the sodiswater project - solar disinfection (sodis) of drinking water

The SODISWATER PROJECTThe SODISWATER PROJECT- Solar Disinfection (SODIS) - Solar Disinfection (SODIS)

of Drinking Waterof Drinking WaterDr Kevin McGuiganDr Kevin McGuigan

Dept. of Physiology & Medical Dept. of Physiology & Medical Physics Royal College of Surgeons Physics Royal College of Surgeons

in Irelandin IrelandDublin 2, IRELANDDublin 2, IRELAND

Email: [email protected]: [email protected]

SODISWATER Project, RCSISODISWATER Project, RCSI 22

More than 1 billion people have no access to safe drinking water.More than 1 million children die from waterborne disease annually

Salgaa, Nakuru, Kenya

SODIS Process - Fetch the SODIS Process - Fetch the waterwater


Wash an Wash an ordinary ordinary plastic Bottle plastic Bottle (supervised (supervised by husband)by husband)


Fill the BottleFill the Bottle(supervised (supervised by cat and by cat and dog)dog)


Expose the water in the bottle Expose the water in the bottle for 6 hours - (supervised by for 6 hours - (supervised by foreman)foreman)


After 6 hrs in the sun, drink the After 6 hrs in the sun, drink the waterwater(supervised by the rest of the (supervised by the rest of the village)village)



RCSI group working on Solar RCSI group working on Solar Disinfection since 1992Disinfection since 1992


2004 2004 Indian Indian Ocean Ocean TsunamTsunamii

Despite >10 years research & > 30 papers, it Despite >10 years research & > 30 papers, it became obvious that Aid Agencies were reluctant became obvious that Aid Agencies were reluctant to promote SODIS as a method of water treatment to promote SODIS as a method of water treatment in aftermath of humanitarian disasters.in aftermath of humanitarian disasters.


1.1. RCSI (RCSI (IRELANDIRELAND) ) 2.2. UUJ (UUJ (UKUK) ) 3.3. CSIR (CSIR (S AFRICAS AFRICA) ) 4.4. EAWAG (EAWAG (SWITZERLANDSWITZERLAND) ) 5.5. IWSD (IWSD (ZIMBABWEZIMBABWE))6.6. PSA CIEMAT (PSA CIEMAT (SPAINSPAIN) ) 7.7. UL (UL (UKUK))8.8. ICROSS (ICROSS (KENYAKENYA))9.9. USC (USC (SPAINSPAIN))10.10.CIC (CIC (CAMBODIACAMBODIA) )

In 2006 obtained €2.7M funding (€1.9M EU, In 2006 obtained €2.7M funding (€1.9M EU, €0.3M Irish Govt. & €0.5M others) for the 3 €0.3M Irish Govt. & €0.5M others) for the 3 year year SODISWATER ProjectSODISWATER Project to expand to expand knowledge of solar disinfection (SODIS) knowledge of solar disinfection (SODIS) and help promote technology.and help promote technology.


Health Impact Assessment Health Impact Assessment study modelstudy model

• Children under age of 5 Children under age of 5 YearsYears

• 14 month trial14 month trial• Control group maintained Control group maintained

usual practices. usual practices. • All test group families given All test group families given

two 2-L bottles per childtwo 2-L bottles per child• Test group placed bottles in Test group placed bottles in

sun for 6hsun for 6h• Drink today what was Drink today what was

treated yesterdaytreated yesterday

Diarrhoeal disease rates Diarrhoeal disease rates recorded using “Smiley-Face recorded using “Smiley-Face Diary”Diary”



Health Impact Assessment - A Tale of Four Studies:

“it was the best of studies, it was the worst of studies”

Zimbabwe Zimbabwe StudyStudy


Total = 839 children Control group = 547Test group = 292

Results Results No Significant Effect ObservedNo Significant Effect Observed• Political tension. Political tension. • Pre- & post-election (3-4 Pre- & post-election (3-4

months) suspension of all months) suspension of all foreign funded projects.foreign funded projects.

• Economic hyper-inflation.Economic hyper-inflation.• Cholera epidemic.Cholera epidemic.• Fear of interference with bottle Fear of interference with bottle

by neighbours.by neighbours.


South Africa South Africa StudyStudy


A total of 649 households were recruited with 386 children in the control group and 438 in the test group.

Of the total of 824 children 402 were male and 421 female

Typical S. African brick Typical S. African brick houseshouses


S. Africa ResultsS. Africa Results• Incidence rates were lower in those Incidence rates were lower in those

drinking solar disinfected water (incidence drinking solar disinfected water (incidence rate ratio* 0.64, 95% CI 0.39-1.0, rate ratio* 0.64, 95% CI 0.39-1.0, P P ) ) 0.071) 0.071) but not statistically significantbut not statistically significant

• Solar disinfection was not significantly Solar disinfection was not significantly associated with non-dysentery diarrhea associated with non-dysentery diarrhea risk overall (risk overall (P P = 0.419). = 0.419).


