. & H. Burchard, 1970, "Experiments to Improve Highly
Odorous or Harmful Sewage With Ozone", Wasser Luft u. Betreib
14(4):134-137.
PL-02* Chen, K.Y. & R.W. Okey, 1977, "Ozone Effect on Synthetic Rubber
Waste Treatment", Industrial Wastes, March/April, p. 46-48.
PL-03* Kwie, W.W., 1969, "Ozone Treats Wastestreams From Polymer Plant",
Water & Sewage Works, Feb., p. 74-78.
PL-04* Linevich, S.N., I.M. Arutyunov, R.M. Siganashvin & V.A. Golos-
nitskaya, 1972, "Ozonization of Phenol- and Formaldehyde-Containing
Wastewaters", Tr. Novocherkassk. Politekh. Inst. 249:12-20 (1972)
Ref. Zh., Khim. (1972). Abstr. No. 201346.
* Abstracts of asterisked articles will be found in EPA 600/2-79- b.
226
-------
PULP AND PAPER
In this category, ozone has been studied for four major purposes:
t Pulp bleaching
• Pulp and paper mill wastewater treatment
• Odor control at paper mills
• Treatment of spent sulfite liquor to generate methane and to grow
yeast
Pulp Bleaching
Although initial studies of the use of ozone for bleaching of paper
pulps were conducted by Dorie & Cunningham in 1913, it has only been during
the past decade that the process has shown promise of becoming commercial
(Abadie-Maumert, Fritvold & Soteland, 1977; Liebergott, 1975). When fluffed
wood pulp is treated with ozone, both the cellulosic and lignin portions can
be oxidized. However, oxidation with ozone never is complete (to produce
C02 and water). In fact, if more than initial oxidation occurs, the proper-
ties of ozone-bleached wood pulps degrade, due to over-oxidation of the
cellulosic and/or lignin portions of the pulp fibers. The key to successful
use of ozone for pulp bleaching appears to involve the judicious selection
of ozonation conditions such that only partial oxidation occurs. This forms
additional oxygen-containing sites on the fibers, and these are capable of
being tightly bonded to each other or to other paper-making ingredients
added later in the paper-making process.
Successful bleaching of wood pulps with ozone would mean that use of
the polluting bleaching agents (sulfite, chlorine, etc.) could be reduced or
even eliminated, thus reducing what today is a severe water discharge problem
in many parts of the world.
The bleaching process with ozone involves passing ozone in the gas
phase (usually in oxygen) saturated with water through fluffed wood fibers.
The fibers are not suspended in water.
Samuelson e_t al_. (1953) showed that the degree of polymerization of
cellulose diminishes appreciably upon exposure to ozone. Initial degrees of
polymerization (DP) of about 1,300 rapidly reach a levelling off DP of just
over 100.
Osawa et aj_. (1963a; 1963b) showed that gas phase ozonation of fluffed
wood pulp using ozonized gas 100% saturated with water degrades the carbo-
hydrate fraction of the wood fiber, without penetrating the cellulose crystal-
lites. The odor of acetic acid was noted.
227
-------
Lantican et_ al_. (1965) showed that ozone in oxygen first degrades the
incrustation on cellulosic walls, then attacks the secondary wall itself,
beginning at the lumen, then progresses slowly through the secondary wall
until it reaches the middle lamella, resulting in pulping of the wood. The
water soluble fraction of wood increases with duration of ozone treatment,
and the cell wall is progressively delignified as ozonation continues.
Katai & Schuerch (1966) showed that the attack of ozone upon cellulosic
fibers follows 2 mechanisms:
(1) A free radical chain mechanism (slow) which forms peroxides,
hydroperoxides, carbonyl and carboxy groups and, presumably,
lactones,
(2) Electrophilic attack which liberates the anomeric carbon of
glucosides via an ozone catalyzed hydrolysis of glycosidic linkages.
Ozonation of several sugars was studied and ozone was found to attack
ketonic, aldehydic and alcoholic groups. At the same time, however, ozonation
of cellulose introduces oxygen atoms into the polymeric structures to form
these same groups, as well as to cause depolymerization of the cellulose and
lignin structures.
Moore e^al_. (1966) studied the gas phase ozonation of wood fibers for
time periods of up to 30 hrs. Significant portions of the hemicelluloses
containing xylose and mannose were found to persist in wood fibers during
the extensive degradation of wood shavings by ozone (in oxygen) in the
presence of cold water under a variety of conditions. Three types of reac-
tions were observed to occur:
(1) Ozonolysis of aromatic and unsaturated structures,
(2) Ozone-initiated chain oxidation of aliphatic functional groups to
yield a variety of oxidized carbohydrate residues,
(3) Hydrolysis of glycoside linkages, with both ozone and proton (H+)
participating as electrophilic catalysts.
Glucose was found to be the wood sugar most resistant to ozone oxidation.
In addition, the average degree of polymerization of the fibers decreased to
250 to 300, before the fiber started to delignify. High water soluble
fraction losses were found under these conditions.
Neimo et al_. (1967) treated bleached pine sulfate pulp with ozone in
the gas phase and found that ozone reacts with the cellulose to form peroxide
and hydroperoxide groups. These slowly decomposed into free macroradicals
by heat treatment (to 80°C). Most of these radicals were found to be located
in the cellulose phase. After ozonation of cellulose, polyacrylamide (1 to
33%} or polyacrylonitrile (1 to 13%) can be grafted onto the cellulose by
these macroradicals.
228
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Ozonation of cellulose by Neimo et_ al_. (1967) gave impaired paper
making properties; however, when grafted with polyacrylamide the paper
making properties were almost restored. The wet breaking length rose, in
fact, to a value 150% above the initial length after grafting.
Ancelle (1966) was issued a patent claiming that when chopped wood pulp
(dry and at pH 6 to 7.5) is ozonized in a stream of air saturated with water
(15.5 mg/1 ozone in the gas phase), a bleached pulp is obtained having
improved whiteness, rupture length, bursting index and tearing index.
Hatekeyama ejt al. (1967) studied the reactions with ozone of the model
lignin compounds vamllyl alcohol and veratryl alcohol in aqueous solution.
The primary oxidation product from each of these model compounds (under
acidic conditions) is a muconolactone methyl ester. In both cases the
aromatic ring was opened, Demethylation also occurred in the position para
to the side chain. Under alkaline conditions the reactions were faster
(Figure 21). These authors concluded that when free hydroxyl groups are
present on aromatic rings, the ring will open upon ozonation, producing
muconic acid derivatives, then maleic and/or oxalic acid derivatives.
CH2OH
CH2OH
vanillyl
alcohol
veratryl
alcohol
OCH0
/
V
°3
^
°3
f
°3
flOH
COOH
COOH
muconolactone
HOOC-COOH (oxalic acid)
Figure 21. Ozonation of model lignin compounds.
229
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Katuscak e_t aj_. (1971a) studied the ozonation of various lignins.
Methanol lignin, HCl-lignin and diazomethane methylated HCl-lignin were
ozonized either as the dry solids or suspended in protogenic solvents
(water, acetic acid or methanol). The objective of this work was to prepare
lignin containing as many hydroperoxide groups as possible. Methanol lignin
ozonized fastest of the three, and oxidation occurred faster in acetic acid.
The ozonized lignins were capable of initiating polymerization of unsaturated
monomers by free radical reactions.
In later work, Katuscak et al_. (1971b) studied the ozonation of low
molecular weight methanol lignin in greater detail. Ozonation increased the
active and total oxygen contents, decreased molecular weight, formed carbonyl
groups and attacked aromatic rings. Bleaching took place within about 10 to
15 minutes of the start of ozonation with methanol lignin in the dry state
and no further color change occurred. Molecular weight reduction was fastest
during the first five minutes of ozonation. The number average molecular
weight dropped from 1,700 to 800 in 5 minutes, then dropped to 550 after 1
hr of ozonation. Aromatic rings were destroyed and carbonyl content increased
within the first 5 minutes of ozonation. These authors concluded that since
the active oxygen in the ozonized lignin initiated radical polymerizations,
the active oxygen must be in the form of hydroperoxides, since ozonides and
quinonoidal structures cannot initiate this type of polymerization.
In Canada, studies of the bleaching of mechanical pulps with ozone have
been described by Liebergott (1969), Clayton, Liebergott & Joachimides
(1971) and Liebergott (1975). In 1969, Liebergott found that addition of
0.2 to Q.6% H202 to groundwood pulp, followed by treatment with 1% ozone in
air increased the brightness of the bleached pulp 4 to 9 points, and also
gave substantial increases in textile and bursting strengths. The ozonation
technique was applied successfully to 6 representative stone and refiner
groundwood pulps.
In 1971, Clayton, Liebergott & Joachimides confirmed that the new
process improved the strength of mechanical pulps, and that the ozone-
bleached mechanical pulps could be used in newsprint furnishes, with a
corresponding reduction in the amount of chemical pulp normally added. This
would reduce the amount of chemical pulp required by the newspaper industry,
thereby reducing the amount of pollution in aqueous discharges from chemical
pulp mills using zinc hydrosulfite bleaching.
Finally, in 1975, Liebergott described the results of continuous run
pilot plant operation of the PAPRIZONE pulp bleaching process. Groundwood
is sprayed with ^02, then ozonized in the gas phase to produce a bleached
mechanical pulp suitable for incorporation into newsprint furnishes. The
mechanical pulp is adjusted to 30 to 40% consistency, fluffed to form loose
fiber aggregates, sprayed with 4 Ibs of H202/ton of pulp, then treated with
4% ozone (in oxygen) (20 Ibs of ozone/ton of pulp). Following ozonation,
the material is retained 15 to 30 minutes before further processing. This
treatment leads to improved breaking lengths, improved burst factors, improved
brightness and lowered opacities. Liebergott (1975) concluded that even if
230
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ozone were to cost 50
-------
Fritzvold & Soteland (1977). The results of laboratory studies at NIPR on
bleaching mechanical and chemical pulps have been so promising that five of
the largest Norwegian paper companies and a mechanical engineering company
have collaborated in the construction of this demonstration plant.
The plant capacity is 200 kg of pulp processed/hour with 6 kg of ozone
produced from oxygen. The plant is located at an existing paper pulp factory
so that the products can be blended and/or used to produce papers in produc-
tion lots and in commercial equipment. The plant has been operational since
May 1976. Newspapers have been prepared from ozone-bleached pulps without
the use of chemical pulp.
NIPR personnel apparently are concerned now only with the quantities of
ozone which will be required if the ozone bleaching process is adopted by
the Norwegian paper industry. For example, a newspaper pulp production
plant producing 250,000 tons/year could replace 30% of its chemical pulp
(75,000 tons) with thermomechanical pulp prepared by ozone treatment (using
2% ozone in oxygen). This 75,000 tons/year of ozone bleached pulp would
require 1,500 tons/year of ozone, or 5 tons/day. For a sulfate bleaching
plant producing 300,000 tons/year the pulp would require treatment with 0.8%
ozone. This equates to 2,400 tons of ozone/year or 8 tons/day (Abadie-
Maumert, Fritzvold & Soteland, 1977).
These quantities of ozone are very much within the current capabilities
of the companies which manufacture ozone generation systems. For example,
the city of Montreal, Canada is installing a new drinking water treatment
plant which when completed in the early 1980s will be capable of generating
15,000 Ibs of ozone per day from air in 1% concentration. This will be the
largest drinking water treatment plant in the world at that time to use
ozone (Miller ejt aj_., 1978). If oxygen were to be used as the feed gas in
the Montreal ozone generators, the ozone generation capacity would be doubled
to 30,000 Ibs/day (15 tons/day).
In the United States, ozone bleaching of wood pulps was first reported
by Secrist & Singh (1971). In 1974 a news release (Anonymous, 1974) announced
that successful demonstration of ozone bleaching of hardwood pulps on 15
ton/day scale had been conducted at the Scott Paper Company, Muskegon,
Michigan plant. The economics as well as the pollution abatement potentials
of the ozone bleaching process "appear to make the process an attractive
alternate for conventional hardwood bleaching". To date, however, full
scale commercial adoption of ozone bleaching has not yet been announced.
Wastewater Treatment
Experiments to eliminate or reduce pollution-causing components in
wastewaters from the pulp and paper industry did not begin seriously until
the early 1970s. Huriet & Gelly (1970) patented a process for totally
decolorizing kraft black liquors using ozonized air in aqueous media, the
concentration of ozone in the air being controlled as a function of color
intensity. The ozonation step preferably should follow partial color removal
using lime.
232
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In the laboratory, Tyuftina (1971) applied ozone to residual liquor
from yeast cultivation before and after biological treatment. In both
cases, a reduction in color intensity was obtained. The best results were
obtained by ozonation of the residual liquor at 37°C in an alkaline medium
-- the reduction in color intensity was 84.5% at an ozone consumption of
3.24 g/1. Treatment of purified residual liquor with 0.2 g/1 of ozone
reduced the color intensity by 78%.
Buley (1973) discussed the coming application of high purity oxygen to
numerous process applications in the pulp and paper industry, and also
discussed the potentials of ozonation in treating pulp mill wastewaters.
Furgason e_t a_L (1973) describes a potable test unit for treating
liquid materials with ozone. Basic characteristics of the unit include:
Reactor Volume 2 gal
Reactor Residence Time 1 to 20 min
Wastewater Feed Rate 0 to 1.5 gal/min
Ozone Production Rate 12 g/hr
Contacting is by Venturi nozzle (vacuum injection) so as to have the
unit size as small as possible and still have good mass transfer of ozone to
the liquid phase. Ozone is prepared from oxygen and contactor off-gases are
passed through a molecular sieve column (to destroy excess ozone) before
discharging to the atmosphere.
Extensive field work using this portable test unit was reported (Furgason
ejt a_l_., 1973) on kraft pulp mill effluents, which are dark brown, pungent
wastewaters. Contaminating materials originate from lignin and its deriva-
tives, which are complex organic molecules containing phenolic structures
and other configurations which are not easily biodegraded. Therefore,
wastewaters from a pulp mill can pass through normal primary and secondary
treatment facilities without the color and odor being significantly reduced.
In fact, color may become even worse (Furgason ejt al_., 1973).
Effluents from the Potlach Forests kraft mill at Lewiston, Idaho were
treated with ozone (Furgason, Smith & Harding, 1973). Wastewaters from the
bleach plant, total plant, primary clarifier and extended aeration secondary
system were tested with ozone. Little differences were noted between the
ozonized streams with regard to color, odor, and COD removals. Therefore,
the bulk of the ensuing data were taken on the primary clarifier output
material with the following results:
The color of the sulfite liquor changed dramatically from a dark
chocolate brown to light straw yellow after about 5 minutes in the reactor.
During this time, the strong sulfur-laden odor disappeared entirely. Also
during this time, COD removal usually was 10 to 15%, but occasionally rose
to 30%, even though less than this amount of COp was formed. This suggested
to Furgason ejt al_. (1973) that ozone should not be used as a post- or tertiary
treatment, but should precede secondary biological treatment.
233
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These tests with ozonation of kraft mill wastewaters definitely estab-
lished the utility of ozone as a decolorizing or deodorizing agent. Prelimi-
nary estimates indicated that ozonation costs for a full scale plant would
be in the range of 30<£/1,000 gal.
Nebel, Gottschling & O'Neill (1974) reviewed the decolorization of pulp
and paper mill secondary effluents by chemical coprecipitation, adsorption,
reverse osmosis and chemical oxidation with KMnOd, Ho02, chlorine and ozone.
Experiments were conducted on pulp and paper mills from four unidentified
plants using ozone generated from air or oxygen. Contacting was conducted
in a 6.5 inch I.D. x 10 ft column using porous plastic (type not specified)
diffusers. Ozone was analyzed at the entry and at the exit of the contactor.
Since normally no ozone was found in the off-gases, the authors concluded
that the numerical amount of ozone dosed to the contactor was the amount of
ozone absorbed by the secondary effluent. Color was determined by the NCASI
(National Council of the Paper Industry for Air and Stream Improvement)
procedure at pH 7.6 and 465 nm wavelength. Results obtained on each plant
effluent are discussed below.
Plant A: this was a kraft mill producing fine papers. To remove color from
520 to 100 APHA units in the wastewater required 70 mg/1 of ozone dosage.
This ozone dosage also produced a 37% reduction in COD values (298 to 188),
98% total bacteria removal (240,000/100 ml to 4,900/100 ml) and 93% total
coliform removal (24,000/100 ml to 1,600/100 ml).
Plant B: also was a kraft mill producing fine papers. The ozonation
objective at this plant was to reduce color levels from 900 APHA units to
200, and this required 81 mg/1 dosages of ozone. At the same time, this
dosage of ozone provided 29% reduction in COD values (248 to 176 mg/1) and
lowered turbidity by 50% (950 to 479 JTU).
Plant C: was a bleached board plant using kraft and neutral sulfite pulps.
To reach the goal of 200 APHA units (from 1,600) required 143 mg/1 ozone
dosages, which also lowered turbidity 67% (620 to 207 JTU), COD by 21% (275
to 217 mg/1), BOD by 16% (147 to 124 mg/1), total bacteria 99% (130,000,000
to 1,180,000) and fecal streptococci 100% (40 to zero). During ozonation of
Plant C effluent, the BOD was found to decrease initially upon ozonation,
then increased to a peak value corresponding to an ozone dosage of 143 mg/1
(Figure 22). This is the same dosage which removes the maximum amount of
color. Therefore, the color of this effluent is associated with the COD and
not the BOD.
Plant D: is a paper mill making paperboard from reclaimed paper. There is
no pulping operation at this plant. Six samples were ozonized, 3 of which
contained dyes and required the highest ozone dosage levels (29 mg/1) to
reduce color levels to 50 APHA units (from 170). At the same time, COD
levels were reduced 51% (67 to 33), turbidity was lowered 63% (230 to 85
JTU), tannin and lignins were 67% removed (3.3 to 1.2 mg/1) (note: original
article says 33% removal) and total coliforms were 99.99% removed (20,700 to
2/100 ml). This same wastewater required 150 mg/1 of chlorine to achieve
234
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the same level of color removal. Costs for chlorination of 2.5 mgd (@
5.25<£/lb for chlorine) were $164.50/day, whereas, ozonation costs were $48.40,
including amortization, with ozone being generated from air.
PLANT C - pulp and paper mill producing
bleach board
Source: Nebel, Gottschling &
O'Neill (1974)
Q
O
CO
100
100 200 300
ozone absorbed, mg/1
Figure 22. Reduction in BOD values by ozonation.
Table 52 shows the estimated daily operating expenses and capital
investments required to attain the color removal objectives (using ozone) at
the 4 plants, and Table 53 shows the treatment costs/1,000 gal at these
plants using ozone.
TABLE 52. DAILY OPERATING COSTS & CAPITAL INVESTMENT
Plant
A
B
C
D
Source:
Daily Ozone
Requirements
8,750 Ibs
10,800 Ibs
29,780 Ibs
605 Ibs
Feed Gas to
Ozone Genera-
tors
Oxygen
Oxygen
Oxygen
Air
Daily
Operating
Expense
$ 393.75
$ 486.00
$1,340.10
$ 48.40
No. of 1 Capital
Ozone 1 Investment
Generators for Ozone
1 Generators
4 $315,000
5 $372,000
14 $976,000
1 $ 95,000
Nebel, Gottschling & O'Neill, 1974.
235
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TABLE 53. OZONE TREATMENT COSTS
Plant
A
B
C
D
Source:
Capital Investment
for Ozone Genera-
tors
$315,000
$372,000
$978,000
$ 95,000
Installed
Cost
$ 378,000
$ 446,400
$1,173,600
$ 114,000
Annual Debt
Retirement
$30,220
$36,370
$96,180
$ 7,706
Cost per
1,000 gal
3.1*
3.2*
6.4*
2.8*
Nebel, Gottschling & O'Neill, 1974.
These data were obtained by applying ozonation after secondary treatment.
The additional advantages of disinfection, COD and BOD removals and turbidity
reductions also are obtained upon ozonation for the primary objective (color
removal), at least partially. Also, since the DO content of the wastewater
is greatest after ozonation, a reaeration step will not be required. The
authors also point out that using ozonation processes for color removal in
these types of effluent will not result in sludges being formed during this
treatment step.
Moergli (1973) reported on the treatment of paper and board mill
effluents by flocculation, followed by filtration (to remove 95% of the SS,
then ozonation, which reduced levels of dissolved organic materials by 55%
and was "very effective" in color removal. Further treatment with activated
carbon reduced the SS content to 1 mg/1 and permanganate consumption to less
than 60 mg/1, producing a water which could be recycled.
Kamishima and Akamatsu (1973,1974) attempted to improve color removals
after activated sludge treatment of alkaline extracted effluents from the
bleaching of kraft pulp. Ozonation of the effluents resulted in improved
removals of TOC, COD, lignin and color, compared with conventional activated
sludge treatment. Subsequent activated sludge treatment of the ozonized
effluent showed "adequate" BOD removal. Activated carbon adsorbed very
little lignin from the ozonized effluent.
Watkins (1973) studied coliform bacteria growth and control in aerated
stabilization basins. The majority of this study involved chlorination of
secondary treated effluents from the Crown Zellerbach plant at Camas, Washing-
ton. A small section of this report was devoted to "Evaluation of Miscellane-
ous Bacteriocides" -- ClO^, NaOCl and ozone.
In the ozonation studies an ozone generator was used which generated
ozone from oxygen. Secondary effluent was passed through a rubber hose (1.5
inches I.D.) which contained an ozone sparger and was used as the ozone
contactor. Ozone dosage rates were calculated from the output of the ozone
generator. Reactions between the effluent and ozone were "monitored" by
smelling the treated wastewater for ozone. "Since ozone at concentrations
of 0.1 mg/1 or less can be smelled -- the absence of an ozone odor was
considered to be evidence that most, if not all, of the applied effluent had
reacted with the effluent".
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Apparently Watkins was unaware that ozone reacts very rapidly with
rubber and with plasticizers for rubber and plastics. Therefore, with this
rubber hose ozone contactor, very little dosed ozone would be expected to
survive for reaction with effluent constituents.
The original ozone concentration was 0.46 mg/1 and the flow rate of gas
through the ozone generator was adjusted so that the applied dosage of ozone
was varied between 0.46 and 4.6 mg/1. After 30 minutes of treatment under
these conditions, Watkins found no effect upon bacterial motility and no
reduction in the concentration of bacteria.
Watkins then increased the rate of oxygen flow through the ozone
generator by 5 times, in an attempt to increase the ozone dosage to 21 mg/1.
However, no mention is made of increasing the power applied to the ozone
generator as the oxygen flow rate was increased. If power were not increased,
then the total amount of ozone generated in five times the gas volume would
be slightly more, but the concentration of ozone in that increased volume of
gas would have been lowered considerably.
Thus the results of Watkins (1973) should be disregarded as meaning-
less.
Smith & Furgason (1976) studied the effect of ozonation on the ability
of microorganisms to biodegrade kraft pulp mill liquid wastes. Four different
examination procedures were utilized. First, oxygen uptake rate experiments
were conducted in a 1,600 ml system using full strength, undiluted pulp mill
wastewater. These tests illustrated the combined effects of biodegradability
and toxicity upon biological treatment of both non-ozonated and ozonated
waste materials. Then oxygen uptake rate studies were made on diluted
wastewater in 300 ml bottles. Dilution eliminated the effects of toxicity
and allowed examination mainly of biodegradation. Two extended aeration
biological systems, one treating ozonated waste and the other treating non-
ozonated waste, were examined in a small pilot plant system. Finally, NMR
(nuclear magnetic resonance) spectra of the original and ozonated wastes
were examined to determine changes in the basic chemistries of the wastewaters
due to ozonation.
Wastewaters from the Potlatch Corporation kraft mill at Lewiston, Idaho
were studied. The materials were ozonized in simple batch diffusion, with
ozone concentrations being measured at the entrance and exit of the contact
column (contactor details are not given). From the difference in ozone
concentrations before and after, the gas flow rates and times of contact,
ozone utilizations (usually 190 to 800 mg/1) were calculated for each sample.
The pH of the raw wastewaters (3 to 3.3) was adjusted to 7 to 7.5 before a
run was made. Activated sludge cells were acclimatized to the waste before
measuring oxygen uptake at 2,000 to 3,000 mg/1 of mixed liquor suspended
solids (MLSS).
Results of the oxygen uptake studies showed that ozonation of full
strength raw wastewater increased its biodegradability. However, ozonation
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of the diluted wastewaters produced little change in biodegradability.
Therefore, Smith and Furgason (1976) concluded that the original inhibition
of biodegradability of the full strength wastewater is caused by toxic
components, which are destroyed by ozonation and/or are rendered less toxic
upon dilution.
During extended aeration studies comparing ozonated and non-ozonated
kraft mill wastewaters with normal sewage being treated by activated sludge
organisms, in every category (MLSS, BOD and COD removals and in sludge
volume indices) the ozonated wastes were more biodegradable than the non-
ozonated wastes. The differences were not large, however, and were of about
the same magnitude as those obtained during the oxygen uptake studies. In
nearly every measure, the normal sewage system was much more biodegradable
than either the ozonated or non-ozonated pulp mill waste.
The NMR spectra taken of the non-ozonated and ozonated wastes showed
that the major peaks remained unchanged, except for one peak which was
absent after ozonation. This peak could have been due to a Cl or S group,
either of which would have had a distinct toxic effect upon the biodegra-
dation of the waste material.
Smith and Furgason (1976) concluded that since ozonation reduces color
by about 70 to 80%, eliminates noxious odors and destroys inherent toxicity
of full strength kraft pulp mill wastewaters, rendering them more biodegrad-
able, it would be advantageous to have the ozonation treatment step incor-
porated prior to a biological treatment step. Prolonged ozone treatment is
required in order for the ozone to actually sever the lignin molecules and
break them into much smaller, more readily biodegradable materials. Such
prolonged ozone treatment probably is outside of the range of economic
feasibility. On the other hand, if wastewater stream recycle is contemplated,
ozonation should be studied in more detail.
Melnyk and Netzer (1976) conducted a kinetic study of the reactions
between ozone and those lignin compounds which produce an intense color in
wastewaters originating from kraft pulping and pulp bleaching processes.
For the ozonation studies, a 1 liter sparged reactor was employed and ozone
was generated from oxygen. Analyses were conducted for ozone in the contactor
influent and effluent gases. Ozonized wastewaters were analyzed for changes
in pH, COD, biodegradability and color content. Wastewater studies included
caustic bleachery (softwood), unbleached pulp washer (softwood), combined
caustic chlorine bleach stages (softwood) and caustic bleach stage (hardwood).
For development of the kinetic model, it was assumed that color is
contributed by 2 unidentified species, each of which differs in its reactivity
with ozone. Each species was assumed to react with soluble ozone indepen-
dently and as a first order rate process. The 2 species differ in their
reactivity with ozone, and it is concluded that the more reactive (to ozone)
species also is responsible for most of the initial color (65 to 87%). The
rate of color removal was found to be linearly dependent upon the soluble
ozone concentration. Decreases in COD values were observed to parallel
238
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decreases in color intensity in the ozonated samples, but the amount of COD
reduction is significantly smaller than the amount of color removed.
Melnyk & Netzer (1976) also monitored the oxygen uptake rates of
ozonated wastewater samples. It was not clear that ozonation enhanced
biodegradability. Ozonation clearly increased the amount of material which
could be oxidized biologically, but this new material was degraded at a
slower rate.
Nebel ejt aj_. (1974a) discussed pilot plant studies with ozone treatment
of kraft mill effluents for color removal. Examples are presented of color,
COD and BOD level reductions in kraft mill effluents by ozonation at various
dosages, and the economics of ozone treatment and generation by using air or
oxygen are compared.
Nebel et_aJL (1974b) discussed experimental data indicating the cost of
color removal by ozonation in 4 different pulp and paper mill secondary
effluents. Costs were in the range of $0.007 to $0.017/cu m (2.65 to 6.44<£/-
1,000 gal) of wastewater treated, with the predominating factor being the
cost of electrical power. Both of these last two articles appear to be very
similar in content to that of Nebel, Gottschling & O'Neill (1974).
Kamishima and Akamatsu (1974a,b) studied the mechanism of BOD removal
in an ozonated diluted black liquor subjected to activated sludge treatment.
With BOD levels of 600 mg/1, the removal rate approximated a first order
reaction, and at BOD levels of 100 to 200 mg/1 the reaction followed second
order kinetics. BOD removals of 90% were obtained at loadings less than 0.5
kg BOD/day/kg of mixed liquor volatile suspended solids (MLVSS), and sludge
yield was the same or lower than that for other pulp mill effluents. For
liquors treated with 4 to 15 mg/1 of ozone, BOD removal efficiency decreased
at higher loadings, but not at loads less than 0.4 kg/day/kg of MLVSS. In
2-stage ozone/activated sludge treatment, total permanganate COD and BOD
removals depended upon the efficiencies of the individual stages, which were
61.6% and 87.5%, respectively, even with ozone residuals of 0.4 mg/1.
Lignin and color removal efficiencies depended upon ozonation effectiveness
and were 66.6% and 81.5%, respectively.
Bauman and Lutz (1974) ozonized effluent from the P.M. Glatfelter Co.,
Spring Grove, Pennsylvania integrated kraft mill making 500 tons/day of
fully bleached pulp and 600 tons/day of fine papers using a 5 gal/minute
pilot plant on the total mill effluent after primary and secondary biological
treatment. The primary objective of this study was color removal, but the
effects of ozonation upon COD, BOD, SS, bacterial counts and DO also were
studied.
Ozone was prepared from oxygen at 80 g of ozone/hr using 3.5 kwhr of
electrical energy per Ib of ozone. Contacting was conducted in four 8-inch,
schedule 40 steel pipes, each 13 ft high. Ozone was introduced through 2
inch stainless steel spargers, 1 per tower, located about 1 ft from the base
of the contact towers. The liquid heights in each tower, therefore, were
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about 11 ft. Most of the pilot studies were conducted at 4 gal/min, which
provided about 30 minutes total retention time, or about 7 minutes per
tower. The inlet gas flow was divided and regulated so that 40% of the
ozone was applied in Tower #1, 30% in Tower #2, 20% in Tower #3 and 10% in
Tower #4. Liquid samples could be taken from each tower effluent and the
gas streams also were sampled. Contactor vent gases could be tested for
ozone and gas flow rates to each tower were adjusted so that no ozone was
"wasted out the vents". This means that the ozone added to each tower was
utilized, but not necessarily that the ozone demand of the liquid was
satisfied.
For each sample, a minimum of 2 hrs running time was conducted for each
level of ozone applied. For reduction in color level, little was gained by
applying more than 30 mg/1 of ozone, and nothing was gained at dosages above
40 mg/1. Almost no bacteria were killed at ozone dosages up to 20 mg/1.
When bacteria began to be killed by ozone, the coliform organisms were
destroyed selectively first. At 30 mg/1 of ozone, significant reductions in
coliform levels (60 to 80%) were observed, and at 40 mg/1 ozone dosage,
nearly 100% coliform kills were obtained. However, the bacterial counts
remained surprisingly high, even after addition of 40 mg/1 of ozone.
Initial experiments were conducted with air feed to the ozone generator,
and 5 y mean pore size spargers quickly became plugged after only a few
hours of running time. A brown deposit which adhered tenaciously was shown
to be almost entirely CaC03. This was soaked with HC1 to remove the deposit,
but this required removing the spargers.
Therefore the 5 y spargers were exchanged for 20 y mean pore size
diameter spargers, which allowed 72 hrs continuous runs with air feed.
However, when oxygen feed was used, even the 20 y spargers became plugged
within 24 hrs of use. Therefore, daily cleaning with acid was required.
At equivalent ozone dosages, no differences in color level reductions
were observed due to the different (5 and 20 y) pore sizes of the spargers.
Ozone at 20 to 40 mg/1 doses consistently increased the BOD-5 about
100% (BOD of the secondary effluent was about 10 mg/1). When ozone was
prepared from air, the DO level became about 8 mg/1. Oxygen dissolves in
direct relation to its proportion in the mixture of gases. Since the concen-
tration of oxygen in air is about 21%, only 20% of its ultimate solubility
in water is attained. But when ozone is prepared from oxygen, the DO attained
approaches 40 mg/1, the ultimate oxygen solubility in water. The doubling
of BOD-5 was obtained by Bauman & Lutz (1974) regardless of whether ozone
was generated from air or from oxygen.
By varying the power applied to the generator, the concentration of
ozone in the feed gas was varied as follows:
240
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0.45% at 10 mg/1 dosage
0.90% at 18 mg/1 dosage
1.35% at 30 mg/1 dosage
1.8 % at 38 mg/1 dosage
The color remaining after ozonation depended upon the amount of ozone
applied, not on the concentration of ozone in the gas stream. On the other
hand, there was a significant decrease in the time necessary to apply the
required amount of ozone at the higher ozone concentrations. Bauman and
Lutz (1974) recommend that this relationship should be investigated in
detail before capital expenditures for a full scale plant treatment system
are made.
Multiple regression analyses were conducted during 48 hrs of continuous
running at 20 mg/1 of ozone dosage and over 48 hrs at 30 mg/1 ozone dosages.
The % color removed was related to the BOD levels (which increased 105%),
COD (decreased 12%) and SS (decreased 22%). For an initial color of 600
mg/1, COD of 225 mg/1, BOD of 10 mg/1 and SS of 25 mg/1, the regression
equation predicted that 100 mg/1 of ozone dosage would be required to provide
80% color removal.
Extended ozonation runs then were conducted using ozone dosage levels
up to 300 mg/1. Color removals of 80% were obtained at 80 mg/1, but even
after addition of 300 mg/1 of ozone, 30 mg/1 of color remained. The BOD
rose from 10 to 24 mg/1 at 40 mg/1 of ozone, remained at 20 to 25 mg/1 up to
200 mg/1 ozone dosages, then dropped back to 10 mg/1 by 280 mg/1 ozone
dosages. About 99% of the coliform bacteria were killed by 40 mg/1 ozone
dosages and 99% of the total bacteria were killed at 100 mg/1 ozone dosage.
Cost estimates were made on an ozonation installation designed to treat
15 mgd and providing up to 40 mg/1 of ozone generated from oxygen. Capital
investment would be $1 million - $1.25 million and 5 kwhr of electrical
energy/lb of ozone generated would be required (at a power cost of $0.015/-
kwhr). Table 54 shows the estimated operating costs for treating 15 mgd of
pulp mill secondary effluent containing less than 1,000 mg/1 of color, about
200 mg/1 of COD and less than 50 mg/1 of SS (the plant would be sized to
process 500 tons/day of pulp).
Whittemore & McKeown (1974) conducted preliminary laboratory studies to
determine the oxidation and disinfection properties of ozone applied to a
variety of pulp and paper mill effluents. Specific objectives of the study
were to determine the amount of color reduction attainable by ozonation with
and without prior lime decolorization treatment, the amounts of ozone required,
changes caused in COD and BOD, then to define ozonation conditions (amounts
and contact times) required to disinfect selected pulp and paper mill
effluents.
The ozone contactor was a 90-cm high x 5 cm-diameter column of 1.8
liter total volume, but samples to be ozonized all were 1 liter in volume.
A fritted-glass diffuser was installed at the base of the column, but was
241
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covered with an inverted polypropylene funnel to restrict the gas phase from
being drawn out of the reactor by the downflowing liquid. The column was
designed originally to be packed with glass beads, but preliminary observa-
tions showed that bubble sizes were smaller and overall turbulence was
greater without the packing. The beads seemed to coalesce the bubbles and
promote gas phase channeling. Foaming was reduced when beads were removed.
TABLE 54. ESTIMATED OPERATING COSTS FOR TREATING
15 MGD OF PULP MILL SECONDARY EFFLUENT WITH OZONE
mg/1 of
ozone
_ _
10
20
30
40
Source: Bauman & Lutz,
Color of
Ozonated
Effluent
(mg/1)
1,000
300-450
250-350
150-200
125-175
Operating Cost
Annual
$121,500
$243,000
$364,500
$486,000
per ton
of pulp
$0.675
$1.35
$2.03
$2.70
1974.
Ozone was generated from oxygen. Off-gas ozone was passed through a KI
trap for determination of the amount of unused ozone, and ozone material
balances were determined so as to calculate the ozone utilization of the
system. After completion of each run the residual ozone was determined in
the ozonized solution by addition of KI and determining the amount of libera-
ted iodine. In nearly all cases this was 0.0 mg/1 of ozone, so that ozone
utilization could be calculated simply by subtracting the concentration of
ozone in the off-gases from that in the feed to the reactor.
