Appropriate Water Purification Technology and Sanitation

Promotion in Rural Communities:The Dominican Republic

Dr. Pedro Bernal

Chemistry Department, Rollins College, Winter Park, FL

The Magnitude of the Water Problem

Worldwide 3.4 million people, mostly children, die annually from water-related diseases

Approximately 4 billion cases of diarrhea each year cause 2.2 million deaths

2.4 billion people lack access to basic sanitation services

Sanitation coverage in rural areas is less than half that in urban areas

WHO 2000

The Magnitude of the Water Problem

Cases of disease Deaths

Typhoid 500 000 25 000

Giardiasis 500 000 low

Amoebiasis 48 000 000 110 000

Schistosomiasis 200 000 000 800 000

Diarrheal disease (including cholera)

4 000 000 000 2 200 000

Number/Year or Total Reported

Global morbidity and mortality rates of some water-related diseases.

Adopted from WHO 1995 - 2000

The Magnitude of the Water Problem

The Dominican Situation

There are approximately 300,000 reported cases of diarrhea each year

Diarrheal diseases account for approximately 30.4% of all diagnosed deaths from communicable diseases

Acute diarrhea is the leading cause of diagnosed mortality among children aged 1 to 4

PAHO 1994

The Nature of the Water Problem

Several factors influence water-related disease transmission

Water quality

Water quantity/availability

Personal and environmental hygiene and sanitation

Why Both Quality and Quantity are Important

Water-borne

Diseases

Quality

Water-washed

Diseases

Water-based

Diseases

Water-related Insect

Vector Diseases

Quantity

Water

Water-washed can also be impacted by

quality

Diarrhea is the most important public health problem affected by water and sanitation and can be both waterborne and water-

washed. -- WHO 2000

Routes of Disease Transmission

Excreta

Water HandsFlies

Food

Mouth

Courtesy of WHO: Principal elements of fecal-oral disease transmission

Impact of Water Quality

DiseasesProjected reduction in morbidity (%)

Cholera, typhoid 80-100

Diarrheal diseases, dysentery, gastroenteritis

40-50

Dracunuliasis 100

Schistosomiasis 60-70Adopted from WHO 1995

Potential reductions in morbidity of different water-related diseases as a result of improvements in water supply and sanitation

Our Approach to the Problem

Distribution of a technologically simple family-based water filter

Hygiene and sanitation promotion

Chemical and microbiological testing of sources and filtered water

Assessment of the health impact of the filter program

An attack on water quality . . .

The System: A Description

3-bucket system designed to eliminate the bacteria responsible for water-related disease

Chlorination Sediment removal Chlorine removal

Filter Distribution Currently ~ 3000 units distributed throughout 40

communities

Sabaneta de YasicaSummer 2002, West Jacksonville Rotary Club

~ 240 units Rincon

La Piña

Islabon

Haitian/Dominican BorderSummer 2002, Ecological Unit of the Dominican Army

Hygiene Promotion

ILAC network of health promoters

Brochures and pictorial publications

What Do We Measure?The WHO Drinking-Water Guidelines

Chemical parameters

Turbidity < 5 NTU

Residual Chlorine 0.2 - 0.5 ppm

pH 6.5 - 8.5

Microbiological parameters

E. coli 0 cfu*/100 mL * colony forming units

Chemical Testing

Water from the filters and sources is analyzed for: Turbidity Residual chlorine pH

Red colonies = Total coliforms

Blue colonies = E. coli

Microbiological Testing Determine the number of “colony forming units” per 100 mL of

water (cfu/100 mL)

Total coliforms: ubiquitous in tropical environments

Fecal coliforms (E. coli): indicative of fecal contamination

Incubation in m-ColiBlue24 for 24 hours

Results of Chemical and Microbiological Testing

Village of “El Venú”, Dominican Republic, Summer 2001 and 2002

Sources 2 local rivers Rainwater

Filters

Chemical Parameters - Sources

Thiele & Bray 2001 - 2002

Source Turbidity Residual Chlorine pH

Rivers 0.61 - 6.91 NTU 0 ppm 7.92 - 8.16

Stored Rainwater 0.6 - 2.05 NTU 0 ppm 7.52 - 10.13

Rivers Stored Rainwater

Ranges

Turbidity Free Cl2 pH

1 0.74 0 7.632 1.43 0 7.553 3.7 0 10.134 0.6 0.02 7.525 0.9 0 7.636 1.01 0 7.717 2.05 0.02 7.588 0.99 0 8.899 1.01 0 7.58

