Post on 13-Apr-2017
THE PERILS OF USING CHLORINE FOR
WASTEWATER DISINFECTION A LOOK AT OZONE ALTERNATIVE
Ozone Research and Applications (India) Pvt. Ltd
This document examines the risks of using chlorine for water disinfection and tries to share the
worldwide opinion about the adverse effects of chlorine on human health and aquatic life. This
document also tries to make the reader aware about the alternative- ozone; which has recently gained
huge popularity across the globe. This document also studies the benefits of using ozone in waste water
treatment.
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 2
TABLE OF CONTENTS
MINIMISING RELEASE AND ENVIRONMENTAL IMPLICATIONS OF
CHLORINE AND ITS COMPOUNDS {CPCB
DOCUMENT(SEPTEMBER, 2008) } 4
PERFORMANCE OF SEWAGE TREATMENT PLANTS-COLIFORM
REDUCTION (CPCB DOCUMENT 2008) 6
EFFECT OF WASTEWATER AND COOLING WATER CHLORINATION
ON AQUATIC LIFE (US EPA DOCUMENT-1976) 9
IMPACTS OF TOXIC CHEMICALS ON TRINITY RIVER FISH AND
WILDLIFE (US DEPARTMENT OF THE INTERIOR) 11
COMPARITIVE TOXICITY OF SEWAGE-EFFLUENT DISINFECTION
TO FRESHWATER AQUATIC LIFE (US EPA DOCUMENT-
NOVEMBER 1975) 13
DISINFECTION OF TREATED WASTEWATER (EPA VICTORIA
SEPTEMBER 2002) 15
MANAGING SEWAGE DISCHARGES TO INLAND WATERS 17
DISINFECTION TECHNOLOGIES FOR POTABLE WATER AND
WASTE WATER TREATMENT-ALTERNATIVES TO CHLORINE 18
PILOT PLANT FOR TERTIARY TREATMENT OF WASTEWATER
WITH OZONE(US EPA 1973) 23
MAHARASHTRA POLLUTION CONTROL BOARD NOTICE 25
CHLORINE HAZARDS 26
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 3
ORAIPL’s TAKE ON THE CURRENT SCENARIO 27
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 4
MINIMISING RELEASE AND ENVIRONMENTAL IMPLICATIONS OF
CHLORINE AND ITS COMPOUNDS (CPCB
DOCUMENT(SEPTEMBER, 2008)
Minimising Release And Environmental Implications of Chlorine and its Compounds
This is a technical report which talks about the adverse effects of chlorine in water treatment and also
advocates the practise of minimising its release in water bodies in any product form. The following are
excerpts taken from the same document.
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 5
Ref: Minimising Release And Environmental Implications of Chlorine and its Compounds-Foreword by
J.M. Mauskar, IAS
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 6
Ref: Minimising Release And Environmental Implications of Chlorine and its Compounds- Section 9.2
Page No. 66
PERFORMANCE OF SEWAGE TREATMENT PLANTS-COLIFORM
REDUCTION (CPCB DOCUMENT 2008)
Performance Of Sewage Treatment Plants - Coliform Reduction:
This report, published by CPCB in 2008 presents its study of how the sewage treatment plants in India are
performing when it comes to microbial reduction. The following are excerpts taken from the same
document.
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Ref: Performance of Sewage Treatment Plants - Coliform Reduction: Foreword by J.M. Mauskar, IAS
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 8
Ref: Performance of Sewage Treatment Plants - Coliform Reduction: Section 5.2-Page No.172
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 9
EFFECT OF WASTEWATER AND COOLING WATER CHLORINATION
ON AQUATIC LIFE (US EPA DOCUMENT-1976)
Effect Of Wastewater and Cooling Water Chlorination on Aquatic Life:
This report; submitted to US EPA in 1976; summarizes the effect of total residual chlorine on aquatic life
when chlorine is used for wastewater and cooling water treatment. Following excerpts aretaken from
the same pointing out the effect of chlorinated effluent on receiving streams.
Ref: Effect of Wastewater and Cooling Water Chlorination on Aquatic Life: Section I- Introduction Page
No. 8
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 10
Ref: Effect of Wastewater and Cooling Water Chlorination on Aquatic Life: Section III- Conclusions
Page No. 11
Ref: Effect of Wastewater and Cooling Water Chlorination on Aquatic Life: Miscellaneous Page No. 27
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 11
IMPACTS OF TOXIC CHEMICALS ON TRINITY RIVER FISH AND
WILDLIFE (US DEPARTMENT OF THE INTERIOR)
Impact of Toxic chemicals on Trinity River Fish and Wildlife: This report summarizes the kind of
contaminants found in rivers which cause various kinds of health impacts on aquatic life. Following
excerpts are taken from the same document stating the adverse impacts of chlorine on the mortality of
aquatic life.