Using unbleached kraft pulp mill effluent synthesized from weak kraft
black liquors, hardwood caustic stage bleaching effluents (CE), softwood
chlorination stage bleaching effluents (C12E) and biologically treated
bleached kraft total mill effluents (TTME), in all four cases, effluent
color decreased with increasing ozone useage (up to 800 mg/1 of ozone utili-
zed). Where the amount of ozone dosed was sufficient to satisfy the ozone
demand, the percent color reduction was time-dependent -- about 45 minutes
residence time being required to produce more than 80% reduction consistently
(residual color levels of less than 100 APHA units). In most cases, lime-
decolorized effluents required substantially less ozone to attain a given
level of color reduction. Pertinent data are summarized in Tables 55, 56,
57 and 58.
Color reversion also was investigated. This is defined as the return
of color 24 hrs after ozone treatment. Generally, it was found to be in the
0 to 10% range, but in some cases it was greater. The median amount of
color reversion was 5 to 8%, but this did not occur consistently with any
one effluent or with any single class of effluent.
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TABLE 55. ESTIMATED OZONE REQUIREMENTS FOR
SYNTHESIZED UNBLEACHED KRAFT BLACK EFFLUENT DECOLORIZATION
Waste
Description
lardwood - Black
Liquor, Diluted
1/100
Hardwood - Black
.iquor, Diluted
1/100, Lime Decolor*
Softwood - Black
Liquor, Diluted
1/100
Softwood - Black
Liquor, Diluted
1/100, Lime Decolon
Source: Whittemore
Initial
Color,
APHA Units
4,800
370
3d
2,200
145
>d
I
Ozone Requirements (mq/1)
Color Reduction
50i
500
300
400
250
75%
650
400
500
350
90%
>700
>600
>750
450
and McKeown, 1974.
Kraft total mill effluents were disinfected (determined by total
coliform densities) rapidly with 70 to 90 mg/1 of ozone utilization.
Eighty percent total coliform reduction was obtained at about 40 mg/1 ozone
dosage, 90% reduction at about 50 mg/1 and 100% reduction at about 80 mg/1.
However, boxboard mill effluents showed total coliform densities reduced to
zero with only 25 mg/1 dosages of ozone.
Effluent color appeared to be a significant factor in the amount of
ozone required for disinfection. Primary settled total mill effluent
containing coliforms was split and 1 portion was spiked with color in the
form of kraft bulk liquor. After 7 days of biological oxidation, both
samples were ozonized and the degree of disinfection tested by determining
the total bacterial and total coliform counts. Complete coliform kills were
not attained at levels of 190 to 300 mg/1 dosages. An increase in color
(from 800 to 4,000 APHA units) retarded disinfection efficiency. In the
ozonated sample, levels of added color, bacteria and total coliform organisms
were reduced 15% and 57%, respectively, at 300 mg/1 ozone dosage. The
sample with fewer color bodies gave 99% bacterial and 97% coliform kills at
190 mg/1 ozone dosage. It was also shown (by filtering a biologically
treated kraft total mill effluent) that lowering the SS will reduce the
ozone demand for effluent disinfection following biological oxidation (75
mg/1 dosage versus 190 mg/1).
243
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TABLE 56. ESTIMATED OZONE REQUIREMENTS FOR
CAUSTIC STAGE BLEACH EFFLUENT EXTRACT DECOLORIZATION
Waste
Description
Mill A - Hardwood
Mill B- Hardwood
Mill B - Hardwood
Lime Decolored
Mill C - Softwood
Caustic Extract D -
Softwood
Caustic Extract E -
Softwood
Source: Whittemore
" ~
Initial
Color,
APHA Units
3,900
2,600
425
7,250
15,000
7,200
Ozone Requirements (mg/1)
color Reduction
50%
200
200
60
200
300
220
75%
360
300
100
>250
625
275
and McKeown, 1974.
90%
>450
>400
130
>300
775
350
Ozonation generally lowered the COD by as much as 30% (occasionally up
to 50%). Boxboard, integrated kraft ASB (aerated stabilization basin)
effluents and sodium base NSSC (neutral sulfite semi-chemical) total mill
effluents produced significant increases in BOD-5 (boxboard effluents showed
a 60% increase; integrated kraft ASB effluents showed a 200% increase).
With other effluents the BOD generally decreased slightly (0 to 20%) or
increased slightly (0 to 10%).
Ozone decolorization had negligible effects upon the subsequent rates
of biodegradability of effluents.
Less than 3 Ibs of ozone were required to remove 1 Ib of COD from
various pulp mill effluents. Actual data ranged from 0.3 to 33 Ibs, with an
average value of 1.61 Ibs. In theory, if only 1 oxygen atom in the ozone
molecule is utilized in oxidation of the COD, then 3 Ibs of ozone should be
required to remove 1 Ib of COD. Those wastes in which less than 3 Ibs of
ozone were required per Ib of COD removed indicates that more than 1 atom of
oxygen in the ozone molecule is utilized in the oxidation process.
Whittemore & McKeown (1974) concluded from this preliminary laboratory
study that:
t Ozone is capable of removing color from a wide range of process streams
and total mill effluents,
244
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15 to 20 color units are removed per mg of ozone dosage in caustic
bleach effluents; 4 to 5 color units are removed/mg of ozone dosage in
total kraft mill effluents and less than 1 color unit/mg of ozone is
removed in lime treated effluents,
TABLE 57. ESTIMATED OZONE REQUIREMENTS FOR
CHLORINATION STAGE BLEACH EFFLUENT DECOLORIZATION
Waste
Description
Mill A - Hardwood
Mill A - Hardwood
Lime Decolored
Mill B - Hardwood
Mill B - Hardwood
.ime Decolored
Mill C - Softwood
Mill C - Softwood
.ime Decolored
Mill D - Softwood
lill D - Softwood
.ime Decolored
Source: Whittemore
Initial
Color,
APHA Units
220
45
590
100
175
175
700
80
Ozone Requirements (mg/1)
Color Reduction
50%
>275
185
65
45
80
110
75
160
75%
—
260
200
95
150
>150
190
200
90%
>900
325
>275
175
>250
175
225
>300
& McKeown, 1974
0 24 hour color reversions usually are less than 10%, and average 5 to
8%
t 90 percent or greater total coliform reductions are attained at about
the same ozone requirements as the one hour chlorine demand for integra-
ted kraft mill effluents, but are several times the chlorine dose
required for disinfection. Color bodies and SS both showed preferential
ozone demand, thus increasing the amount of ozone required for disin-
fection.
Ng et al_. (1978) reported results of ozonizing kraft mill wastewaters.
Ozone was generated by passing 0.3 cu m/hr of oxygen at 3 psig through an
air-cooled plate type generator (W.R. Grace & Co.). Ozonations were conducted
in a dynamic system and in a batch system. In the dynamic system, the
245
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TABLE 58. ESTIMATED OZONE REQUIREMENTS FOR
TOTAL MILL EFFLUENT DECOLORIZATION
Waste
Description
Boxboard Secondary
Total Mill Effluent
(ASB)
toxboard Secondary
Total Mill Effluent
After Settling
NSSC Total Mill
Effluent, Na Base
NSSC Total Mill
Effluent, NH3 Base
Sulfite Secondary
Total Mill Effluent
Kraft A Secondary
Total Mill Effluent
Kraft B Secondary
Total Mill Effluent
Kraft C Primary
Total Mill Effluent
(raft D Secondary
Total Mill Effluent
Source: Whittemore
Initial
Color,
APHA Units
180
140
7,500
40,000
1,620
400
540
1,180
1,150
Ozone Requirements (mg/1)
Color Reduction
50%
20
30
>850
Color Incre
550
38
18
>260
70
75%
100
150
—
ase noted (
>800
70
85
___
88
90%
>600
>175
—
at 1,200 mg/1
-.»«
>125
>300
___
250
& McKeown, 1974.
contact tower was a polyvinyl chloride column 3 m (10 ft) high and 15 cm (6
inch) diameter containing a concentrically mounted 10 cm (4 inch) diameter
pipe sealed to the 15 cm pipe at the lower end. A centrally mounted dip
tube extending to the base of the 10 cm pipe was connected at the top to the
ozone/effluent mixing device (Figure 23). Effluents adjusted to pH 3, 7 and
9 were pumped at 5 gal/min into the mixing device where they were treated
with 1% ozone in oxygen. The ozonized effluent then entered the 15 cm
diameter contact column through the annular opening and passed through the
contact column within two minutes. Each passage allowed an ozone dosage of
8.8 mg/1. Residual ozone could not be detected at the top of the contact
column, thus it was assumed that all ozone applied to the effluent was
consumed by the effluent.
246
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The batch system consisted of a 40 liter polyethylene container fitted
with a porous gas dispersion tube. Ozone (1% in oxygen) was dispersed into
the effluent which had been adjusted to the desired pH value and was stirred
by means of a magnetic stirrer. Ozone was determined in the inlet and off-
gases.
Four batches of bleached kraft whole-mill effluents were obtained from
a British Columbia interior bleached kraft mill (1 sample) and a coastal
bleached kraft mill (3 samples). Samples were composited over 24 hours,
shipped immediately to the laboratory and stored at 4°C. Coarse particles
and fibrous materials were removed prior to ozonation by straining. Toxicity
of treated effluents to juvenile rainbow trout (Salmo gairdneri) was measured
as medial survival time (MST), the time to death of 50% of the fish population
exposed to 100% effluent. For bioassays, the effluents were neutralized to
pH 7.0 ± 0.1, DO was kept at saturation and temperature was controlled at
15° ± 1°C. All samples were toxic to fish, except the one taken from the
interior mill. The MST values ranged from 290 to 420 minutes, color varied
from 1,780 to 3,200 APHA units, BOD-5 values ranged from 190 to 250 mg/1 and
TOC from 270 to 330 mg/1.
Non- *"' '
return
valve
-E]
Drying
agent
To gas
sampling
device
Gas cylinder
or compressed
air source
] Ozone-water
mixing device
Ozone
contact
tower
Pump
Source; Ng et ah (1978)
Figure 23. Dynamic ozone treatment system.
247
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In batch experiments, detoxification of the effluents by ozonation was
marginal at pH 4.2; detoxification was significantly better at pH 7.0 and
was substantial at pH 9,0. However, detoxification in the control samples
was as effective as with ozone, and also gave the best toxicity lowering at
pH 9.0. Removal of color by 8.8 mg/1 of ozone averaged 10% and was of
similar magnitude at all three pH ranges tested. Color was not improved in
the control. At the low level of 8.8 mg/1, ozonation did not significantly
affect BOD-5 and TOC.
Sequential removal of pollutants was studied at pH 9 as a function of
ozone dosage by dosing up to about 50 mg/1 of ozone. Initial color levels
of 2,080 and 1,880 APHA units were lowered to 1,500 and 1,250, respectively.
The rate of color removal was fastest during initial stages of ozonation. A
mathmatical relationship was developed which predicted the ozone dosage
required for various levels of color removal:
In (color removed) = 0.72 In (ozone applied) + 3.78.
No color was removed in the control samples, indicating that color removal
was due to the ozone.
Upon initial treatment with 4 mg/1 of ozone, the BOD-5 values increased
by 5 to 6%, but as ozone dosages were increased, BOD-5 values peaked, then
decreased as a function of ozone dosage. Treatment of effluents with 48
mg/1 of ozone reduced BOD-5 values from 180 and 190 mg/1 to 145 and 150
mg/1, respectively, or showed 20 to 22% reduction. The removal of BOD-5
could be expressed as:
In (BOD-5 removed) = 0.86 In (ozone applied) + 0.26.
About 260 to 270 mg/1 of ozone would have to be applied to lower the
BOD-5 by 90% (to 20 mg/1). If 150 to 175 mg/1 of ozone were to be applied,
as would be necessary to remove 90% of the color, then about 61 to 66% of
the BOD-5 also would be removed.
Concurrent with BOD-5 removal, some reduction in TOC was observed,
averaging 0.25 to 0.3 mg/1 TOC removed/mg of ozone applied. The ratios of
BOD-5/TOC removed per unit of ozone applied ranged between 3:1 and 4:1,
suggesting that the carbon removed by ozone treatment is oxidized to C02 and
water and that BOD-5 removal is congruent with the carbon removal. In the
control experiments, oxygen had no effect upon BOD-5 and TOC.
Color was attacked most readily by ozone, followed by BOD-5. TOC was
attacked slightly by ozone and toxicity was not affected. However, oxygena-
tion conditions prevailing during ozonation resulted in toxicity removal.
Segregated sequential attack of ozone did not occur; color and BOD-5 were
destroyed concurrently.
248
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Ozonation For Deodorizing Kraft Mill Gaseous Emissions
Tuggle (1972) studied the effects of ozone on 4 odorous, reduced
sulfur compounds associated with kraft mill gaseous emissions: hydrogen
sulfide (H?S), methyl mercaptan (Cl^SH), dimethyl sulfide (CH3SCH3) and
dimethyl di sulfide (CHaS-SCHg). He concluded that at least double the
theoretical dosage of ozone is necessary for complete oxidation of these 4
compounds and that residence times in contact chambers in excess of plant
exit stack residence times are required for total oxidation. Excluding cost
considerations (which were not conducted), Tuggle concluded ozone to be
effective in eliminating methyl mercaptan, dimethyl sulfide and dimethyl
disulfide from actual kraft mill emission sources (smelt, tank and vent
gases). Complete removal from these three gases was achieved at an ozone/-
total reduced sulfur ratio of about 2.5.
In these experiments, ozone was generated from oxygen and nitrogen was
used as the carrier gas. For both laboratory and field studies, the contact
times ranged from 10 seconds to 1 minute.
Oxidation of ^S with ozone was found to be much more rapid than that
of the other 3 gases. Methyl mercaptan oxidation with ozone produced
dimethyl disulfide with slightly more than the theoretical amount of ozone
required. Subsequent reaction of the dimethyl disulfide required more than
double the theoretical amount of ozone for complete oxidation.
An additional 23 references for the use of ozone for deodorizing pulp
and paper mill gaseous effluents are given by Rice & Browning (1976). In
this publication, abstracts of each article cited are included.
Ozonation Of Spent Sulfite Liquor To Generate Methane And To Grow Yeast
Jurgensen & Patton (1976-77; 1977a) describe a laboratory feasibility
program, funded by the U.S. Department of Energy, Industrial Energy Conser-
vation Division, to study the production of methane and protein by fermen-
tation of spent sulfite liquor (SSL) from pulp mills. Although anaerobic
fermentation of carbonaceous materials is well known for the production of
methane, as is the growth of yeasts and algae on wastewaters, the use of
ozonation to convert SSL to substrates more amenable to these biological
processes is novel.
It has been estimated (Mueller & Walden, 1970) that 2,100 gal of SSL
are produced for every ton of sulfite pulp manufactured. This waste material
can be treated mechanically or biologically before discharge. However, the
general lack of success with biodegradation of lignosulfonates has suggested
that some pretreatment should be utilized to degrade the SSL, or to transform
it into a state which can be better metabolized by biologically functioning
organisms.
Stern & Gasner (1974) have shown that ozonation of kraft mill waste
liquors causes a shift in the molecular weight distribution of lignins to
249
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lower molecular weight fractions. Ozonation also was shown to increase the
susceptibility of waste liquors to biological decomposition.
Jurgensen & Patton (1977b) are testing a multistage treatment process
in the laboratories of Michigan Technological University, Houghton, Michigan.
This process involves 3 fermentation stages, ozonation, steam stripping and
centrifugation, to harvest useful products from SSL.
Raw waste pulp mill effluent enters the primary yeast fermenter where
all assimilated organics are converted to protein and CC^. Effluent from
the primary fermenter is centrifuged to harvest protein and the centrifugate
is ozonized to modify the sulfur bonds and to break down the high molecular
weight organics. Ozonized effluent is cooled and fed to the anaerobic
digester, which contains a mixed bacterial culture and Desulfovibrio, which
are needed to transform ozonized fragments into substrates satisfactory for
methane synthesis.
Effluent from the anaerobic digester still may contain unassimilated
ozonated fragments which can be utilized by Torula yeast. Therefore, the
effluent is fed to the secondary yeast fermenters, then to centrifugation
for protein removal. Any BOD-5 still present is removed by activated sludge
treatment or soil infiltration.
During initial phases of the Michigan Technological University study,
ozone was prepared from oxygen and ozonation was carried out in a 1 inch
I.D. x 6 ft tall glass column (500 ml volume) packed with berl saddles. The
pH was monitored and controlled automatically. Preliminary experiments were
conducted by bubbling ozone through 300 ml of SSL for 1 to 6 hrs. After 6
hrs, ozone consumption had reached minimum values and significant quantities
of ozone were present in the off-gases. Infrared analyses of the raw and
ozonized SSL samples showed significant transformation of aromatic structures
to carboxylic acids.
Samples ozonized 6 hrs also were analyzed for BOD, COD and sulfur.
Concentrations of metabolizable organics increased by 100% when ozonations
were conducted at pH = 3, but very little increase in BOD was obtained at
alkaline pH. The COD values were reduced about 23% upon ozonation under
either acid or alkaline conditions, but no change in the sulfur content was
found.
Continuous reactor studies were conducted initially at pH = 3 over 3
hours (the point at which ozone became just detectable in the contactor off-
gases). Ozone consumption averaged 12.8 g/1 of SSL, which theoretically
should have reduced the COD value by 8,500 mg/1 (from an initial value of
101,000 mg/1) on the basis of only one oxygen atom in the ozone molecule
reacting. The actual reduction in COD value observed was 13,000 mg/1,
indicating that at least part of the oxidation occurs by means of a second
oxygen atom in the ozone molecule.
250
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Methane production was consistent with the change in concentration of
BOD-5 (10,500 mg/1 in raw water; 11,600 mg/1 in ozonized water; 8,400 mg/1
in fermented, ozonized SSL). Methane was produced at the rate of 17 ml/hr
(423 ml/day) from a 700 ml volume fermenter with 2.8 days retention time.
Fermenter gas was comprised of 65% methane and 35% C02 and gas yields decrea-
sed with detention time in the fermenter. About 75% of the ozone consumed
was expended in the production of COp, rather than in producing biodegradable
fragments.
In continuation of these studies, Jurgensen & Patton (1977c; 1977d)
have shown that the gas composition from ozonized SSL averages greater than
80% methane, while that from non-ozonized SSL effluent is mostly C02.
Initial ozonation times of 3 hrs have been shortened to 10 minutes, and
maximum yields of yeast growths have been obtained under these conditions.
Yields of methane gas at 2 to 6 day fermenter residence times have stabilized
at 10 ml/hr (70 to 80% methane), and the fermentation process has been shown
to be carbon-limited.
Current work on this program at Michigan Technological University is
scheduled to be completed in June, 1979. The investigators currently
believe that the production of yeast from ozonized SSL is economically
feasible, but that the economics of methane production are marginal (Jurgen-
sen, 1978, Private Communication).
Conclusions
1) Ozonation has been studied for:
• Pulp bleaching
• Pulp and paper mill wastewater treatment
• Odor control of pulp and paper plant gaseous exhausts
• Treatment of spent sulfite liquors to produce methane and yeasts
In Pulp Bleaching:
2) Ozone can produce pulps which give satisfactory physical and paper-
making properties. Aqueous effluents from ozone bleaching processes
therefore are free of chlorine, hypochlorite or sulfites.
3) Ozone partially degrades cellulosic polymers and wood sugars, liberating
lignin. However, over-ozonation of wood pulp liberates sufficient
lignin so that the physical properties of fabricated paper products can
be unsatisfactory.
4) Norwegian Institute of Paper Research personnel have been developing
pulp bleaching processes with ozone since the late 1960s. Since May,
1976, the NIPR process has been operating on semi-commercial scale at a
Norwegian paper pulp factory. This demonstration is being co-sponsored
by 5 major Norwegian paper companies and a Norwegian mechanical engineer-
ing company. Similar studies are being conducted in Canada and the
USA.
251
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In Wastewater Treatment:
5) Ozonation has been studied for color removal, reduction in levels of
BOD and COD, for bacterial disinfection and for removing toxicity of
effluents to juvenile rainbow trout. The use of ozonation either for
removal of color or COD or for disinfection also provides partial
lowering in levels of the other parameters as well as SS. BOD levels
generally increase (up to 100%) upon ozonation. High suspended solids
and color contents appear to reduce the disinfection effectiveness of
ozone. Detoxification of ozonized effluents is effective at pH 9,
partially effective at pH 7.0 and only marginal at pH 4.2. However,
oxygenation at pH 9 was as effective as ozonation for detoxification.
6) The increased biodegradability of ozonized pulp and paper mill effluents
generally has been attributed to the partial oxidation of cellulosic
polymers by ozone. However, a recent paper indicates that this may be
caused by ozone destruction of materials toxic to biological organisms,
rather than by formation of more biodegradable materials upon ozonation.
7)
Because of the increased biodegradability of ozonized pulp and paper
mill effluents, it appears advantageous to incorporate ozonation
before biological treatment rather than after, for removal of BOD, COD
and perhaps color.
8) Ozonation reduces color levels 65 to 90%, but up to 10% reversion of
specific wastewaters can occur within 24 hrs.
9) For color removal, about 30 mg/1 of ozone dosage (assuming 100% ozone
utilization) are required. Ozone dosages of 40 mg/1 provide 100% kills
of fecal coliforms, but total bacterial counts remain high. These
ozone dosages effect 100% increases in BOD-5 and lower COD levels 15 to
20%. About 3 Ibs of ozone are required to remove 1 Ib of COD in this
type of wastewater system.
10) Color is attacked most readily upon ozonation, then BOD-5, then TOC.
However, segregated sequential attack by ozone does not occur; color
and BOD-5 are destroyed concurrently.
11) Costs for ozone treatment of pulp and paper mill wastewaters have been
estimated from as low as 3 to 6<£/l,000 gal for color removal to as high
as 30
-------
longer than those normally found in plant exhaust stacks. The oxidation
rate for HLS with ozone is much faster than for the other compounds.
13) Ozonation of spent sulfite liquor (SSL) to produce substrates suitable
for anaerobic production of methane and/or for the growth of yeast is a
new concept just being studied. Laboratory results to date show that
10 minute ozonation of SSL allows methane production at the rate of 10
ml/hr in a 700 ml fermenter with 2 to 6 day retention times. The gas
composition is 70 to 80% methane. At the present stage of this research,
it appears that production of yeast from ozonized SSL is economically
feasible, but that methane production is only marginal.
LITERATURE CITED — PULP AND PAPER (PU)*
PU-01* Absdie-Maumert, F.A., B. Fritzvold & N. Soteland, 1977, "The
Norwegian Semi-Industrial Pilot Plant for Processing of Paper Pulp
by Ozone". Presented at 3rd Intl. Symp. on Ozone Technol.,
Paris, France, May. Intl. Ozone Assoc., Cleveland, Ohio.
PU-02 Ancelle, B. & M. Plancon, 1966, "Bleaching Wood Pulp", French
Patent 1,441,787, June 10. Chem. Abstr. 66:20152s.
PU-03* Anonymous, 1974, "Ozone Bleaching Pilot Plant Called Success",
Paper Trade J., Feb. 4, p. 9.
PU-04* Bauman, H.D. & L.R. Lutz. 1974, "Ozonation of a Kraft Mill Efflu-
ent", TAPPI 57(5):116-119.
PU-05* Buley, V.F., 1973, "Potential Oxygen Application in the Pulp &
Paper Industry", TAPPI 56(7):101-104.
PU-06 Clayton, D.W., N. Liebergott & T. Joachimides, 1971, "Evaluation
of Ozone Treatment of Mechanical Pulp", Pulp & Paper Rsch. Inst.
of Canada, Prog. Rept. 39, Oct. 1, p. 106-115.
PU-07* Furgason, R.R., H.L. Harding & M.A. Smith, 1973, "Ozone Treatment
of Waste Effluent." Research Completion Report, OWRR Project No.
A-037-IDA, Water Resources Inst., Univ. of Idaho, April. NTIS
Report No. PB-220,008.
PU-08 Furgason, R.R., H.L. Harding, A.W. Langeland & M.A. Smith, 1974,
"Use of Ozone in the Treatment of Kraft Pulp Mill Liquid Wastes.
Part I. Color, Odor and COD Reduction". Am. Inst. Chem. Engrs.
Symp. Series 70:139.
PU-09 Furgason, R.R., M.A. Smith & H.L. Harding, 1973, "Ozone Treatment
of Pulp Mill Wastes", presented at Natl. Am. Inst. Chem. Engrs.
Mtg., Vancouver, B.C., Sept.
* Abstracts of asterisked articles will be found in EPA 600/2-79- b.
253
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PU-10* Hatakeyama, H., T. Tonooka, J. Nakano & N. Migita, 1967, "Ozonol-
ysis of Lignin Model Compounds", Kogyo Kagaku Zasshi 70(12):148-
152, 2348-2352.
PU-11* Hatakeyama,'H., T. Tonooka, J. Nakano & N. Migita, 1968, "Degrada-
tion of Lignin with Ozone." Chem. Abstr. 70:12768 (1969). Kogyo
Kagaku Zasshi 71(8):1214-1217.
PU-12* Hosokawa, J., T. Kobayashi & T. Kubo, 1976, "Bleaching of Pulp",
Japan. Kokai 76,139,903, Dec. 2, 1976, Appl. 75/62,661,
26 May 1975. Chem. Abstr. 86:57076 (1977).
PU-13 Huriet, B. & P. Gelly, 1970, "Improvements to Processes for the
Decoloring of Effluents From Kraft Pulping", French Patent 1,599,588
(July 15, 1970); Abstr. Bull. Inst. Paper Chem. 42:4413 (1971).
PU-14* Jackowski, J., 1970, "Ozone Treatment of Pulp and Paper Mill
Effluents", Private Communication, Nov. 1970 to I. Gellman. Noted
in Nat'l. Council of the Pulp and Paper Industry for Air and
Stream Improvement, Tech. Bull. #269, Jan. 1974, by R.C. Whittemore
(p. 2).
PU-15 Josephson, J., 1974, "Cleaning Up: Paper Industry's Mess", Env.
Sci. & Technol. 8(l):22-24.
PU-16 Jurgensen, M.F. & J.T. Patton, 1976-1977, "Energy and Protein
Production From Pulp Mill Wastes", Annual Rept., 6/15/76-6/15/77
under ERDA Contract E(ll-l)-2983. See also Progress Reports for
the periods 6/15/77-9/15/77 and 9/15/77-12/15/77 under same contract.
PU-17 Jurgensen, M.F. & J.T. Patton, 1977a, "Energy and Protein Produc-
tion From Pulp Mill Wastes", Prog. Rept. (Dec. 15, 1976-Mar. 15,
1977) under Contract EY-76-S-02-2983, U.S. Dept. of Energy,
Washington, D.C.
PU-18 Jurgensen, M.F. & J.T. Patton, 1977b, "Energy and Protein Produc-
tion From Pulp Mill Wastes", Annual Rept. (June 15, 1976-June 15,
1977) under Contract EY-76-S-02-2983, U.S. Dept. of Energy,
Washington, D.C.
PU-19 Jurgensen, M.F. & J.T. Patton, 1977c, "Energy and Protein Produc-
tion From Pulp Mill Wastes", Prog. Rept. (June 15, 1977-Sept. 15,
1977) under Contract EY-76-S-02-2983, U.S. Dept. of Energy,
Washington, D.C.
PU-20 Jurgensen, M.F. & J.T. Patton, 1977d, "Energy and Protein Produc-
tion From Pulp Mill Wastes", Prog. Rept. (Sept. 15, 1977-Dec. 15,
1977) under Contract EY-76-S-02-2983, U.S. Dept. of Energy,
Washington, D.C.
254
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PU-21* Kamishima, H. & I. Akamatsu, 1973, "Attempts to Modify the Acti-
vated Sludge Process for Sulfite Pulp Wastewater", Japanese TAPPI
27(9):449. Abstr. Bull. Inst. Paper Chem. 44(10): 10878 (1974);
44(8):368 (1974).
PU-22* Kamishima, H. & I. Akamatsu, 1974a, "Ozone-Activated Sludge Treat-
ment of Sulfite Pulp Wastewater. Mechanism of BOD Removal, Treat-
ment conditions and Sequential Treatment". Japanese TAPPI 28(8):35-
44.
PU-23 Kamishima, H. & I. Akamatsu, 1974b, "Ozone-Activated Sludge Treat-
ment of Sulfite Pulp Wastewater". Japanese TAPPI 28(8):368.
Abstr. Bull. Inst. Paper Chem. 45(5):4865 (1974).
PU-24 Katai, A.A. & C. Schuerch, 1966, "Mechanism of Ozone Attack on a
Methyl Glucoside and Cellulosic Materials." J. Poly. Sci., Part A-
1, 4:2683-2703.
PU-25* Katuscak, S., A. Hrivik & M. Mahdalik, 1971a, "Ozonization of
Lignin, Pt. I. Activation of Lignin with Ozone", Papper och Tra1,
9:519-523.
PU-26* Katuscak, S., I. Rybarik, E. Paulinyoya & M. Mahdalik, 1971b,
"Ozonation of Lignin, Pt. II. Investigation of Changes in the
Structure of Methanol Lignin During Ozonation." Papper och Tra1,
11:665-670.
PU-27* Kiryushina, M.F. & D.V. Tishchenko, 1968, "Soda Lignin III.
Lignin-Carbohydrate Bond in Soda Lignin From Hardwoods", Zhur.
Priklad. Khim. (Leningrad) 41(8):1848-1853. Chem. Abstr. 70:12767p
(1969).
PU-28* Kobayashi, T., J. Hosokawa & T. Kubo, 1976, "Bleaching of Pulp
with Ozone", Japan. Kokai 76,139,902, Dec. 2. Appl. 75/62,660, May
26, 1975.
PU-29 Lantican, D.M., W.A. Cote, Jr. & C. Skaar, 1965, "Effect of Ozone
Treatment on the Hygroscopicity, Permeability and Ultrastructure
of the Heartwood of Western Red Cedar", Indl. Engrg. Chem., Prod
R&D 4(2):66-70.
PU-30 Liebergott, N., ca 1969, "Paprizone Treatment. A New Technique
for Brightening and Strengthening Mechanical Pulps." Publication
Not Identified.
PU-31 Liebergott, N. 1975, "Use of Ozone in the Pulp & Paper Industry
for Pulp Bleaching." in Ozone for Water &_ Wastewater Treatment,
R.6. Rice & M.E. Browning, Eds7T~Intl. Ozone Assoc., Cleveland,
Ohio, p. 614-624.
255
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PU-32 Melnyk, P.B. & A. Netzer, 1976, "Reactions of Ozone With Chromo-
genic Lignins in Pulp and Paper Mill Wastewater", in Proc. Sec.
Intl.. Syjnp. on Ozone Techno]., R.G. Rice, P. Pichet OCT.TTncent,
Eds. Intl. Ozone Assoc., Cleveland, Ohio, p. 321-335.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, W. KUhn & H.
Wolf, 1978, "An Assessment of Ozone and Chlorine Dioxide Technolo-
gies for Treatment of Municipal Water Supplies", U.S. EPA Report
EPA 600/2-78-147. U.S. Environmental Protection Agency, Municipal
Environmental Research Laboratory, Cincinnati, Ohio.
PU-33 Moergeli, B., 1973, "Possible Uses of Filtration in the Clarifi-
cation of Residual Wastewater." Wochenbl. Papierfabr. 101 22):875.
Chem. Abstr. 80(12):63609c (1974).
PU-34* Moore, W.E., M. Effland, B. Sinha, M.P. Burdick & C. Schuerch,
1966, "The Resistance of Hemicelluloses in Wood Fiber to Degrada-
tion by Ozone". TAPPI 49(5):206-209.
PU-35 Mueller, J.C. & C.C. Walden, 1970, "Microbiological Utilization of
Sulfite Liquor", British Columbia Research Report 323.
PU-36 Nakano, J. & N. Migita, 1968, "Degradation of Lignin With Ozone",
Kogyo Kagaku Zasshi 71(8):1214-1217. Chem. Abstr. 70:12761n
(1969).
PU-37 Nebel, C. e_t al_._, 1974a, "Ozone Decolorization of Effluents From
Secondary Effluents", Paper Trade J. 158(4):24.
PU-38* Nebel, C., R. Gottschling & H.J. O'Neill, 1974b, "Ozone: A New
Method to Remove Color in Secondary Effluents". Pulp & Paper
48(10):142-145.
PU-39* Nebel, C., R.D. Gottschling & H.J. O'Neill, 1974c, "Ozone Decolo-
rization of Pulp and Paper Mill Secondary Effluents", in Proc. 7th
Mid-Atlantic Indl. Wastes Conf.. Drexel Univ., Philadelphia, PaTT"
p. 161-187.
PU-40 Nebel, C., R.D. Gottschling & H.J. O'Neill. 1975, "Ozone Decolori-
zation of Secondary Pulp & Paper Mill Effluents." in Ozone for
Water & Wastewater Treatment. R.G. Rice & M.E. Browning, EdsTT
Intl. Ozone Assoc., Cleveland, Ohio, p. 625-651.
PU-41* Neimo, L., H. Sihtola, 0, Harva & A. Sivola, 1967, "Graft Copoly-
mers of Cellulose. Polymerization Initiated by Decomposition of
Cellulose Peroxides." Papper och Tra1. 8:509-516.
PU-42 Ng, K.S., J.C. Mueller & C.C. Walden, 1978, "Ozone Treatment of
Kraft Mill Wastes", J. Water Poll. Control Fed. 50(7):1742-1749.
256
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PU-43 Osawa, Z. & C. Schuerch, 1963a, "The Action of Gaseous Reagents on
Cellulosic Materials. I. Ozonization and Reduction of Unbleached
Kraft Pulp". TAPPI 46(2):79-84.
PU-44* Osawa, Z., W.A. Erby, K.V. Sarkanen, E. Carpenter & C. Schuerch,
1963b, "The Action of Gaseous Reagents on Cellulosic Material. II.
Pulping of Wood with Ozone". TAPPI 46(2):84-88.
PU-45* Ottman, R., 1972, "Ozonation of Kraft Pulp & Paper Effluents",
Private Communication.
PU-46* Pristupa, A.M., 1974, "Treatment of Industrial Effluents and
Gaseous Discharges in U.S. Industries", Bumazhn. Promy. (Moscow)
12:23-26.
Rice, R.G. & M.E. Browning, editors, 1976, Ozone: Analytical
Aspects and Odor Control. Intl. Ozone Assoc., Cleveland, Ohio.
PU-47 Samuelson, 0., G. Grang§rd, K. Jonsson & K. Schramm, 1963, Svensk.
Papperstidn. 56:779-784.
PU-48 Secrist, R.B. & R.P. Singh, 1971, TAPPI 54(4):581.
PU-49 Smith, M.A. & R.R. Furgason, 1976, "Use of Ozone in the Treatment
of Kraft Pulp Mill Liquid Wastes. Part II. Biodegradation", in
Proc. Sec. Intl. Symp. on Ozone Techno!., R.G. Rice, P. Pichet &
MT^AT Vincent, Eds., Intl. Ozone Assoc., Cleveland, Ohio, p. 309-
320.
PU-50 Soteland, N. & K. Kringstad, 1968, "The Effect of Ozone on Some
Properties of High Yield Pulps". Norsk Skogindustri 22(2): 46-
52.
PU-51 Soteland, N., 1971, "The Effect of Ozone on Some Properties of
Groundwoods of Four Species. Part 1." Norsk Skogindustri 25(3):-
61-66.
PU-52 Soteland, N. 1974, "Bleaching of Chemical Pulps with Oxygen and
Ozone." Pulp & Paper Mag. of Canada 76(4):91-96.
PU-53 Soteland, N. & V. Loras, 1974, "The Effect of Ozone on Mechanical
Pulps." Norsk Skogindustri 28(6):165-169.
PU-54 Stern, A.M. & L.L. Gasner, 1974, "Degradation of Lignin by Combined
Chemical and Biological Treatment", Biotech. Bioengrg. 16:789-805.
PU-55 Tuggle, M.L., 1972, "Reactions of Ozone With Reduced Sulfur Com-
pounds Present in Kraft Mill Gaseous Emissions", Natl. Council of
the Paper Indy. for Air & Stream Improvement, Techn. Bull. No. 58,
Feb.
257
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PU-56 Tyuftina, V.I., 1971, "Reduction of Effluent Color Intensity by
Ozonization", Sb. Tr. VNII Gidroliza Rast. Mater. (USSR) 19:209
Abstr. Bull. Inst. Paper Chetn. 42:11444 (1972).
