1. The Need for Chlorine

2. Mission of Water Missions
Provide Access to Safe Water and the opportunity to hear the Living Water message
1.2 Billion people lack access to safe water
WHO defines reasonable access as “availability of 20 liters per person per day within 1 kilometer of user’s dwelling.”
Each year:
1.7 – 2.2 million persons die from waterborne diseases
Each day:
5,000 children die from infectious diarrhea acquired from unsafe drinking water
4 billion episodes of diarrhea are caused by unsafe water

3. Safe Water
WHO Guidelines for Drinking Water Quality, 3rd Edition, Section 1.1
“Safe drinking-water, as defined by the Guidelines, does not represent any significant risk to health over a lifetime of consumption, including different sensitivities that may occur between life stages.”
Recommend each country use of risk-benefit analysis to set limits
Types of Contaminants
Large suspended matter (eg. soil)
Dissolved contaminants
Fertilizers, pesticides
Industrial run-off
Microbial contamination
Most disease is caused by microbial contamination (WHO Guidelines, 3rd Edition, Section 1.1)
“The great majority of evident water-related health problems are the result of microbial (bacteriological, viral, protozoan or other biological) contamination.”
“In general terms, the greatest microbial risks are associated with ingestion of water that is contaminated with human or animal (including bird) faeces.”
“The potential health consequences of microbial contamination are such that its control must always be of paramount importance and must never be compromised.”

4. Types of Microbial Contamination
Protazoa
Bacteria
Viruses

5. Protazoa Life Stages Cysts Examples of diseases
Cysts in water or elsewhere in environment
Out of cysts (excyst) in intestines
Cysts
Highly resistant to chlorine
Large size (3 – 8 microns)
Can be removed by filtration
Examples of diseases
Cyrtosporidium
Giardia
Giardia Cyst

6. Bacteria Smaller size Easily destroyed by chlorine Diseases
0.5 – 1.0 micron
Effectively removed only by very tight filters such as membranes
Easily destroyed by chlorine
Diseases
Cholera
Typhoid
Gastroenteritis (diarrhea)
Vibrio Cholerae Bacteria
Vibrio Vulnificus Bacterium

7. Viruses Very Small Many effectively inactivated with chlorine Diseases
micron
Not removable by common filtration
Many effectively inactivated with chlorine
Diseases
Polio
Hepatitis
Rotavirus (intestinal, a leading cause of diarrhea)
Poliovirus
Hepatitis B Virus

8. Protazoa Tolerance to Chlorine
Source: CDC Pathogen Clearance List
PATHOGEN
Health Significance
Persistance in Water Supplies
Resistance to Chlorine
Relative Infectivity
Concentration of Chlorine (ppm)
Time of Exposure (min)
% Inactivation
Entomoeba Hystolitica
High
Moderate
Low
2.0 10
99%
Giardia Lamblia
1.5
99.9%
Toxoplasma gondii
Unknown
100
1440 -
Cryptospo-ridium parvum
Long 80 90

9. Bacteria Tolerance to Chlorine
Source: CDC Pathogen Clearance List
PATHOGEN
Health Significance
Persistance in Water Supplies
Resistance to Chlorine
Relative Infectivity
Concentration of Chlorine (ppm)
Time of Exposure (min)
% Inactivation
Burkholderia pseudomallei
Low
May Multiply
1.0 60
99%
Campylobacter jejuni
High
Moderate
0.1 5
99 – 99.9%
Escherichia coli
0.5
<0.5 %
E. coli
(enterohemorrhagic)
99.98 – %
Salmonella typhi
0.05 20
99.2%
Shigella dysenteriae.
Short
<1
99.9%
Shigella sonnei - 1
Vibrio cholerae
(smooth strain)
100%
(rugose strain)
2.0
99.999%
Yersinia enterocolitica
Long
>30
82 – 92%

10. Virus Tolerance to Chlorine
Source: CDC Pathogen Clearance List
PATHOGEN
Health Significance
Persistance in Water Supplies
Resistance to Chlorine
Relative Infectivity
Concentration of Chlorine (ppm)
Time of Exposure (min)
% Inactivation
Coxsakie A
High
Long
Moderate
0.46 – 0.49
0.3
99%
Coxsackie B
4.5
Echovirus
0.48 – 0.52
1.8
Hepatitis A
0.41
<1
99.99%
Polio Virus
0.5
12.72
Adenovirus
0.17
4.41
Noroviruses
1.0
0.07
Rotavirus
0.20
0.25

11. What Does Chlorine Do?

12. Chlorine Will inactivate microbes if sufficient quantity and time Time
Often <1 minute, but some organisms more resistant
30 minutes is WMI goal
Quantity
0.2 – 0.5 ppm is common amount in developed countries
Need residual appropriate for distribution system
Consider tanks, household containers
We want to have safe water as the water is delivered to the person’s mouth
Sample water and test and “end” of distribution system to determine amount needed at LWTS or chlorinator

13. Living Water Treatment System
Combines both filtration and chlorination
Effectively treats water that is contaminated by major classes of microbial contaminants
Similar to the water treatment used by most public water treatment facilities in developed countries.
Both filtration and chlorination are necessary to provide safe water

14. What to do if beneficiaries object to chlorine taste
Do not eliminate chlorine!
Start at lower concentration and increase if necessary
0.2 – 0.5 ppm initially
If we are not chlorinating water
We are not providing safe water
We are not meeting the mission of Water Missions