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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.
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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 Global morbidity and mortality rates of some water-related diseases. Adopted from WHO 1995 - 2000
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
W a t e r Water-washed can also be impacted by quality Q u a l i t y Q u a n t i t y W a t e r - b o r n e W a t e r - w a s h e d W a t e r - b a s e d W a t e r - r e l a t e d I n s e c t D i s e a s e s D i s e a s e s D i s e a s e s V e c t o r D i s e a s e s Why Both Quality and Quantity are Important Diarrhea is the most important public health problem affected by water and sanitation and can be both waterborne and water-washed. -- WHO 2000
Excreta Water Flies Hands Food Mouth Routes of Disease Transmission Courtesy of WHO: Principal elements of fecal-oral disease transmission
Impact of Water Quality Potential reductions in morbidity of different water-related diseases as a result of improvements in water supply and sanitation Adopted from WHO 1995
Our Approach to the Problem An attack on water quality . . . • 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
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 Yasica Summer 2002, West Jacksonville Rotary Club • ~ 240 units • Rincon • La Piña • Islabon
Haitian/Dominican Border Summer 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 TestingVillage of “El Venú”, Dominican Republic, Summer 2001 and 2002 • Sources • 2 local rivers • Rainwater • Filters
Chemical Parameters - Sources • Rivers • Stored Rainwater Ranges Thiele & Bray 2001 - 2002
Chemical Parameters - Filters • 60 filters were tested • Total of 75 tests -- 12 filters were revisited Thiele & Bray, 2001 - 2002
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.
Rivers • Stored Rainwater Thiele & Bray 2001 - 2002 Results of Microbiological Testing: Sources
CATEGORY Fecal Coliforms/100mL HEALTH RISK A 0 No Risk B 1-10 Little Risk C 11-50 Intermediate Risk D >50 High Risk WHO Guidelines: How Bad Can Bad Water Be? How Many Colonies are Dangerous? Courtesy of WHO “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
Bacterial content of crude river water Bacterial content of river water after filtration Results of Microbiological Testing:Are the Filters Reducing the Risk? • 60 filters were tested • Total of 75 tests -- 12 filters were revisited Thiele & Bray 2001-2002
High Risk Intermediate Risk >50 cfu/100mL 11-50 cfu/100mL 5% 9% 28% 58% Little risk No risk 1-10 cfu/100mL 0 cfu/100 mL Are the Filters Reducing the 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