PU-57* Watkins, S.H., 1973, "Coliform Bacteria Growth and Control in
Aerated Stabilization Basins". EPA Report No. EPA/660/2-73-029,
Dec., p. 220-221.
PU-58* Whitteraore, R.C. & J.J. McKeown, 1974, "Preliminary Laboratory
Studies of the Decolorization and Bactericidal Properties of Ozone
in Pulp and Paper Mill Effluents." Nat'l Council of"the Paper
Industry for Air & Stream Improvement, Inc., Technical Bulletin
#269, January, (40 pages).
PU-59 Wigren, G.A. 1965, "Bleaching of Pulp in a Chlorine-containing
Bath Treated with Ozone." German Patent #1,293,875, January.
258
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SOAPS AND DETERGENTS
Ozonation Of ABS (Alkylbenzene Sulfonate)
The first reported studies of ozonation of wastewaters containing
synthetic detergents were reported by Buescher & Ryckman (1961) who ozonized
settled raw sewage and activated sludge sewage treatment plant effluent
samples which contained ABS (tertiary AlkylBenzene Sulfonate) detergents.
The objectives of this work were to reduce the foaming observed in aeration
basins of activated sludge plants caused by ABS (sometimes 2 to 5 ft deep)
and to remove ABS from surfactant-laden wastewater solutions. Foam properties
were observed in ozonized sewage treatment plant waters and distilled water
solutions of ABS were ozonized to determine the extent of ABS oxidation.
Ozone was generated from air and concentrations in the reactor feed gas and
off-gases were measured. The ozonation reactor was a flask (unspecified
size, but larger than 2,500 ml) through which ozone was bubbled by means of
a glass tube (not fritted).
Two types of measurement were made. The first was an aeration test
under conditions similar to those existing in an activated sludge aeration
basin. Foam heights above a U500 ml sample in a tall column were measured
after 10 minutes of aeration. The second method was the shake test, in
which a 50 ml sample in a 100 ml Nessler tube was shaken 25 times. The foam
volume and time for the foam to break were determined, giving measures of
foam production and foam stability.
Settled raw sewage containing 168 mg/1 of BOD and an ABS concentration
of 21 mg/1 was ozonized (2.5 liter samples) for 2.5 hrs each, and subjected
to 10 minute aerations before and after ozonation. Of the ]»057 mg/1 ozone
dosage, only 342 mg/1 was absorbed, thus the contacting efficiency was only
32%. After about 300 mg/1 of ozone (per 2.5 1) had been absorbed, the
samples produced no foam upon subsequent aeration. Before ozonation, the
foams produced were 10.5 inches in height. The sewage changed color during
ozonation from an opaque gray to chalky white, and the odor changed to a
chemical odor which was judged to be "not objectionable". Foam reduction
and ABS removal proceeded at the same rates as ozonation progressed.
Additional quantities of ABS (10 mg/1) were added to sewage treatment
plant effluents containing 13 mg/1 of BOD. This gave ABS concentrations of
6.8 and 16.8 mg/1. Effluents containing 6.8 and 16.8 mg/1 of ABS were
ozonized 20 and 40 minutes, respectively. Both samples absorbed about 50%
of the applied ozone. The amounts of absorbed ozone required to reduce ABS
concentrations in the effluents were less than those needed for the raw
sewage. By the shake test, foaming ceased when 24 mg/1 of ozone had been
absorbed. Ozonation to this level also eliminated foaming (23 inches in
height before ozonation).
To halt foaming, raw sewage required 135 minutes of ozonation, whereas
activated sludge effluent required only 5 minutes of ozonation. The ABS-
spiked activated sludge effluent required 10 minutes of ozonation to eliminate
259
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foaming. As ozonation progressed, the foams became progressively less
stable.
Solutions of distilled water containing 50 mg/1 of ABS (62.4% + 31%
Na2S04) were ozonized and the degree of oxidative destruction of ABS was
followed by determining the amount of inorganic sulfate formed (above the
starting level). ABS concentration decreased linearly up to about 90 mg/1 of
ozone absorbed (about 80% ABS destruction) and then levelled off up to 125
mg/1 of ozone absorbed (88% ABS destruction). During the linear portion,
from 2 to 4 parts of ozone absorbed were required to remove 1 part of ABS in
either sewage effluent or distilled water.
Buescher & Ryckman (1961) concluded that ozonation of activated sludge
effluent to eliminate foaming caused by ABS would be economical if the ABS
concentration is not greater than about 4.5 mg/1. This would require 12
mg/1 of ozone absorbed at 4.5 mg/1 of ABS (2.67 mg of ozone/mg of ABS).
They also concluded that ozonation of activated sludge effluents from sewage
treatment plants has additional advantages, such as color and odor removal.
Ozone oxidized the ABS molecule, but "apparently not completely to CO? and
water, though there are indications that the para-substituted benzene rings
and the sulfonate rings are removed".
Evans & Ryckman (1963) reported further studies on the ozonation of
Highland, Illinois sewage containing ABS detergents. In this work, 45 gal
samples of primary and secondary treated sewage (containing 6.4 mg/1 ABS),
of sewage treatment plant effluents containing an additional 10 mg/1 ABS
(16.4 mg/1 total) and distilled water containing 50 mg/1 of ABS were ozonized,
Biochemical behavior of the ozonized samples was observed by following the
changes in BOD.
For this study, the ozone contactor was a single column 10 ft tall with
a vertical mixing recirculating system in the lower section. Samples (3.8
liters) were ozonized for 2 to 120 minutes. The amount of ozone absorbed
was determined by subtracting the amount of ozone found in the contactor
off-gases from the amount of ozone dosed. Ozonized liquids were analyzed
for ABS, COD and BOD. Secondary effluent samples and those with 10 mg/1 of
added ABS were ozonized in duplicate for 2.5, 10, 20, 30, 45, 60, 90 and 120
minutes. The sample of 50 mg/1 ABS in distilled water was ozonized at an
ozone/air flow rate of 0.1 cu ft/min for periods up to 120 minutes.
Removal of ABS was rapid at first for the sewage samples, then began to
taper off at 45 mg/1 of ozone dosage (sample spiked with 10 mg/1 of ABS) and
25 mg/1 (unspiked sample), respectively. Reduction of ABS concentration
from 6.4 to 1.0 mg/1 (unspiked sample) required 150 mg of ozone; reduction
of ABS concentration from 16.4 mg/1 (spiked sample) required 250 mg of ozone
(in 3.8 liters of sample). The additional 10 mg/1 of ABS in the spiked
sample required 100 mg of ozone. Stated another way, 2.64 mg/1 of absorbed
ozone was required to eliminate 1.0 mg/1 of ABS from the samples.
260
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The greater the starting concentration of ABS, the greater the amount
of ABS that was removed while maintaining ozone transfer efficiency at 86 to
90%. As the quantity of ozone utilized increased, the COD of the samples
decreased.
The BOD-5 of sewage treatment plant effluent samples was reduced to 0
mg/1 after absorption of 180 mg/1 of ozone, but twice as much ozone was
required to reduce the BOD of the ABS-spiked sample to 1 mg/1. The BOD of
the spiked sample increased with increasing ozonation until the point at
which ABS no longer was detectable, then fell. Thus at low concentrations,
ABS was converted to intermediates which were biodegradable. At higher
concentrations of ozone, the ozonation products were oxidized further, such
that the products no longer exerted a BOD.
For the first 10 minutes of ozonation, the distilled water sample
containing 50 mg/1 of ABS inhibited activated sludge organisms, but this
effect disappeared after 10 minutes of ozonation. By increasing the amount
of applied ozone, the rate of biological reaction increased.
Evans & Ryckman (1963) postulated that when alkylbenzenes are ozonized,
the alkyl group is converted to a carboxyl group, the point of attack being
the carbon attached to the benzene ring. Upon continued ozonation, the
aromatic ring is ruptured:
CHoCH D
2 2 RCOOH
Ring Rupture
Evans & Ryckman (1963) concluded that ozonation of wastewaters containing
ABS lowers both COD and BOD concentrations and destroys the biological
inertness of ABS.
Kandzas & Mokina (1968, 1969) confirmed that ozonation easily oxidizes
ABS compounds. They studied sewage which contained ABS and sodium dodecyl-
benzene sulfonate. Both of these compounds were readily oxidized upon ozone
treatment.
On the other hand, Kwie (1969) found during the ozonization of SANS
that only 1 aromatic ring of its molecule was ruptured, which did not improve
the biodegradability of this compound.
261
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Other Surface-Active Agents
Verde, Meucci & Vanni (1969) and Kuiz (1970) established that ozone
effectively oxidized several anionic surface active agents in water. The
extent of oxidative destruction depended not only on the properties of the
treated substances and their concentrations, but also upon the dose of ozone
and the time of ozonation.
MaTkina & Perevalov (1970) ozonized solutions of the Russian-made non-
ionic surface active agents OP-10, OZhK and Disolvan 4411 and noted that
these materials were destroyed effectively by ozonation.
Recycle Of Car Wash Haters
Baer (1970) described a Viennese car wash wastewater treatment and
recycling system which uses ozonation. The city of Vienna would only allow
this car wash facility to draw 793 gal/day of potable water, although initial
needs were forecast at 12,417 gal/day. The solution to the problem in this
700-car parking garage was to install a wastewater treatment system capable
of treating 19,915 gal/day of wastewater and add to it the 793 gal/day of
potable water allowed by the city.
The treatment process involves collecting car wash water in an open
3,963 gal tank. In an oil separator, an upward gush of compressed air
causes foaming. After the foam has been skimmed off, the solution is trans-
ferred to a solids separator and held for three hours to allow sediment to
settle. Flocculating agents can be added at this point to promote further
separation of colloidal matter. The intermediate solution contains soluble
detergents and very fine sediment, which is trapped in a gravel filter as
the solution is transferred to the ozonation tank.
Both the contaminated water and some fresh water enter the ozonation
tank countercurrently to the upward flow of ozone gas being applied at 4 to
6 atmospheres pressure. This causes high turbulence in the reaction vessel
during the 15 to 20 minute contacting time. Water is drawn out of the
bottom of the tank and reinjected at the top. In the final step, the treated
water is passed through a charcoal filter on its way to a storage tank.
One alternative to this treatment process would have been to dig a
well, however the groundwater level at this location is about 820 ft below
the surface, and the cost of installing a well this deep was estimated at
$61,500. In addition, there would have been the added cost of wastewater
disposal. The cost for the ozonation process was about $23,000 and there is
zero discharge of wastewaters.
This car wash wastewater treatment system is described in detail in 2
U.S. patents issued to Marschall (1973, 1974).
262
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Conclusions
1) Ozonation of sewage treatment plant effluents containing ABS eliminated
the tendency to foam in 5 minutes (1 mg of ABS required 2.67 mg of
ozone). Ozone oxidizes the ABS molecule, but not completely, to C02
and water. The reaction products of ozonation are biodegradable.
2) A Vienese car wash has recycled 19,915 gal/day of its wastewaters by
aeration, skimming, sedimentation, flocculation, filtration, ozonation
and charcoal filtration since 1970.
LITERATURE CITED — SOAPS AND DETERGENTS (SD)*
SD-01* Baer, F.H., 1970, "Ozone Step Allows Recycle of Organic-Fouled
Water", Chem. Engrg., Aug., p. 42.
SD-02 A. Buescher, Jr. & D.W. Ryckman, 1961, "Reduction of Foaming
of ABS by Ozonation", Proc. 16th Ann. Purdue Indl. Waste Conf., p.
251-261.
SD-03* Evans., F.L., III & D.W. .Ryckman, 1963, Ozone Treat-
ment of Wastes Containing ABS," Proc. 18th Indl. Waste Conf.,
Purdue Univ., p. 141-157.
SD-04 Grossman, A., K. Kwiatkowska & M. Zdybiewska, 1970, "Use of Ozone
for the Decomposition of Organic Substances in Water." Zese. Nauk,
Politech. Slask., Inz. Sanit. (Politech, Slaka, Gliwice, Poland).
SD-05 Kandzas, P.F. & A.A. Mokina. 1969, "Use of Ozone for Removing
Synthetic Anionic Surface-Active Agents from Wastewaters". In the
book: Ochistka Proizvodstvennykh Stochnykh Vod. (Purification of
Industrial SewageTMoscow, 4:76.
SD-06 Kandzas, P.F. & A.A. Mokina, 1968, Trudy Vsesoyuzn. Nauchno-
Issled. In-ta Vodosnabzheniya, Knalizatsii Gidrotekhnic heskikh
Sooruzheniy i Inzh. Gidrogeologii (Works of the All-Union Scientific
Research Institute of Water Supply, Sewage, Hydrotechnical Structures
and Hydrogeological Engineering) 20:40.
SD-07 Kuiz, C.G., 1970, Grasas aceit. 21:91.
SD-08 Kwie, W.W., 1969, "Ozone Treats Waste Streams From Polymer Plant",
Water & Sewage Works 116:74-78.
SD-09 Mal'kina, I.I. & V.G. Perevalov, 1970, "Removal of Some Nonionic
Surface-Active Agents from Water by Ozone Treatment." Neft. Khoz.
SD-10* Marschall, K., 1973, "Process of Treating and Purifying Sewage,
Particularly of Sewage Contaminated with Detergents." U.S. Patent
3,733,268, May 15.
Abstracts of asterisked articles will be found in EPA 600/2-79- b.
263
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SD-11* Marschall, K., 1974, "Process of Treating and Purifying Sewage,
Particularly of Sewage Contaminated with Detergents." U.S. Patent
3,822,786, July 9.
SD-12 Verde, L., F. Meucci & G.C. Vanini, 1969, Ing. Mod. 62:277.
264
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TEXTILES
Wastewaters from dye manufacturing and textile dyeing plants normally
are highly colored and contain organic dyestuffs, sizing agents (organic and
inorganic), surface active agents, organic acids and inorganic acid salts.
Depending upon the season, different organic dyes are employed. Therefore,
the specific causes of color, BOD and COD change seasonally in this industry.
Ozonation of textile industry wastewaters, primarily for the elimination of
color, began to be reported in the early 1970s.
Bauch & Burchard (1970) studied the ozone treatment of odorous and
"harmful" wastewaters from a number of industries, including a textile
processing plant. Textile plant wastewaters treated in various manners
showed the properties listed in Table 59. The ozone contactor employed was
a perpendicular glass tube 2 m long and 40 mm in diameter, which contained a
porous G-3 frit. The sample volume was 1.5 liters.
TABLE 59. TREATMENT OF TEXTILE WASTEWATERS WITH OZONE
Treatment
After 2 hrs sedimentation
After pptn with FeClg + NaOH
After 2 hrs settling, + 10
min chlori nation
After 2 hrs sedmtn, + ozone*
After 2 hrs settling + 10 min
C12 + 20 min ozone*
KMn04 No.
(mg/D
460
430
590
81
42
BOD-5
(mg/1)
300
70
40
Fats &
Oils
(mg/1)
43
traces
32
20
Foami ng
Strong
Distinct
Slight
Slight
Hardly
* 20 mq/1 of ozone in air
Source: Bauch & Burchard, 1970.
From the data of Table 59 it can be seen that treatment of the settled
wastewater with chlorine increased the permanganate number 20 to 25%, whereas
treatment with ozone lowered the permanganate number about 82% and the BOD-5
by 77%. However, treatment with chlorine followed by ozonation lowered
these values by 91% and 87%, respectively.
Smirnova et aj_. (1972) studied the use of ozone for removing sodium
thiocyanate from an acrylic fiber wastewater stream. An ozone dosage of 1.2
to 1.3 mg/1 of ozone/g of NaCNS "was effective under alkaline conditions".
Maeda ejt aj_. (1972) described a field test at an industrial plant "for
the first time in the world" involving ozonation of a dyeing wastewater.
265
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The test unit had a wastewater treatment capacity of TOO cu m/hr and followed
coagulation. It was installed at the Kurokawa Kogyo Jyoyo plant in Japan in
I y /1 •
GAC alone was found to be effective for color removal, but required
frequent regeneration. Ozonation of the wastewaters followed by GAC adsorp-
tion was effective and "sludgeless". The time for ozonation was 20 to 30
minutes and no pH adjustment was required during ozonation.
Hydrophilic dyes (reactive, cationic or acidic) were shown to be quite
reactive to ozone, less than 1 g of ozone being required to decolorize 1 g
of this type of dye. For disperse dyes, however, more than 1 g of ozone was
required to decolorize 1 g of dye, although the exact amount of ozone required
depended upon the individual dye.
The Kurokawa test unit contained three ozonizers, each capable of
producing a maximum of 2.4 kg/hr (normally 1.8 kg/hr) of ozone from air.
The wastewater treatment process steps in this installation were: lime
addition, coagulation, polymer flocculation, precipitation, ozonation, first
stage aeration and second stage aeration. The normal addition rate of ozone
ranged from 19 to 22 g/cu m. Injection of ozone also could be accomplished
after the first treatment step of aeration, after the second aeration step,
or both, either in parallel or in series. Wastewaters tested contained
about 140 mg/1 of BOD.
The pH was adjusted to 9 with NaOH, coagulant and polymer were added,
the mixture was sent to a sedimentation tank, then to the aeration tank
where it was ozonized using an injector contactor. The BOD level was lowered
from 150 to 78 mg/1 and the percent transmission increased from 80.5 to
96.2%.
Ozone concentrations in the gas phases were monitored before and after
two stage injection into the wastewater. The ozone contacting efficiencies
were 83 to 100%, the amount of decolonization obtained was 79 to 98% and the
mg of ozone consumed per mg of TOC destroyed was 0.105 to 0.225.
Maeda et al_. (1972) make the point that one cannot determine the ozone
capacity that will be required to treat textile wastewaters simply by deter-
mining the concentrations of pollutants. One must test the actual wastewaters
to be treated, which vary quite widely in composition. Therefore, the best
approach is to sample at different time intervals, then mix these samples.
This will provide a sample of "average" wastewater quality.
Although ozonation was effective for decolorization, it was not effective
with sulfide dyes nor with chromium-containing dyes at this pilot facility.
Table 60 summarizes the cost data presented by Maeda ejt a]_. for the
Kurokawa test facility.
266
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TABLE 60. COSTS FOR TREATMENT OF.DYEING WASTEWATERS BY OZONATION
Wastewater to be treated
Volume of water to be treated
Installation cost
(pretreatment + ozonation)
Ozonizer
Operating Costs
Chemicals
NaOH
PAC
Polymer Coagulant
Electrical Power
Pretreatment
Ozonation
Total
From synthetic fiber plants,
mainly cationic dyes
1,500 cu m/day (360,000 gal/day)
About 28 million yen
Model OS-1200
62 (54 mg/1, 30 yen/kg)
Mitsubishi
Yen/cu m
7.47
1.
5.00 (200 mg/1, 25 yen/kg)
0.85 (1 mg/1, 850 yen/kg)
2.72
0.96 (32 kW, 4.5 yen/kWhr)
1.76 (58 kW, 4.5 yen/kWhr)
10.19 yen/cu m
Source: Maeda et al., 1972
Stuber (1973, 1974, 1975a,b,c) studied the ozonation of carpet dye
wastewaters after secondary biological treatment at the Dalton, Georgia
municipal wastewater treatment plant. Ozone was generated from oxygen and
the contactor was a 5.5 inch diameter x 8 ft tall cylindrical plexiglass
column which contained a polyethylene diffuser. The contactor volume was 10
gal (37 liters).
The Dalton, Georgia municipal wastewater treatment plant is a 40 mgd
activated sludge plant. Approximately 90% of its wastewater feed originates
from more than 200 carpet producing and tufted dyeing plants. Table 61
lists the characteristics of the wastewater influent and Table 62 lists the
characteristics of the secondary treated effluent.
TABLE 61. SELECTED INFLUENT CHARACTERISTICS: DALTON. GEORGIA PLANT
Constituent
BOD-5
COD
Total Solids
Total Suspended Solids
Volatile Suspended Solids
Alkalinity (Methyl Orange)
PH
Source: Stuber, 1973
Concentration
(ma/1)
200
540
850
125
100
73
6.8
267
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TABLE 62. SELECTED EFFLUENT CHARACTERISTICS: DALTON. GEORGIA PLANT
Constituent
True Color, APHA units
Total Phosphate,
COD
Total Col i forms
Fecal Col i forms
BOD-5
Total Suspended Solids
Volatile Suspended Solids
Total Solids
Ammonia Nitrogen
MBAS
Biphenyl
Source: Stuber, 1973
Concentration
300
50 mg/1
150 mg/1
3,000,000 per 100 ml
2,000,000 per 100 ml
20 mg/1
30 mg/1
30 mg/1
580 mg/1
0.3 mg/1
3 mg/1
2.0 mg/1
For this study, Stuber used 20 gal grab samples which were refrigerated
until the ozonation experiments were conducted, which was always within 24
to 48 hrs of sampling. Ozone was monitored in both-the contactor influent
and effluent gases; ozone transfer efficiencies were 79% to 100%, depending
upon the dosage applied. Pertinent data are listed in Table 63.
TABLE 63. OZONE TRANSFER EFFICIENCIES INTO DALTON, GEORGIA WASTEWATER
TREATMENT PLANT EFFLUENT
Ozone Applied
0 -
28 -
58 -
100 -
28 mg/1
58 mg/1
100 mg/1
150 mg/1
Transfer Efficiency
85
82
79
100%
- 100%
- 95%
- 85%
Source: Stuber, 1973.
Stuber (1973) drew the following conclusions from ozonation studies of
the Dal ton, Georgia wastewaters:
1) Reductions in COD concentrations of 40% were attained at ozone dosages
of 45 mg/1. SS removal prior .to ozonation did not enhance COD removal
by ozonation.
2) No fecal coliforms were present at ozone dosages above 25 mg/1.
3) Total coliforms were less than 100 MPN/100 ml at ozone dosages of 45
mg/1.
268
-------
4) True color levels were reduced to less than 30 APHA units at ozone
dosages of 40 mg/1. Lowering of SS levels prior to ozonation lowered
the ozone dose necessary to attain less than 30 APHA color units to
26.5 mg/1.
5) Soluble organic carbon levels increased slightly with increasing ozone
dosages when SS were present, but eventually decreased at extremely
high dosages.
6) SS levels were reduced about 90% by ozonation.
7) The BOD-5 increased 150% at ozone dosages of 8 to 15 mg/1, but was
essentially unchanged at dosages above 25 mg/1. Therefore, biorefractory
organics were being converted into biodegradable organics during the
early stages of ozonation.
8) Biphenyl concentrations were reduced from about 2 mg/1 to less than 0.1
mg/1 at ozone dosages of 89 mg/1.
9) Anionic detergent levels were reduced from about 0.6 mg/1 to below 0.1
mg/1 at ozone dosages of 15 mg/1.
10) Foaming problems were reduced with increasing ozone dosages and were
eliminated in the range of 50 to 100 mg/1 ozone dosage.
11) DO residuals were on the order of 40 mg/1 when oxygen was used to
generate ozone.
12) Ozone residuals could be measured up to 20 minutes after contacting.
13) The transfer efficiency of ozone into solution was 85% to 100% at ozone
dosages up to 58 mg/1.
Nebel and Stuber (1976) expanded upon the earlier work of Stuber
(1973, 1974, 1975a,b,c) of ozonation of Dalton, Georgia municipal wastewater
secondary effluents. Grab samples 20 gal in size were stored under refrigera-
tion and treated within 48 hrs of collection. The ozonation contactor was a
plexiglass column having a height of 8 ft, a diameter of 5.5 inches and a
capacity of 37 liters (10 gal). Ozone was generated from oxygen and sparged
into the column through a 60 u, high density polyethylene diffuser. Ozone
was analyzed both in the contactor feed gas and in the off-gases. GAC
adsorption was tested to compare the amount of reduction in color and COD
levels.
The major sources of colors in Dal ton's wastewaters are synthetic
organic dyes which are not destroyed by activated sludge treatment. These
produce color levels of about 300 APHA units. Filtered and unfiltered
wastewaters were ozonized to determine the amount of ozone necessary to
attain a target color removal to levels of 30 to 60 APHA units. The amount
of ozone required to lower the color of filtered secondary effluent to 20
269
-------
APHA units was 32.5 mg/1; that required to lower the color of unfiltered
effluent to 30 APHA units was 45 mg/1 of ozone.
At these ozone dosages, the levels of COD decreased rapidly as ozone
dosages rose to 45 mg/1, then slowed and approached 40 to 45% total reduction
in value. There was no significant advantage to removing SS to effect
higher COD removals. This indicated that the SS present in this effluent
were attacked by ozone at a much slower rate than was the dissolved COD.
The BOD-5 increased from 21 to 53 mg/1 as the ozone dosage increased
from 0 to 13.6 mg/1, then decreased to 21 mg/1 at an ozone dosage of 34
mg/1. The COD concentration decreased in the range in which BOD-5 increased,
proving that an oxidation process was taking place. Soluble organic carbon
increased from 48 to 58 mg/1 up to an ozone dosage of 75 mg/1, then decreased
to about 33 mg/1 at an ozone dosage of 165 mg/1. Samples containing SS
showed increased levels of soluble organic carbon after ozonation, while
samples which showed decreased levels of soluble organic carbon contained no
suspended material.
SS levels were lowered significantly upon ozonation, from 20 mg/1 to 2
mg/1. Total coliform counts were reduced from 850,000 MPN/100 ml to 2,500
MPN/100 ml at ozone dosages of 28.6 mg/1. Fecal coliform counts were lowered
from 8,000 MPN/100 ml to 0 MPN/100 ml at 22 mg/1 ozone dosages.
Table 64 shows the changes in wastewater parameters obtained by treating
unfiltered Dal ton, Georgia secondary effluent with 45 mg/1 of ozone, to
reach 30 APHA units of color level — considered to be acceptable by the
local regulatory agency since background levels of the receiving river are
about 20 APHA units.
TABLE 64. TREATMENT OF.UNFILTERED DALTON. GEORGIA EFFLUENT WITH 45 MG/L OZONE
Parameter
Color,
COD
BOD
DO
Organic Carbon
Inorganic Carbon
Suspended Solids
Biphenyl
Initial
275 APHA
156 mg/1
21 mg/1
2 mg/1
53 mg/1
3 mg/1
20 mg/1
1.85 mg/1
Anionic Detergents 0.6 mg/1
Fecal Col i forms
Total Coli forms
PH
8,000/100 ml
850,000/100 ml
6.8
Final
30 APHA
94 mg/1
21 mg/1
8.5 mg/1
54 mg/1
5 mg/1
3 mg/1
0.90 mg/1
0.05 mg/1
0/100 ml
>1, 000/100 ml
7.1
Change
- 89%
- 40%
0%
+ 325%
+ 2%
+ 67%
- 85%
- 51%
- 92%
- 100%
-99.99%
+ 4%
Source: Nebel & Stuber, 1976
270
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Economic comparisons between ozonation treatment at dosages of 45 mg/1
and GAC treatment to attain the same degree of color removal are shown in
Table 65. Assumptions made in this comparison were as follows: 12 mgd
wastewater flows require generation of 4,500 Ibs/day of ozone and 780 Ibs/day
makeup GAC; the cost of GAC is 50<£/lb; 5% of the GAC is lost during reacti-
vation; reactivation cost is 8
-------
contained sodium sulfide, sodium sulfite, sodium thiosulfate, p-aminophenol,
p-nitrophenol and various organic intermediates as major constituents; the
plant discharged 15 tons/day of wastewater. Soluble organic substances
accounted for about 50% of the initial 60,000 mg/1 COD values.
Ozonation was conducted in either of 2 tanks, a 6-liter tank and a 14-
liter tank, using gas dispersion tubes. Ozone was generated from air and
could be measured in the contactor inlet and off-gases. Alkaline oxidation
of 60 g of Na2S203.5H20 plus 20 g of NaOH (in 6 liters) over 7 hours used
25.87 g of ozone (1.47 g of thiosulfate/g of ozone). Sodium sulfite was
produced as an intermediate, which was oxidized to sodium sulfate. When the
concentration of thiosulfate was less than 7.0 g/6 liters, the solution
contained 5 to 7 g of sodium sulfite at all times during ozonation as long
as thiosulfate was present (Figure 24).
A 3-liter sample containing 171.65 g of sodium thiosulfate was treated
with 107 g of sulfuric acid and the solution was aerated for 2 hrs. Under
these conditions, S02 was produced and the COD dropped from 20,670 to 10,500
mg/1 (49.2% reduction in COD level; 79.3% reduction in thiosulfate concentra-
tion). This solution then was ozonized for 1 hr and the COD dropped to
7,500 mg/1 (total COD reduction of 63.7%; total thiosulfate reduction 99.9%).
Concentration
of thiosulfate
40
& sulfite in
6 1 of 30
water
(mg/1)
20-
10
Source: Maeda (1974)
Figure 24.
i 2 3
Ozonation time (hours)
Ozonation of thiosulfate solution.
Three treatments were conducted on 1 liter samples of reducing waste
liquids at pH 9.5 to 10.5: (1) ozonation alone; (2) addition of 10 ml of
formalin, stir, heat (to promote condensation polymerization of phenolics),
filtration and ozonation; (3) 4 liters of liquid treated with formalin,
condensation products filtered, FeS04 added to remove sulfite, H2SO/i added
to pH 3.0 to 3.5, aerated to remove thiosulfate, then pH re-elevatea and
ozonized. Pertinent results are shown in Table 66. Method (3) gave the
best removal of COD.
272
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Maeda (1974) concluded that initial treatment of this type of wastewater
(at pH 9.5 to 10.5) with formalin will remove some soluble organics by
condensation polymerization, and the corresponding reduction in COD levels
can reach 50%. Adjustment of pH to 3.0 to 3.5 will remove some sulfide and
some condensation polymers which were soluble at elevated pH levels; COD
removal then will reach 63%. Thiosulfate then can be removed by ozonation,
chlorine oxidation or aeration at pH 1, giving 6,000 to 10,000 mg/1 COD (83%
to 85% overall reduction). Readjustment of pH to the alkaline side, followed
by ozonation now should produce a wastewater having a final COD value of
3,000 to 4,000 mg/1.
TABLE 66. OZONATION OF REDUCING WASTE LIQUID FROM DYE MANUFACTURING*
Treatment
Method**
1
2
3
4
* Initial ph
k* Method 1 :
Method 2:
Method 3:
Source:
Total
Ozonation
Time
11 hrs,
55 min
8 hrs
2 hrs
7 hrs
Initial
COD
(mg/1)
40,000
45,000
7,650
7,650
Final
COD
(mg/1)
7,800
4,400
3,230
981
Ozone
Consumption
(2}
42.5
29.6
% Reduction
of COD
value .
80
90.3
57.8
87.2
: 9.5 to 10.5
Ozonation alone
Polymerization with formaldehyde, filtration, ozonation
Polymerization with formaldehyde, filtration, add FeS04
(for sulfite), add h^SO* to pH 3.0 - 3.5, aerate (for
thiosulfate removal), elevate pH and ozonize.
Maeda, 1974
Snider & Porter (1974) described the ozone treatment of selected
wastewater streams from dyeing operations. Ozone was generated from air and
the contactor was a 750 ml gas washing bottle with a sintered glass dispersion
stone. Then 500 ml samples were ozonized. The off-gases were collected in
a second gas washing bottle and analyzed for ozone. The time required for
ozone to penetrate into the second bottle ranged from less than 1 to about
30 minutes.
All experiments were conducted at room temperature and the usual ozone
contact time was 1 hr. Three pH ranges were studied: near neutral, acidic
and basic. Ozone was generated at the rate of 0.5 g/hr. Dye wastewaters
were analyzed for COD, color, total solids, volatile solids and dissolved
solids both before and after ozonation. In addition to actual wastewater
streams, solutions of 2 commercial disperse dyes also were ozonized (Disperse
Red 60 Foron Brill Red E-2BL and Eastman Fast Blue B-GLF #27).
Data obtained confirmed the complexity and variability of the wastewater
systems studied, but pointed out some general trends, for which there were
exceptions observed in almost all cases. Ozonation normally lowered the COD
levels from a few percent to more than 50%. No significant decreases in
273
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total solids, dissolved solids or volatile solids were observed after ozona-
tion, indicating that complete oxidation of the organics to CO? and water
did not occur to any great extent. In most cases, the solids contents
increased after ozonation, mostly as a result of addition of sulfuric acid
or NaOH to adjust the pH before ozone was added.
The amount of visible color decreased dramatically in all cases, but
in some cases turbidity increased and contributed to the color readings.
Disperse dyes showed the most dramatic color decreases with no turbidity
formation. Color reduction occurred even though the COD decreases were
small. Thus, either ozone or hydroxyl radicals selectively attacked the dye
molecules, or only 1 or 2 bonds in the dye molecules needed to be broken to
render the dye colorless.
Snider & Porter (1974) concluded the following:
1) There was no steadfast relationship of pH to efficiency of color
removal by ozonation. The highest COD removal occurred at low pH in
several cases.
2) In all cases, use of low concentrations of ozone alone for removal of
the majority of the organics was not feasible (maximum removals were
55% by low level ozonation, compared with above 90% by conventional
treatment).
3) Color was reduced dramatically by application of about 1 g/1 of ozone,
but in most cases this led to an increase in turbidity which contributed
significantly to color as measured spectrophotometrically.
4) Ozone was best applied to textile wastewaters as a polishing agent to
remove dyes which were inert to conventional treatment.
In Japan, the Kanebo Company installed an ozone/GAC treatment system at
its Nagahama factory in 1974 (Anonymous, 1974). This system handles 3,300
cu m/day (0.87 million gal) of dyeing wastewaters. A "synergistic effect"
of the sequential combination of ozonation followed by GAC is noted in this
article, which also states that "the combined use of ozone and activated
carbon, as compared with the separate use of each, will often produce a
doubled effect and result in low investment costs/1 This statement is not
expanded upon further, however.
At the Nagahama factory, dyeing wastewaters are sent to a 600 cu m
holding tank from whence it is passed, consecutively, through 2 ozone
reaction towers, each 2,800 mm in diameter and 5,000 mm in height. The
specifics of ozone contacting in this installation are not described, but
ozone is supplied by means of 3 generators, each capable of producing 2.4
kg/hr of ozone from air (7.2 kg/hr total ozone generation capacity). At its
maximum addition rate, ozone dosage is 50 mg/1, and dye colors and dissolved
organic substances are decomposed at this point.
274
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Ozonized wastewater then passes through an intermediate tank and is
sent upflow at 17 m/hr through a carbon adsorption tower (pulse head type)
packed with GAC. The carbon adsorption tower is 3,200 mm in diameter and
7,500 mm in height and contains 38 tons of GAC. After carbon adsorption,
the pH of the treated v/astewater is adjusted and the water is discharged.
schematic of this system is shown in Figure 25.
Exhaust gases from the ozone contacting tower are heated and passed
through a 500 liter tower packed with activated carbon. This treatment
destroys residual ozone remaining in the contactor off-gases.
Wast» water and treated water
_._._ Ozonized air
----. Granular activated carbon
Exhaust gas
Exhaust gas treating
apparatus
•— Waste dyeing water
Discharge *
Ozone generators
and control room
Regenerating unit of
activated carbon
pH adjusting bath
I t
I Ozone reactio
Intermediate bath
Waste dyeing water
storage bath
Adsorption tower with
activated carbon
Source: Anonymous (1974a)
Figure 25. Dye wastewater treatment plant at the Kanebo Company, Japan.
Pertinent wastewater parameters obtained on these dyeing wastewaters
using the ozone/GAC process are listed in Table 67. Major points to be
noted are that the BOD values of the ozonized wastewaters are about the same
as those of the raw wastewater, and that COD values are lowered 10 to 15% by
ozonation. After GAC adsorption, both BOD and COD values have been reduced
60% to 80% from those of the raw water.
275
-------
The Nagahama factory ozone/GAC installation is claimed to be completely
free from sludges (normally produced by coagulative precipitation methods or
activated sludge treatment), only a small plant area is required for the
^,?'lat10n (about 50° sq m) and the costs of operation of the process are
34(^/1,000 gal of wastewater treated (Anonymous, 1974a).
TABLE 67. DYEING WASTEWATER TREATMENT BY OZONE/GAC AT KANEBO CO..
Parameter
Color*
PH
SS (mg/1)
BOD (mg/1)
COD (mg/1)
Phenol (mq/1)
Initial
0.2-0.35
6.0-8.0
8-15
110-160
120-170
1-2
After Ozonation
0.05-0.1
6.0-7.0
5-10
100-140
100-150
0.1-0.2
* color determined by average of absorbance at 4
and 660 nm.
