ORAIPL STP

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

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


ORAIPL’s TAKE ON THE CURRENT SCENARIO 27


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.


Ref: Minimising Release And Environmental Implications of Chlorine and its Compounds-Foreword by

J.M. Mauskar, IAS


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.


Ref: Performance of Sewage Treatment Plants - Coliform Reduction: Foreword by J.M. Mauskar, IAS


Ref: Performance of Sewage Treatment Plants - Coliform Reduction: Section 5.2-Page No.172


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


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


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


Ref: Impact of Toxic chemicals on Trinity River Fish and Wildlife: Influence of Chlorine Treated Sewage


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.


Ref: Comparative Toxicity of Sewage Effluent Disinfection to Freshwater Aquatic Life: Section 1 Pg 12


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.


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


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



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


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:


ALTERNATIVES TO CHLORINE

Alternatives To Chlorine Gas:

Alternatives To Chlorine Gas:


Ref: Disinfection Technologies For Potable And Waste Water Treatment- Alternatives To Chlorine Gas:

Chlorine Gas Implications


By-Product Contamination


Disadvantages



Ozone


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


MAHARASHTRA CONTROL BOARD NOTICE(SEPTEMBER 2010)


CHLORINE HAZARDS


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


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.


• 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):


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.


and Applications (India) Pvt. Ltd, Nagpur


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.”


Following is a list of municipal wastewater treatment plants where ozone has been used so far.

(Table taken from US EPA Document)


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.


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.


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 [email protected] .

Call Us At: 0712-2551055

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