Ref: Impact of Toxic chemicals on Trinity River Fish and Wildlife: Chlorine Impacts
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Ref: Impact of Toxic chemicals on Trinity River Fish and Wildlife: Influence of Chlorine Treated Sewage
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 13
Ref: Impact of Toxic chemicals on Trinity River Fish and Wildlife: Influence of Low Oxygen Levels
COMPARATIVE TOXICITY OF SEWAGE-EFFLUENT DISINFECTION
TO FRESHWATER AQUATIC LIFE (US EPA DOCUMENT-
NOVEMBER 1975)
Comparative Toxicity of Sewage Effluent Disinfection to Freshwater Aquatic Life: This report compares
the amount of toxicity caused to aquatic life by various disinfectants. Following is an excerpt taken from
the same.
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Ref: Comparative Toxicity of Sewage Effluent Disinfection to Freshwater Aquatic Life: Section 1 Pg 12
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 15
DISINFECTION OF TREATED WASTEWATER (EPA VICTORIA
SEPTEMBER 2002)
Disinfection Of Treated Wastewater: This document contains the recommended guidelines to be
followed during consideration of any disinfection technique. Following are the excerpts taken from the
same.
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 16
Ref: Disinfection Of Treated Wastewater: Performance Objectives
Ref: Disinfection Of Treated Wastewater: Disadvantages of Chlorination
Ref: Disinfection Of Treated Wastewater: Comparison Of Chlorine and Ozone
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 17
MANAGING SEWAGE DISCHARGES TO INLAND WATERS
Managing Sewage Discharges To Inland Waters: This document was published by EPA Victoria and talks
about how one should manage sewage discharges to inland waters. Following are excerpts taken from
the same.
Ref: Managing Sewage Discharges To Inland Waters: Page No. 12
Ozone Research and Applications (India) Pvt. Ltd, Nagpur
DISINFECTION TECHNOLOGIES FOR POTABLE WATER AND
WASTE WATER TREATMENT
Disinfection Technologies For Potable And Waste Water Treat
Following are excerpts taken from the same.
Ref: Disinfection Technologies For Potable And Waste Water Treat
Performance Table
and Applications (India) Pvt. Ltd, Nagpur
DISINFECTION TECHNOLOGIES FOR POTABLE WATER AND
WASTE WATER TREATMENT-ALTERNATIVES TO CHLORINE
r Potable And Waste Water Treatment- Alternatives To Chlorine Gas:
Following are excerpts taken from the same.
r Potable And Waste Water Treatment- Alternatives To Chlorine Gas:
Page 18
DISINFECTION TECHNOLOGIES FOR POTABLE WATER AND
ALTERNATIVES TO CHLORINE
Alternatives To Chlorine Gas:
Alternatives To Chlorine Gas:
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 19
Ref: Disinfection Technologies For Potable And Waste Water Treatment- Alternatives To Chlorine Gas:
Chlorine Gas Implications
Ref: Disinfection Technologies For Potable And Waste Water Treatment- Alternatives To Chlorine Gas:
By-Product Contamination
Ref: Disinfection Technologies For Potable And Waste Water Treatment- Alternatives To Chlorine Gas:
Disadvantages
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 20
Ref: Disinfection Technologies For Potable And Waste Water Treatment- Alternatives To Chlorine Gas:
Ozone
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 21
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 22
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 23
PILOT PLANT FOR TERTIARY TREATMENT OF WASTEWATER
WITH OZONE(US EPA 1973)
Pilot Plant For Tertiary treatment Of Wastewater with Ozone: This report published by US EPA studies
the benefits of ozone when using in wastewater. Following is an excerpt taken from the same.
Ref: Pilot Plant For Tertiary Treatment Of Wastewater with Ozone: Benefits Of Ozone
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 24
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 25
MAHARASHTRA CONTROL BOARD NOTICE(SEPTEMBER 2010)
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 26
CHLORINE HAZARDS
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 27
ORAIPL’s TAKE ON THE SCENARIO
Increasing populations and improving standards of living are placing increasing burdens on water
resources. The maintenance or improvement in quality of our finite supplies of fresh water and, in
the not distant future, the necessity for direct recycling of water in some parts of the country will
demand improved technology for the removal of contaminants of wastewater.
Most municipal wastewater treatment plants in India currently employ the age old disinfection
method of chlorinating sewage. Recently, it has come into the eyes of many that chlorinating
wastewater whether industrial or domestic has shown many negative impacts on the receiving
streams of chlorinated wastewater.