JAPAN
After GAC
0.02-0.05
6.5-7.5
0.6-2
20-50
20-50
0
30, 530, 550,
610
Source: Anonymous. 1974a.
The synergistic effect of following ozonation with granular activated
carbon adsorption also was noted by Mizumoto and Horie (1974). They concluded
that the overall cost of a treatment plant using both ozone and GAC in
sequence would be less than 1 using either process alone, to attain the same
level of treatment. Ozone treatment removed only about 10% of the BOD,
while activated carbon removed 60% to 80%. Ozonation removed most of the
color and GAC adsorbed that which remained.
Even earlier, Kawazaki (1965) had studied the ozonation of surface
active agents and found that greater than 90% decomposition of these materials
could be obtained using a 5-fold excess of ozone. On the other hand, these
same surface active agents also could be adsorbed onto activated carbon,
which then could be "regenerated" using ozone. Further details of the
"ozone regeneration" of activated carbon were not given in the abstract
available.
Matsuoka (1973) in reviewing the uses of ozonation in the treatment of
drinking water and industrial wastewaters, describes 7 Japanese dye manufac-
turing plants which were using ozone at that time for treating their waste-
waters. The plants and their treatment processes are as follows:
Mitsubishi-Denki: Press & Float. Ozonation of 12,000 cu m/day of wastewater;
installed August, 1973.
Mitsubishi-Kurogawa Industries: Coagulation, then ozonation of 100 cu m/hr
of wastewaters; installed October, 1971.
Kyoshenski-Mitsubishi: Filter, activated carbon, ozonation of 50 cu m/hr of
wastewater; installed April, 1973.
276
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Organo-Shobo (Ozone Fuji-Denki): Ozonation, activated carbon treatment of
3,300 cu m/day; installed summer, 1973.
Nishimo-Mitsubishi: Press & Float. Ozonation then activated sludge treatment
of 200 cu m/day of wastewater; installed January, 1973.
Fukui-Senkyoshi: Spray filter beds, then ozonation.
Mitsubishi-Juko (Ozone Mitsubishi-Denki): Secondary treatment, coagulation,
sand filtration, ozonation then activated carbon treatment of 1,800 cu m/day
of wastewater.
Sato, Yokoyama & Imamura (1974) studied the organic oxidation products
formed when representative azo dyes were decomposed by ozone. Azobenzene
and its derivatives substituted in the para-position with -NHg, -NMe2, -OH
or -OMe groups were studied as water-insoluble dyes. Methyl orange was the
only water soluble dye studied.
Ozonation of water-insoluble azo dyes was conducted in a 100 ml bottle
containing 20 ml of CC14 plus 10 ml of water. Ozonation of methyl orange
was conducted in a 300 ml bottle containing 100 ml of methyl orange-water
solution. The amount of ozone fed was 24 mg/l/min and ozone consumption was
determined by the KI technique.
68.
Major oxidation products isolated and identified are listed in Table
TABLE 68. PRODUCTS OF OZONATION OF AZOBENZENES
Starting AzObenzene Compound
azobenzene (I)
p-anvino-I and p-dimethylamino-I
p-hydroxy-I
p-methoxy-I
methyl oranqe
Oxidation Products Identified
azoxybenzene, oxalic + glyoxalic acids
nitrosoazobenzene, nitroazobenzene,
oxalic + glyoxalic acids, N03~
oxalic + glyoxalic acids
oxalic + glyoxalic acids, NOs"
oxalic + glyoxalic acids, NOq- + HSOyf
Source: Sato, Yokoyama & Imamura, 1974.
Ozonation of p-aminoazobenzene initially formed nitroazobenzene and
other products neither soluble in water nor in CC1*, but resulted in a
temporary increase in color. Prolonged ozonation finally caused decolori-
zation with concomittant decomposition of the oxidation products.
Ikehata (1975) described batch and continuous ozonation studies on
aqueous solutions of nearly 100 dyes having various chemical structures.
These dyes comprised direct dyes, acid dyes, basic dyes (which were rapidly
and completely decolorized by ozonation) and insoluble and disperse dyes
which were removed by chemical coagulants. In addition, the wastewater from
a dye printing works was nearly completely decolorized by injection of less
than 30 g of ozone/cu m. The purpose of this study was to develop a concep-
277
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tual design of an ozonation process for treatment of dye wastewaters and to
evaluate costs.
For batch tests, ozone was prepared from oxygen, but for continuous
ozonation tests and plant wastewater studies, ozone was generated from air.
In the batch tests, ozone was sparged into the dye wastewater solutions and
the rate of decolorization was measured spectrophotometrically. Ozone in
both the feed gas and contactor off-gases was measured so that ozone utiliza-
tion efficiencies could be determined.
For the continuous tests the concentration of ozone in air was 20 g/cu
m. An Otto type injector contactor* was employed in two contacting columns.
The dye solution flow rate was 0.5 cu m/hr, but different flow rates for
ozone in air were used. Ozone in the contactor feed and off-gases also was
determined.
Pilot tests were conducted on the effluents from the printing dye works
at Jyoyo Kogyo Ltd. (near Kyoto city) which began operating in 1972. Prior
to the ozonation step, the wastewaters were sent through clarification to
remove suspended organic materials and colloidal substances. The flow rate
was 100 cu m/hr.
Ozonation was conducted by 3 different contacting techniques. In
Method A, all ozone was injected into the water in a packed, cylindrical
steel chamber of 4 cu m volume and having 5 Otto injector units* on its
lower side. In Method B, the wastewater to be ozonized was divided. One-
half was ozonized in the steel chamber and the other one-half was ozonized
in a 15 cu m concrete chamber containing a single Otto injector contactor*.
In method C the wastewater again was divided and ozonized in each of 2
single injector concrete chambers. Method C gave the best performance
results of the 3 (more than 95% decolonization and more than 80% ozone
utilization).
Decolorization reactions were found to follow first order kinetics up
to almost 90% removal of color. Cleavage of the -N=N- (azo) bonds probably
was involved, since NO and N02 were formed during ozonation. More than 95%
decolorization of dyes was obtained in all cases. The ratio of dye to ozone
necessary to obtain 85% decolorization was less than 1. Preflocculated and
filtered rayon wastewaters required only 33% of the amount of ozone to
provide 85% decolorization as did untreated wastewater. BOD and COD values
of these wastewaters decreased by 10% and 25%, respectively.
Costs for ozonizing by all 3 methods are given in Table 69, and were
1152.7 yen/100 cu m of wastewater treated by Method A, 1367.5 for Method B
and 1203.4 for Method C. By comparison, costs for chemical clarification
were 2475.5 yen/cu m to attain a similar level of treatment.
* An Otto type contactor is an injector (such as a Venturi nozzle) apparatus
in which a small portion of the water initially is treated with all of the
ozone to be dosed. Then this small portion of water (now containing all of
the added ozone) is drawn into the balance of the water to be ozonized by
means of the injector.
278
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TABLE 69. COST.OF OZONE TREATMENT OF JYOYO KYOGO DYE WASTEWATERS*
Item
:apital Cost (Yen x 10,000)
Operating Cost (Yen/100 cu m)
Amortization, 15 yrs @ 7%
Power
Maintenance
Total Operating Cost (Yen/100 cu m'
Cost for
Method A
2,400
628.5
319.5
4.5
1,152.7
Ozonation by
Method B
2,800
775.5
382.5
9.5
1,367.5
Contacting By
Method C
2,600
680.5
315
7.5
1,203.4
* Plant Capacity: 100 cu m/hr
Source: Ikehata, 1975.
Tsukabayashi (1975) studied various methods of treating textile dyeing
wastewaters and concluded that "ozone treatment is excellent, but very
expensive; it can be used as a secondary treatment method".
Anonymous (1975b; TX-05) concluded that for destroying color, ozonation
is excellent for textile wastewaters containing reactive dyes, but inefficient
for those containing threne, naphthol and/or sulfur dyes. However, since
about 90% of the dyes used in the towel dyeing industry in the Ehime Prefec-
ture of Japan are reactive dyes, treatment with ozone is a viable method.
Treatment with activated carbon also was effective in removing color, but
the decolorization effect was greatly enhanced by the combined use of activa-
ted carbon and ozone.
Anonymous (1975a; TX-04) studied the treatment of various dyeing
wastewaters containing oil/water emulsions used in the oiling process of
fiber dyeing. These were treated with ozone and inorganic coagulants and
the process removed about 100% of the oil emulsion and colored organic
compounds. The sludge formed in using the ozone/inorganic coagulant process
was about 33 to 50% that of the "normal volume".
Anonymous (1975c; TX-06) studied the decolorization of wastewaters
containing dyes by ozonation. The amount of ozone required for decolorization
was higher for effluents containing disperse dyes than for wastes containing
hydrophilic dyes. The weight ratio of added ozone to dye ranged between 0.5
and 1.0 for wastes containing hydrophilic dyes, but was 1 for wastes contain-
ing disperse dyes. This author states that "disperse dyes which have a high
solubility can be decolorized with a smaller amount of ozone because of the
higher contacting efficiency of dyes with ozone during treatment".
Pretreatment, such as coagulation/precipitation, used before ozonation,
removed most of the disperse dyes from solution. However, removal of hydro-
philic dyes could not be accomplished by coagulation/precipitation, and
ozonation was effective in these instances. The presence of reducing sub-
stances, such as dithionites, interferred with ozone decolorization of these
dyes by reacting with the ozone before the dyes reacted. Therefore, such
reducing agents should be removed prior to introduction of ozone (Anonymous,
1975).
279
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Rinker (1975) studied the treatment of textile wastewaters by activated
sludge and alum coagulation. These produced an effluent from a mill producing
a synthetic knit fabric for the apparel and automotive markets which needed
additional treatment to meet anticipated discharge limitations. Research
studies were conducted using carbon adsorption, resin adsorption and ozonation
for color removal.
Netzer et aK (1976) described the ozonation of dye wastewaters.
Exhausted dyebath effluents were collected from 3 different Canadian textile
mills which produced dyed fibers for carpets, hats and yarns. These samples
were filtered through Whatman #54 filter paper and stored at 4°C prior to
use.
Ozonation was conducted in a 3 liter glass vessel containing a sparger.
Ozone was generated from oxygen at a concentration of 25 ppm and was passed
through the sparger tube at the rate of 1 liter/minute. Contacting time was
15 minutes, but the off-gases were not analyzed for excess ozone. After
ozonation, the samples were filtered and analyzed for TOC, COD, heavy metals
and color.
Foaming was persistent during ozonation, but usually subsided by the
end of the ozonation experiment. After analyses were made, the samples were
split. One-half of the samples were treated with lime to a pH of 11 to 12,
and the second one-half were treated with 3,000 mg/1 of powdered Nuchar C-
190N activated carbon. The mixtures then were stirred 0.5 hr and filtered.
In a second set of experiments, the sequence was reversed. Powdered
activated carbon treatment preceeded ozonation. Ozonation did not lower the
amounts of free or complexed heavy metals appreciably. The most notable
effect observed was nearly complete color removal.
The ratio of TOC/COD for untreated and treated samples remained essen-
tially constant, but in several cases the ratio of TOC/COD of ozonated
wastewaters was greater than in the raw effluent. Netzer e£ al_. (1976)
concluded that no firm conclusions could be drawn as to the effect of ozona-
tion on the content of TOC or COD. Therefore, neither TOC nor COD are
appropriate parameters to gauge the effectiveness of ozonation of textile
wastewaters.
Powdered activated carbon alone gave good decolonizations and good TOC
and COD removals in nearly all cases. Lime was effective in precipitating
heavy metals, such as zinc, and also resulted in good color removals and
some lowering of TOC and COD values. However, none of the hat dyeing efflu-
ents was decolorized to any appreciable extent by lime addition.
Powdered activated carbon followed by ozonation gave better TOC and COD
removals in all but one case. Lime addition followed by ozonation was
superior to ozonation followed by lime addition with carpet mill effluents.
Hat dyeing wastewaters were decolorized by lime followed by ozonation, but
showed little removal of TOC or COD.
280
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In conducting similar studies, Netzer (1976) characterized effluents
from dyehouses of various textile mills in Canada, and studied the removal of
color, soluble organics and heavy metals from these wastewaters by massive
lime coagulation, by activated carbon adsorption, by ozonation and by resin
adsorption. Ozone was generated from oxygen (25 mg/1 of ozone in oxygen)
and the gas mixture sparged into 100 ml samples of effluent in a 250 ml gas
washing bottle for 20 minutes, after which the samples were filtered and
analyzed. Lime coagulation achieved excellent removals of free heavy metals
and very good color removals in some cases as well. Substantial soluble
organics and color removals were obtained with activated carbon and resin
adsorption. Ozonation was "very potent" for decreasing color intensities,
but not for reducing the concentrations of soluble organics.
Anonymous (1976b; TX-08) treated dyeing factory wastewater by activated
sludge immobilized on polyurethane sponge. Although this process with
extended aeration was sufficient to lower the BOD to acceptable levels, it
was necessary to inject ozone into the aeration bath in order to obtain
acceptable COD values.
Anonymous (1976c) tested ozonation for treating dye bath, scour and
rinse waters from the dyeing processing of cotton. Reactive and basic dye
colored waters were successfully decolorized with ozone, but it could not
adequately decolorize wastewaters containing disperse dyes.
A Dutch patent (Anonymous, 1976a) describes a process for recycling dye
works effluents. Neutral wastewaters containing organic dyes and auxiliary
agents are subjected to continuous oxidative degradation with ozone in
several stages, with strong agitation.
Conclusions
1) At least 9 Japanese dye manufacturing or textile processing plants are
known to be using ozonation on commercial scale for treating their
wastewaters. The major purpose for ozone in these wastewater treatment
processes is decolorization.
2) Hydrophilic dyes (reactive, cationic or acidic) are quite reactive with
ozone, less than 1 g of ozone being required to decolorize 1 g of this
type of dye. This ozone requirement has been determined with actual
plant wastewaters treated by the sequence of lime coagulation, polymer
flocculation, precipitation, ozonation and 1- or 2-stage aeration. BOD
levels were lowered from 150 to 78 mg/1 and 79 to 98% decolorization
was obtained.
3) With the above wastewaters (of conclusion 2), ozonation was not effective
in treating sulfur-containing or chromium dyes.
4) For a synthetic fiber plant using mainly cationic dyes and treating
1,500 cu m/day (360,000 gal/day) of wastewater (the plant of conclusion
2), capital costs in 1972 were 28 million yen and operating costs were
10.19 yen/cu m.
281
-------
5) Ozonation of unfiltered secondary treated combined municipal/industrial
wastewaters (90% being wastewaters from carpet producing and tufted
dyeing plants in Dalton, Georgia) with 45 mg/1 dosages of ozone lowered
the effluent color from 275 to 30 APHA units. At the same time, this
45 mg/1 ozone dosage also lowered COD levels by 40%, SS by 85%, biphenyl
by 51%, detergents by 92%, fecal col 1 forms by 100% and total coliforms
by 99.99%. BOD levels increased during the early stages of ozonation,
but at the 45 mg/1 total dosage level, there was no overall change in
BOD level. Cost comparisons between ozonation and GAC to achieve the
same amount of color reduction at the 12 mgd Dalton, Georgia wastewater
treatment plant and taken over a 20-yr period showed ozonation costs to
be about 50% of those of activated carbon.
6) Japanese dyeing plant wastewaters treated by trickling filter, then
ozonation showed 80% lowering of color, 73% lowering of BOD and 53%
lowering of COD levels.
7) Reducing waste liquids from a Japanese dye manufacturing plant were
pretreated with formaldehyde to polymerize phenolics, filtered, ferrous
sulfate added to remove sulfite, adjusted to pH 3.0 to 3.5, aerated (to
oxidize thiosulfate), the pH increased and the waste ozonized. This
treatment lowered a starting COD value of 7,650 by 58% in 2 hrs of
ozonation and by 87% in 7 hrs.
8) Laboratory studies on 500 ml samples of wastewaters from a U.S. dyeing
plant showed that disperse dyes are decolorized best upon ozonation
with no increase in turbidity and little reduction in COD levels. With
other types of dyes, ozonation increased turbidity.
9) An 0.87 mgd Japanese dyeing plant uses 2-stage ozonation (maximum
dosage 50 mg/1) followed by GAC adsorption. The process is free of
sludges and total operating costs are 34<£/l,000 gal. The combined
process of ozone followed by GAC is lower in cost than the cost of
using either treatment process alone.
10) Ozonation of p-aminoazobenzene in water initially formed nitrosoazo-
benzene, nitroazobenzene and gave an increase in color. Continued
ozonation decolorized the solution and formed oxalic acid, glyoxalic
acid and nitrate ion.
11) Wastewaters from a Japanese dye printing works were nearly completely
decolorized by injection of less than 30 g of ozone/cu m (after clarifi-
cation). Double-stage ozone injection gave greater than 95% decolori-
zation and greater than 80% ozone utilization. Preflocculated and
filtered rayon wastewaters required 33% of the ozone to provide 85%
decolorization as untreated wastewater. The ozone/dye ratio necessary
to obtain 85% decolorization was less than 1. Ozonation costs for
treating 100 cu m/hr were 26 million yen (capital) and 1,203 yen/100
cu m (operating).
282
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12) Ozonation is viable for decolorizing wastewaters containing reactive
dyes, but is inefficient for those containing threne, naphthol or
sulfur-containing dyes.
13) Dyeing wastewaters containing oil/water emulsions used in the oiling
process of fiber dyeing were successfully.treated with ozone and inor-
ganic coagulants; about 100% of the oil emulsion and colored organics
were removed. Only 33 to 50% of the sludge normally produced by conven-
tional processing was formed by this ozonation/inorganic coagulant
process.
14) The ozone/dye ratio required to decolorize wastewaters containing
hydrophilic dyes is 0.5 to 1.0, but 1 or greater for disperse dyes.
Reducing agents (such as dithionite) should be removed prior to ozonation.
15) Neither TOC nor COD are appropriate parameters to gauge the effective-
ness of decolorization of dye-containing wastewaters. Decolorization
occurs, but without causing significant changes in TOD or COD.
16) In decolorizing Canadian dye mill wastewaters, lime addition followed
by ozonation was more effective than ozone followed by lime with
carpet mill effluents.
LITERATURE CITED - TEXTILES (TX)*
TX-01 Anonymous, 1973, "Japanese Develop Water Treatment", Daily News
Record 3(9):23.
TX-02* 1974a, Anonymous, "Ozone-Carbon Dye-Waste Treatment", Textile Ind.
138(10):43, 45.
TX-03 Anonymous, 1974b, Gijutsu to Kogai 4(4):22-28.
TX-04* Anonymous, 1975a, Kogai 10(4):20-27.
TX-05* Anonymous, 1975b, Kogai 10(4):34-48.
TX-06* Anonymous, 1975c, Kako Gijutsu 10(8):31-36.
TX-07* Anonymous, 1976a, Netherlands Patent NL 7506-370 (Dec 2, 1975).
Derwent Netherlands Patents Report W(51):D2, Jan 27, 1976(a).
TX-08* Anonymous, 1976b, Mizushori Gijutsu 17(1):53-62.
TX-09* Anonymous, 1976c, Textile World 126(11):108, 111, 113, 115, 116,
118, 121.
*Abstracts of asterisked articles will be found in EPA 600/2-79- b.
283
-------
TX-10 Bauch, H. & H. Burchard, 1970, "Experiments to Improve Highly
Odorous or Harmful Sewage with Ozone", Wasser, Luft & Betrieb
14(4):134_137.
TX-11 Best, G.A., 1974, "Water Pollution and Control", J. Soc. Dyers
& Colourists (G.B.) 90:389-393.
TX-12 Horikawa, K., H. Wako & E. Sato, 1976, "Treatment of Dye Waste
Effluents by Ozonation with Ultraviolet Radiation", Kogyo Yosui
214:21-24.
TX-13 Ikehata, A., 1975, "Dye Works Wastewater Decolorization Treatment
Using Ozone", in Ozone for Water & Wastewater Treatment, R.G. Rice
& M.E. Browning, Eds., Intl. Ozone Assoc., Cleveland, Ohio, p.
688-711.
TX-14 Kawazaki e_t aj^, 1965, Water & Wastewater (Japan) 6:643-648, 778-
TX-15 Maeda, M., Y. Hashimoto, T. Ozawa, T. Imamura, M. Matsuoka & N.
Tabata, 1972, "Ozone Treatment of Dyeing Wastewater", Mitsubishi
Denki Giho, 46(10):1110-1115.
TX-16* Maeda, S., 1974, "Studies on the Liquid Waste Treatment of Dye
Manufacturing Plants (II)", Gijutso to Kogai (Technology & Public
Nuisance) 4(4):22-28.
TX-17 Maggiolo, A., F. Davis, N. Lowe & R. Montgomery, 1977, "Ozone vs
Chlorine in Treatment of Textile Chemical Wastes; Its Problems and
Possible Solutions", presented at 3rd Intl. Symp. on Ozone Tech-
nology, Paris, France, May. Intl. Ozone Assoc., Cleveland, Ohio.
TX-18* Matsuoka, H., 1973, "Ozone Treatment of Industrial Wastewater",
1973, PPM 4(10):57-69.
TX-19 Mizumoto, K. & M. Horie, 1974, "Dyeing Wastewater Treatment by
Combination of Ozone and Activated Carbon". Japan Textile News
89:238.
TX-20* Nakayama, S. & M. Maeda, 1976, "Decoloring Mechanism of Dyes with
Ozone and the Effect of pH", Mizu Shori Gijutsu 17(2)157-161.
Chem. Abstr. 86:60133f.
TX-21 Nebel, C. & L.M. 1976, Stuber, "Ozone Decolorization of Secondary
Dye Laden Effluents" in Proc. Second Intl__._ Symp. on Ozone Technology,
R.G. Rice, P. Pichet & M.-A. Vincent, Eds., Intl. Ozone Assoc.,
Cleveland, Ohio, p. 336-358.
TX-22* Netzer, A., 1976, "Advanced Physical-Chemical Treatment of Dye
Wastes", Progress in Water Technology 8(2-3):25-37.
284
-------
TX-23 Netzer, A., S. Beszedits, P. Wilkinson & H.K. Miyamoto, 1976,
"Treatment of Dye Wastes by Ozonation" in Proc. Second Intl.
Symposium on Ozone Technology, R.G. Rice, P. Pichet & M.-A. Vincent,
mo log
rrcT
Eds., Intl. Ozone Assoc., Cleveland, Ohio, p. 359-373.
TX-24* Rinker, T.L., 1975, "Treatment of Textile Wastewater by Activated
Sludge and Alum Coagulation". Blue Ridge-Winkler Textiles,
Bangor, PA., NTIS Report PB-248,142/2 WP. EPA Rept. No. EPA/600/2-
75-055, Oct., 216 pages.
TX-25* Sato, S., K. Yokoyama & T. Imamura, 1974, "Decomposition of Azo
Dyes by Ozone." Preprint, 31st fall Mtg., Chem. Soc. of Japan,
Oct., p. 614.
TX-26 Smirnova, L.V. et al_., 1972, "Use of Ozone for Purification of
Effluent from Nvtron Fibre Production." Khim. Volokna (USSR)
14(1):70. World Textile Abs. 4:4016 (1972).
TX-27* Snider, E.H. & J.J. Porter, 1974, "Ozone Treatment of Dye Wastes",
J. Water Poll. Control Fed. 46(5):886-894.
TX-28* Stuber, L.M., 1973, "Tertiary Treatment of Carpet Dye Wastewater
Using Ozone Gas and Its Comparison to Activated Carbon", Special
Rsch. Prob., School of Civil Engrg., Georgia Inst. Tech., Atlanta,
GA (Aug.), 17 pp.
TX-29 Stuber, L.M., 1974, "Tertiary Treatment and Disinfection of Tufted
Carpet Dye Wastewater." Engrg. Bull., Purdue Univ. Ext. Ser.,
145(2):964-77.
TX-30 Stuber, L.M., 1975a, "Tufted Carpet Dye Wastewater Treatment,
Pt. I", Indl. Wastes, Jan/Feb.
TX-31 Stuber, L.M., 1975b, "Tufted Carpet Dye Wastewater Treatment,
Pt. II", Indl. Wastes, Mar/Apr, p. 29-30.
TX-32 Stuber, L.M., 1975c, "Tufted Carpet Dye Wastewater Treatment,
Pt. Ill", Indl. Wastes, May/June, p. 13-14.
TX-33* Tsukabayashi, K., 1975, "Treatment of Wastewater from Textile
Dyeing Processes", Yuki Gosei Kagaku Kyokai-shi 33(5):377-383.
TX-34 Urushigawa, Y., G. Kurata & Y. Noji, 1974, "Treatment of Dyeing
Wastes by Trickling Filter and Ozone Treatment System", Kogai
(Poll. Contr.) 9(3):118-124.
TX-35 Yamashita, Y., H. Asai & K. Kitano, 197?, "Treatment of Dyeing and
Finishing Effluent with Ozone" Sen'i Kako 25(5):289-302.
285
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SECTION 6
OXIDATION PRODUCTS OF ORGANIC MATERIALS
INTRODUCTION
There does not exist a great deal of literature in which the investi-
gators deliberately attempted to isolate and identify the oxidation products
of organic compounds from actual wastewaters or drinking water supplies.
Most of the research has been directed toward determining the dosage of
oxidant necessary to reduce the concentration of a particular organic
compound to below a limit detectable by means of an analytical technique
specific for that compound. It has not been generally recognized that
oxidation products formed from these materials still may be present, may
not be detectable by the analytical technique used to determine the original
compound, and may pose a public health concern. It has been only recently
that Rook (1974) has shown chloroform to be a product of the chlorination
9f drinking water supplies containing humic materials. Since then, research
into the formation and nature of organic oxidation products under drinking
water and/or wastewater treatment conditions has accelerated.
Most of the experiments dealing with organic oxidation products from
ozonation and other oxidation processes have not been conducted under
controlled water or wastewater treatment plant conditions, i.e., dilute
aqueous solutions of compounds, low dosages of oxidant, short contact
times, absence of pH control, etc. At the rather low concentrations of
organic materials normally encountered in water and wastewater treatment
plants, oxidation of o organic compound usually produces other compounds in
even lower concentrations. 'Therefore, recent research studies have utilized
the approach of starting with relatively concentrated solutions of organic
compounds, and using high dosages of oxidants for prolonged periods of
time, in order to force the oxidations to proceed to later stages. Others
have started with high concentrations of organic compounds, but have delibera-
tely underdosed with oxidant in order to be sure of producing partially
oxidized, early intermediate materials for isolation and study.
Miller et aj_. (1978) and Rice & Miller (1977) have reviewed the avail-
able literature on the use of ozone and chlorine dioxide with the intent of
determining specific oxidation products which have been isolated and identi-
fied without regard to the relationship of their experimental synthetic
conditions (mostly laboratory studies) to actual wastewater or drinking
water treatment plant conditions under which ozone and chlorine dioxide
normally are employed. A list of specific organic chemicals known to be
formed upon oxidation by ozone and/or chlorine dioxide would be useful to
toxicologists and other water and wastewater treatment scientists.
286
-------
Similarly, once it is known with certainty which specific organic
compounds can be formed upon oxidation with ozone, reaction conditions can
be designed for wastewater treatment processes which will minimize their
formation.
BACKGROUND
The capability of one substance to oxidize another is measured by its
"oxidation potential", normally expressed in volts of electrical energy
(referenced to the hydrogen electrode). The oxidation potential is a measure
of the relative ease by which an atom, ion, molecule or compound is able to
lose electrons, thereby being converted to a higher state of oxidation. If
the oxidation potential of substance A is higher than that of substance B,
then substance B will be oxidized in the presence of substance A. Oxidation
potentials of representative oxidants encountered in drinking water treatment
are listed in Table 70.
Although the relative position of an oxidant in this table is indicative
of its ability to oxidize other materials, it does not indicate how fast 1
material will be oxidized by another, nor how far toward completion the
oxidation potentials alone whether a specific organic compound will be
oxidized completely (to C02 and water) or only to the first of several
intermediate stages.
One significant fact can be learned from this table, however, at this
point. As will be discussed in detail later in this section, it is rare
that organic compounds treated with an oxidant as powerful as ozone will be
converted totally to C02 and water, under conditions normally encountered in
wastewater treatment plants.
Therefore, no other commonly employed and less powerful water treatment
oxidant (such as chlorine, bromine, chlorine dioxide, etc.), all of which
have lower oxidation potentials than ozone, will oxidize an organic material
completely to COp and water if ozone will not.
All oxidants weaker than ozone will be less effective than ozone in
converting organic compounds to carbon dioxide and water, ancTthus may
produce higher quarttities of partially oxidized organic materials uncler
wastewater treatment plant conditions. It is important, therefore, for the
wastewater treatment engineer to understand the chemistry of the organic
components of the wastewater when considering the use of ozone or other
oxidants in the processing.
FUNDAMENTAL PRINCIPLES
All oxidants react with organic materials by 1 or more of 3 different
mechanisms:
• Addition
• Substitution
• Oxidation
287
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TABLE 70. OXIDATION-REDUCTION POTENTIALS OF WATER TREATMENT AGENTS*
REACTIONS
F2 + 2e = 2F"
03 + 2H+ + 2e = 02 + H20
H202 + 2H+ + 2e = 2H20 (acid)
Mn04" + 4H+ + 3e = Mn02 + 2H20
HC102 + 3H+ + 4e = Cl" + 2H20
Mn04~ + 8H+ + 5e = Mn2+ + 4H20
HOC1 + H+ + 2e = Cl" + H20
C12 + 2e = 2C1"
HOBr + H+ + 2e = Br" + H-O
03 + H20 + 2e = 02 + 20H"
C102 (gas) + e = C102"
Br2 + 2e = 2Br"
HOI + H+ + 2e = I" + H20
C102 (aq) + e = C102~
CIO" + H20 + 2e = Cl" + 20H"
H2°2 + H30+ + 2e = 4H2° (bas1c)
C102" + 2H20 + 4e = Cl" + 40H"
OBr" + H20 + 2e = Br" + 40H~
I2 + 2e = 21"
I' + 2e = 31-
01" + H20 + 2e = I" + 20H"
02 + 2H20 + 4e = 40H"
POTENTIAL IN VOLTS (E°) 25°C
2.87
2.07
1.76
1.68
1.57
1.49
1.49
1.36
1.33
1.24
1.15
1.07
0.99
0.95
0.9
0.87
0.78
0.70
0.54
0.53
0.49
0.40
'Handbook of Chemistry & Physics, 56th Edition, 1975-76. CRC
Press Inc., Cleveland, Ohio, p. D-141-143.
288
-------
In some cases, oxidants will react with organic compounds by all 3
mechanisms, although in sequential steps.
Addition
Addition occurs with organic compounds containing aliphatic unsaturation,
such as olefins. Chlorine can add across an olefinic double bond to produce
a dichloride:
RR'C = CRR1 + C12 >-RR'C-
Hypochlorous acid can add across a double bond to form a chlorohydrin:
RR'C = CRR1 + HOC1 ^RR'C. - CRR1
Cl OH
Ozone can add across a double bond to form an ozonide:
°r°-§
+ 0- >-RR'C - CRR1
RR C ~ CRR ' uo
This last reaction occurs readily in non-aqueous solvents, but as soon
as water is added, the ozonide hydrolyzes to other products, with cleavage
of the former double bond:
RR'C - CRR1 >RR'CH2OH + 0=CRR'
9-°-2
I'C - CRR1
ozonide alcohol ketone
Substitution
Substitution involves replacement of 1 atom or functional group with
another. For example, chlorine can react with phenol to produce o-chloro-
phenol. In this reaction the ortho-hydrogen atom is replaced by chlorine:
phenol o-chlorophenol
Oxidation
Oxidation involves the introduction of oxygen into the organic molecule,
with or without degradation of the organic compound. For example, oxidation
of phenol with either chlorine, chlorine dioxide or ozone can produce
catechol as a first oxidation product:
289
-------
phenol
or C10
or ozone
catechol
This specific reaction also can be viewed as an insertion reaction,
whereby oxygen is inserted between the ring carbon and hydrogen to form the
hydroxy group on the ring.
Oxidation also can involve cleavage of carbon-carbon bonds to produce
fragmented organic compounds. For example, ozonation of styrene produces
formaldehyde, benzaldehyde, and benzole acid (Yocum, 1978):
CH=CH
°
HCHO +
CHO 0,
styrene
benzaldehyde
OOH
benzoic acid
At the last stage in treatment of organic compounds with oxidants,
oxidation also can involve production of C0? and water:
HCOOH + 0, > C09 + H,0
O C. L~
formic acid
REACTIONS OF ORGANIC COMPOUNDS WITH OZONE
Reactions With Phenol
Eisenhauer (1968) ozonized aqueous solutions of phenol for 30 minutes
(until phenol was destroyed) and isolated catechol, p-quinone, cis-muconic
acid, oxalic acid and fumaric acid:
OH
OH
catechol
COOH
COOH
muconic acid
p-quinone
+ (equation continued)
290
-------
H
(continued) + HOOC-C=C-COOH (fumaric acid)
+ HOOC-COOH (oxalic acid)
When ozonation was conducted for only 10 minutes, Eisenhauer isolated
a 20% yield of catechol, but only 70% of the phenol was destroyed. This
indicates that upon oxidation of phenol, other organic compounds (10%) or
C02 are produced along with the catechol.
Gabovich e_t al- (1969) treated 10 mg/1 aqueous solutions of phenol with
ozone dosages of 0.7 to 2.3 mg/1. To attain 90% destruction of phenol (to 1
mg/1 concentration) required 1.85 mg of ozone/mg of phenol; complete destruc-
tion of phenol required 2.3 mg ozone/mg phenol.
Bauch e_t aJL (1970) found monobasic and polybasic (aliphatic) acids
upon ozonation of water solutions of phenol. They concluded that oxidation
of phenol by ozone proceeded via the ozonide and produced hydrogen peroxide.
Initial phenolic oxidation products themselves consumed additional ozone.
Bauch & Burchard (1970) ozonized aqueous solutions of phenol and
isolated and identified maleic acid, tartaric acid, glyoxylic acid, oxalic
acid and C02:
OH H H OH OH
0, HOOC-C=C-COO + HOOC-CH-CH-COOH
2—>
maleic acid tartaric acid
HOOC-CHO + HOOC-COOH + C02
phenol glyoxylic oxalic
acid acid
Smith et.al_. (1972) found that the rate of disappearance of phenol ^ .
ozonation in water is increased by combining ultrasonics and/or Raney nickel
with ozonation. After 2.5 hours of ozonation, an initial solution of 500
mg/1 phenol showed the complete absence of phenol. On the other hand, the
COD of the original solution decreased only slowly, and was still fairly
high after the phenol had disappeared, indicating the presence of intermediate
oxidation products. Considerable carbon loss indicated the formation of
some COp.
Mallevialle (1975) ozonized 100 to 200 mg/1 aqueous solutions of
phenol with 25 mg/1 ozone doses and identified catechol, o-quinone, hydro-
quinone and p-quinone as oxidation products:
291
-------
(100-200
catechol o-qiffnone
U A °H '
hydroquinone
p-benzoquinone
Spanggord & McClurg (1978) were the first investigators to identify
resorcinol as an initial oxidation product, along with catechol, upon
ozonation of phenol in water:
OH
resorcinol
catechol
Gould & Weber (1976) have made the most complete study to date on the
ozonation of phenol. They found that the early oxidation products (catechol
and hydroquinone) are further oxidized as ozonation continues, and fall to
relatively insignificant concentrations as the reactions proceed. Glyoxal
is formed by ring rupture, but itself decreases to a low concentration level
as the reactions proceed. Glyoxylic acid is the main oxidation product
isolated after 30 minutes of treatment with ozone, together with smaller
amounts of oxalic acid.
OH
hydroquinone
OHC-CHO
glyoxal
HOOC-COOH
oxalic
acid
(major product after 30 minutes)
HOOC-CHO
lyoxylic
acid
292
-------
Throop (1977) showed that ozone dosages of 5.32 mg/1 produced non-
detectable quantities of phenol, starting with concentrations of 110 ppb of
phenol in water. This dosage is equivalent to 48 parts of ozone/part of
phenol. However, ozone dosages of 25.5 mg/1 (200 parts ozone/part phenol)
were required to produce a measureable (trace) amount of residual ozone in
the solution. This confirms that although ozone rapidly destroys phenol
itself, significant amounts of ozone-demanding oxidation products are formed.
