Health benefits of point-of-use water treatment systems Bettina
Genthe 2 October 2012
Slide 2
Links of poor water and sanitation services to poverty In
addition to direct health effects, the United Nations Millennium
Declaration confirmed the central role of water and sanitation in
sustainable development and the major contribution expanded access
to safe drinking water and adequate sanitation can make to poverty
alleviation (WHO, 2004). The poor bear the brunt of inadequate
water services more than those with money in financial terms too.
They pay high prices where water is sold, yet often have unreliable
supplies, and so do not get value for money as do the rich. The
poor are also less able to adopt strategies to lower risk where
water supply is unreliable, such as investing in storage or
treatment technologies
Slide 3
The World Health Organization (WHO) concluded that there was
now conclusive evidence that simple, acceptable, low-cost
interventions at the household and community level are capable of
dramatically improving the microbial quality of household stored
water and reducing the attendant risks of diarrheal disease and
death (WHO, 2007). CSIR 2007 www.csir.co.za
Slide 4
Economic benefits of improvements in drinking water quality
According to the WHO assessment (2004), achieving the water and
sanitation MDG target would bring economic benefits, ranging from
US$3 to US$34 per US$ invested, depending on the region. Additional
improvement of drinking-water quality, such as point-of- use
disinfection, in addition to access to improved water and
sanitation would lead to a benefit ranging from US$5 to US$60 per
US$1 invested. In addition, health and the socio-economic benefits
accrue when improving access to safe water supply and sanitation.
CSIR 2007 www.csir.co.za
Slide 5
Cost of diarrhoea in Olifants catchment Description < RDP
(Low service level) Direct health costs (R3 769) >RDP (High
service level) Direct health costs (R 3 349) Number of people2 223
4271 164 244 Estimated diarrhoea incidences 2 220 151210 636 # of
cases treated(8%) 177 612(5%) 10 532 Average Treatment costsR 3
769R 3 349 Total Direct Health costsR 669 419 899R 35 270 978 Total
number of people 3 387 671 Total direct cost R704 690 877 (R208 per
person) The Economic Burden of Diarrhoeal Disease in the Olifants
WMA, SA. Steyn M, Maherry A and Genthe, B 2011
Slide 6
Economic burden of diarrhoea CSIR 2010Slide # Image Pollution
Prevention is cheaper than Treatment Providing people with >RDP
level water is cheaper than the cost of Diarrhoea
Slide 7
Cause of death South Africa is one of a few countries globally
where the under five mortality rate has increased rather than
decreased (60 per 1,000 live births in 1990 to 66 per 1,000 live
births in 2003) (UNICEF, 2005). Diarrhoeal disease is the third
largest cause of death among children under the age of five in
South Africa. Fewtrell et al., (2007) quantified the health impact
in countries with incomplete water and sanitation coverage. They
estimated that services related to water, sanitation and hygiene
(WSH) are responsible for between 70 and 90% of diarrhoea in areas
where coverage is below 98%. CSIR 2007 www.csir.co.za
Slide 8
South Africa Approx 12% of population have no improved water
supply nor sanitation CSIR 2007 www.csir.co.za
Slide 9
Slide 10
Types of point of use systems Solar disinfection (SODIS)
Filters CSIR 2007 www.csir.co.za
Slide 11
Chemical disinfection Biosand filter CSIR 2007
www.csir.co.za
Effectiveness of the various Point-of-Use systems Intervention
Result Log reduction SODIS Viruses 2- 3 log Bacteria 4 log
Parasites 4 log Chlorination Viruses 3-4 Bacteria 3-4 log Parasites
2-3 log Floc filter + disinfect (PuR) &WaterMaker produced in
SA Viruses 5 log Bacteria 8 log Parasites 4 log Ceramic filter
candles Virus 0.5 log Bacteria 4 log Parasites 3 log Ceramic Pot
filters Virus 0.5 log Bacteria 4 - 7 log Parasites 2 - 5 log Sand
Filtration (BioSand) Virus 0.5 log Bacteria 2 log Parasites 1
log
Slide 14
Diarrhoeal disease reduction by technology source Sobsey et al
2008 TechnologyDiarrhoeal reduction SODIS31% (26%-37%) Disinfection
and safe storage37% (25%- 48%) Coagulation /chlorination31% (18%-
42%) Ceramic candle filtration63% (51%-72%) Ceramic pot filters46%
(29%-59%) Biosand filter47% (21%-64%) CSIR 2007 www.csir.co.za
Slide 15
Advantages and disadvantages of point-of-use water quality
interventions Advantages of combined treatment systems
Disadvantages Highly effective against all waterborne pathogens.
