Secondary Disinfection with Chloramines

Charlotte Smith

Charlotte Smith & Associates, Inc.

Groveland Community Services District

Community Education Meeting

December 16, 2006

copywrite: Charlotte Smith & Associates, Inc.

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Bacteria, viruses, parasites and organic molecules

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ClGCSD Adds Chlorine to Disinfect the Water

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Chlorinated-organic molecules (e.g. THMs) are Formed

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Add Chlorine and Ammonia-N to the Water

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Chlorine Binds to Ammonia-N Instead of DBP (e.g.THM)

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Instead of THM: Chloramine:

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Organic molecule remains un-chlorinated

Questions & Answers

I’ll go first

Why does Federal Law Require Addition of Disinfectants

to Drinking Water ?

• Microbes (including E. Coli, Hepatitis, Polio, Giardia, Cryptospordium) exist in the environment. These microbes can find their way into lakes and reservoirs that are drinking water sources.

• The Safe Drinking Water Act sets both minimum and maximum levels for disinfectants in drinking water to protect customers from disease-causing organisms.

How are Disinfectants Used in Drinking Water ?

• By Law, “primary” and “secondary” disinfection must be applied to drinking water which uses surface water as the source of supply.• “Primary disinfectants” are used to kill microbes. Ranked by ability to kill bacteria: primary disinfectants include ozone, ultraviolet light, chlorine dioxide, chlorine and chloramine.

• “Secondary disinfectants” are used to maintain the quality of water in the distribution system. Secondary disinfectants are chlorine and chloramine. Chlorine dioxide is allowed but not often used for this purpose.

How Do Utilities Select Disinfectants ?

• Disinfection selection must conform to public health laws. All aspects of disinfection of public water systems including chemicals used, concentrations, training and licensing of operators are regulated.

• Disinfectant selection is also based on source water quality, size of the system, and whether it’s being used for primary or secondary disinfection.

What is the Best Disinfectant ?

• Chlorine, ozone, UV and chlorine dioxide are better than chloramine for primary disinfection (to kill microbes).

• Chloramine is best for secondary disinfection: Chloramine is more protective against biofilm (slime) in distribution systems and the bacteria that causes Legionnaires Disease (Legionnella) than chlorine.

• GCSD will use chlorine and UV for primary disinfection and chloramine for secondary disinfection.

What is the Negative Aspect of Drinking Water that Contains a Chlorine Based

Disinfectant ?

• Disinfection by-products (such as trihalomethanes) result from disinfectants combining with naturally occurring organic matter in the water.

• Disinfection by-products at high levels are suspected carcinogens.

Can GCSD Water Meet Drinking Water Standards for DBP if they Continue to Use Free Chlorine for Secondary Disinfection ?

No.

GCSD water would not meet future regulations for disinfection by-products.

Can GCSD Water Meet Drinking Water Standards for DBPs if They Use Chloramine ?

Yes.

GCSD water would meet Safe Drinking Water Act levels for DBP (Trihalomethanes and Haloacetic Acids)

Can Very Concentrated Chlorine or Ammonia Solutions Used for Laundry or Cleaning Cause

Health Problems such as Skin Irritation?

• Yes. That’s why Sodium Hypochlorite (chlorine solution) and Ammonium Hydroxide (ammonia solution) used as cleaning solutions should be handled carefully and not mixed together.

• OSHA requires a Material Safety Data Sheet (MSDS) for very concentrated solutions of these chemicals – to protect the workers.

• An MSDS does not relate to drinking water because of the extremely low concentration of these chemicals in water. There is about 25,000 to 100,000 times less chlorine in drinking water than household bleach.

The Washington Post has Reported Increased Lead Levels in Washington DC After They Switched to Chloramines.

Will GCSD Customers Experience Higher Lead Levels in the Future ?

• Lead comes from lead pipes and solder in homes.

•DC has 23,000 lead service pipes. If your home does not have a lead service it is not comparable to this situation.

Note: Customers should check the Annual Water Quality Report known as the “Consumer Confidence Report” for Lead Levels, for a District-wide picture of this issue.

Can Dialysis Patients Drink Chlorinated or Chloraminated Water ?

• Dialysis patients can drink chlorinated or chloraminated water even though neither can be in the water used for cleansing their blood.

• Food and beverages that we digest don’t come in direct contact with the blood stream.

Is Chloraminated Water Safe for Children and the Elderly ?

Yes. Some cities in the US have been using chloramines since the 1920s.

Is Chloraminated Water Safe for Pets and Wildlife ?

Yes. The levels in drinking water are safe for animals.

When should Customers Replace Home Plumbing Parts ?

• Plumbing parts should be replaced when they wear out. Non-chloramine resistant parts will wear out faster. Therefore, it’s wise to replace parts with chloramine resistant ones.

Where Can Consumers Find Informationon Bottled Water or

Home Devices such as Filters?

• Home filters are not regulated. The National Sanitation Foundation website provides some information. www.nsf.org

• The Food and Drug Administration regulates bottled waters. Consumers of bottled water should contact the FDA or the manufacturer. www.fda.gov

What are Reliable Information Sources ?

• Details About Your Drinking Water:

The water utility and GCSD water quality www.gcsd.org

• Drinking Water Standards:

USEPA www.epa.gov

California Department of Health Services www.dhs.ca.gov

• Public Health Issues:

Centers for Disease Control www.cdc.gov

State and County Health Departments www.tuolumnecounty.ca.gov

• Personal Health Issues:

Clinical specialist (e.g. dermatologists, nephrologists)

• Other: Peer reviewed scientific literature www.awwa.org

Your Turn