Reactions With Other Phenols
Hillis (1977) studied the oxidation of 14 phenols with ozone over the
pH range 4 to 10, but did not identify oxidation products. With 30 mg/1
concentrations of phenols and ozonation conducted 4 to 12 minutes [except
for pentachlorophenol (PCP), which required 35 minutes], residual concentra-
tions of phenols of less than 0.10 mg/1 were obtained. However, COD values
were reduced only about 50%, indicating that organic carbon-containing
oxidation products were still present.
With solutions of phenol, phenolsulfonic acid, hydroquinone and pyro-
gallol, COD was destroyed steadily upon ozonation. However, with pentachloro-
phenol and 3-naphthol, there was a steady rise in COD values during the
first few minutes of ozonation, followed by a steady reduction in COD values.
The amount of ozone required to lower the concentration of these
phenols from 30 mg/1 to below 0.5 mg/1 in 10 minutes (except for PCP) was
2.0 to 3.0 g/g phenol (4 to 6 moles ozone/mole phenol).
Bauch, Burchard & Arsovic (1970) compared the rates of ozonation of
phenol with cresols and xylenols, and also isolated and identified ring
ruptured oxidation products. Cresols decomposed more rapidly than phenol,
and m-cresol decomposed faster than did the o- and p-isomers. Cresols
reacted faster with ozone in acid solution than in basic solution. An 80%
decomposition of cresols was accomplished with 2 moles of ozone/mole of
cresol (85 g ozone/100 g cresol).
Upon initial ozonation, the methyl group in cresols oxidized to the
carboxylic acid. The compound o-cresol, for example, produced salicylic
acid: OH
0,
o-cresol T II ° *-> salicylic acid
Continued ozonation of cresols ruptured the aromatic ring and produced
maleic acid (which further oxidized to mesotartaric acid), acetic acid,
propionic acid, glycolic acid, glyoxylic acid, oxalic acid and C02:
293
-------
HOOC-CH=CH-COOH
maleic acid
HOOC-CH(OH)-CH(OH)-COOH
mesotartaric acid
CH3CH2COOH
CH3COOH
HOCH2COOH
OHC-COOH
HOOC-COOH
CO,
All 3 cresols (o-, m- and p-) formed the same oxidation products upon
ozonation. Only the rates of oxidation varied.
Xylenols with ortho or para hydroxy groups reacted fastest with ozone
and produced the same oxidation products as the cresols (Bauch, Burchard &
Arsovic, 1970). In addition, 1,2,3- and 1,2,4-xylenols produced diacetyl,
glyoxal (which disproportionates to glyoxylic acid), hydroxyphthalic acid
and ketoaldehydes:
H
0 0
II II
CH3C-CCH3 + OHCCHO
diacetyl
HOOC-CHO
glyoxylic
acid
COOH
COOH
hydroxyphthalic
acid
Gilbert (1978) ozonized 1 mmole/1 of 2-nitro-p-cresol with 10 mg of
ozone/minute until the cresol was destroyed. He found that 90% of the
original nitrogen was converted to nitrate ion, indicating rupture of the
aromatic ring.
OH
NO,
(90%)
Reactions With Chlorinated Phenols
Shuval & Peleg (1975) compared the ozonation of phenol with o-chloro-
phenol. At the same initial pH, the rates of oxidation with ozone are the
same for both compounds, but the rate is fastest at higher pH. Starting at
pH 10 the reactions are faster when the pH is maintained at 10, rather than
letting it drop (to 2.5) as ozonation proceeds.
294
-------
In addition, the rate of formation of chloride ion was followed during
ozonation of chlorophenol. In all experiments, about 80% of the aromatic
chlorine was converted to chloride ion upon ozonation, indicating that
covalent C-C1 bonds are broken with ozone. There was an induction period
during which the concentration of o-chlorophenol decreased but without
formation of chloride ion. On the other hand, after all o-chlorophenol had
disappeared, chloride ion still was being produced upon continued ozonation.
This indicates that the active oxidation species attacks the aromatic ring
at a site or sites other than the chlorine site, producing chlorinated
aliphatic compounds as intermediates.
Gilbert (1978) ozonized aqueous solutions of 2-chloro-, 4-chloro-, 2,3-
dichloro-, 3,5-dichloro- and 2,4,6-trichlorophenols until the phenols could
not be detected by gas chromatography and no phenolic functionality could be
detected by 4-aminoantipyrine. This required 3.2 to 5 mmoles of ozone/mmole
of phenol. The rate of oxidation increased from mono- to trichlorophenol.
After ozonation, 60% to 95% of the chlorine was found as chloride ion.
Ozonation of 4-chlorophenol produced chloride ion at the start of ozonation;
chloride ion was found only after 40% of the 2-chlorophenol had been degraded.
The different rates of dechlorination are explained in terms of different
electron density distributions on the aromatic rings.
Ozonation of 2,4-dichlorophenol produced formic and oxalic acids and
chloride ion:
OH
°3
HCOOH + HOOC-COOH + CT
Biodegradabilities of the ozonized products were higher with increasing
degree of oxidation arfd with decreasing chlorophenol concentration. After
total oxidation of the phenols, the COD level had been reduced from 200 to
100 mg/1 and the TOC level had been reduced from 72 to 59 mg/1.
After chlorophenols had disappeared, thin layer chromatography techniques
indicated the presence of carbonyl or carbonyl/carboxylic acid functionalities,
In instances of incomplete dechlorination, chlorinated aliphatic moieties
were isolated but not identified.
Gilbert (1978) ozonized 4-chloro-o-cresol and identified 67% of its
oxidation products. After 80 minutes of treatment with ozone (800 mg of
ozone total dosage added to 1 mmole of chlorocresol) none of the starting
cresol was present and 100% of the chlorine was found as chloride ion. In
the ozonate, methylglyoxal, pyruvic acid, acetic acid, formic acid and
oxalic acid were isolated and identified, along with C02. The course of
reaction is as follows:
295
-------
80 min
OHC-C=0
1
CH3
methyl
glyoxal
HCOOH +
formic
acid
+ CH3C-COOH
pyruvic
acid
HOOC-COOH +
oxalic
acid
+ CH3COOH
acetic
acid
co2
Methylglyoxal was produced from the beginning of the reaction, its
concentration reaching a maximum after 60 minutes of reaction, then slowly
decreasing. This means that its rate of formation from the cresol is faster
than its rate of oxidation.
Pyruvic acid and acetic acid concentrations increased steadily during
ozonation, even after complete elimination of the cresol, indicating that
these two acids are produced from the initial oxidation products of the
cresol.
All TOC was accounted for by these organic compounds at various times
during ozonation. Therefore, the above compounds, plus C02, water and
chloride ion are the only oxidation products of this cresoT.
Figure 26 summarizes the reactions of phenols with ozone.
Reactions With Other Aromatics
Ahmed & Kinney (1950) ozonized 0.8693 g of 3,8-pyrenequinone for 33 hrs
in water and isolated 0.56 g of 1,2,3,4-benzenetetracarboxylic acid plus
acetic acid:
0 \\ // 0.8693 g
3,8-pyrenequinone
COOH
+ CH3COOH
OOH
0.56 g
1,2,3,4-benzenetetracarboxylic
acid
296
-------
OH
ro
OH
OH
Cl -T "TT Cl
plus CT
HOOC-C=C-COOH
HOOC-C=C-COOH
i!i il
n n
HOOC-CH-CH-COOH
OH OH
HOCH2-COOH
OHC-COOH + HCOOH
OHC-CHO
HOOC-COOH + CO,
OH
R —1- -H- R
(R = CH3,
etc.)
COOH
Figure 26. Reactions of ozone with phenol.
plus:
CH3COOH + CH3CH2COOH
CH.-C-C-CH, +
3JB
CH.-C-COOH + 0=C-CHO
3 It I
0 CH3
-------
Kinney & Friedman (1952) ozonized an alkaline solution of phthalic acid
for 24 hrs and isolated 28% of the carbon as oxalic acid, 34% as CO., 3% as
acetic acid and 35% as other water soluble acids:
COOH
'COOH
phthalic acid
24 hrs
C0
+
CH3COOH
HOOC-COOH 2
(28%) (34%) (3%)
+ other water soluble acids
Kinney & Friedman (1952) also ozonized a solution of pyrene for 24 hrs
and isolated 2.4% of the carbon as acetic acid, 0.6% as C09, 0.1% as oxalic
acid and 19.9% as water soluble acids.
24
CHCOOH
C0
pyrene \—
2 HOOC-COOH
(2.4%) (0.6%) (0.1%)
+ other water soluble acids
Sturrock ejtal. (1963) ozonized phenanthrene in a 1/1 water/methanol
solution (methanoTis resistant to ozonation). Water was used to avoid the
formation of explosive ozonides or peroxides, which are formed under neat or
non-aqueous solvent conditions. After ozonation of 15 g of phenanthrene,
1.3 g of unreacted phenanthrene was recovered, along with 16.4 g of oxidation
products. These were identified as 2'-formylbiphenylcarboxylic acid, 2'-
hydroxymethyl-2-biphenylcarboxylic acid, diphenide and diphenic acid.
phenanthrene
CH2OH
COOH
diphenic acid
-------
It is of significance that only 1 ring in phenanthrene was opened by
treatment with ozone. This indicates that the material is fundamentally
resistant to ozone.
ITnitskii e_t aj_: (1968) found that 3,4-benzopyrene in distilled water
was destroyed much more rapidly than when the pyrene was added to raw drinking
water containing added soil particles. In 1 minute, ozone destroyed 61% of
the pyrene in distilled water, but only 33% in naturally occurring raw
water. In 2.5 minutes of ozonation, 100% of the pyrene was destroyed in
distilled water, but only 60% was destroyed in this time (same concentration)
in raw water containing added soil particles.
These investigators concluded that 3,4-benzopyrene is adsorbed onto
fine soil particles and thus is "protected" from oxidation. In designing
the ozonation treatment for waters containing 3,4-benzopyrene, an effective
filtration step should precede ozonation. Protection of organic compounds
from oxidation by naturally occurring colloidal materials also was noted by
Mallevialle et al_. (1978) in studies with aldrin (see— "Reactions With
Pesticides").
ITnitskii (1969) ozonized 0.6 to 1.2 mg/1 concentrations of 3,4-
benzopyrene in water maintaining a 0.4 mg/1 residual of ozone. In 7.5
minutes the pyrene had been oxidized to below the detectable limit.
Gabovich et al. (1969) compared the oxidation rate of 3,4-benzopyrene
when treated with chlorine and with ozone. Chlorine reduced the concen-
tration of the pyrene 5 to 10 times in 0.5 to 2 hrs. Ozonation for 3 to 5
minutes reduced the concentration 10 to 50 times.
The compound 3,4-benzopyrene (4 yg/1) treated 3 minutes with 2.5 mg/1
of ozone was reduced in concentration to 0.06 ug/1; treating the same concen-
tration 3 minutes with 4.5 mg/1 of ozone dosages lowered the pyrene concentra-
tion to 0.04 yg/1 (Coin ert a]_., 1964, 1967).
Reichert (1969) dissolved 3,4-benzopyrene in 1 ml of acetone, then
diluted this to 1,000 ml with water. Samples containing 1 to 100 yg/1 of
pyrene were ozonized with 0.5 to 1.5 mg/1 doses. In 30 minutes of ozonation,
99% decomposition of the pyrene was observed.
Gabovich ejt aj_. (1969) also studied the rates at which ozone would
reduce the concentrations of other aromatic compounds in water. Diethyl-
benzene in concentrations of 10 to 100 mg/1 upon treatment for 7 to 10
minutes with quantities of ozone similar to those used in drinking water
treatment (1 to 5 mg/1) was reduced in concentration to 0.5 to 0.8 mg/1.
The compound 2,4-dinitrophenol at 50 mg/1 was reduced in concentration to
0.35 mg/1 using 2 mg of ozone/mg of phenol; using 5 mg of ozone/mg phenol,
the final concentration of 2,4-dinitrophenol was lowered to 0.05 mg/1.
Chlorobenzene reacts with ozone slower than does phenol, probably
because of its lower solubility in water, but gives the same oxidation
299
-------
products as does phenol. In addition, HC1, chlorotartaric acid and o-, m-
and p-chlorophenols are formed (Bauch, Burchard & Arsovic, 1970):
(o- m- and p-chlorophenols)
HOOC-CH(OH)-C-(OH)-COOH + HC1 H
Cl
the same ring-ruptured, aliphatic
oxidation products as from the
ozonation of phenol
Chlorocresols, chlorophenols, naphthols, thiophenols and polyhydroxy-
phenols give similar oxidation products as do phenols upon ozonation (Bauch,
Burchard & Arsovic).
Hoigng (1975) showed that ozonation of benzoic acid caused 10% decarboxy-
lation to produce CO^.
Mallevialle (1975) ozonized 100 to 200 mg/1 aqueous solutions of
salicylic acid. The TOC remained constant during the first 10 minutes of
ozonation (25 mg/1 total dosages), but then dropped steadily. Phenol,
catechol and three unidentified phenols were isolated from the ozonate.
2,3-Dihydroxybenzoic acid was shown to be absent. Three moles of ozone/mole
of salicylic acid were required to destroy all of the starting acid. Infrared
analysis showed the products to have strong -OH and -COOH absorptions,
indicating that a mixture of carboxylic acids was formed.
COOH
+ 3 unidentified
phenols,
COOH
salicylic acid
but NO
OH
300
-------
Spanggord & McClurg (1978) ozonized aqueous solutions of N,N-diphenyl-
hydrazine hydrochloride at pH 7 and identified ring- and N-hydroxylated
derivatives, plus free uns-diphenylhydrazine;
N-NH2.HC1
N-NH,
N-NH-OH
Jtlrs (1966) reviewed the current literature of the time and concluded
that ozonation of benzene (in benzene) produced a triozonide which, when
treated with water, rapidly decomposed to form glyoxal, glyoxylic acid and
oxalic acid:
°3 in
benzene
OHC-CHO +
HOOC-CHO +
HOOC-COOH
(a triozonide)
JUrs also concluded that ozonation of phenol, even in water, proceeds
through a triozonide, which is transient, decomposing into aldehydes,
oxalic acid, glyoxal and hydroperoxides:
aldehydes +
HOOC-COOH +
OHC-CHO +
hydroperoxides
H20
1966):
Ozonation of naphthalene in water produced salicylic acid (Jilrs,
301
-------
OH
COOH
Ozonation of indole and skatole proceeds through ozonides which, when
treated with water, form o-aminobenzaldehyde and/or o-aminobenzoic acid
(Jurs, 1966):
CHO COOH
i
x CH-> Uo
H20
indole
skatole
Yocum (1978) studied the ozonation of styrene under aqueous conditions,
but only to the benzoic acid stage of oxidation. He found that initial
cleavage of the exocyclic double bond occurred rapidly, producing benzal-
dehyde and formaldehyde. Further oxidation of formaldehyde to CO? and water
occurred rapidly, as did the oxidation of benzaldehyde to benzoic acid.
This last step (benzaldehyde to benzoic acid) required 1.47 moles of ozone/-
mole of aldehyde.
styrene
+ HCHO
OOH
H20
benzoic acid
Further ozonation of benzoic acid solutions caused attack at the o~,
m- and p- positions on the aromatic ring. After 30 minutes of ozonation of
a 300 mg/1 solution of acid with 4 moles of ozone/mole of benzoic acid, the
benzoic acid was 85% oxidized to other products.
°3* 30 miV 85% oxidation to other
products
302
-------
Finally, Yocum (1978) determined that the biodegradability of ozonized
styrene is much higher than that of styrene itself. The starting BOD-5/TOC
ratio was 0.47, but after 150 minutes of ozonation it had increased to 2.69.
This shows that ozonation in aqueous solution can convert relatively non-
biodegradable compounds into compounds which are biodegradable.
Ozonation of naphthalene-2,7-disulfonic acid (Gilbert, 1978) for 120
minutes produced formic, oxalic and mesoxalic acids, (accounting for 25% of
the TOC) sulfate ion, plus organic carbonyl compounds and organic sulfonic
acids. After 300 minutes of ozonation, nearly complete desulfonation was
achieved (nearly quantitative yield of sulfate ion). Glyoxal and mesoxalic
acid semialdehyde also were identified. The BOD-5/COD ratio increased from
0 to 0.8, indicating that the oxidation products are biodegradable.
S03H 120 min
HCOOH + HOOC-COOH
HOOC-C(:0)-COOH •
organic carbonyl
- so4^ +
+ sulfonic
acids
nearly complete desulfonation +
OHC-CHO + HOOC-C(:0)-CHO
Ozonation of 4-aminobenzoic acid (Gilbert, 1978) gave formic and
oxalic acids, ammonia and nitrate. After 80 minutes of ozonation, only 70%
of the organically-bound nitrogen was measured as ammonia and nitrate. This
indicates that organic compounds containing nitro or ami no groups still were
present. The BOD-5/COD ratio increased from 0 to 0.4.
COOH
80 min
HCOOH
HOOC-COOH
N0
Chian & Kuo (1976) ozonized aqueous solutions of o-toluidine and found
acetic and oxalic acids:
H20
HOOC-COOH + CH3COOH
o-toluidine
303
-------
Ozonation of aqueous solutions of N,N-diethyl-m-toluamide produced
formic, acetic and oxalic acids (Chian & Kuo, 1976):
°3
——> HCOOH + CH3COOH + HOOC-COOH
C-N-(C2H2)2
0
Gilbert (1977) found that 3 to 8 kg of ozone are required to remove 1
kg of aromatic sulfonic acids from aqueous solutions. Ozonation of p-
toluene sulfonic acid in water formed organic peroxides, the concentrations
of which decreased to 0 mg/1 in 120 minutes, plus H002<
Sato, Yokoyama & Imamura (1974) ozonized aqueous solutions of azobenzene.
During the early stages of ozonation, they identified nitrosoazobenzene and
nitroazobenzene as initial oxidation products. However, with further ozona-
tion, these products were converted into oxalic acid, glyoxylic acid and
nitrate ion. This indicates that nitroso compounds can be formed in aqueous
solution from azobenzenes, but that if sufficient oxidant is used, the
intermediate nitroso compounds can be converted into innocuous organic
materials.
Many papers by Prengle and his co-workers (1976, 1977, 1978) describe
the combination of ozone with UV radiation. The combination oxidizes organic
compounds at a faster rate than does ozone alone. Prengle ejt al_. (1977)
followed the UV/ozonation of pentachlorophenol (PCP) by gas chromatography.
After 1 hr of treating a 7 mg/1 aqueous solution at pH 9.6 with ozone/UV,
the PCP concentration had dropped and the amount of chlorine found in solution
as chloride ion was more than 50% of that available. In addition, the TOC
value had dropped. This indicates that the aromatic ring had been ruptured,
forming C02> in addition to chloride ion.
Similarly, a 100 mg/1 solution of o-dichlorobenzene treated 30 minutes
by UV/ozonation showed 100% destruction of the aromatic compound, but only
50% of the available chlorine was recovered as chloride ion.
Reactions With Aliphatic Compounds
Dobinson (1959) ozonized aqueous solutions of malonic acid and identified
hydroxymalonic acid and ketomalonic acid as products:
HOOC-CH2-COOH > HOOC-CH(OH)-COOH +
HOOC-C-COOH <^
Ci
ketomalonic acid
304
-------
Jdrs (1966) in reviewing the literature, concluded that in non-aqueous,
non-polar solvents (carbon tetrachloride, hexane,'etc.) ozonation of aliphatic
double bonds proceeds through polymeric ozonides. In non-aqueous polar
solvents (such as acetic acid), monomeric ozonides are favored.
In water, however, Jtlrs concluded that ozonides hydrolyze to peroxy-
diesters, which further hydrolyze to dialcohols and aldehydes. Peroxyacids
decompose in water to aldehydes or acids and \\fl2- Acids and aldehydes can
recombine to form dialcohols.
Pryde et^al- (1968) studied the ozonolysis of aliphatic unsaturated
materials in water. Methyl oleate (5 g in 25 g of distilled water) ozonized
20 to 30 minutes with 2 to 3% ozone in oxygen produced an 82% yield of
compounds containing new carbonyl groups.
°3
CH3(CH2)7-CH = CH-(CH2)7COOCH3 ^-> compounds containing
*.u -i n a. ^C = 0 groups
methyl oleate s
When T-decene (0.2 to 0.5 g) was ozonized for 16 hrs in water an
aldehyde, a dimethyl acetal, a methyl ester and a hydrocarbon were produced.
All of these resulted from cleavage of the double bond:
°3
CH3(CH2)?CH = CH2 (or R-CH=CH2) - - - > RCHO +
decene decene 3
RCOOCHg +
RCH3
Pryde ejb al_. (1968) concluded that ozonolysis of dispersions of slightly
soluble (in water) organics in water proceeds through hydroperoxides and/or
dihydroxyperoxides, both of which rearrange readily in water to produce
acids, hydrocarbons and C02 or aldehydes and CO.
305
-------
0
RR'CH = CH
2— >RR'CH - CH2 or RR'CH - CH2
OOH OH OOH OOH
V
acids + C02 aldehydes + CO
< Dorfmann (1973) ozonized cysteine in water and isolated cystine as an
initial oxidation product. Cystine then formed unidentified degradation
products upon continued ozonation:
HSCH2CH(NH2)COOH > -[SCH2CH(NH2)COOH]2
cysteine cystine
degradation
products
Kraznov et. al_. (1974) ozonized aqueous solutions of aliphatic alcohols
and aldehydes. Ethanol, butanol and octanol in dilute aqueous solution with
33 mg/1 ozone dosages produced aldehydes, then acids, but did not produce
any C02. The rate of oxidation increased with increasing pH:
CH3CH2OH
CH3CH2CH2CH2OH
CH3(CH2)6CH2OH
0
'3
33 mg/1
aldehydes - acids (no C02)
Secondary alcohols readily produced ketones upon ozonation, which
oxidized further to organic acids and HpO (Kraznov et al., 1974). Ketonic
intermediates were lower boiling than the alcohols,~a"nd~were more readily
stripped into the gas phase:
CH2OH
°3
R1
R-COOH + R'-COOH +
Aldehydes formed peroxy acids, which produced organic acids + H000 on
continued ozonation in dilute aqueous media (Kraznov et aJL, 1974). ^ '
RCH = 0 "?> R-C^O-0-H -" ;* > R_COOH
H20
306
-------
Gilbert (1977) ozonized 1 liter solutions (0.001 mole/1) of maleic acid
at an initial pH of 5. After 50 minutes of ozonation, during which time 195
mg of ozone (39%) was utilized, oxidation of maleic acid was complete.
Degradation of maleic acid was rapid, and glyoxylic and formic acids were
formed simultaneously -as maleic acid disappeared. After complete disappear-
ance of maleic acid, formic acid was ozonized to C02 and water, and glyoxylic
acid was ozonized to oxalic acid:
H H
HOOC-C=C-COOH - > HOOC-CHO + HCOOH
HCOOH
HOOC-CHO — > HOOC-COOH
The total amounts of maleic, glyoxylic, oxalic and formic acids and C02
determined on each sample analyzed was equal to the amounts calculated on
the basis of this mechanism. Therefore, these specific materials are the
only oxidation products of maleic acid. Gilbert also concluded that under
his experimental conditions, little oxidation of oxalic acid occurs upon
ozonation.
Prengle ejt aj_. (1977) studied the UV/ozonation of 1,4-dichlorobutane
and of chloroform in water. With ozone alone, 1,4-dichlorobutane was 50%
destroyed in 1 hr of ozonation, whereas UV/ozonation destroyed 100% of the
material in 1 hr. The stoichiometric amount of chloride ion was found after
1 hr of UV/ozonation.
UV/ozonation for 2 hrs resulted in 80% destruction of chloroform.
However, only 25% of the theoretical amount of chloride was recovered,
therefore, much of the "destroyed" chloroform must have been stripped out
of solution. The rate of decrease of TOC was almost as rapid as the rate of
decrease of chloroform concentration, therefore there are few non-volatile,
carbon-containing organic oxidation products of chloroform.
Chian & Kuo (1976) studied the oxidation of several refractory aliphatic
compounds in aqueous solution with ozone and ozone/UV combinations, and with
the pH contolled by addition of HC1 or NaOH solutions as needed during the
reactions. After 1-propanol (408 mg/1) was ozonized for 1 hr at pH 9 (1,980
mg total ozone dose), a solution having 0 mg/1 ozone concentration was
produced. Propionaldehyde (85 mg/1) was formed and carbon balance analyses
showed that this compound and 1-propanol (145 mg/1 remaining) were the only
two organic materials present. TOC was reduced from 225 to 210 mg/1, indica-
ting that some C02 had been formed.
CH3CH2CH2OH - > CH3CH2CHO + C02
UV/ozonation of 1-propanol (410 mg/1) under the same conditions produced
95 mg/1 of propionaldehyde; 120 mg/1 of propanol remained, and TOC was
reduced to 205 mg/1 .
307
-------
In both cases of ozonation of 1-propanol, TOC levels did not begin to
fall significantly until after aldehyde production had peaked (45 minutes
with ozone alone, 40 minutes with UV/ozone).
Propionic acid (490 mg/1) was ozonized at pH 9 for 2 hours (2,960 mg
total ozone dose). Again, dissolved ozone concentration was 0 mg/1, indica-
ting that the ozone demand had not been satisfied. Unreacted acid concentra-
tion was 235 mg/1 and TOC had dropped from 235 to 200 mg/1. Oxidation
products were not identified.
For the balance of this work of Chian & Kuo (1976) lower concentrations
of organic compounds were chosen so that ozone residual concentrations of 4
mg/1 or higher were present. Ozonation of propionic acid at pH 7 resulted
in 17% TOC reduction and formation of acetone. No monocarboxylic acids were
detected and acetone accounted for over 85% of the TOC of the reaction
mixture:
CH3CH2COOH *CH3-C-CH3 (85% yield)
0
UV/ozonation of 2-propanol substantially increased the rate of TOC
removal. An initial TOC of 110 mg/1 was reduced to 20 mg/1 (85%) after 135
minutes of UV/ozonation. The compound 2-propanol disappeared after 30
minutes and the concentration of acetone formed reached its maximum value at
this time. On continued UV/ozonation, the acetone level decreased to 0
mg/1 after 75 minutes. The C2 to C6 monocarboxylic acids were not detected
in the ozonate, but NaOH addition was required throughout the reaction in
order to maintain a constant pH. This indicates that formic and/or oxalic
acids were produced from the ozonation of acetone.
CH3CH(OH)CH3 >-CH3-C-CH3 >HCOOH and/or HOOCCOOH
0
Ozonation of methyl ethyl ketone (MEK) for 2 hrs at pH 7 produced a
small amount of acetate ion. MEK accounted for over 85% of the ozonate TOC.
Much of the loss of MEK was attributed to air stripping (40% TOC removed
after 2 hrs). By contrast, after 2 hrs of UV/ozonation, MEK was completely
eliminated. Acetate ion reached its maximum concentration after 35 minutes,
then decreased to 0 mg/1 at 105 minutes. Trace amounts of acetone and
ethanol were detected.
CH3CH2C(:0)CH3 »> CH3COO"
Ozonation of acetic acid for 2 hrs at pH 7 (adjusted at the beginning,
but allowed to rise during treatment) resulted in 14% removal of TOC.
Glyoxylate anion concentration increased with time, but was always low:
308
-------
03
CH-COOH - >OHC-COO
6 uv
UV/ozonation of acetic acid was much more rapid. After 75 minutes, no
acetate was detected. Glyoxylate ion (at lower concentrations than with
ozone alone) remained level in concentration during the first hr, but then
decreased to 0 mg/1. No alcohols were found, nor formic acid, but oxalate
ion was found in the ozonate:
CH-COOH - - 3»OHC-COO~ — >~OOC-COO~
6 UV
Ozonation of di ethyl ether for 2 hrs at pH 9 produced ethyl acetate and
acetate ion as the major oxidation products, but small amounts of acetalde-
hyde, methyl formate, ethanol, acetone and ethyl formate also were isolated.
During the later stages of ozonation, TOC reduction rates became slower,
when ethyl acetate and acetate ion were the major constituents. Good agree-
ment between the calculated and experimentally determined TOC indicated that
all the oxidation products were accounted for and that C02, therefore, is
not an oxidation product:
CH3CH2OCH2CH3 • — 93->,CH3COOC2H5 + CH3COO~ (major) +
CH3CHO + HCOOCH3 + CHgCHgOH + CH3C(:0)CH3
UV/ozonation of di ethyl ether resulted in 94% removal of TOC under the
same conditions, because of further oxidation of ethyl acetate and acetate
ion to COo. Formation of acetate ion occurs by 2 routes: from the ether and
from ethyl acetate. Small amounts of the same other organics as obtained
with ozone alone also were isolated after UV/ozonation.
Quantitative determination of oxalate and glyoxylate showed that
acetate concentration reached 0 mg/1 when oxalate concentration reached its
maximum. This indicates that the degradation route of acetate by UV/ozonation
is through glyoxylate and oxalate to COg. Since the amount of oxalate
formed was not equal to the amount of acetate present, it is likely that
glyoxylate (the precursor of oxalate) can be oxidized directly to C02-
CH3COO~ - > OHC-COO" + "OOC-COO" - > C02
Spanggord & McClurg (1978) ozonized aqueous solutions of oleic acid and
isolated 3 organic acids. During ozonation, the pH dropped to 3.8:
CH3(CH2)7CH=CH(CH2)yCOOH + 0
HOOC(CH2)7COOH
OHC(CH2)7COOH
309
-------
Ozonation of diethylamine produced acetaldoxime plus an unidentified
nitrogen-containing compound, not a nitrosamine (Spanggord & McClurg,
1 978) :
(C2H5)2NH — ^ — -> CH3CH=NOH + unidentified compound
Spanqgord & McClurg (1978) ozonized concentrated solutions of ethanol
in water (several percent) with very large doses of ozone (several thousand
mg/1) for 1 to 2 hrs. Acetaldehyde and acetic acid were identified along
with a dihydroperoxide, which was shown to exhibit mutagenic activity:
CH3CH£OH + 03 — >• CH3CHO + CH3COOH
.2
CH-CH CHCH,
3, , 3
OOH OOH
These authors do not believe that the dihydroperoxide will form in
drinking water or wastewaters containing low concentrations of ethanol and
when ozonized under conditions normally employed in water and wastewater
treatment (low ozone dosages, short contact times).
Gilbert (1978) ozonized 1 liter samples of 1 mmole/1 aqueous solutions
of aliphatic compounds with 10 mg of ozone/minute until the initial compound
became undetectable. Oxal acetic acid consumed 1.8 mmole of ozone/mmole of
acid, and a 60% yield of oxalic acid was isolated along with mesoxalic acid
(both formed by oxidation of glyoxylic acid intermediate) and formic acid:
HOOCC(:0)CH2COOH + 03 - ^-OHCCOOH + HOOC-COOH (60%) +
HOOC-C(:0)-COOH + HCOOH
Dihydroxyfumaric acid consumed 1.4 mmoles of ozone/mmole of acid and
rapidly produced oxalic acid as the major product, plus traces of dihydroxy-
tartaric acid, mesoxalic acid and the semialdehyde of this acid:
HOOC-C(OH)=C(OH)COOH + Q3 - > HOOC-COOH (major) +
HOOC-C(OH)2C(OH)2COOH +
HOOC-C(:0)-COOH +
HOOC-C(:0)-CHO
310
-------
Malonic acid consumed 4 mmoles of ozone/mmole acid. Oxalic acid and
mesoxalic acids were the major oxidation products isolated. The concen-
tration of tartronic acid increased from the start of ozonation, then
decreased, forming mesoxalic acid and HLCL:
HOOCCH2COOH + 03 >HOOC-COOH + HOOCCH(OH)COOH (tartronic acid)
HOOC-C(:0)-COOH + H^
Tartronic acid was converted totally to mesoxalic acid arid in 40
minutes of ozonation had used 1 mmole of ozone/mmole acid. There was no
decrease in TOC nor formation of HLOp during this time:
HOOC-CH(OH)-COOH + Og - > HOOC-C(:0)-COOH
Glyoxal disappeared after 50 minutes of ozonation, producing glyoxylic
acid which further oxidized to oxalic acid, then disappeared after 60
minutes of total ozonation. No \\^2 was formed:
OHC-CHO + 03 — > HOOC-CHO — >HOOC-COOH
Ozonation of the 6-carbon containing muconic acid, HOOCCH=CHCH=CHCOOH,
produced 2-carbon containing fragments and only traces of 3-carbon containing
compounds. The 4-carbon containing fumaric acid, HOOCCH=CHCOOH, behaved
similarly upon ozonation.
Kuo, Chian & Chang (1978) treated 2-propanol and acetic acid with ozone
and UV/ozone. The compound 2-propanol formed acetone, which then formed
acetic acid and oxalic acid plus traces of formaldehyde and formic acid upon
continued ozonation:
CH3CHOHCH3 + 03 — >CH3C(:0)CH3— >CH3COOH + HOOC-COOH +
HCHO + HCOOH
Acetic acid produced glyoxylic acid initially, which rapidly formed
oxalic acid, which slowly formed C02 upon continued ozonation or UV/ozonation:
CH3COOH + 03-> HOOC-CHO - > HOOC-COOH
Schalekamp (1977) reported that the Lake of Ztlrich water contains
various organic aldehydes (heptanal through tetradecanal ) in concentrations
of 8 to 40 nanog/1. After ozonation (1 to 1.5 mg/1 dosages) these aldehydes
plus hexanal were present in higher concentrations (up to 920 nanog/1).
Passage of ozonized Lake Ztlrich water through activated carbon reduced the
concentrations of these aldehydes to below the levels originally present.
Gilbert (1977) ozonized aqueous solutions of several aliphatic compounds.
In pure solutions at pH 3 to 7, 1 kg of COD was removed from solution with
311
-------
1.2 kg of ozone. In wastewaters, 2 to 5 kg of ozone were required to remove
1 kg of COD. Ethanol ozonized for 350 minutes produced acetaldehyde, acetic
— _J_l-ff_._.__-!___-*_l^%rt lltSN
2U2;
acid, formic acid, C09 and H000:
CH3CH2OH + 03— > CH3CHO + CHgCOOH + HCOOH + C02 + H202
Tartaric acid ozonized for 80 minutes at pH 3 and pH 7 produced dihydroxy-
tartaric acid, glyoxal, oxalic acid, mesoxalic acid and H202:
HOOCCH-CHCOOH + 0, - > HOOCC(OH)9C(OH)0COOH +
II 3 c. c.
OH OH
OHC-CHO + HOOC-COOH +
HOOC-C(:0)-COOH + H^
Malonic acid ozonized for 90 minutes at pH 4 produced tartronic acid,
mesoxalic acid, oxalic acid and (XL plus H202:
HOOCCH2COOH + 03— >HOOC-CH(OH)-COOH + HOOC-C(:0)-COOH +
HOOC-COOH + C02 + H202
Finally, Gilbert (1977) showed that the presence of H20? had a remarkable
catalytic effect on the oxidative decomposition of oxalic acid. In the
absence of peroxide, ozonation of oxalic acid produced C02 very slowly, but
when small amounts of H202 were added, oxalic acid produced C02 rapidly.
HOOC-COOH ° >C02 + H20
\
rapidly
Reactions With Miscellaneous Compounds
Fremery & Fields (1963) studied the reactions of cyclic olefins with
ozone in aqueous alkaline emulsions containing hydrogen peroxide. In general,
a,cu-dicarboxylic acids were isolated, depending upon the specific cyclic
olefin starting material:
HOOC-CH2-CH2-CH-CH2-COOH
Cyclohexene upon treatment with ozone prepared from oxygen gave a
mixture of products containing peroxides and peroxypolymers. These were
shown to be side products of the main reaction, for when nitrogen was
substituted for oxygen as the ozone carrier gas, cyclohexene gave 20 to 28%
adipic acid plus small amounts of 6-hydroxyvaleric acid and its lactone:'
312
-------
HOOC-(CH2)4-COOH (adipic acid)
+
HOCH2CH2CH2CH2COOH
0
Weber & Waters (1972) ozonized aqueous, 0.0005M solutions of dimethyl
mercury. After 10 minutes of ozonation, the concentration of alkyl mercury
compound became undetectable.