Can be applied to high turbidity waters, and waters with high pH
and low temperatures Provides a residual level of free chlorine No
need for highly skilled labour, so only moderate level of training
required, Visually observable improvement in water quality
(turbidity reduction). Expensive (initial cost of US$5-
10/household for vessel + annual operating cost of US$35-
55/household/year). Filter cloth may not be appropriate Low
production capacity10L/day/household Cultural resistance - chlorine
taste of the water. Dependence on supply of materials
Slide 16
Advantages of Ceramic Candle Filters Disadvantages- Highly
effective against most waterborne pathogens Operate consistently
regardless of turbidity No addition of chemicals to the water.
Therefore absence of tastes and odours + Easy to use and maintain,
+ Visual observation of the water quality improvement (turbidity
reduction). + High levels of user acceptability. - Low viral
removal. - No residual protection, -Relatively high cost if
produced in developed countries: - Low production capacity
(20L/day, or 0.5-2L/h, depending on the filter and the turbidity of
water). - Breakage is possible. - Systems require regular cleaning
to restore normal flow rate (each week or two weeks). - Candles
must be changed (life expectancy of 6 months to 2 years). CSIR 2007
www.csir.co.za
Slide 17
Advantages of Ceramic Filter Pots Disadvantages Reduction of
diarrhoea 46% in filter users vs non users (Brown 2006) Improved
water quality for bacteria and protozoan parasite removal
Sustainable and transferable technology Easy to use and maintain
Rate of discontinuation of filter use Low virus removal Performance
not consistent Low filtration rate insufficient drinking water for
an average household. Risk of recontamination of water Advantages
of SODIS Disadvantages Proven reduction of viruses, bacteria, and
protozoa in water; Proven reduction of diarrheal disease incidence
Acceptability to users No cost to the user after obtaining the
plastic bottles; Minimal change in taste of the water; and,
recontamination is unlikely. need for pretreatment of waters of
higher turbidity limited volume of water that can be treated length
of time required to treat water; or not reaching T for disinfection
if cloudy / cold community motivation and training for users on how
to correctly and consistently use SODIS
Slide 18
South African-Zim-Kenyan study ceramic filters CSIR 2007
www.csir.co.za
Slide 19
Southern African study ceramic candle filters filtration
reduced the risk of all types of diarrhoea by approx 80%. The
reduction was most marked for bloody diarrhoea. CSIR 2007
www.csir.co.za
Slide 20
Testing of water at community level At community level, after
initial characterising of the water, chemical tests are not
necessary for community testing as the chemical quality does not
vary significantly over time. Microbiological testing is important
to ensure that contamination of the drinking water has not
occurred. This can be checked easily making use of a field
microbiological test called the H 2 S strip test. Black H 2 S
producing bacteria present No H 2 S producing bacteria CSIR 2007
www.csir.co.za
Conclusion The World Health Organization (WHO) concluded that
there was conclusive evidence that simple, acceptable, low-cost
interventions at the household and community level are capable of
dramatically improving the microbial quality of household stored
water and reducing the risks of diarrheal disease and death (WHO,
2007). CSIR 2007 www.csir.co.za