A survey conducted by Central Pollution Control Board (CPCB) of existing Sewage Treatment Plants
found that a lot of STPs in India do not disinfect the treated sewage and release the infected
sewage into aquatic bodies which has resulted in the eutrophication and loss of dissolved oxygen
levels in the receiving streams.
A lot of STPs in India were designed just to comply with the pollution control norms. Majority of
factors were neglected while designing these STPs; hence we often come across STPs which are
running over capacity and are unable to produce the desired results.
In order to achieve 3 Log or 4 Log reduction in the coliform levels and to comply with the new draft
guidelines proposed by Ministry of Environment, Forest and Climate Change (MoEF); coliform levels
below 100 MPN/100 ml; chlorination will fail to achieve this unless the chlorine dose is increased to
above 10 ppm in treated sewage. However, such high doses of chlorine will increase the Total
Residual Chlorine (TRC) in the disinfected waters to above 0.5 ppm which is not recommended in
discharge waters. To reduce the TRC levels in discharge streams, dechlorination needs to be done
as practiced in many European countries. However, the combination of chlorination and
dechlorination will not be a viable and sustainable option for a developing country like India.
Also, the formation of chlorides and chlorates have resulted in the increase in Total Dissolved Solids
(TDS) of the receiving streams which has become a major concern in some of our major rivers like
Ganga and Yamuna.
The most popular disinfectant used in STPs all over is chlorine. But its effects on aquatic life have
been highly dangerous. Chlorine gas is particularly insidious. Even small exposures can burn the
eyes, skin and throat. Inhaling large amounts constricts the airways, while at the same time, fluid
accumulates in the lungs. People can literally drown in their own body fluids. At high exposures, a
few deep breaths are lethal.
"Chlorine was used as a war gas for a reason. It was designed not just to kill the enemy but also to
inflict fear in the enemy...You don't know where to go. You see your clothes bleach before your very
eyes. You see animals die.”
– Erik Svendsen, Tulare University
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 28
As per a research paper ‘Don’t Chlorinate Sewage’ presented by Mr. James B. Coulter of Maryland
Department of Natural Resources at the National Symposium organized by US EPA; the practice
of chlorinating sewage was examined to find if it is a significant factor causing damage to aquatic
life. The following are some highlights from the talk:
“When sewage is chlorinated, toxic compounds such as cyanogen chlorides can be formed.”
“Work of Michigan’s Department of Natural Resources was described which proved that chlorinated
sewage is toxic to sewage. Fathead Minnows and RainbowTrout were exposed to chlorinated and
unchlorinated sewage effluents. Survival was high during the non-chlorinated phase.”
“There is an assumption that the act of chlorinating sewage will decrease the danger of diseases,
but for all practical purposes that assumption is not valid.”
“In the debate over the public health benefit or lack thereof that comes from chlorinating effluent,
the health of the sewage treatment plant is ignored. That is a mistake because chlorine creates an
occupational hazard and there have been a significant number of incapacitating accidents. Chlorine
in the air is almost as toxic as chlorine in water is to aquatic life.”
“Chlorination of ordinary sewage treatment plant effluent kills more of any of the various indicator
bacteria than it does of the virus in sewage effluent, and virus as well as other chlorine resistant
organisms; are the main cause of concern.”
“No knowledgeable person would contend that chlorination of ordinary sewage treatment plant
effluent would render it disinfected, incapable of producing disease. The reverse is true; chlorinated
sewage treatment plant effluents are highly infectious and should be treated with caution.”
“Chlorine introduced into sewage effluent can form a large variety of daughter compounds of
concern to drinking water supplies.”
With the industrial revolution and advancement in every sector including household items, the
household discharge these days are getting even more complex. In order to get the desired results,
Old STPs have started using excess chlorine to comply with norms thereby ignoring the
consequences this chlorinated water will have on the receiving streams.
Following are the disadvantages of excessive chlorination of sewage:
• The chlorine residual, even at low concentrations, is toxic to aquatic life.
• All forms of chlorine are highly corrosive and toxic. Thus, storage, shipping, and handling
pose safety risks.
• Chlorine oxidizes organic matter in wastewater, sometimes creating compounds that could
be harmful to human life and the environment. (Example: Trihalomethanes (THMs))
• The level of total dissolved solids is increased in the treated effluent.
• The chloride content of the wastewater is increased which directly has an impact on the
aquatic life.
• Certain types of microorganisms have also shown resistance to low doses of chlorine.
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 29
• Also, storage and handling chlorine is a risk in its own.
Ozone serves as a great alternative under such circumstances and has the following advantages:
• Ozone is more effective than chlorine in destroying viruses and bacteria.