10 0.34 0 7.5611 0.99 0 7.912 1.89 0 9.313 0.55 0.01 7.2814 1.09 0 7.3315 0.6 0 7.7816 2.33 0.01 7.24

Sample Turbidity Free Cl2 pH1 0.79 ---- 7.992 0.63 0.03 8.063 0.61 0.01 7.954 2.35 0 7.925 5.28 0.02 8.026 6.91 0 8.16

River 2, 2002

River 1, 2001

River 1, 2002

Chemical Parameters - Filters

Under Acceptable

Range

Within Acceptable

Range

Over Acceptable

Range

Turbidity

< 5 NTU

Residual Cl2

0.2 - 0.5 ppm

pH

6.5 - 8.5

15% 9%

WHO Parameters and Guidelines

Percent of Filters

0% 84% 16%

------ 100% 0%

76%

Thiele & Bray, 2001 - 2002

60 filters were tested

Total of 75 tests -- 12 filters were revisited

Why Are These Parameters Important to the Filters?

High turbidity provides a more adequate environment for microorganisms.

At a pH of around 6 the chlorine is almost 100% effective. As the pH increases the effectiveness of the chlorine decreases. (pH 9 ~ 5% efficacy)

Residual chlorine helps to maintain the disinfection.

Results of Microbiological Testing: Sources

Thiele & Bray 2001 - 2002

E. coli

1 02 03 04 15 16 97 108 109 10

10 1211 1312 4013 7014 11015 36016 TNTC

Stored Rainwater RiversSample E. coli

1 2002 300

3 64004 6600

5 21006 3500

River 1, 2001

River 1, 2002

River 2, 2002

How Bad Can Bad Water Be?

High Risk>50D

Intermediate Risk11-50C

Little Risk1-10B

No Risk0A

HEALTH RISK

Fecal Coliforms/100mL

CATEGORY

Courtesy of WHO

How Many Colonies are Dangerous?

“Under conditions of widespread fecal contamination, … surveillance agencies are recommended to set intermediate goals that … will not lead to improper

condemnation of relatively acceptable supplies.” -- WHO 2000

E. coli 0 cfu/100 mLWHO Guidelines:

Results of Microbiological Testing:Are the Filters Reducing the Risk?

Thiele & Bray 2001-2002

Bacterial content of crude river water

Bacterial content of river water after filtration

60 filters were tested

Total of 75 tests -- 12 filters were revisited

Risk cfu/100mL # of Filters PercentageNo risk 0 43 58%

Little 1-10 21 28%

Intermediate 11-50 7 9%

High > 50 4 5%

Are the Filters Reducing the Risk?

58%28%

9%

5%

0 cfu/100 mL

No risk1-10 cfu/100mL

Little risk

11-50 cfu/100mL

Intermediate Risk >50 cfu/100mL

High Risk

Thiele & Bray, 2001-2002

Conclusions

The “water problem” is complex, but the appropriate interventions can make a difference

The vast majority or filters (~90%) are producing water that presents little or no risk to the consumer

The reduction of water related diseases requires an improved water supply and an effective hygiene promotion program

Future Work

Distribution of filter systems in cooperation with interested organizations

Further development of the sanitation and hygiene education promotion

Continued assessment of filter performance

Continued student involvement in all aspects of the project

Acknowledgements

Rollins College Associated Colleges of the South (ACS) Operation Blessing International Eagle Springs Filtration Port Orange Ministerial Association Institute of Latin American Concern (ILAC) West Jacksonville Rotary Unidad Ecológica del Ejército Nacional de la República

Dominicana