Shapiro ejt aj_. (1978) ozonized aqueous solutions of caffeine (660 mg/1)
with 1,630 mg of ozone over 90 minutes; 4.2 moles of ozone were consumed/mole
of caffeine. Four major products were isolated (above 5% each) plus 4 minor
products. One of the major products was shown to be dimethyl parabanic acid
by independent synthesis. Caffeine has been shown to be a constituent of
sewage treatment plant effluents:
dimethyl parabanic acid
Reap tions Wi th Pes tici des
Robeck e£ aj_. (1965) ozonized aqueous solutions of lindane, dieldrin,
DDT and parathion and found that dosages of 10 to 38 mg/1 of ozone were
required to destroy these pesticides to acceptable levels. These dosages
were considered to be too high to be practical in drinking water treatment
plants. These authors also concluded that the more usual drinking water
treatment plant ozone dosages of 1 to 2 mg/1 probably would oxidize parathion
to paraoxon, a compound which is more toxic than is parathion.
Gabovich e_t aj_. (1969) ozonized aqueous solutions containing 10 mg/1 of
malathion. Ozone dosages of 3.5 mg/1 (0.5 mg ozone/mg malathion reduced the
concentration of malathion to 2 mg/1. Increasing the ozone dosage to 9.8
mg/1 (1/1 ozone/malathion) reduced malathion concentration to 1 mg/1. A
dosage of 26 mg/1 of ozone caused 100% destruction of malathion.
Hoffman & EichelsdSrfer (1971) dissolved various pesticides in hexane
or acetone, then diluted the pesticide solutions with water to make aqueous
solutions as high in concentration as 2 mg/1 of pesticide. These were
313
-------
ozonized over 45 minutes with total ozone dosages up to 240 mg/1. At these
dosages, aldrin and heptachlor were "quantitatively" reacted to destruction,
but oxidation products were not identified. On the other hand, solutions of
dieldrin, heptachlorepoxide, chlordane, lindane, DDT and endosulfan were
hardly affected by ozone at all. This raises the question as to whether the
ozonation of heptachlor produces heptachlor epoxide. If so, the epoxide
will be stable to further ozonation, and itself is a toxic material.
Cl Cl
H Cl
heptachlor
heptachlor-
epoxide
Richard & Brener (1978) showed that ozonation of parathion with 3 mg/1
ozone dosage forms paraoxon, a more toxic material than parathion itself.
The reaction proceeds fastest in acid medium. Continued ozonation of paraoxon
(5 mg/1 ozone dosage) proceeds slower, with destruction of paraoxon and
formation of 2,4-dinitrophenol, picric acid, H2$04 and H3P04:
(CH3CH20)X,|
(CH3CH20)'
parathion
0,
3 mg/1
(acid)
0
(CH3CH20)2-P-
paraoxon
paraoxon
5 mg/V
(basic)
H3P04
Similarly, Richard & Brener (1978) ozonized malathion and isolated
malaoxon as the first step intermediate. Continued ozonation destroyed the
malathion, producing HPO and unidentified, degraded organic compounds.
CH-0X||
0 P-S-CH-COOC2H5
CH30 CH2COOC2H5
malathion
CH3°\
CH30
0
II
P-S-CH-COOC2H5
CH0COOC2H5
malaoxon
H3P04
degraded oxidation
products
314
-------
Phosalone upon ozonation did not produce an oxon intermediate. Instead
the benzoxalone moiety was cleaved to produce the parent alcohol. This
alcohol also underwent self-condensation to produce an ether. Both the
alcohol and the ether were isolated and identified by Richard & Brener
(1978):
C2H50-
Cl
N-CH2OH
N-CH2-0-CH2-N
JL,
Cl
Richard & Brener (1978) concluded that under-ozonation of an organic
material can produce other organic materials that are toxic, and that it is
essential to know the chemical content of waters to be treated with ozone
(or any oxidant),
Mallevialle e_t a_l_. (1978) ozonized aqueous solutions of aldrin and
found this compound to be easily degraded by ozone. On the other hand, when
aldrin was added to aqueous solutions containing humic acids, 0.45 yg/1 of
aldrin was detected even after 10 minutes of ozonation. These researchers
concluded that ozonation studies on organic compounds conducted in pure
solutions can be misleading. It is necessary to know the humics or soils
content of water to be ozonized, since these materials can adsorb dissolved
organics and thereby "protect" them from the oxidizing action of ozone.
Prengle and Mauk (1978) showed that ozonation of DDT in water proceeds
very slowly, but the oxidation rate is accelerated by combining UV radiation
with ozonation.
Weil §t al.. (1977) ozonized 0.001M solutions of 2,4,5-T with 0.048
mole/hour of ozone and identified oxalic acid, glycolic acid, dichloromaleic
acid, chloride ion and C02 as oxidation products. No ozonides or polymeric
peroxides could be found. The concentration of dichloromaleic acid peaked
after 8 to 9 minutes, that of glycolic acid peaked after 12 minutes and that
of oxalic acid peaked after 20 minutes of ozonation, after which the concentra-
tion of all three intermediate products decreased with increasing time of
ozonation. The concentration of dichloromaleic acid became zero in 25
minutes:
315
-------
0-CH2COOH
HOOC-CH-CH-COOH peaked in 8 to 9 tnin
Cl Cl
+ HOOC-CH2OH
+ HOOC-COOH
+ Cl" + C00
peaked in 12 min
peaked in 20 min
Cl
2,4,5-T
Reactions With Humic Materials
Ahmed & Kinney (1950) ozonized KOH solutions containing 2 g of humic
materials. Water soluble, ozone-resistant acids were isolated, and 65% of
the original carbon was isolated as CO-.
Kinney & Friedman (1952) ozonized aqueous alkaline solutions of humic
acids and isolated and identified small amounts of acetic acid, terephthalic
acid, C02 and traces of oxalic acid:
humic acids
CHgCOOH +
HOOC
HOOC-COOH
Dobinson & Lawson (1959) ozonized solutions of humic acids isolated
from coal and identified small amounts of acetic acid and C09 as reaction
products.
-------
20 minutes of ozonation the solution turned violet, which was ascribed to
the decomplexing of manganese, followed by oxidation to permanganate.
Chromatography of this solution showed the presence of phenolic compounds
and formic acid. The author concludes that insufficient ozonation will
increase the concentrations of these materials, but for most water supplies,
maintaining a residual of 0.4 mg/1 of ozone over 6 minutes will be a suffi-
cient dosage.
Waters containing 525 mg of humic acids required 100 mg of ozone to
destroy 95% of the color and 320 mg of ozone to destroy 95% of the polyhydroxy-
aromatics (Mallevialle, 1975).
Rook (1976) coagulated and filtered Meuse River water, then ozonized it
8 minutes with 2 mg/1 doses, then chlorinated the ozonized waters. After 8
minutes of ozonation, haloform formation was reduced by 65%. However, after
the ozonized water had stood for 24 hours, then was chlorinated, the amount
of haloforms produced was about the same as without chlorination.
SUMMARY OF OZONATION REACTIONS
With Aromatic Compounds
• Phenol reacts readily with ozone in aqueous solution to produce the
dihydroxybenzenes catechol, hydroquinone and resorcinol. The first 2
compounds are further oxidized to o- and p-benzoquinone, respectively.
• All of the above oxidized aromatic compounds, upon further oxidation
with ozone, undergo ring cleavage to produce aliphatic unsaturated
diacids: muconic, fumaric and maleic, plus the hydroxylated saturated
diacids: tartaric and mesotartaric. In addition, glyoxal, glyoxylic
acid, glycolic acid and oxalic acid are formed, along with C02«
• Oxalic and acetic acids are relatively stable to ozonation in the
absence of a catalyst such as UV light or h^Oo, and thus can be con-
sidered to be relatively stable oxidation products from the ozonation
of phenol in water.
• Ozonation just to the point of destruction of phenol requires 2 to 3 mg
of ozone/mg of phenol, but COD levels are reduced only 50%. To destroy
phenol and lower COD levels to zero requires 8 to 12 mg of ozone/mg of
phenol.
t Ozonation of chloro-substituted phenols ultimately cleaves the aromatic
C-C1 linkages, forming chloride ion plus the same types of ring-ruptured
aliphatic compounds as does phenol.
• Cresols and xylenols undergo oxidation with ozone at faster rates than
does phenol. Before ring cleavage occurs, o-cresol forms salicylic
acid.
317
-------
t Upon ring rupture, ozonized cresols produce the same types of aliphatic
products as does phenol, plus mesotartaric, propionic and acetic acids.
• Xylenols produce all these aliphatic products plus hydroxyphthalic acid
(before ring-rupture) and diacetyl and glyoxal (after ring-rupture).
t Nitro, amino and sulfonic acid groups on aromatic rings are split off
by ozonation, but at much slower rates than is chlorine. Amino groups
are converted to ammonia and nitrate ion. Sulfonic acid groups are
converted to sulfate.
• Azobenzene in water gave nitrosoazobenzene and nitroazobenzene as
initial oxidation products. However, continued ozonation converted
these intermediate compounds into oxalic acid, glyoxylic acid and
nitrate ions. Thus, nitroso compounds can form during the early
stages of ozonation; these will continue to oxidize to innocuous
organic materials provided that sufficient amounts of ozone and/or
oxidation times are supplied.
t Aromatic hydrocarbons such as pyrene, phenanthrene and naphthalene
oxidize by ring rupture. Only 1 ring in phenanthrene opens readily,
however. When aliphatic hydrocarbon groups are present on the aromatic
rings, these oxidize first, before the ring ruptures.
• Chlorobenzene reacts with ozone slower than does phenol, but gives the
same ring-ruptured, aliphatic oxidation products as does phenol.
Intermediate oxidation products include o-, m- and p-chlorophenols plus
chlorotartaric acid. Chlorocresols, chlorophenols and thiophenols give
ozonation products similar to those from phenol.
With Aliphatic Compounds
• There is no evidence that ozone reacts with saturated aliphatic hydro-
carbons under water or wastewater treatment conditions.
• There is also no evidence that ozone oxidizes trihalomethanes. Reduction
in concentration of THMs upon ozonation appears to occur by air stripping
of aqueous solutions. Ozone combined with UV radiation does oxidize
chloroform to produce chloride ion, but no identified organic oxidation
product.
t Unsaturated aliphatic or alicyclic compounds react with ozone, usually
at the unsaturated bond, cleaving the molecule into 2 oxidized fragments
(aliphatics) or into diacids or carbonyl acids (alicyclics). The 2
aliphatic fragments normally are an acid plus an aldehyde or ketone.
• Primary aliphatic alcohols generally are oxidized to aldehydes, then to
acids, but at slower rates than phenol oxidation with ozone.
318
-------
• Secondary aliphatic alcohols produce ketones, then acids plus H^
upon ozonation.
• Formic acid readily produces C02 and water upon ozonation, but oxalic
acid is relatively stable to ozonation in the absence of UV radiation
or He02. Acetic acid and propionic acid also are relatively stable to
ozonation.
t Oxalic acid oxidizes directly to CO? without producing formic acid.
Reaction with ozone alone is very slow, but proceeds rapidly in the
presence of UV radiation or H^CL.
• Maleic acid produces glyoxylic and formic acids initially. Glyoxylic
acid then produces oxalic acid, CO^ and water. These are the sole
products of ozonation of maleic acid.
• Propionic acid and 2-propanol produce acetone upon ozonation. Acetone
can undergo the haloform reaction and produce chloroform if present
during post-chlorination of ozonized water.
• Ozonation of acetate ion and acetic acid ultimately produces glyoxylate
ion or glyoxylic acid, respectively, which then form oxalic acid.
• Diethylamine produces acetaldoxime upon ozonation, plus an unidentified
nitrogen-containing compound, not a nitrosoamine.
t Prolonged ozonation of a concentrated ethyl alcohol solution in water
produces a stable dihydroperoxide which exhibits mutagenic activity.
• Ozonation of Lake of Zdrich raw water increased the aldehyde concen-
trations. Ozonation followed by activated carbon adsorption reduced
the aldehyde concentrations below their original concentrations.
t UV/ozonation of refractory organic materials increases the rate at
which they are oxidized by ozone, but not the nature of the oxidation
products.
x
With Pesticides
• Ozonation of parathion and malathion produces paraoxon and malaoxon,
respectively, as intermediates, which are more toxic than are the
starting materials. Continued ozonation degrades the oxons, but
requires more ozone than does the initial thion oxidation. Phosalone
oxidizes without forming an oxon intermediate. Thus, under-ozonation
can produce intermediates which are more toxic than are the starting
materials.
* Ozonation of heptachlor produces a stable product, not yet identified.
Heptachlorepoxide is known to be stable to ozonation. This suggests
that ozonation of heptachlor may produce the epoxide, which then would
be unaffected by further ozonation.
319
-------
t Aldrin and 2,4,5-T are readily oxidized by ozone, but dieldrin, chlor-
dane, lindane, DDT and endosulfan are only slightly affected by ozone.
• UV/ozonation destroys DDT, PCBs, malathion and many other pesticides,
but requires more extended contact times and ozone doses.
• Ozonation of aldrin in pure water solutions proceeds rapidly, but at a
much slower rate in the presence of humic acids. Similar oxidation
rates were observed with solutions of benzopyrene in pure water (rapid)
versus water containing colloidal soil particles (slow). This indicates
that dissolved organic materials can be adsorbed by humics or soil
particles and be "protected" from oxidation, at least partially. This
would also indicate that oxidation of water supplies or of wastewaters
with ozone should follow a filtration step.
With Humic Materials
• Humic materials are resistant to ozone, requiring lengthy times of
ozonation to produce small amounts of acetic, oxalic, formic and
terephthalic acids, C02 and phenolic compounds.
• Ozonation of humic materials in water followed by immediate chlori-
nation (within 8 minutes) reduced trihalomethane formation by 65%.
However, when ozonized waters containing humics were allowed to stand
24 hours and then chlorinated, there was no change in the amounts of
trihalomethanes formed. This indicates that although ozone changes the
chemical nature of trihalomethane precursors, there is continued reaction
upon standing, not entirely with residual ozone, to form materials
equally capable of producing trihalomethanes upon chlorination.
• Ozonized organic materials generally are more biodegradable than the
starting, unoxidized, compounds.
A comparative summary of the reactions of organic materials with
ozone, chlorine dioxide and chlorine is given in Table 71, which is taken
from Miller e_t al_. (1978), who conducted a detailed assessment of the state-
of-the-art of the treatment of water supplies with ozone and with chlorine
dioxide for EPA's Water Supply Research Laboratory.
CONCLUSIONS
• Complete oxidation of dissolved organic materials to C02 and water in
aqueous solutions is rare by means of any oxidant.
• In general, if an organic material is resistant to oxidation by ozone
(the most powerful oxidant used in water and wastewater treatment), it
will also be resistant to oxidation by other (weaker) oxidants.
320
-------
TABLE 71. COMPARISON OF OXIDATION OF ORGANIC COMPOUNDS WITH OZONE, CHLORINE DIOXIDE AND CHLORINE
Type of
Organic
Oxidation Products Isolated Upon Treatment With
ozone
chlorine dioxide
chlorine
Phenol
intermediates: polyhydroxy-
aromatics and quinones.
Then ring ruptured, non-
halogenated difunctional
products (alcohol-aldehyde;
aldehyde-acid; alcohol-
acid). End Products:
oxalic acid, C02+H20
Same as for ozone plus chlori-
plus
chlor
nated phenols and chloroqui-
nones. Upon ring rupture, the
same non-chlorinated products
as for ozone are obtained, plus
some chlorinated aliphatics
chlorophenols plus
ring-ruptured
products (presumably
chlorinated); also
non-chlorinated
products (aromatic
and ring-ruptured)
oo
ro
Cresols and xylenols
Same products as from
phenol, p_l_us_ methyl-substi-
tuted compounds (sailcyclic
acid as aromatic intermedi-
ate, propionic and acetic
acids after ring rupture).
Acetic acid, oxalic acid,
C02+H20 end products
probably chlorinatec
aromatics, then ring
rupture.
Chlorinated phenols
Chloride ion plus same
products as from phenol
Oxalic acid
products.
C00 end
Chioroquinones plus ring-
ruptured, halogenated and
non-halogenated aliphatics
probably more highly
chlorinated phenols,
then ring rupture.
(continued)
-------
TABLE 71. (continued) ozone
chlorine dioxide
chlorine
Chlorinated benzenes
Chlorophenols, then chlo-
ride ion and non-chlori-
nated, ring-ruptured pro-
ducts, as with chloro-
phenols, plus some chloro-
tartaric acid.
probably more highly
chlorinated products
miscellaneous
aromatics
nitro, amino and sulfonic
acid groups are cleaved,
but more slowly than chlo-
rine. Oxalic acid + C0?
are end products.
benzoic, phenysulfonic and
cinnamic acids are not reactive
to 0102- Nitro groups are
split off during ring oxidation
CO
ro
ro
polycyclic
aromatics
undergo ring rupture
producing polycarboxylic
aromatics, which become
increasingly resistant
to further oxidation.
produces polycyclic non-halo-
genated quinones plus chlori-
nated polycyclic aromatics.
Eventual ring rupture likely,
but at slower rate than with
ozone.
Probably same
products as with
chlorine dioxide.
diphenylhydrazine
or diphenylamine
hydroxylamines and ring
hydroxylated
diphenylamine.
ring-chlorinated, ring-hydro-
xylated and ring-chlorinated +
hydroxylated diphenylamine.
nitrogen heterocycles
ring rupture to amino
acids, then further
degradation to aliphatic
end products
thianine stable. Pyrimidine
and indole rings apparently
stable. Substituents oxidize,
but do not chlorinate
(continued)
-------
TABLE 71. (continued) ozone
chlorine dioxide
chlorine
unsaturated
aliphatics
cleavage of double bond
to aldehydes, ketones and
acids. Possible formation
of epoxides.
dichloro compounds, chloro-
ketones, chlorohydrins, then
epoxides
dichloro compounds,
chlorohydrins, then
epoxides under
alkaline conditions
primary
aliphatic
alcohols
yield aldehydes, then
acids, then C02. Ethanol
forms a dihydroperoxide
with tnutagenic properties
under stringent conditions.
yield acids which are stable
to further oxidation. Un-
saturated acids (crotonic,
maleic and fumaric) are
stable to C102-
secondary alcohols
yield ketones, then
fragmented acids, then CO
yield ketones, then acetic
acid, which is stable.
CO
ro
co
primary aliphatic
amines
no reaction.
secondary aliphatic
amines
aldoximes + other N-con-
taining compounds, not
nitrosamines
very slow reaction
tertiary
aliphatic amines
secondary amine + aldehyde
chloroform
no reaction except in
presence of UV
probably no reaction
no reaction
(continued)
-------
TABLE 71. (continued) ozone
chlorine dioxide
chlorine
humic materials
slowly reactive, producing
phenols, ozone - resistant
acids (increasing COD) and
co2.
slowly reactive, producing
phenols and increasing COD
trihalomethanes
sugars, carbohydrates
ring substituents oxidize
without ring rupture until
excess C10 employed.
CO
ro
-pa
trihalomethane
precursors
1) Oq + rapid chlorination
0 65% lowering of THM
2) Oo + chlorination after
24 hrs has no effect on
THM yield.
no THMs produced from pure C10?
(containing no free chlorine)
trihalomethanes
phosalone, aldrin
readily oxidized to
destruction.
2,4,5-T
ring rupture to oxalic acid
+ C02 + chloride ion.
parathion,
malathion
produces oxons, then
degradation products.
dieldrin, chlordane,
lindane, DDT,
PCBs, PCP,
endosulfan
only slightly reactive
with ozone, but will
oxidize with ozone/UV.
-------
Conversely, ozone will oxidize some organic materials that other
oxidants will not oxidize (such as primary and secondary amines, amino
acids, double bonds conjugated with carbonyl groups, etc.), and at
faster rates.
Oxidation products formed by ozonation do not contain halogen atoms,
unless bromide ion is present. In this case, bromide is oxidized to
bromine, which then may react with organic materials present.
Oxidation of phenols with ozone or chlorine dioxide produces oxidized
aromatic compounds as intermediates, which undergo ring rupture upon
treatment with more oxidant and/or longer reaction times. In many
cases, the same, non-chlorinated, ring-ruptured aliphatic products are
produced using ozone or chlorine dioxide.
Oxidation of phenols with chlorine dioxide or chlorine produces chlori-
nated aromatic intermediates before ring rupture.
Ozonation of chlorinated aromatic compounds ruptures the rings and
cleaves carbon-chlorine bonds, forming chloride ion, non-chlorinated
aliphatic oxidation products and C02«
Oxidation products formed upon ozonation, and non-chlorinated oxidation
products from chlorine dioxide are more biodegradable than are the
starting organic materials.
Oxalic and acetic acids are only slowly reactive with ozone, and are
the most stable organic end products of oxidation of organic materials
with ozone.
Combination of ozone with UV light increases the rate of oxidation of
ozone-resistant organic materials, but the same organic oxidation
products are obtained as with ozone alone.
Epoxide compounds have been isolated from reactions of compounds
containing double bonds with chlorine o_r chlorine dioxide. Hepta-
chlorepoxide is stable to ozonation, indicating that it may form upon
ozonation of heptachlor.
Oxidation of aldrin or 3,4-benzopyrene with ozone in clean water
proceeds rapidly, but proceeds significantly slower when humic materials
or soil particles are present. Thus dissolved organics can be adsorbed
onto humic or soil materials and be resistant to oxidation.
Oxidation of parathion and malathion with ozone proceeds through the
more toxic oxon intermediates (paraoxon and malaoxon, respectively).
These same intermediates may form with other oxidants, but no literature
has been found to confirm"this.
325
-------
• Bromide and iodide ions are readily oxidized to the free halogens by
chlorine or by ozone. The free halogens then can undergo the haloform
reaction to produce trihalomethanes, if the proper organic compounds
are present. Formation of bromine-containing trihalomethanes upon
treating humic materials with chlorine dioxide (even containing a
slight excess of free chlorine) has not been observed.
• Ozonation of humic materials followed by immediate chlorination shows a
significant reduction in trihalomethane formation. However, ozonation
followed by chlorination 24 hrs later shows no reduction of trihalo-
methane formation.
t Regardless of the oxidant employed, many (possibly all) of the same
organic oxidation products will be present in the water or wastewater
at the same treatment point. More significantly, in the case of
chlorine, these same (non-chlorinated) oxidation products probably have
been present all along. A detailed review of the organic oxidation
products of chlorine should be made for comparison with this survey of
oxidation products of organic compounds with ozone.
t Trihalomethane formation in drinking waters can be eliminated by
changing the disinfecting oxidant, but this will have no effect upon
formation of the other, non-chlorinated organics.
• Similarly, formation of chlorinated organics in wastewaters can be
eliminated by substituting another oxidant for chlorine, but this will
have no effect upon the formation of the other, non-chlorinated organics,
• These last three conclusions indicate that rather than considering an
"alternative oxidant to chlorine" for treating water or wastewater, it
is more meaningful to consider "alternative treatment schemes for
removing organic materials" before the oxidant is added. Depending on
the source of organic pollution and its nature, little may be gained by
simply changing the oxidant.
• There are 3 basic approaches to minimize the amount of oxidized organic
materials remaining in wastewaters treated with oxidants:
Add sufficient oxidant (with oxidation catalyst, if appropriate)
to convert all organic materials to CC>2 and water. This may be
the most costly approach, in terms of oxidant, and may not even be
possible, depending upon the specific organic materials present.
-- Eliminate or significantly reduce the amount of organic materials
present before oxidant is added. This would involve better
pretreatment, filtration, use of more or improved flocculants,
etc.
Oxidation with a non-halogenating reagent (ozone, chlorine dioxide
in some cases, permanganate, H202, etc.) usually will produce
326
-------
oxidized organic materials which are more biodegradable. Following
oxidation with a biological filtration step (such as Biological
Activated Carbon—see next section) will allow significant reduction
of dissolved organics and ammonia concentration using smaller
amounts of oxidant than in the first two approaches.
• Since halogenated organic materials are both more difficult to oxidize
and are less biodegradable, their formation during the early stages of
water or wastewater treatment processes should be avoided, if at all
possible. If early stage emphasis is placed on removal of organics to
the maximum degree practicable under specific plant conditions, the
following benefits can accrue:
1) chlorine demand will be reduced.
2) amounts of oxidized organics formed later in the process will
be reduced.
3) amounts of formed trihalomethanes and other halogenated
organics will be reduced.
4) Detrimental effects on finished wastewater caused by high
organic and high chlorine levels will be reduced.
t If the presence of halogenated organic compounds cannot be avoided (for
example, if they are present in high concentration in the raw wastewater),
pretreatment with the combination of ozone with UV radiation should be
considered, especially as a pretreatment step before BAG media.
LITERATURE CITED -- OXIDATION PRODUCTS OF ORGANIC MATERIALS
Ahmed, M. & C.R. Kinney, 1950, "Ozonization of Humic Acids Prepared from
Oxidized Bituminous Coal", J. Am. Chem. Soc. 72:559-561.
Bauch, H., H. Burchard & H.M. Arsovic, 1970, "Ozone as an Oxidative Disin-
tegrant for Phenols in Aqueous Solutions". Gesundheit Ingenieur 91(9):-
258-262.
Buydens, R., 1970, "L'Ozonation et ses repercussions sur le mode d'gpuration
des eaux de rivieres", Tribune du Cebedeau 319-320:286-291.
Chian, E.S.K. & P.P.K. Kuo, 1976, "Fundamental Study on the Post-Treatment
of RO Permeates From Army Wastewater". Sec. Annual Summary Rept., U.S.
Army Medical R & D Command, Washington, D.C., Rept. No. UILU-ENG-76-
2019, Oct.
Coin, L., C. Hannoun & C. Gomella, 1964, "Inactivation of Poliomyelitis
Virus by Ozone in the Presence of Water", La Presse M§dicale 72(37):2153-
2156.
327
-------
Coin, L.s C. Gomella, C. Hannoun & J.C. Trimoreau, 1967, "Ozone Inactivation
of Poliomyelitis Virus in Water", La Presse Medicale 75(38): 1883-1884.
Dobinson, F., 1959, "Ozonisation of Malonic Acid in Aqueous Solution", Chem.
& Ind. (6):853-854.
Dobinson, F. & G.J. Lawson, 1959, "Chemical Constitution of Coal VI—Optimum
Conditions for the Preparation Of Sub-humic Acids from Humic Acid by
Ozonization", Fuel 38:79-87.
Dorfmann, L.M., 1973, NSRDS, U.S. Natl. Bureau of Standards, Gaithersburg,
Md.—46i
Eisenhower, H.R., 1968, "The Ozonization of Phenolic Wastes". J. Water Poll.
Control Fed. 40(11):1887-1899.
Fremery, M.I. & E.K. Fields, 1963, "Emulsion Ozonization of Cycloolefins in
Aqueous Alkaline Hydrogen Peroxide", J. Org. Chem. 28:2537-2541.
Gabovich, R.D., K.K. Vrochinskii & I.L. Kurinnyi, 1969, "Decolonization,
Deodorization and Decontamination of Drinking Water By Ozonization,"
Hygiene and Sanitation (Gig. y Sanit.) 34:336-340.
Gabovich, R.D., I.L. Kurinnyi & Z.P. Fedorenko, 1969, "Effects of Ozone and
Chlorine on 3,4-Benzopyrene During Water Treatment". Gig. Naselennikh
Mest., p. 88.
Gilbert, E., 1978, "Reactions of Ozone with Organic Compounds in Dilute
Aqueous Solution: Identification of Their Oxidation Products", in
Ozone/Chlorine Dioxide Oxidation Products of Organic Materials. R.G.
Rice & J.A. Cotruvo, editors, Intl. Ozone ATsocT, Cleveland, Ohio, p.
227-242,
Gilbert, E., 1977, "Chemical Reactions Upon Ozonation", Presented at Intl.
Symp. on Ozone and Water, Wasser Berlin, May, Intl. Ozone Assoc.,
Cleve-land, Ohio.
Gould, J.P. & W.J. Weber, Jr., 1976, "Oxidation of Phenols by Ozone", J.
Water Poll. Control Fed. 48(1):47-60.
Hillis, R., 1977, "The Treatment of Phenolic Wastes by Ozone". Presented at
3rd Intl. Symp. on Ozone Technology, Paris, France, May. Intl. Ozone
Assoc., Cleveland, Ohio.
Hoffman, J. & D. Eichelsdbrfer, 1971, "Zur Ozon Einwirkung auf Pestizide der
Chlorkohlenwasserstoffgruppe im Wasser," Vom Wasser 38:197-206.
Hoigne, J., 1975, "Comparison of the Chemical Effects of Ozone and of
Irradiation on Organic Impurities in Water", Proc. Radiation for a
Clean Environment, Intl. Atomic Energy Agency, Vienna, p. 297-305.
328
-------
Il'nitskii, A.P., 1968, "Effect of Ozonation upon Aromatic Hydrocarbons
Including Carcinogens", Hygiene and Sanit. (Gig. y Sanit.) 33(3):323-7.
Il'nitskii, A.P., 1969, "Experimental Investigation of the Elimination of
Carcinogenic Hydrocarbons from Water During its Classification and
Disinfec-tion", Hygiene and Sanit. (Gig. y Sanit.) 34(9):317-321.
JUrs, R.H., 1966, "Die Wirkung des Ozons auf im Wasser gelflste Stoffe" ("The
effect of ozone on materials which are dissolved in water") Fortschr.
Wasserchem. Ihrer Grenzgebiete 41:40-64.
Kinney, C.R. & L.T. Friedman, 1952, "Ozonization Studies on Coal Constitu-
tion", J. Am. Chem. Soc. 74:57-61.
Krasnov, B.P., D.L. Pakul' & T.V. Kirillova, 1974, "Ozonization of Indus-
trial Wastewater", Khim. Prom. 1:28-30. Engl. Trans!. in Intl. Chem.
Engrg. 14(4):747-750 (1974).
Kuo, P.P.K., E.S.K. Chian & B.J. Chang, 1978, "Identification of End Pro-
ducts Resulting From Ozonation of Compounds Commonly Found in Water",
in "Ozone/Chlorine Dioxide Oxidation Products o_f Organic Materials", R.
G. Rice & J. A. Cotruvo, editors, Intl. Ozone AssocV, Cleve!and, Ohio,
p. 153-166.
Mallevialle, J., 1975, "Action of Ozone in the Degradation of Simple and
Polymeric Phenolic Compounds-- Application to Humic Materials Contained
in Waters", T.S.M. TEau 70(3):107-113.
Mallevialle, J., Y. Laval, M. LeFebvre & C. Rousseau, 1978, "The Degradation
of Humic Substances in Water by Various Oxidation Agents (Ozone,
Chlorine, Chlorine Dioxide)", in Ozone/Chlorine Dioxide Oxidation
Products Of Organic Materials, R.G. Rice & J.A. Cotruvo, editors,
Intl. Ozone Assoc., Cleveland, Ohio, p. 189-199.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, W. KUhn & H. Wolf, 1978,
"An Assessment of Ozone and Chlorine Dioxide Technologies for Treatment
of Municipal Water Supplies". U.S. EPA Report 600/2-78-147. U.S.
Environmental Protection Agency, Municipal Environmental Research
Laboratory, Cincinnati, Ohio 45268.
Prengle, H.W., Jr., C.E. Mauk & J.E. Payne, 1976, "Ozone/UV Oxidation of
Chlorinated Compounds in Water", in Forum on Ozone Disinfection, E.G.
Fochtman, R.G. Rice & M.E. Browning, editors, "Intl. Ozone Assoc".,
Cleveland, Ohio, p. 286-295. .
Prengle, H.W., Jr., C.G. Hewes, III & C.E. Mauk, 1976, "Oxidation of Refrac-
tory Materials by Ozone with Ultraviolet Radiation", in Proc. Sec.
Intl. Symp. on Ozone Techno!., R.G. Rice, P. Pichet & M.-A Vincent,
ecFTtors. IntTT Ozone Assoc., Cleveland, Ohio, p. 224-252.
329
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Prengle, H.W., Jr., 1977, "Evolution of the Ozone/UV Process for Wastewater
Treatment". Presented at Seminar on Wastewater Treatment & Disinfection
With Ozone, Cincinnati, Ohio, Sept. 15. Intl. Ozone Assoc., Cleveland,
Ohio.
Prengle, H.W., Jr. & C.E. Mauk, 1978, "Ozone/UV Oxidation of Pesticides in
Aqueous Solution", in "Ozone/Chlorine Dioxide Oxidation Products of
Organic Materials". R.G. Rice & J.A. Cotruvo, editors. Intl. Ozone
Assoc., Cleveland, Ohio, p. 302-320.
Reichert, J., 1969, "Examination for the Elimination of Carcinogenic, Aro-
matic Polycyclics in the Treatment of Drinking Water, with Special
Consideration of Ozone", Wasser-Abwasser 110(8):477-482.
Rice, R.G. & G.W. Miller, 1977, "Reaction Products of Organic Materials with
Ozone and Chlorine Dioxide in Water". Presented at Symp. on Advanced
Ozone Technology, Toronto, Ontario, Canada, Nov. Intl. Ozone Assoc.,
Cleveland, Ohio.
Richard, V. & L. Brener, 1978, "Organic Materials Produced Upon Ozonization
of Water", in "Ozone/Chlorine Dioxide Oxidation Products £f Organic
Materials. R.G. Rice & J.A. Cotruvo, editors. Intl. Ozone Assoc.,
Cleveland, Ohio, p. 169-188.
Robeck, G.G., K.A. Dostal, J.M. Cohen & J.F. Kreissl, 1965, "Effectiveness
of Water Treatment Processes in Pesticide Removal", J. Am. Water Works
Assoc. 57:181-200.
Rook, J.J., 1974, "Formation of Haloforms During Chlorination of Natural
Waters", Water Treatment and Examination 23(2):234-243.
Rook, J.J., 1976, "Haloforms in Drinking Water," J. Am. Water Works Assoc.
68(3):168-172.
Rook, J.J., 1976, "Developments in Europe", J. Am. Water Works Assoc.
68(6):279-282.
Schalekamp, M., 1977, "Experience in Switzerland with Ozone, Particularly in
Connection with the Neutralization of Hygienically Undesirable Elements
Present in Water". Presented at Intl. Symp. on Ozone & Water, Wasser
Berlin, Germany, May. Intl. Ozone Assoc., Cleveland, Ohio.
Shapiro, R.H., K.J. Kolonko, P.M. Greenstein, R.M. Barkley & R.E. Sievers,
1978, "Ozonization Products From Caffeine in Aqueous Solution", in
"Ozone/Chlorine Dioxide Oxidation Products of Organic Materials", R.G.
Rice & J.A. Cotruvo, editors. Intl. Ozone Assoc., Cleveland, Ohio, p.
284-290.
Shevchenko, M.A. & P.N. Taran, 1966, "Investigation of the Ozonolysis Pro-
ducts of Humus Materials", Ukrainskii Khimicheskii Zhurnal 32(5):532-
536.
330
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Shuval, H. & M. Peleg, 1975, "Studies on Refractory Organic Matter from
Wastewater by Ozonization", Progress Report of work sponsored by Ges.
fUr Kernforschung, Karlsruhe, Germany and Natl. Council for R&D, Jeru-
salem, Israel (Dec.).
Smith, G.V., J.W. Chen & K. Seyffarth, 1973, "Catalytic and Sonocatalytic
Oxidations of Aqueous Phenol", in Proc. 5th Intl. Congress on Catalysis,
Palm Beach, Fla., Aug. 1972, p. 893-903 TT973). Am. Inst. Chem. Engrs.,
New York, N.Y.
Spanggord, R.J. & V.J. McClurg, 1978, "Ozone Methods and Ozone- Chemistry of
Selected Organics in Water", in "Ozone/Chlorine Dioxide Oxidation
Products of_ Organic Materials," R.G. Rice & J.A. Cotruvo, editors.
Intl. Ozone Assoc., Cleveland, Ohio, p. 115-125.
Sturrock, M.G., E.L. Cline & K.R. Robinson, 1963, "The Ozonation of Phenan-
threne with Water as Participating Solvent". J. Org. Chem. 28:2340.
Throop, W.M., 1977, "Alternative Methods of Phenol Wastewater Control", J.
Hazardous Materials 1:319-329.
Weber, P. & W.L. Waters, 1973, "Ozonation of Aqueous Dimethylmercury", Proc.
Montana Acad. Sci. 32:66-69.
Weil, L., B. Struiff & K.E. Quentin, 1977, "Reaktion mechanismen beim Abbau
organischer Substanzen im Wasser mit Ozon", Presented at Intl. Conf. on
Ozone & Water, Wasser Berlin, May, Intl. Ozone Assoc., Cleveland, Ohio.
Yocum, F.H., 1978, "Oxidation of Styrene With Ozone in Aqueous Solution", in
"Ozone/Chlorine Dioxide Oxidation Products of Organic Materials", R.G.