• The ozonation process utilizes a short contact time (approximately 10 to 30 minutes).
• There are no harmful residuals that need to be removed after ozonation because ozone
decomposes rapidly.
• Ozone is generated onsite, and thus, there are fewer safety problems associated with
shipping and handling.
• Ozonation elevates the dissolved oxygen (DO) concentration of the effluent. The increase
in DO can eliminate the need for reaeration and also raise the level of DO in the receiving
stream.
• Ozone can further reduce the COD due to its oxidizing property and help meet the new
discharge norms.
The future STPs have to be designed in such a way that they are capable of treating Endocrine
Disruptors released in the modern day sewage from Shampoos, Cleansing Agents, etc. Disinfection
with chlorine for endocrine disruptors has been found to be ineffective when compared to ozone.
The City of Indianapolis installed state of the art advanced wastewater treatment systems to
enlarge its existing sewage treatment facility which also led to the improvement of the water
quality in flowing streams (United States Geological Survey Water-Supply Paper 2393).
Comparison of various alternative disinfectants on key parameters (US EPA Manual for Water
Disinfection):
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As seen from the above table, the parameter of persistent residual is the best when it is nil; which
is the case when ozone is used for disinfection.
As per clause 25 of the ‘Waters of Victoria’ which states that:-
“Waste disinfection methods which do not increase discharge toxicity and which constitute the least
environmental and human hazards in their generation transport and utilisation shall be employed
where practicable. In particular, the use of chlorine as a wastewater disinfectant shall be avoided
where there is a practical alternative.”
Following is an article published by American Chemical Society which says that chlorine use in
sewage can promote antibiotic resistance.
Ozone Research and Applications (India) Pvt. Ltd, Nagpur
and Applications (India) Pvt. Ltd, Nagpur Page 31
Ozone Research and Applications (India) Pvt. Ltd, Nagpur Page 32
Following is what US document named ‘Disinfection Technologies for Potable and Waste Water
Treatment- Alternatives to Chlorine Gas’; released in July 1998; had to say about Ozone as an
alternative disinfectant:
“ Ozone disinfects by oxidizing the cell walls of microorganism, which then disintegrate(lyse),
destroying the microorganism. This is a very different mechanism than with chlorine, which diffuses
through the cell wall susceptible, to enzymatic attack (Nebel, 1981). For this reason, ozone
disinfects much faster than chlorine, killing E.Coli, for example, approximately 3000 times faster
than chlorine. Ozone offers a number of significant advantages over chlorine gas and other
chlorine-based disinfection alternatives. First, because ozone is always generated on-site, it does
not require transportation or storage of dangerous materials. Second, ozone is highly efficient for
killing bacteria, viruses, and protozoa (e.g., Giardia lamblia and Cryptosporidium). For example, the
Ct value (dose in mg/l x time in minutes) required for the inactivation of Giardia cysts is about 100
times greater for free chlorine than for ozone; for viruses it is six times greater. Ozone is the only
recommended primary disinfectant for Cryptosporidium. Ozone also oxidizes inorganic and organic
impurities such as iron and manganese, and will also oxidize sulfides. This assists in filtration.
Because it is a 50 percent stronger oxidizer than chlorine, ozone requires significantly less contact
time to remove inorganic/organic compounds than conventional methods. Wastewaters treated
with ozone do not contain chlorine or chlorinated disinfection byproducts, thereby making
dechlorination unnecessary. In addition, ozone treatment increases dissolved oxygen levels in
wastewater, eliminating the need for effluent reaeration. An added advantage for wastewater
treatment plants already having oxygen activated sludge processing is that the off-gas oxygen from
the ozone process can be recycled directly into the activated sludge reactor, resulting in no loss of
O2.”
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Following is a list of municipal wastewater treatment plants where ozone has been used so far.
(Table taken from US EPA Document)
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Following are the experiences of few Sewage Treatment Plants which are undergoing ozonation in
Japan discussed at International Conference of Ozone and UV in 2006: As per this, more than 60
sewage treatment plants in Japan have already adopted ozonation technology and more are
expected to come in future especially where sewage is reused or high quality water is required.
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Following is a news report which shares the plans of Montreal which is planning to install the
largest ozonation plant of North America and third largest in the world.
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Ozone will certainly be an excellent alternative at this juncture when the water quality has been
deteriorating all over and alternatives need to found in order to maintain sustainability.
We thank you for going through the above document and hope the world will seriously take
consideration of opting ozone over chlorine.
To know more about the application of ozone in drinking water or other fields, please visit our website
www.oraipl.com .
For any queries, please write to us oraipl@oraipl.com .
Call Us At: 0712-2551055