* IRR = Incident rate in test group / Incident rate in control group

S. Africa Results – cont’dS. Africa Results – cont’d• Incidence of dysentery was Incidence of dysentery was significantly significantly

associated with higher motivationassociated with higher motivation, defined , defined as 75% or better completion of diarrhea data.as 75% or better completion of diarrhea data.

• Compared with the control, participants with Compared with the control, participants with higher motivation achieved a higher motivation achieved a significant significant reduction in dysentery (incidence rate reduction in dysentery (incidence rate ratio (IRR = 0.36, ratio (IRR = 0.36, 95% CI 0.16-0.81, 95% CI 0.16-0.81, P P = = 0.014). However, there was no significant 0.014). However, there was no significant reduction in risk at lower levels of motivation.reduction in risk at lower levels of motivation.


S. Africa Results – cont’dS. Africa Results – cont’d• A statistically significant reduction in A statistically significant reduction in

dysentery was achieved only in dysentery was achieved only in households with higher motivation, households with higher motivation, showing that motivation is a significant showing that motivation is a significant determinant for measurable health determinant for measurable health gains.gains.

• SODIS works but only if you use it!SODIS works but only if you use it!


Other problems•Overall compliance rate was poor

(~35%). Many S. African users feared SODIS use would release local govt. from responsibility to provide clean water (S.A.) so they stopped using it!

doi: 10.1021/es103328j.

Kenya StudyKenya Study


Bondena Urban Slums in Bondena Urban Slums in NakuruNakuru



Rural Maasailand, KenyaRural Maasailand, Kenya


Test Group = 555 children in 404 households using SODIS.

Control Group = 534 children in 361 households with no intervention.

Post-election violence, disruption, interruption.

Kenya Kenya ResultsResults


Dysentery and non-dysentery diarrhea were significantly (P<0.001) reduced by use of solar disinfection:

1.dysentery days IRR = 0.56 (95% CI 0.40 to 0.79);

2.dysentery episodes IRR = 0.55 (95% CI 0.42 to 0.73);

3.non-dysentery days IRR = 0.70 (95% CI 0.59 to 0.84);

4.non-dysentery episodes IRR = 0.73 (95% CI 0.63 to 0.84).

Anthropometry – height & Anthropometry – height & weightweight


Effect of SODIS on child Effect of SODIS on child development?development?


•Median height-for-age was significantly increased in those on SODIS, corresponding to an average of 1.3 cm taller over a 1-year period over the group as a whole (95% CI 0.54 to 2.2 cm, P=0.001).

•Median weight-for-age was similarly higher in those on SODIS, corresponding to a 0.4 kg heavier difference in weight after a year on SODIS (95% CI 0.16 to 0.64 kg, P<0.001).

CommentComment


• Anthropometric benefit only observed in Kenyan study. Probably because only area where we saw significant malnutrition.

• This is the first trial to show evidence of the effects of SODIS on childhood anthropometry & should alleviate concerns that the lower disease rates associated with household water treatment are the product of biased reporting rather than genuinely decreased incidence.

Cambodia – Prey Veng & Svay Reng provinces


Cambodia - results• Children drinking SODIS water

were at lower risk of dysentery (IRR = 0.40, 95% CI 0.18 to 0.92, P=0.032). Incidence was low, hence wide C.I.

• Children drinking SODIS water were at lower risk of non- dysentery diarrhoea (IRR = 0.40, 95% CI 0.31 to 0.50, P < 0.001).


General SODISWATER Conclusions:

• SODIS significantly reduces incidence of dysentery (0.36<IRR<0.56) in most study communities (S Africa, Kenya, Cambodia).

• SODIS associated with height & weight benefit in child development for Kenyan children.

• No genotoxic risk observed for standard SODIS method over 6 months (Recommend replace bottles every 6 months).


33 countries where SODIS is currently 33 countries where SODIS is currently in daily use by > 4.5 million peoplein daily use by > 4.5 million people


AcknowledgementsAcknowledgements• Health Research Board Health Research Board

(NS/2003/007)(NS/2003/007)

• Irish Aid and Health Research Irish Aid and Health Research Board Board (GHRA/06/01)(GHRA/06/01)

• European Science Foundation European Science Foundation COST Action P9COST Action P9

• European Commission European Commission (FP6-INCO-CT-2006-031650 - (FP6-INCO-CT-2006-031650 - SODISWATER)SODISWATER)

the sodiswater project - solar disinfection (sodis) of drinking water

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