Rice & J.A. Cotruvo, editors. Intl. Ozone Assoc., Cleveland, Ohio, p.
243-263.
331
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SECTION 7
BIOLOGICAL ACTIVATED CARBON
INTRODUCTION
Biological Activated Carbon (BAC) is a terminology applied to the
sequential combination of water or wastewater treatment process steps
involving:
(1) oxygenation or chemical oxidation (usually with ozone) followed by
(2) sand or anthracite filtration, followed by
(3) GAC adsorption.
This processing sequence promotes the growth of aerobic bacteria on
both the inert media and GAC filters. These aerobic bacteria simultaneously
reduce levels of Dissolved Organic Carbon (DOC) and ammonia (by conversion
to nitrate). The functions of ozonation are to:
(1) partially oxidize the dissolved organic materials, promoting further
oxidation by the aerobic bacteria,
(2) lower the molecular weights of the non-carbon adsorbable organic
materials and
(3) raise the level of DO.
BAC processes were discovered and developed in European drinking water
treatment plants, and now are in full scale operation in some 23 plants in
Germany, France, Switzerland and Holland. The process also is being developed
at the Cleveland, Ohio Westerly Sewage Treatment Plant in the United States.
BAC processes have never been designed specifically for treating industrial
wastewaters, and the potentials for this type of processing are discussed in
this section.
BACKGROUND
In a recent article which discusses the use of GAC in water treatment,
McCreary & Snoeyink (1977) state that "beds of GAC are a convenient place
for microorganisms to grow because bacteria attach themselves to the irregular
external surfaces of the carbon particles and are very difficult to dislodge
via backwashing procedures." In the presence of soluble carbonaceous matter,
which serves as food for these organisms, and in the absence of oxygen,
anaerobic bacteria can develop. There are numerous instances in which
sulfidic odors have been reported emanating from GAC columns used for the
removal of dissolved organic materials contained in sewage treatment plant
332
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effluents (Guirguis, Melnyk & Harris, 1976d; Directo, Chen & Kugelman,
1977) and drinking water supplies (Monsitz & Ainesworth, 1970).
On the other hand, given sufficient DO and carbonaceous matter, the
bacteria which develop in carbon beds will be aerobic. These do not produce
sulfidic odors.
Many of the advantages of BAG (ozonization, followed by filtration
through inert media, then GAC adsorption) were first recognized by German
water treatment scientists in the 1960s in drinking water plants along the
Rhine River in the DUsseldorf area. Subsequently, BAG processes also have
been installed in Swiss, French and Dutch drinking water treatment plants,
and are subjects of active pilot studies in Belgium. In the United States,
the U.S. Environmental Protection Agency's Water Supply Research Laboratory
in Cincinnati, Ohio has been testing a pilot BAG unit since late in 1976
(Carswell, 1977).
Independently of this research on BAG for drinking water treatment,
research workers in the United States at the Cleveland Regional Sewer
District have successfully adapted BAG for the processing of physical/-
chemical treated sewage (Guirguis ejb al. 1976a,b,c,d; 1978, Prober et,
al_., 1977; Hanna, Slough & Guirguis, T977). The process also is being
studied for treating sewage treatment plant effluents in Israel (Wachs ejt
al.. 1977).
FUNDAMENTAL PRINCIPLES
The terminology, BAG, has been applied by Rice, Miller, Robson & Ktlhn
(1977, 1978) to the combination of treatment processes consisting of (1)
ozonation followed by (2) filtration through an inert medium, such as sand
or anthracite, followed by (3) passage through GAC columns or beds. A
reoxygenation step may be desirable before passage of the water through GAC.
Figure 27 shows a schematic of the BAG subsystem.
GAC is made biologically active by the deliberate introduction of
sufficient DO to aqueous streams just before they are passed through GAC
columns or beds. As long as the water contains sufficient DO to maintain
aerobicity of the bacteria and sufficient dissolved carbon to provide food,
the aerobic bacteria will thrive in this environment. Eberhardt (1975) has
likened bacterial activity in such an ideal environment to a "herd of cows
grazing in a luscious meadow".
At our present stage of understanding, there are 2 mechanisms by which
biological activity is utilized in. the BAG media. Microorganisms are present
both on the surface of the carbon and in the large macropores. Dissolved
organics will be adsorbed both at the surface and in the large and small
pores of the GAC, but can be biodegraded directly only when adsorbed in the
macropores. However, those surface- and macropore-adsorbed organics do not
have to be well adsorbed, provided that they are biodegradable. Preozonation
converts larger, less biodegradable organic molecules into smaller, more
biodegradable organics, for example, into acetic and oxalic acids.
333
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co
oo
VENT OFF
GASES
/ TREATED WATER
/ OR WASTEWATER
ANALYSIS OF
OZONE OR
INFLUENT GAS
) > •
,. • •>
v •.•'.•'.-••
v ..j i :'.' • <
OZONE CONTACTOR
OZONE
GENERATOR
MAKE-UP GAS
EITHER AIR OR
ENRICHED OXYGEN
Figure 27. Biological activated carbon system.
SAND FILTER
(RECYCLE
OPTIONAL)
EFFLUENT
AERATION TANK
(OPTIONAL)
GRANULAR ACTIVATED
CARBON COLUMN
-------
The larger, less biodegradable organic molecules can be captured and
adsorbed in the carbon pores. When these are present in the macropores, the
bacteria can degrade the adsorbed organics and reactivate the loaded GAC.
According to the'second mechanism (Rice et al., 1979) organic materials
which are adsorbed in the micropores of the GA"C~ wRere bacteria cannot pene-
trate, can be desorbed either by enzymes generated by the bacteria present,
or by more tightly adsorbed organics. Enzymatic action itself will convert
non-polar, tightly adsorbed organic compounds into more polar compounds,
which are less tightly adsorbed, thus assisting the desorption process.
Both proposed mechanisms result in extended operating lives of the GAC
media before it has to be physically removed from the columns or beds and
regenerated.
Sontheimer (1977b) has summarized the German findings to date which
have led to the current theories of operation of BAG.
Although aerobic bacteria are necessary to obtain-the benefits from
BAG, so also is the adsorptive capacity of the GAC for the dissolved organic
materials which will serve as food for these bacteria. This means that the
macropore surface area and internal pore volume of the carbon both should be
high. Stated another way, it is important that the less readily biodegraded
organic materials present in solution be adsorbable onto the activated
carbon column, since the empty bed contact times of solutions with the
carbon particles in the columns or beds in water and wastewater treatment
plants are relatively short (15 to 30 minutes). This does not necessarily
give the bacteria sufficient time to degrade larger organic carbon molecules,
ideally to C02 and water. Therefore, it is important to be able to retain
the dissolved organic molecules in the activated carbon medium so that the
bacteria then will have sufficient time to degrade them, even though the
actual contact times involved are relatively short.
Many organic materials are readily adsorbed by GAC, but many others are
not. It is well known, for example, that high molecular weight natural
humic acids, so prevalent in drinking water supplies, are not readily adsorbed
by activated carbon (KUhn, Sontheimer & Kurz, 1978).
If solutions of these high molecular weight, non-sorbable organic
materials are ozonized before passage through the GAC columns, they are
converted to lower molecular weight, more readily biodegradable organic
materials (KUhn, Sontheimer & Kurz, 1978; Guirguis e_t aj_., 1976a, 1976c).
At the same time, ozonation introduces a large quantity of oxygen into the
water which promotes aerobic bacterial growth.
ADVANTAGES OF BIOLOGICAL ACTIVATED CARBON IN DRINKING WATER TREATMENT
In European pilot studies and in drinking water treatment plants it has
been shown by many workers (Scheidtmann, 1975; Schalekamp, 1975; Van Lier ejt
al., 1975; Sontheimer, 1975; Eberhardt, 1975; Van der Kooij, 1975; Kdhn,
335
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Sontheimer & Kurz, 1978; Gomella & Versanne, 1977; Sontheimer et al.f 1978)
that pre-ozonation followed by activated carbon adsorption resuTts~in:
• Increased capacity of the carbon to remove organics (by a factor of
about 10),
• Increased operating life of the carbon columns before having to be
regenerated (up to 3 yrs), especially if the GAC can be kept free of
halogenated organics,
• Biological conversion of ammonia to nitrate in the GAC columns, which
occurs simultaneously with removal of dissolved organics,
• Use of less ozone and less GAC for removing a given amount of organics
than using either process alone,
Independent studies on physical/chemical treated sewage at Cleveland
Regional Sewer District (Guirguis et al., 1976a,b,c,d; 1978) and in Israel
(Wachs £t al_., 1977), have confirmed" tFese advantages with respect to removing
organic materials.
EUROPEAN BACKGROUND
Introduction of GAC into European drinking water treatment practices
occurred shortly after World War II. Its initial application was for dechlori-
nation, then for tastes and odors (Hopf, 1960). Many surface waters contain-
ing ammonia undergo breakpoint chlorination at the beginning of the treatment
process. This technique effectively removes ammonia, but produces consider-
able amounts of residual chlorine and chlorinated products in the water
(Sontheimer e_t aj_., 1978). German water treatment objectives are to process
surface waters to the same quality as that of natural groundwater (which
does not have to be treated in many cases). Therefore, waters treated by
breakpoint chlorination have to be dechlorinated before they are treated
further or distributed (Sontheimer, 1977a).
The City of DUsseldorf originally installed ozone for oxidation of iron
and manganese in its sand bank filtered Rhine River raw water in the mid-
1950s (Miller et a_l_., 1978; Hopf, 1960). GAC was installed in 1961 for
removing organics. Today, ozonation is followed by storage for 20 to 30
minutes in a holding tank, then by filtration through an inert medium, then
GAC adsorption, then treatment with a small quantity (up to 0.3 mg/1) of
chlorine dioxide for residual.
Over the years which followed installation of "the Dusseldorf Process",
it was noted that more dissolved organic carbon was being removed than could
be expected on the basis of the simple summation of the known effects of
ozonation and of GAC treatments. When it was also discovered that ammonia
levels were much lower after GAC treatment than before ozonation (at pH
below 9.0, ozone does not oxidize ammonia), the biological activity within
the carbon columns was examined in closer detail.
336
-------
The Rhine River in the DUsseldorf area contains considerable amounts of
chlorinated organic materials which are not removed during river sand bank
filtration. These halogenated organics also are more resistant to oxidation
by ozone than are non-halogenated organics and thus are less likely to be
converted into readily biodegradable materials. In addition, halogenated
organics are more tightly adsorbed by the GAC (Kilhn & Fuchs, 1975; Kdlle,
Sontheimer & Steiglitz, 1975).
Combining the stronger adsorptivity of halogenated organics onto GAC
with their lesser reactivity upon ozonation and their lower biodegradability,
simply means that breakthrough of halogenated organics can occur more rapidly
than does breakthrough of non-halogenated organic compounds from GAC columns,
even though the GAC columns may contain optimal biological activity. Thus
German water works along the Rhine in the DUsseldorf area monitor their
carbon column capacities for Total Organic Chlorine (TOC1) (KUhn & Sontheimer,
1973a,b; KUhn, 1974; KUhn & Sontheimer, 1974), as well as for DOC (Wdlfel
& Sontheimer, 1974), and/or UV absorption. Carbon columns at three DUssel-
dorf plants along the Rhein (Flehe, Am Staad, Holthausen) are backwashed
every 4 to 6 weeks and regenerated every 5 to 6 months (Miller et al.,
1978). GAC regeneration is paced by TOC1 levels, and biological activity is
maximized so as to prevent breakthrough of biodegradable materials before
TOC1.
When activated carbon columns at Dtlsseldorf are regenerated, however,
only 80% of the carbon charge is taken out of the columns. This leaves 20%
of biologically active GAC in the column so that the level of bioactivity
will not drop significantly when fresh or regenerated carbon is added. With
fresh carbon columns, about 15 days of operation usually are required for
biological activity to build up to an effective "steady state", particularly
for ammonia removal (Poggenburg, 1977).
EUROPEAN DRINKING WATER TREATMENT EXPERIENCES WITH BAC
Switzerland
Activated carbon was installed at ZUrich initially to protect against
oil spillage, later for protection against phenol spills, and for dechlorina-
tion (Schalekamp, 1975). ZUrich's Lengg and Moos plants take raw water from
the Lake of ZUrich, which contains very low concentrations of chlorinated
organics and is otherwise a very clean raw water supply. There is no" need
for breakpoint chlorination (because of very low ammonia content), but a
small dose of chlorine (1 mg/1 maximum) ij_ added at the intake to prevent
growth of mussels. GAC treatment insures dechlorination of this amount of
chlorine. Before passage through.activated carbon, however, the water is
ozonized with dosages of 1 to 1.5 mg/1.
In actual plant studies (Schalekamp, 1975), both the top and bottom
layers of the carbon beds showed equal loadings of organics at the end of 7
months. This indicates that the GAC should be regenerated. However, regenera-
tion of this carbon was not required because the continued efficient removal
337
-------
of DOC from the aqueous medium by this carbon remained nearly the same as
that of the new carbon (Figure 28). This behavior was attributed by Schale-
kamp to biological activity within the carbon bed.
At the Zurich Moos plant, the slow sand filter was fitted with a 5 cm
layer of GAC. The efficiency of DOC removal from the aqueous solution
remained essentially constant over the 3 year period (about 2.8 mg/1 residual
COD in the filtrate) (Figure 29). This performance, again attributed to
bacterial degradation of the adsorbed organics, was obtained without reactiva-
tion of the carbon, although twice weekly backwashes were required.
Operational costs for the carbon beds at the Zurich Lengg plant are
$0.016/cu m (6.05*/1,000 gal) which is 12.5% of the total plant operating
costs. Since treated Swiss surface waters must not be inferior to unobjection-
able well or groundwater, BAC filtration is a necessary and also economically
feasible component in the treatment process (Schalekamp, 1977).
Holland
Van Lier ejt al_. (1975) describe experiences with activated carbon
filters in Dutch pilot plant studies at Amsterdam. Three carbon pilot units
were studied side by side, using 2 meter column heights and 8 cu m/sq m/hr
flow rates for 3 months. The water was treated by iron coagulation, rapid
sand filtration, chlorination, then:
Process #1: Ozonation, rapid sand filtration, BAC, slow sand filtra
tion,
Process #2: Rapid sand filtration, slow sand filtration,
Process #3: Activated carbon, slow sand filtration.
These researchers concluded that:
1) Ozonation increases bacterial counts considerably after rapid and slow
sand filtration,
2) Water treated by Process #1 (with ozone) produces water with reduced
levels of color, UV absorption and KMnOd consumption than waters treated
by Processes #2 or #3 without ozone,
3) Slow sand filtration in all 3 systems reduces bacterial counts, color
and KMn04 consumption,
4) Water qualities by Processes #2 and #3 are about the same, but the
frequency of backwashing of the slow sand filters is more frequent in
these processes, which do not include ozonation,
5) Service time of the GAC column with ozone was much longer (300 days)
than those without ozone (175 days) as measured by UV absorption of the
fi1trates.
338
-------
co
CO
to
4.0
I 3.0
0)
til
£ 2.0
irapid filter
i activated carbon
35th 40th
Source: Schalekamp (1975)
45th
50th
WEEK 1974
Figure 28. Efficiency of removal of COD from rapid filter and activated carbon at Lengg plant,
ZOrich, Switzerland.
-------
CO
.£>
o
<
a:
u.
2
D ~
O g1
O E
SLOW ACTIVATED CARBON FILTRATE
1972
1973
Source: Schalekamp (1975)
1974
1975
Figure 29. Efficiency of COD removal of BAG over 3 years at Moos Water Works, ZUrich, Switzerland.
-------
For the same concentration of DOC in the influent, the amount of DOC
removed by the carbon in the summer is much greater than in the winter.
This is explained on the basis of increased biological activity in the
carbon columns at the higher summer temperatures. Oxygen consumption in the
winter was found to be 0.006 g/hr/kg of carbon and 0.024 to 0.030 g/hr/kg of
carbon in summer.
Longer service times were observed for BAG columns which had optimum
contact times of 20 to 25 minutes (empty bed).
Costs of operating carbon filters decreased with increasing retention
times. Costs of 0.06 guilder/cu m (2.55 i) were estimated for 25 to 30
minute retention times. Reactivation costs were estimated at 0.03 guilder/cu
m (1.23
-------
microbial activity in winter, as indicated by oxygen consumption and CO?
production values. However, changes in raw water quality also can cause
substantial and distinct changes in the colony numbers.
• n isotherms were determined for bacteria loaded on the carbon.
At high colony numbers (above 10'0/ml) the system tended to saturation. At
10' to 10°/ml, up to 90% of the bacteria were adsorbed onto the carbon
(Figure 30). After 20 to 30 hrs of operation, adsorption and desorption
were nearing the steady state (Figure 31) of about 108 colonies/g of carbon.
Electron scan microscopic analysis of GACs treated differently showed that
the bacteria are always present in the form of a single bacterial layer
Thus the carbon surface is only fractionally utilized (about 1%) by the
adsorbed bacteria, leaving 99% of the surface area of the carbon free for
adsorption of dissolved organic materials.
Bremen
Extensive pilot plant studies on the BAG process have been conducted by
Eberhardt, Madsen & Sontheimer (1974). The original Bremen plant treats
Weser River water by flocculation, rapid sand filtration, slow sand filtration
and chl on nation. A semi -works size pilot facility employing GAC with
preozonation was constructed in 1969, and research reported in this article
was conducted on BAG over a 3 yr period. DOC of the raw water was 5 to 10
mg/1, and the permanganate numbers varied from 10 to 22 mg/1 .
/n -, Th!. test facility (Figure 32) consisted of an ozone contact chamber
(0.7 m diameter, 3 m high), 2 holding tanks (each 2.5 cu m), a slow sand
filter (0.7 m diameter, 3 m height) and an activated carbon filter (0.8 m
diameter, 3 m height). Provision also was made to periodically close off
the flow of water through the carbon column. At these times, the water in
the carbon columns was recycled back through the carbon beds, and analytical
parameters were measured. These included DO, DOC, C02, ammonia, nitrate,
etc. In this manner, material balances were determined.
Eberhardt, Madsen & Sontheimer (1974) concluded that BAG provides the
following performance advantages in producing drinking water from the River
Weser:
1) 100 to 140 g of DOC is bacterially oxidized/cu m of activated carbon
per day. Consumption of oxygen during the summer averaged 360 g/cu m
of activated carbon/day and 240 g/cu m/day during winter.
2) After 3 years of operation without regeneration, the total bacterial
count reductions averaged 97% and the E. coli reductions averaged 96%.
3) The amount of organic substances removed is dependent upon the concentra-
tion in the influent and the residence time in the filter. Theoretical
empty-bed residence times of 30 minutes are sufficient for optimum
organics removal .
342
-------
CO
-p»
CO
RAW WATER INLET
SAND FILTRATE
CARBON FILTER OUTLET
BACTERIAL COLONIES/ML OF WATER
M|J|J|A|S|0|N|D
1972
M | J | J | A | S f O | N | D
J|F|M|A|M|J|J|A|S|O|N|
J|F|M|A|M|J|J|A
Source: Klotz, Werner & Schweisfurth (1975)
Figure 30. Behavior of microbial populations on activated carbon over 3 years at Wiesbaden,
Federal Republic of Germany.
-------
o
m
oc
o 10i2
Q
LU
< 101
9 101°
O)
UJ
m
O >
Z 2
0°
109
108
107
rl w ior
106 107 108 109 1010 1011 1012
ADSORPTIVE CONCENTRATION (COLONY
NUMBERS/200 ml BUFFER)
100
O
g
75
25
106 107 10* 109 1010 1011 101
Figure 31.
ADSORPTIVE CONCENTRATION (COLONY
NUMBERS/200 ml BUFFER)
Source: Klotz, Werner & Schweisfurth (1975)
Microbiological loading of activated carbon - dependence on
adsorptive concentration.
344
-------
CO
-P»
cn
OZONE
CONTACTOR
WATER FROM
RAPID FILTER
TREATED
WATER
Source: Eberhardt, Madsen & Sontheimer (1974)
Figure 32. Bremen, Federal Republic of Germany, water works pilot plant.
-------
4) Higher efficiencies of organics removal are obtained at lower filtration
rates.
5) Increased efficiencies of organics removal are obtained with smaller
grain sizes of GAC.
6) Best results are obtained from activated carbons which have high
adsorptive capacities (for organics) and high pore volumes.
7) BAG columns are 10 to 100 times more biologically active per unit
volume of carbon than are slow sand filters, probably because of the
high concentrations of organic materials in the carbon pores.
Once the bacterial activity in the activated carbon column has been
fully established, the organics removal process starts with adsorption of
organics, biological mineralization (degradation) of the adsorbed organics
and biological regeneration of the activated carbon. The process kinetics
at Bremen were found to follow a zero order reaction.
The operative process is adsorption from water containing only organic
substances with fresh GAC. However after 2 to 3 months of operation, biochemv
cal processes have reached a steady state and are in full operation. After
biological equilibrium has been attained, then adsorption and biochemical
degradation (mineralization) of the organic substances both occur in parallel,
and either adsorption or mineralization processes may predominate. At
constant temperature and bed loading, the mineralization rate was found to
be constant and independent of the concentration of organics in the feed
water during the Bremen studies.
In other tests conducted at Bremen (Eberhardt, 1975), prechlorination
of the water was found to have an adverse effect on the operation and the
effectiveness of BAG columns, even with preozonation. Prechlorination
reduced both the growth of bacteria and efficiency of removal of the organics
by the carbon. In addition, chlorinated organics are less biodegradable.
Detrimental prechlorination effects are not related to the oxidative powers
of chlorine, since pretreatment with KMnO. did not reduce the biochemical
degradation effectiveness.
Nitrification of Ammonia
Under aerobic conditions, ammonia nitrogen is converted biologically to
nitrate ion in two discrete steps:
NH4+ + 1.502 *N02~ + 2H+ + H20 (step 1)
N02" + 0.502 >• N03" (step 2)
Step 1 is accomplished by means of Nitrosomonas bacteria; step 2 is accomp-
lished by Nitrobacter. During nitrification, some ammonia-nitrogen becomes
part of the cell tissues of the bacteria.
346
-------
The nitrification process is known to occur in rapid sand filters if
the temperature is above 5°C (Eberhardt, 1975). It is only necessary to
assure that there is sufficient oxygen in the water and sufficient retention
time for the bacteria to work.
Nitrification of ammonia takes place in activated carbon at the same
rate as in sand filters, which is not surprising since ammonia is not adsorbed
by the carbon. There is some indication, however, that activated carbon may
be somewhat more efficient at temperatures below 5°C (Eberhardt, 1975),
possibly because of the large surface area and increased pore volumes of
carbon as compared with sand. These may provide more space or volume for
the nitrifying bacteria.
Ammonia nitrification in carbon columns usually requires 3 months to
attain steady state conditions, and during this time there may be problems
caused by sudden surges of ammonia in surface waters. However, if fresh
activated carbon columns are dosed with small amounts of ammonium salts,
nitrification is attained more rapidly, sudden surges in ammonia concentra-
tions can be handled better, and the efficiency below 5°C will also improve
(Eberhardt, 1975).
Total nitrification of 1 gram of ammoniacal nitrogen requires 3.56 g of
oxygen, according to the stoichiometry (Jekel, 1978):
+ 2H+ + H20
However, Gomella & Versanne (1977) found that only 3.2 g of oxygen is required
for nitrification at the drinking water treatment plant at Rouen-la-Chapelle,
France. Since aerobic bacteria on activated carbon columns and nitrification
processes both consume DO, it is therefore necessary to provide oxygen to
the water before it enters the carbon columns. This can be done by simple
aeration, by addition of oxygen, or by pre-ozonizing the water.
Aeration will provide DO levels of 6 to 10 mg/1 in water, depending
upon the temperature of the water. Therefore, if more than 3 mg/1 of ammonia
is present originally, more DO will be required for nitrification than can
be supplied by aeration. In such cases, pure oxygen should be added, which
can increase DO levels to as high as 40 to 50 mg/1. These higher levels of
DO can be obtained using pure oxygen because the solubility of pure oxygen
is not reduced by the presence of large quantities of nitrogen present in
air.
It is equally necessary to prevent the presence of bacterial growth
inhibitors, such as toxic heavy metals and halogenated organic micropollutants,
from entering the BAG media and interfering with the growth of bacteria
and/or the progress of biological oxidation.
347
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CASE HISTORIES
MUlheim, Germany
The "Rheinisch-Westfaiische Wasserwerksgesellschaft mbH" has taken
advantage of BAG to radically change the drinking water treatment process at
the 48,000 cu m/day (12.7 mgd) Dohne plant in MUlheim, Germany (Sontheimer
et ah, 1978). Raw water for this plant is the River Ruhr, which until mid-
April, 1977 was treated by breakpoint chlorination for ammonia removal,
flocculation, sedimentation then GAC dechlorination and ground filtration.
Over the years, ammonia concentrations have increased, requiring prechlorina-
tion doses of 10 to 50 mg/1. In turn, these hir' chlorine doses produced
large amounts of chlorinated organics (Table 72> which not only were incom-
pletely adsorbed by the carbon columns and passed through the plant into the
distribution system, but also caused frequent regeneration of activated
carbon columns (every 4 to 6 weeks).
TABLE 72. ORGANOCHLORO COMPOUNDS AFTER BREAKPOINT CHLORINATION TREATMENT
(DOHNE PLANT. MULHEIM. FEDERAL REPUBLIC OF GERMANY)
Sampling Point
Raw water (Ruhr River)
After flocculation +
sedimentation
After sand filtration
After GAC adsorbers
After ground passage +
chlorination
DOC1*
ppb
17
203
151
92
DOC1N**
ppb
5
30
17
18
Sum of
Haloforms
ppb
9
15
23
21
23
CHCla
ppb
<1
6
7
7
9
* DOC1 = Dissolved Organic Chlorine
** DOC1N = Dissolved Organic Chlorine, Non-polar
Source: Sontheimer, et al . ,
1978
During a 2 year pilot study on the use of pre-ozonation of activated
carbon for removal of chlorinated organics, it was found that breakpoint
chlorination could be eliminated completely and the BAG operation could be
relied upon totally for removal of ammonia. At the same time the DOC was
reduced to the desired levels.
348
-------
This process, involving pre-ozonation of activated carbon, was installed
and began operating in mid-April, 1977. After the first 3 months of operation,
the performance of the full scale plant process was as effective as was the
pilot process at the same stage of development (Sontheimer, 1978).
As the new process at Dohne was installed and operated for the first 90
days (Table 73), the first step was pre-oxidation with about 1 mg/1 of ozone
with addition of poly-aluminum chloride and lime as flocculants. Pre-ozona-
tion oxidizes manganese and aids in flocculating the organics. After floccu-
lation and sedimentation, 2 mg/1 of ozone is added to oxidize dissolved
organics. After a retention time of 15 to 30 minutes, the ozonized water is
preflocculated using 0.2 mg/1 aluminum chloride and 0.1 mg/1 polyelectrolyte,
filtered (rapid sand), then passed through BAG where the bulk of DOC and
ammonia are removed. Filter rates during the first 90 days of plant opera-
tions were 18 m/hr (18 cu m/sq m/hr = 18 m/hr) through 2 m carbon bed
depths. The GAC used during this period was the old GAC, exhausted during
use under the old process.
In November, 1977, the carbon bed depths were increased to 4 m to
increase the empty bed retention time to 15 minutes, and the GAC columns
were charged with fresh GAC. This has further improved process efficiencies
and protects against possible surges in organic pollution or ammonia in the
raw water. After more than 1 yr of operation since November, 1977, the GAC
columns are performing as predicted from the earlier pilot plant studies and
have not yet required regeneration (Jekel, 1978).
After activated carbon filtration, the treated water is sent to ground
infiltration (12 to 50 hrs retention time), after which it is chlorinated
(0.2 to 0.3 mg/1) and sent to the Mulheim distribution system.
A comparison of the performance of the new process (first 90 days of
operation using 2 m deep GAC columns and old GAC) versus the older one is
given in Table 74. The DOC of treated water today is less than one-half
that of water treated by the old process. Even lower DOC values are expected
since the carbon column depths have been increased.
Table 75 shows the bacterial content of waters at the various points in
the new treatment process. E. coli counts/100 ml are essentially 0 mg/1
after filtration and remain essentially 0 mg/1 after BAC filtration as well.
Pilot plant data are presented in Table 76 which show the effects of
variation of activated carbons on removal of DOC, inorganic carbon, ammonia
and DO. In addition, this table also compares the removal of these same
parameters with carbon column depths of 2.5 m and 5.0 m for two different
activated carbons.
Removal of ammonia and DO are fairly independent of carbon type or
column depth. On the other hand, removals of DOC and inorganic carbon are
affected by the carbon type. Most significant, the amount of DOC removed
with 5.0 m columns is about 50% higher than with 2.5 m columns, although the
amount of inorganic carbon measured increases only slightly.
349
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TABLE 73. PROCESS PARAMETERS-AT THE DOHNE WATERWORKS, MULHEIM, FEDERAL
REPUBLIC OF.GERMANY. BEFORE AND AFTER CHANGE OF TREATMENT
Old process
10-50 mg/1 C12
4-6 mg/1 Al+3
0.1 kw/cu m
ca. 0.5 min
Treatment step
New process
Preoxidation
Chemical dosing
Power input
Retention time
1 mg/1 03
4-6 mg/1 A1
2.5 kw/cu m
ca. 0.5 min
+3
5-15 mg/1 Ca(OH)2
ca. 1.5 hr ret. time
Flocculation
Sedimentation
5-15 mg/1 Ca(OH)2
ca. 1.5 hr ret. time
Ozonation
2 mg/1 03
ca. 5 min ret. time
v* = 22 m/hr
h** = 2 m
Activated carbon
adsorber
v* = 18 m/hr
h** = 2 m
12-50 hr ret. time
Ground passage
12-50 hr ret. time
0.4-0.8 mg/1 Cl.
Safety chlorination
0.2-0.3 mg/1 C12
v* = filter velocity = cu m/sq m/hr = m/hr
h** = bed height
Source: Sontheimer et al. (1978)
350
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TABLE 74. MEAN DOC AND UV EXTINCTION VALUES FOR THE DIFFERENT TREATMENT STEPS AT THE DOHNE PLANT,
Measurement point
Raw water (Ruhr River)
After flocculation +
sedimentation
After filtration
After GAC adsorption
After ground passage
1975
DOC
mg/1
3.9
3.2
3.2
3.0
1.8
** UV extinction measured
UV**
nf1
6.8
4.5
4.4
4.0
3.1
UV/DOC
1.7
1.4
1.4
1.3
1.7
1976
DOC
mg/1
5.0
4.0
3.8
3.7
2.1
uv**
rrf1
9.1
5.5
5.4
5.3
4.0
UV/DOC
1.8
1.4
1.4
1.4
1.9
April-July
DOC
mg/1
3.6
2.9
2.6
2.3*
0.9
uv**
m-1
6.1
3.2
1.8
1.6*
1.6
1977
UV/DOC
1.7
1.1
0.7
0.7*
1.6
at 254 nm and extrapolated to a 1 meter long cell
* GAC adsorbers filled with fully loaded GAC used in the old process
Source: Sontheimer et al. (1978)
GO
en
-------
TABLE 75. GEOMETRIC MEAN VALUES OF BACTERIAL COUNTS AT THE DOHNE PLANT,
MULHEIM, FEDERAL REPUBLIC OF 'GERMANY, USING OZONE
Sampling point
Raw water (Ruhr River)
After floccn + sedimtn
After filtration
After GAC adsorption
After ground passage
Total
v
14,490
2,340
6,010
3,700
27
Bacterial
counts/ml
a **
g
2.0
4.2
4.9
4.0
2.3
E. coli/100 ml
v
1,620
6.7
«1
«1
«1
a **
g
1.7
3.2
—
— _
—
* Mg = geometric mean ** a = geometric standard deviation
Source: Sontheimer et al (1978)
TABLE 76. PERFORMANCE OF BIOLOGICAL ACTIVATED CARBON ADSORBERS. MEAN VALUES
FOR 6-MONTH OPERATION AFTER A 3-MONTH STARTING PERIOD (DOHNE
GAC
type
LSS
LSS
ROW
ROW
NK-12
F-400
BKA
bed depth
m
2.5
5.0
2.5
5.0
2.5
2.5
2.5
A DOC
mg/1
0.92
1.69
1.09
1.59
0.99
1.26
1.00
AInorg C
mg/1
0.83
0.96
0.97
1.05
1.36
1.11
0.97
Source: Sontheimer et al. (1978)
ANH4+
mg/1
1.31
1.34
1.31
1.34
1.28
1.32
1.28
A02
mg/1
6.32
6.67
6.49
6.71
6.03
6.95
5.99
352
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During pilot plant studies at the Dohne plant with the BAG process,
activated carbon columns were found to have operational lives of at least 1
yr, and in some cases 2 yrs, without requiring regeneration. Life of the
full scale carbon columns at Dohne is now estimated to be at least 2 yrs
(Sontheimer, 1978). No signs of loss in performance of the activated carbon
have been noted during the first 12 months of operation, and the carbon
columns have not yet had to be regenerated (Jekel, 1978).
Elimination of breakpoint chlorination at the beginning of the Mulheim
process eliminates formation of chlorinated organics which caused the activa-
ted carbon columns to have to be regenerated every 2 months under the old
process. The 10 to 50 mg/1 of chlorine previously required for this step
now has been replaced with 3 mg/1 of ozone. Additional cost-savings associa-
ted with this change include the labor which was required with breakpoint
chlorination. Formerly, a technician was required to sample water every two
hours and to analyze for chlorine and for ammonia. This labor requirement
has been eliminated (Sontheimer, 1977a,b). In all, annual cost savings
at Mulheim are on the order of $200,000 to $400,000, allowing for depreciation
of ozonation equipment and the doubled-size 6AC columns (Rice e_t al_., 1979).
Rouen-la-ChapelTe, France
At the 50,000 cu m/day (13.2 mgd) plant at la Chapelle St. Etienne de
Rouvray in Seine Maritime (west of Paris near the Atlantic Ocean), well
waters drawn from near the Seine contain 2 to 3 mg/1 ammonium ion, 0 to 0.2
mg/1 manganese, various micropollutants [detergents, phenols, substances
extractable with chloroform (SEC), etc.] and are practically devoid of DO.
Since 1968, the ammonia content of the raw water has risen from an average
of 0.3 mg/1 to an average of 2.6 mg/1. This increase required that the
treatment process be improved. Breakpoint chlorination was discarded because
it would have required very large contact chambers (close to 7,000 cu m) and
would have produced chlorinated organics which then would have to be removed.
After 3 yrs of pilot plant studies, the following process was developed,
was installed and began operating in February 1976 (Gomella & Versanne,
1977):
• Pre-ozonation (0.7 mg/1) for Mn, organics and adding DO to the water
• Filtration through quartz sand
• Filtration through BAC
• Ozonation for disinfection (1.4 mg/1)
• Post-chlorination (0.4 to 0.5 mg/1)
Any residual ozone remaining from the preozonation step will be decom-
posed to oxygen when it enters the carbon column, providing further quantities
of DO for the bacteria. This single operation of preozonation assures the
following:
353
-------
• oxygen demands of the materials in water are satisfied,
• water is oxygenated,
• complex, biorefractory molecules are broken down and become biode-
gradable,
• the content of various micropollutants is lowered,
• manganese is oxidized and precipitates, to be retained on the sand
filter so that it does not block adsorption sites on the BAG.
Most of the nitrification occurs in the sand filters. Periodic backwash-
ing of these sand filters to remove oxides of manganese does not upset the
action of these bacteria. Similarly, bacterial activity in the activated
carbon beds (75 cm deep) is not displaced during backwashing. The BAG beds
are backwashed once each month, but have not yet had to be regenerated after
more than 2 yrs of operation (Gomel!a, 1978).
This plant began operating in February, 1976 and showed the perfor-
mances listed in Table 77 for the first year of operation. The average
performance for the first several months of 1977 are stated to be superior
to those for the same period of 1976 (Gomella & Versanne, 1977). A case
history of the Rouen plant has been published recently by Rice, Gomella &
Miller (1978).
BAG IN SEWAGE TREATMENT
In the United States
Independently of results obtained in European drinking water treatment
plants, researchers at the Cleveland Regional Sewer District, Cleveland,
Ohio, have discovered the same advantages of preozonizing GAG columns (Guir-
guis e^aJL_, 1976, 1978; Prober et al., 1977; Hanna, 1977; Hanna, Slough &
Guirguis, 1977).
The Westerly sewage treatment plant (50 mgd) treats 50/50 industrial/-
municipal sewage. In order to assure meeting EPA discharge standards for
BOD, SS, phosphorus and fecal coliforms, Cleveland Regional Sewer District
chose to install a physical/chemical treatment process involving lime addition,
flocculation, precipitation, filtration, pH reduction, then GAG for removal
of organics, and finally, disinfection with ozone.
During early operation of the 30 gpm pilot plant at Cleveland's Westerly
plant, however, it was quickly found that the performance of the GAC columns
was unsatisfactory. The amount of BOD and COD being passed through to
disinfection was quite erratic, requiring different amounts of disinfectant
from day to day, and even from hour to hour. Upon attempted disinfection of
the carbon column effluent with ozone, significant reductions in COD values
were obtained, indicating that some dissolved organic materials (which were
quite reactive with ozone) were not being adsorbed by the activated carbon.
354
-------
TABLE 77. ROUEN-LA-CHAPELLE (FRANCE) PLANT OPERATIONAL DATA (1976) f
Parameter
Turbidity
Ammonia
mg/1 NH4+
Mn mg/1
Detergents
mg/1 DBS
Phenols yg/1
SEC* yg/1
Substances
extbl w/-
cyclohexane
yg/1
Raw
water
4
1.80
0.15
0.12
6.5
590
1,335
Pre-ozo-
nized
—
1.80
0.07
0.09
4.0
470
740
Filtered
(sand & 6AC)
—
0.40
0.04
0.06
1.5
250
535
Post-ozo-
nized
2
0.26
0.02
0.03
0
150
410
% Elimination
50%
86%
87%
75%
100%
75%
69%
* SEC = substances extractable with chloroform
av. NH3 content of raw water: 0.3 mg/1 in 1968
2.6 mg/1 in 1975
Source: Miller et al. (1978)
355
-------
In addition, intolerable sulfidic odors were being generated in large
quantities by the anaerobic bacteria which had developed in the activated
carbon columns. It was also anticipated that the carbon would have to be
regenerated every 30 to 40 days. The original Westerly process and a summa-
tion of its major problems is shown in Figure 33.
Provision then was made to add ozone prior to the GAC column of the
pilot plant. This caused growth of aerobic bacteria in the column, and the
production of sulfidic odors quickly ceased. Soon after, the capacity of
the column for dissolved organics was found to have increased dramatically
I by a factor of 10). The organic removal performance became steady and the
pilot plant column (30 gpm pilot process) was operated for 11 months without
the need for regeneration.
+u onrboi),column effluents after preozonation consistently contained less
than 20 rng/1 BOD and 40 to 70 mg/1 COD (influent to carbon column contained
150 to 200 mg/1 COD). During the 11 month initial operating period without
carbon regeneration, the cumulative COD loading on the carbon increased to
about 1.05 Ibs (476 g) of COD/kg of activated carbon. This remarkable
behavior is shown in Figure 34. The disinfectant demand of the carbon
column effluent became steady, and no further reductions in COD values were
observed upon ozonation of the carbon column effluent.
Figure 35 summarizes the total performance of the Cleveland pilot plant
BAC column through mid-September, 1977. After a total of 17 months of
operation with preozonation, there was still no indication that regeneration
was necessary, and the cumulative COD loading had reached 1.6 Ibs/lb of GAC
by mid-September, 1977 (Hanna, 1977).
Other pertinent data relative to the Cleveland Westerly plant research
have been reported by Prober, Hanna & Guirguis (1977). A fresh activated
carbon column without preozonation or preoxygenation reached a steady state
within 1 week after being placed in operation. Soluble COD concentration in
the effluent quickly increased until it was within about 20 mg/1 of the
influent concentration (about 90 mg/1). Over a long term average, the
column was steadily removing about 20 mg/1 of COD, regardless of the influent
COD concentration, which varied between 80 and 110 mg/1.
Optimum performance of the Cleveland preozonized activated carbon
columns occurs when the influent DO content is about 20 mg/1 and when the
preozonation dose is 5 mg/1. At steady state operation, the BAC columns
remove 0.005 Ib of COD/lb of activated carbon/day. DO uptake of the BAC
columns averages 14 mg/1 (Prober et a]_., 1977).
At present, Cleveland Regional Sewer District is designing a modification
to the 50 mgd Westerly plant which will incorporate 6,700 Ibs/day of ozone
generation capacity for preozonizing the activated carbon at a dosage of 5
mg/1.
356
-------
LIME
4-
CLARIFICATION
*
RECARBONATION
•»
ACTIVATED
CARBON
*
DISINFECTION
00
en
Problems:
Regenerate Carbon Every 30-40 Days
Sulfidic Odors
Erratic TOC Reductions
Erratic Disinfection Demands
Figure 33. Westerly plant, Cleveland, Ohio -- original design.
-------
OVERALL PERFORMANCE OF ACTIVATED CARBON
CO
en
CO
z
o
CD
CC
<
O
a
S
o
o
n
~>
§
0
1.15
1.10
1.05
1.00
0.95
0.90
0.85
O.BO
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
« «^,
/
/ •*
I/
^
IL.S
^A y
Jf \/
s V
i
_ x'
- ^
iX^— «— 9***
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^^
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e : Gu i rg
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f
^
is, Coopt
^'
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r, Harris
•J'*
^
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^X
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1
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u/
J.**^*
•*"
\. -
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100
90
80
70
60
50
-40
30
20
10
Feb Mar Apr May June
Figure 34. Performance of preozonized activated carbon at Westerly plant, Cleveland, Ohio.
July
D
8
-------
COD IN CARBON EFFLUENT, mg/l
O O
g
8
n>
u>
n
-h
o
rol -*
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-S
53
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O — fO W
CUMULATIVE LOADING. Ibs COD/lb CARBON
-------
In Israel
Preliminary studies reported by Wachs et al_. (1977) on treatment of
domestic sewage with ozone, then BAG, also appear striking. These researchers
presented results showing that effluents with TOC contents of less than 2
mg/1 can be obtained by this technique, albeit with rather large ozone
dosages (100 to 120 mg/1).
Ozone-containing air (19 g of ozone/1 of air) was passed through lime
treated sewage at the rate of 10 1/hr. Using ozone contacting times of 30
minutes, COD removal efficiencies were found to be only as high as 50% at pH
8 to 9 (Table 78, Figure 36). Even at pH 11, more than 170 mg/1 of ozone
dosages were required to lower the COD by 50%.
Filtrasorb 300 activated carbon columns 2.5 cm in diameter and 70 cm
high were prepared and used to filter the ozonized lime treated effluents at
flow rates of 3 bed volumes/hr. Ozonized effluents were stored "a number of
hours" before being introduced into the activated carbon columns.
Figure 37 shows that ozonized, lime treated effluent having an average
COD of 33.7 mg/1 upon filtration through BAC produced effluent having an
average COD of 3.4 mg/1. The carbon column was operated 12 days, during
which time the effluent COD concentration ranged from 0 mg/1 to 10 mg/1.
Backwashing was performed on the eighth day of operation.
POTENTIALS OF BAC FOR TREATING INDUSTRIAL WASTEWATERS
During this survey of the state-of-the-art of Ozone for Industrial
Water and Wastewater Treatment, only 3 of the technical articles reviewed
described the conjunctive use of ozonation followed by GAC. Enhancement of
the biological activity in the carbon media was not considered in these
articles.
In Vienna, Austria, a car wash built in 1970 recycles 19,915 gpd of
wash water, ending with ozonation followed by GAC (Baer, 1970). However,
this article was written as the water treatment system was installed, and
the biological aspects of the carbon medium were not considered in the
description of the process.
In Japan, the Kanebo Company installed an ozone/GAC treatment system at
its Nagahama factory in 1974 (Anonymous, 1974). This system handles 3,300
cu m/day (0.87 million gal) of dyeing wastewaters. The "synergistic effect"
of the sequential combination of ozonation followed by GAC is noted in this
article, which also states that "the combined use of ozone and activated
carbon, as compared with the separate use of each, will often produce a
doubled effect and result in low investment costs". This statement is not
explained further, however.
At the Nagahama factory, dyeing wastewaters are sent to a 600 cu m
holding tank from whence it is passed, consecutively, through 2 ozonation
360
-------
TABLE 78. OZONATION OF LIME-TREATED EFFLUENTS IN ISRAEL (1). REACTION
COD
mg/1
37
33
33
40
40
(3) 26
pH
initial
11.6
11.2
8.3
11.2
7.2
8.3
final (2)
11.2 (60)
11.2 (90)
5.5 (90)
11.1 (70)
6.2 (70)
7.7 (90)
K x 10d
min~
4.7
5.6
3.2
4.9
2.6
2.4
COD60
mg/1
19
15
21
20
28
19
% COD
removed
in 60 min
48%
54%
36%
49%
30%
28%
(1) Flow rate of gas stream into reactor was 0.4 1/min. Concentration of
ozone in gas stream varied between 18 and 19 ppm.
(2) In brackets: length of ozonation time, in minutes.
(3) Ammonia desorption practiced priot to ozonation.
Source: Wachs, Narkis, Schneider & Wasserstrom (1977)
361
-------
180
160
140
120
o> 100
O
<
80
60-
40-
20-
60
50
40
O)
E
Q
O 30
O
20-
10-
0-
COD VALUES AND CORRESPONDING REMOVAL
EFFICIENCIES AFTER 30 MIN. OZONATION AT
DIFFERENT INITIAL pH.
O FINAL COD VALUES
Q REMOVAL EFFICIENCY E
A OZONE CONSUMED AOj
COD0=48 mg/l
A £f
Source: Wachs, Narkis, Schneider & Wasserstrom (1977)
0.5
0.4
0.3
0.2
0.1
Q
O
LU
a
0 1 2 3 4 56 7 8 9 10 11 12 V
INITIAL pH
Figure 36. Ozonation of Israel lime treated sewage effluents
without BAG.
362
-------
A COD
• TOC
OF COLUMN FEED
O COD\
D TOC/
OF COLUMN EFFLUENT
co
en
co
50
40-
O5
E 30
O
O
O
O
20
10-
AVERAGE COD OF FEED 33.7
BACKWASH
AVERAGE COD OF
COLUMN EFFLUENT 3.4
6
DAYS
10
11
12
Source: Wachs et al. (1977)
Figure 37. Biologically extended activated carbon treatment of ozonated effluent.
-------
reaction towers, each 2,800 mm in diameter and 5,000 mm in height. The
specifics of ozone contacting in this installation are not described, but
ozone is supplied by means of 3 generators, each capable of generating 2.4
kg/hr of ozone from air (7.2 kg/hr total ozone generation capacity). At its
maximum addition rate, ozone is dosed at 50 mg/1, and dye colors and dissolved
organic substances are decomposed at this point.
Ozonized wastewater passes through an intermediate tank, then is sent
upflow at 17 m/hr through a pulse head type carbon adsorption tower packed
with Pittsburgh GAC. The carbon adsorption tower is 3,200 mm in diameter,
7,500 mm in height and contains about 38 tons of GAC. After carbon adsorption,
the pH of the treated wastewater is adjusted and the water is discharged.
Spent GAC is regenerated on-site at the rate of 3.3 tons/day, using a
Nicols-Herreshoff vertical type gas furnace. Exhaust gases from the ozone
contacting tower are heated and passed through a 500-liter tower packed with
activated carbon. This treatment destroys residual ozone remaining in the
off-gases.
Pertinent wastewater parameters obtained on these dyeing wastewaters
using the ozone/GAC process are listed in Table 79, and a schematic drawing
of the plant is shown in Figure 25 in Section 5, under Textiles. Major
points to be noted are that the BOD values of ozonized wastewaters are about
the same as those of the raw wastewater, and that COD values are lowered by
10 to 15% by ozonation. After GAC adsorption, both BOD and COD values have
been reduced 60 to 80% from those of the raw wastewater. There is no recogni-
tion in this article of biological activity in the carbon tower.
TABLE 79.
Parameter
Color*
1 pH
SS (mg/1)
BOD (mg/1)
COD (mg/1)
Phenol (mg/1)
Initial
0.2-0.35
6.0-8.0
8-15
110-160
120-170
1-2
After Ozone
0.05-0.1
6.0-7.0
5-10
100-140
100-150
0.1-0.2
After GAC
0.02-0.05
6.5-7.5
0.6-2
20-50
20-50
0
* color determined by average of absorbance at 430, 530, 550, 610 &
660 nm
Source: Anonymous,
1974
364
-------
It should be noted that the COD values of the raw and finished waste-
waters are similar in magnitude to those of the Cleveland Westerly sewage
treatment plant, where the pilot plant activated carbon column has operated
biologically for 20 months without requiring regeneration. Although Cleve-
land's influent contains 60/40 municipal/industrial wastes, whereas Nagahama s
influent is specifically dyeing wastewater, Cleveland obtains extended
performance of its BAG column using a preozonation dosage of only 5 mg/1,
whereas Nagahama employs a maximum of 50 mg/1 dosage of ozone.
The Nagahama factory ozone/GAC installation is claimed to be completely
free of sludges (normally produced by coagulative precipitation methods or
activated sludge), only a small plant area is required for the installation
(about 500 sq m) and the costs of operation of the process are 34
-------
For example, if the toxic organic materials do not contain halogens and
contain carbon-carbon unsaturation, they can be converted to oxygenated
carbonaceous materials during preozonation by attack at the unsaturation.
Oxidation with ozone during the pretreatment step will occur with unsaturated
aliphatic organics as well as aromatics (phenols) and even many polycyclics,
such as phenanthrene and benzpyrenes.
Organic compounds which contain halogens are not as rapidly biodegradable
as are organics which do not contain halogens, nor are they as reactive with
strong oxidizing agents, including ozone. On the other hand, the combination
of UV radiation with ozone (Prengle et al_., 1978, 1977, 1976, and references
cited therein) or of ultrasound with ozone (Sierka, 1977) has shown remarkable
ability to degrade these refractory organic compounds in a much shorter time
than can ozone alone. If such materials are present in industrial wastewaters
to be treated, consideration should be given to these synergistic oxidation
techniques.
In addition, it has been shown (Gilbert, 1978, 1977) that small amounts
of hydrogen peroxide also enhance the oxidative powers of ozone toward
organic materials normally resistant to ozonation.
Finally, the ozone/UV or ozone/ultrasound combination is capable of
breaking carbon-chlorine bonds in many organic compounds normally refractory
to ozone. Arsovic & Burchard (1977) showed the degradative effects of
ozone/ultrasound on the formation of chloride ion when chlorobenzenes and
chlorophenols are oxidized. Since it is generally accepted that the carbon-
halogen bond is the moiety in the organic molecule which renders it more
resistant to biodegradation, if this bond can be destroyed in pretreatment,
the oxidized organic fragments, without covalently bonded halogen, will be
more rapidly biodegraded in the subsequent biologically active sand and GAC
filters.
DESIGN PARAMETERS
In designing BAG systems for removal of dissolved organics and conversion
of ammonia, it is important to consider parameters such as column or bed
size, wastewater flow rates, empty bed contact time of water with GAC,
temperature of operation, preozonation dosage, the need for sand filtration
prior to GAC adsorption and the need for supplemental oxygen prior to the
BAC medium. If the GAC medium is too small, and the water contaminants are
of high concentration and the flow rates are high, obviously the wastewater
contaminants will break through the carbon rapidly. Even though the bacterial
activity may be in full operation, the rate of pollutant charge will be
greater than the rate of pollutant removal, by means of biological processes.
Biological degradation of dissolved organic materials will be faster
the more oxygen the compounds contain. Therefore, the amount of preozonation
required will be determined by the elemental composition of the dissolved
organics as well as their structures (which will affect their reactivity
with ozone). It is possible that some organic pollutants are sufficiently
366
-------
oxygenated that preoxidation with ozone will not be required. In such
events, it should be acceptable merely to apply sufficient DO before the
sarrd filter (by aeration or by oxygenation) to promote the aerobic bacterial
growths in the prefilter and in the GAC media.
In operating BAG columns or beds, it is important to monitor the influent
and effluent to the BAG medium for DOC, ammonia (if present), C02 (formed by
biological conversion of DOC) and DO, in order to determine the rate at
which biological decomposition is occurring under the specific conditions at
hand. Similar analyses of the influent to the prefilter also will be useful
to determine the degrees of pollutant removals obtained in thi's step.
COSTS
Because BAG systems have not yet been defined, optimized and installed
for treating industrial wastewaters, it is not possible to offer accurate
cost estimates of specific systems for specific wastewaters. In addition,
costs of specific systems will be affected considerably by the amount of
preozonation required, the volume of carbon media to be employed, as well as
the wastewater components and their concentrations. Nevertheless, the
following projections are applicable from the drinking water treatment field
where both ozone and GAC have been employed for a number of years.
Miller et_ al_. (1978) surveyed the costs for ozone treatment of European
drinking water supplies. With average ozonation doses ranging from 1.5 to
3.0 mg/1 and with ozone generation capacities of 1,000 to 3,000 Ibs/day, the
ozonation costs range from 1.75 to 4.0
-------
Recent estimates by the U.S. Environmental Protection Agency Water
Supply Research Laboratory (Clark & Stevie, 1978) have been made for GAC
installations to satisfy the requirements of EPA's newly proposed regulations
for the control of organics in drinking water (U.S. EPA, 1978). For a plant
treating 12 to 13 mgd of water, the estimated cost of activated carbon
adsorption will be about 22<£/l,000 gal of water treated. This estimate is
based upon the following considerations:
• the cost of installed capital (GAC columns plus reactivation facilities)
is equal to the cost of operation and maintenance
• GAC columns are 13 ft deep and 12 ft in diameter
t empty bed contact time is 18 minutes
• on-site regeneration of GAC will be required, and capital costs for
regeneration are equal to the capital costs of the GAC installation
t GAC regeneration will be conducted every 2.4 months
Assuming that a properly designed and operating BAC facility would
reduce the regeneration requirements for GAC, to allow the wastewater treat-
ment to send spent carbon out for regeneration on a contract basis, then the
22(^/1,000 gal figure would be lowered by about one-third, to the 14 to
15(^/1,000 gal range (Table 80). To this should be added the costs for
ozonation treatment, which EPA estimates (Clark & Stevie, 1978) to be
1.8(^/1,000 gal per mg/1 dosage of ozone in the 12 to 13 mgd treatment plant
size.
TABLE 80. ESTIMATED COSTS FOR GAC TREATMENT*
EPA estimate (Clark & Stevie, 1978)
plant size
GAC column size (1 unit)
empty bed contact time
GAC regeneration
cost of capital
operation & maintenance cost
if off-site regeneration
22(^/1.000 gal
12 to 13 mgd
13 ft deep x 12 ft wide
18 minutes
on-site, every 2.4 months
1U/1.000 gal
lU/1,000 gal
14 to 15(^/1,000 gal
* These estimates are made for treating drinking water
This would mean that for a plant treating 12 to 13 mgd of wastewaters
requiring a 5 mg/1 preozonation dosage, GAC costs would be about 15<£/1,000
gal, plus 5 x 1.8 = 9<£/l,000 gal ozonation costs, or 24<£/l,000 gal (Table
81). This figure should be compared with the costs at:
368
-------
(1) the Nagahama dye waste treatment plant in Japan, of 34<£/l,000 gal for
treating 0.87 mgd using a maximum ozone dosage of 50 mg/1 (Anonymous,
1974) and
(2) the Rouen-la-chapelle water treatment plant in France, of 46(^/1,000
gal, which produces 12 mgd of drinking water using a 2-stage ozonation
process (total ozone dosage = 2 mg/1) and BAG (Rice, Gomella & Miller,
1978).
TABLE 81. PROJECTED COSTS FOR BAC TREATMENT
BASES
• plant size : 12 to 14 mgd
• preozonation dosage : 5 mg/1
t GAC column size : 13 ft deep x 12 ft diameter
t empty bed contact time : 18 minutes
ESTIMATED COSTS
ozonation : 1.8
-------
might be oxidized in pretreatment by a combination of ozone with UV radiation
or ultrasonics. Demonstrations of the BAG process are needed with specific
industrial wastewaters before its potentials can be determined.
LITERATURE CITED
Anonymous, 1974, "Ozone-Carbon Dye Waste Treatment", Textile Industries,
Oct. 1974, p. 43, 45.
Arsovic, H.M. & H. Burchard, 1977, "Ergebnisse und Neue Erkenntnisse zur
Oxidation von o-Chlorophenol mit Ozon, Unter Anwendung des ETIZON-
Verfahrens", Gesundheits-Ingenieur 98(9):230-239.
Baer, F.H., 1970, "Ozone Step Allows Recycle of Organic Fouled Water", Chem.
Engrg., Aug. 24, 1970, p. 42.
Carswell, J,K., Jr., 1977. U.S. Environmental Protection Agency, Cincin-
nati, Ohio. Private Communication.
Clark, R.M. & R.G. Stevie, 1978, "Meeting the Drinking Water Standards: The
Price of Regulation". Presented at the National Conf. on Drinking
Water Policy Problems, Resources For The Future, Washington, D.C.,
March 6-8, 1978.
Directo, L.S., C.-L. Chen & I.J. Kugelman, 1977, "Pilot Plant Study of
Physical-Chemical Treatment", J. Water Poll. Control Fed. 49(10):
2081-2098.
Eberhardt, M., 1975, "Experience with the Use of Biologically Effective
Activated Carbon", in Translation p_f Reports on Special Problems p_f
Water Technology, Vol. 9 - Adsorption, H. SontFeimer, editor.EPA
Report No. EPA 600/9-76-030, Dec. 1976.
Eberhardt, M., S. Madsen & H. Sontheimer, 1974, "Untersuchungen zur Ver-
wendung Biologisch Arbeitender Aktivkohlefilter bei der Trinkwasser-
aufbereitung", Heft 7, Vertiffentlichungen des Bereichs u. des Lehrstuhls
fur Wasserchemie Leitung: Prof. Dr. H. Sontheimer; Univ. Karlsruhe,
Germany; see also Wasser/Abwasser 116(6):245-247 (1975).
Gilbert, E., 1978, "Reactions of Ozone With Organic Compounds in Dilute
Aqueous Solution: Identification of Their Oxidation Products", in
Ozone/Chlorine Dioxide Oxidation Products of Organic Materials, R.G.
Rice & J.A. Cotruvo, editors. Intl. OzoneTssoc., Cleveland, Ohio
(1978), p. 227-242.
Gilbert, E., 1977, "Chemische VorgSnge bei der Ozonanwendung", presented at
Wasser-Berlin, Berlin, Germany, May, 1977. Intl. Ozone Assoc., Cleve-
land, Ohio.
370
-------
Gomella, C., 1978, (SETUDE, Paris, France). Private Communication, Jan.,
1978.
Gomella, C. & D. Versanne, 1977, "Le Role de 1'Ozone dans la Nitrification
Bacterienne de T'Azote Ammoniacal -- Cas de TUsine de la Chapelle
Banlieue Sud de Rouen (Seine Maritime), France". Presented at 3rd
Intl. Symp. on Ozone Technol., Paris, France, May 1977. Intl. Ozone
Assoc., Cleveland, Ohio.
Guirguis, W.A., T. Cooper, J. Harris & A. Ungar, 1976a, "Improved Perfor-
mance of Activated Carbon by Pre-ozonation", Presented at 49th Ann.
Conf. Water Poll. Control Fed., Minneapolis, Minn., Oct. 1976.
Guirguis, W.A., Y.A. Hanna, R. Prober, T. Meister & P.K. Sriyastava, 1976b,
"Reaction of Organics Nonsorbable by Activated Carbon with Ozone", in
Ozone/Chlorine Dioxide Oxidation Products of Organic Materials, R.G.
Rice & J.A. Cotruvo, editors. Intl. Ozone Assoc., Cleveland, Ohio
(1978), p. 291-301.
Guirguis, W.A., J.S. Jain, Y.A. Hanna & P.K. Srivastava, 1976c, "Ozone
Application for Disinfection in the Westerly Advanced Wastewater Treat-
ment Facility", in Forum on Ozone Disinfection. E.G. Fochtman, R.G.
Rice & M.E. Browning, editors. Intl. Ozone Assoc., Cleveland, Ohio, p.
363-381.
Guirguis, W.A., P.B. Melnyk & J.P. Harris, 1976d, "The Negative Impact of
Industrial Waste on Physical-Chemical Treatment", Presented at 31st
Purdue Indl. Waste Conf., Lafayette, Indiana, May, 1976.
Guirguis, W., T. Cooper, J. Harris & A. Ungar, 1978, "Improved Performance
of Activated Carbon by Pre-Ozonation", J. Water Poll. Control Fed.
50(2):308-320.
Hanna, Y., J. Slough, Jr. & W.A. Guirguis, 1977, "Ozone As A Pre-Treatment
Step For The Physical Chemical Treatment - Part II", Presented at
Symposium on Advanced Ozone Technology, Toronto, Ontario, Canada,
November, 1977. Intl. Ozone Assoc., Cleveland, Ohio.
Hanna, Y.A., 1977, "Application of Ozone as a Carbon Pretreatment Step at
Cleveland's Westerly Plant", presented at Special Seminar on Current
Status of Wastewater Disinfection & Treatment With Ozone, Cincinnati,
Ohio, Sept. 15, 1977. Intl. Ozone Assoc., Cleveland, Ohio.
Hopf, W., 1960, "Versuche mit Aktivkohlen zur Aufbereitung des Dtisseldorfer
Trinkwassers", Wasser/Abwasser 101(14):330-336.
Jekel, M., 1978, "Engler-Bunte Institute of the University of Karlsruhe,
Federal Republic of Germany. Private Communication.
Kawazaki et al., 1965, Water & Wastewater (Japan) 6:643-648, 778-780.
371
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Klotz, M., P. Werner & R. Schweisfurth, 1975, "Investigations Concerning the
Microbiology of Activated Carbon Filters", in Translation of Reports on
Special Problems of Hater Technology, Vol. 9 - Adsorption", op. cit.,
p. 312-330. ~~
Kfllle, W., H. Sontheimer & L. Steiglitz, 1975, "Eignungsprtlfung von Wasser-
werks-Aktivkohlen Anhand Ihrer Adsorptionseigenschaften filr Organische
Chlorverbindungen", Vom Wasser 44:203-217.
KUhn, W., 1974, "Untersuchungen zur Bestimmung von Organischen Chlorver-
bindungen auf Aktivkohle", Dissertation, Fak. f. Chemie-Ing. Wesen,
Univ. Karlsruhe, Fed. Rep. Germany.
KUhn, W. & F. Fuchs, 1975, "Untersuchungen zur Bedeutung der Organischen
Chlorverbindungen und Ihrer Adsorbierbarkeit", Vom Wasser 45:217-232.
Kilhn, W. & H. Sontheimer, 1973a, "Einige Untersuchungen zur Bestimmung von
Organischen Chlorverbindungen auf Aktivkohle", Vom Wasser 41:65-79.
KUhn, W. & H. Sontheimer, 1973b, "Einfluss Chemischer Umsetzungen auf die
Lage der Adsorptionsgleichgewichte an Aktivkohlen", Vom Wasser 40:115-
123.
KUhn, W. & H. Sontheimer, 1974, "Zur Analytischen Erfassung Organischer
Chlorverbindungen mit der Temperaturprogrammierten Pyrohydrolyse", Vom
Wasser 43:327-341.
KUhn, W., H. Sontheimer & R. Kurz, 1978, "Use of Ozone and Chlorine in Water
Works in the Federal Republic of Germany", in Ozone/Chi orine Pi oxi de
Oxidation Products of Organic Materials. R.G. Rice & J.A. Cotruvo,
editors. Intl. Ozone Assoc., Cleveland, Ohio (1978), p. 426-441.
McCreary, J.J. & V.L. Snoeyink, 1977, "Granular Activated Carbon in Water
Treatment", J. Am. Water Works Assoc. 69(8):437-444.
Miller, G.W., 1978, "Capital & Operating Costs of Ozonation Systems",
presented at Seminar on Drinking Water, Intl. Bank for Reconstruction
& Development, Washington, D.C., Jan. 11, 1978.
Miller, G.W., R.G. Rice, C.M. Robson, R.L. Scullin, W. KUhn W. & H. Wolf,
1978, "An Assessment of Ozone & Chlorine Dioxide Technologies for
Treatment of Municipal Water Supplies". U.S. EPA Report No. 600/2-78-
147. U.S. Environmental Protection Agency, Municipal Environmental
Research Laboratory, Cincinnati, Ohio 45268.
Mizumoto, K. & M. Horie, 1974, "Dyeing Wastewater Treatment by Combination
of Ozone and Activated Carbon", Japan Textile News, 89:238.
Monsitz, J.T. & L.D. Ainesworth, 1970, "Detection and Control of Hydrogen
Polysulfide in Water", Public Works 101:113.
372
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Netzer, A. & A. Bowers, 1975, "Removal of Trace Metals From Wastewater by
Lime and Ozonation", in Proc. First Intl. Symp. on Ozone for Water &
Wastewater Treatment, R.G. Rice & M.E. Browning, editors. Intl. Ozone
Assoc., p. 731-747.
Poggenburg, W., 1977, Wasserwerk Dtisseldorf, Federal Republic of Germany.
Private Communication.
Prengle, H.W., Jr. & C.E. Mauk, 1978, "Ozone/UV Oxidation of Pesticides in
Aqueous Solution", in Ozone/Chlorine Dioxide Oxidation Products of
Organic Materials, R.G. Rice & J.A. Cotruvo, editors. Intl. Ozone
Assoc., Cleveland, Ohio, p. 302-320.
Prengle, H.W., Jr., 1977, "Evolution of the Ozone/UV Process for Wastewater
Treatment". Presented at Special Seminar on Current Status of Wastewater
Disinfection & Treatment With Ozone, Cincinnati, Ohio, Sept. 15, 1977.
Intl. Ozone Assoc., Cleveland, Ohio.
Prengle, H.W., Jr., C.G. Hewes, III & C.E. Mauk, 1976, "Oxidation of Re-
fractory Materials by Ozone With Ultraviolet Radiation", in Proc. Sec.
Intl. Symp. on Ozone Techno!., R.G. Rice, P. Pichet & M.-A. Vincent,
editors. IntT.Uzone Assoc., Cleveland, Ohio, p. 224-252.
Prober, R., Y.A. Hanna & W. Guirguis, 1977, "Toward a Model for Activated
Carbon Treatment in the Presence of Significant Bacterial Growth".
Presented at WWEMA Meeting on Wastewater Treatment, Atlanta, GA,
April, 1977. Water & Wastewater Equipment Mfgrs. Assoc., McLean, VA.
Rice, R.G., C.M. Robson, G.W. Miller & J.C. Clark, 1979, "Biological Acti-
vated Carbon And Its Use In Treating Drinking Water Supplies", presented
at Seminar On Control Of Organic Chemical Contaminants in Drinking
Water", Dallas, Texas, March 14. U.S. Environmental Protection Agency,
Office of Drinking Water, Washington, D.C. 20460.
Rice, R.G., C. Cornelia & G.W. Miller, 1978, "Rouen, France, Water Treatment
Plant: A Case History", Civil Engrg., May, 1978, p. 76-82.
Rice, R.G., G.W. Miller, C.M. Robson & W. Ktlhn, 1978, "A Review Of The
Status Of Pre-Ozonation Of Granular Activated Carbon", in Carbon Adsorp-
tion. P.N. Cheremisinoff & F. Ellerbusch, editors, Ann Arbor Science
Publishers, Inc., Ann Arbor, Michigan.
Rice, R.G., G.W. Miller, C.M. Robson & W. Ktlhn, 1977, "Biological Activated
Carbon", presented at Symposium on Advanced Ozone Technology, Toronto,
Ontario, Canada, Nov. 16-18, 1977. Intl. Ozone Assoc., Cleveland,
Ohio.
Schalekamp, M., 1975, "Use of Activated Carbon in the Treatment of Lake
Water", in Translation of Reports of Special Problems of_ Water Technology,
Vol. 9 - Adsorption^ op. cit., p.T28-159.
373
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Sghalekamp, M., 1977, "Experience in Switzerland with Ozone, Particularly in
Connection with the Neutralization of Hygienically Undesirable Elements
Present in Water", Presented at Intl. Symposium on Ozone & Water,
Wasser Berlin, Berlin, Germany, May 1977. Intl. Ozone Assoc., Cleveland,
Ohio.
Scheidtmann, W, 1975, "Investigations of the Optimization of Pretreatment
When Using Ozone", in Translation of Reports on Special Problems of
Water Technology, Vol. 9 - Adsorption, op. cit., p. 98-111.'
Sierka, R.A., 1977, "The Effects of Sonic and Ultrasonic Waves on the Mass
Transfer of Ozone and the Oxidation of Organic Substances in Aqueous
Solution". Presented at Third Intl. Symp. on Ozone Techno!., Paris,
France, May. Intl. Ozone Assoc., Cleveland, Ohio.
Sontheimer, H., 1975, "Considerations on the Optimization of Activated
Carbon Use in Waterworks", in Translation of Reports on Special
Problems of Water Technology, Vol. 9 - Absorption, op. cit., p. 208-
_
Sontheimer, H., 1977a, Engler-Bunte Inst. der Univ. Karlsruhe, Federal
Republic of Germany. Private Communication.
Sontheimer, H., 1977b, "Biological Treatment of Surface Waters in Activated
Carbon Filters", presented at Seminar on Current Status of Wastewater
Treatment & Disinfection With Ozone, Cleveland, Ohio, Sept. 15, 1977.
Intl. Ozone Assoc., Cleveland, Ohio.
Sontheimer, H., E. Heilker, M. Jekel, H. Nolte & F.-H. Vollmer, 1978, "The
Mtllheim Process", J. Am. Water Works Assoc. 70(7):393-396.
Sontheimer, H., 1978, Engler-Bunnte Inst. der Univ. Karlsruhe, Federal
Republic of Germany. Private Communication.
U.S. Environmental Protection Agency, 1978, "Proposed Regulations For The
Control Of Organic Chemical Contaminants In Drinking Water", Federal
Register, February 9, 1978.
Van Der Kooij, D., 1975, "Some Investigations Into the Presence and Be-
haviour of Bacteria in Activated Carbon Filters", in Translation of
Reports on^ Special Problems of_ Water Technology, Vol. 9 - Adsorption.
op. cit., p. 348-354.
Van Lier, W.C., A. Graveland, J.J. Rook & L.J. Schultink, 1975, "Experiences
With Pilot Plant Activated Carbon Filters in Dutch Waterworks", in
Translation of_ Reports cm Special Problems of Water Technology,
Vol. 9 - Adsorption, op. cit., p. 160-T8T.
374
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Wachs, A., N. Narkis & M. Schneider, 1977, "Organic Matter Removal From
Effluents by Lime Treatment, Ozonation and Biologically Extended
Activated Carbon Treatment", Presented at 3rd Intl. Symp. on Ozone
Technology, Paris, France, May. Intl. Ozone Assoc., Cleveland, Ohio.
Wfllfel, P. & H. Sontheimer, 1974, "Ein Neues Verfahren zur Bestimmung von
Organisch Gebundenem Kohlenstoff in Wasser Durch Photochemische Oxida-
tion", Vom Wasser 43:315-325.
375
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-80-060
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
Ozone for Industrial Water and Wastewater
Treatment, A Literature Survey
April 1980 issuing date
6. PERFORMING ORGANIZATION CODE
and Myron E. Browning
Rip 6. Rice Allied Chemical Co.,
Jacobs Engrg. Group, Wash..D.C. 20005 /Syracuse. NY 1
8. PERFORMING ORGANIZATION REPORT NO.
209
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Jacobs Engrg. Group and Allied Chemical Company
Wash., D.C. 20005 Syracuse, NY 13209
10. PROGRAM ELEMENT NO.
C33B1B
11. CONTRACT/GRANT NO.
Grant No. R-803357
12. SPONSORING AGENCV NAME AND ADDRESS
Robert S. Kerr Environmental Research Laboratory
Office Of Research And Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
13. TYPE OF REPORT AND PERIOD COVERED
Final Report/7-1974 to 7-1977
14. SPONSORING AGENCY CODE
EPA/600/15
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The project explored the technology of ozonation applicable to industrial water
and wastewater treatment. The final report documents existing equipment, extent
of application and practical usage, contract systems, monitoring and detection
devices, general and specific economics, and most recent acceptable procedures.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Ozonation, oxidation, industrial wastes,
industrial waste treatment, activated
carbon treatment
Ozone wastewater treat-
ment, biological activat
carbon treatment
68.d.
ed
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
394
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
376
U.S. GOVERNMENT PRINTING OFFICE: 1980-657-146/5656
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