EAWAG / SANDEC No. 4 May 1999 S DIS · Paper signed by members of international and national...

S DIS

NEWS

EAWAG / SANDEC No. 4 May 1999

SODIS Conference Synthesis

SynthesisPaper signedby members ofinternationaland nationalinstitutions 3

Ongoing Projects

DisseminationMaterial inIndonesia, Togoand Bolivia 8

General Aspects

SODIS helps reducingdeforestation 6

EAWAG / SANDEC No. 4 May 1999

2

The statistics in 1994 reveal that approx. 800 millionpeople in rural areas and 300 million residents in urbansettlements had no access to a safe water supply. As therate of new service provision cannot adequately keeppace with the population growth especially in urbanareas, this situation has hardly changed in the last 4years. Hence, the unserved populations have to findtheir own ways and means to cover their daily waterdemands. Consequently, new water supply approachesand treatment processes for use at household level haveto be developed to allow the poor to help themselves.SODIS is such a simple and low-cost water treatmentprocess for unserved populations to treat their drinkingwater.

As reported in SODIS News No. 3, SODIS wasintroduced in demonstration projects at village level in7 different developing countries, and the experiencegained so far is encouraging. However, the introductionof SODIS to a limited number of demonstration villageswill not change the water supply situation for the 1,100million unserved population. Significant changes in thewater supply coverage are only attained with large-scale dissemination programmes. Such programmesrequire, however, financial resources from external aidagencies and executing institutions, which are prefer-ably provided by local NGOs.

A SODIS e-mail conference was initiated bySANDEC to raise the awareness of SODIS among theinternational donor agencies. The conference partici-pants determined the potentials and limitations of thereviewed process and recommended additional studiesand follow-up activities for the promotion of SODIS.The results of this conference are presented in a synthe-sis paper contained in this SODIS News and in anattached file on the homepage http://www.sodis.ch.This e-mail conference certainly enhanced the dissemi-nation of SODIS at international level.

At national level, local lead agencies are preparingSODIS information material and establishing networksfor the implementation of this new water treatmentmethod. Since these activities require financial re-sources, SANDEC is grateful to the Swiss Agency forDevelopment and Cooperation (SDC) for funding thedevelopment and dissemination of SODIS. Within thisframework, cooperation agreements with three locallead agencies located in Indonesia, Togo and Boliviawere signed to support their promotional activities ofSODIS.

In addition to these formal cooperation agreements,SANDEC is supporting numerous SODIS field testingactivities of local organisations presenting this newwater treatment method at workshops and conferences,

http://www.sodis.ch Phone: +41-1-823 50 19http://www.sandec.ch Fax: +41-1-823 53 99

E D I T O R I A L

preparing information material for target groups, andfinally, implementing SODIS in ongoing projects. Thepresent SODIS News describes some of these activities.Since these organisations face numerous and differentproblems, SANDEC is willing to provide its technicalsupport and expertise in the field of SODIS.

To bring about changes in the water supply situa-tion, the input of all water supply stakeholders isnecessary. SANDEC is committed to contribute to thischange by a sustained development and promotion ofSODIS.

Martin WegelinProgramme Officer Water Treatment

Contents

Filling the Information Gap 3Synthesis Paper signed by members of international and national institutions

SODIS helps reducing deforestation 6

“Seeing is Beleiving” 8Ongoing Projects in Indonesia, Togo and Bolivia

Experiences from the field 11Experiences made in Sri Lanka, Ethiopia, Cameroon,Ecuador, South Africa, and Bangladesh

Outlook 18

EAWAG

SANDEC

Water & Sanitation inDeveloping Countries

Swiss Federal Institute forEnvironmental Science &Technology

Ueberlandstr. 1338600 Duebendorf / Switzerland

3

Demonstration projects in various de-veloping countries revealed goodsocio-cultural acceptance of SODIS.However, it may not attract the re-quired interest and lead to an informa-tion problem. For this reason, an inter-national e-mail conference was heldand a conference paper signed.A field study programme carried outwith the help of demonstration projectslocated in seven different developingcountries (Colombia, Bolivia, BurkinaFaso, Togo, Indonesia, Thailand and,China) revealed good socio-cultural ac-ceptance and affordability of SODIS bythe target population. At the beginningof this programme, a total of approxi-mately 550 households participated inthe SODIS demonstration projects.One year later, 1’260 households usedSODIS. The final evaluation revealedthat 84 % of the households will cer-tainly continue to use SODIS after theformal end of the projects. Hence,SODIS is accepted at village level in thedemonstration projects, however, for alarge dissemination of this water treat-ment alternative general awarenessand acceptance has to be achieved atnational and international level (SODISNews No. 3).

Socio-cultural aspects, scientific evi-dence and control possibilities for ad-equate application might hinder large-scale dissemination and efficient use ofSODIS. The water treatment methodmay, therefore, face the following limi-tations:� Although SODIS is a very simple

and not spectacular water treat-ment method, it is often difficult toinform people about the effects ofUV-A radiation, temperature, andturbidity on the inactivation ofharmful microorganisms. Such in-formation is generally beyond the

understanding of most the commu-nities.

� The need to boil the water before itis consumed has been passed on foryears by teachers to school children,and by health workers and medicalpersonnel to the communities. All ofa sudden, boiling is no longer neces-sary. Exposing the water to sunlightand heating it to 50 °C is sufficientto kill the harmful microorganisms.This message is difficult to under-stand not only by the target popula-tion, but also by the community re-sponsible for public health.

� Common plastic bottles normally donot attract public interest. However,water treatment is generally de-clared as an important factor inmaintaining a healthy life. Impor-tant things are usually handled withspecial care and equipment. SODISapplication is not spectacular andmay, therefore, not attract the samespontaneous interest as somethingexcitingly new.

Information Need

Since SODIS is a modest technology, itmay not attract the required interestand lead to an information problem.Most of the promising new approachesare currently being applied on a rela-tively small scale, often by NGOs. Theyare usually not regarded as serious en-gineering options by professional andscientific circles. Therefore, many newapproaches have already been pio-neered, however, they have not yetwidely been applied or comprehen-sively enough to attain a significantbreakthrough leading to more effectiveand sustainable solutions. The SODISdemonstration projects at village levelhave been accepted by the beneficiar-ies, however, acceptance at national

S O D I S C O N F E R E N C E S Y N T H E S I S

Filling the Information GapSODIS conference synthesis paper signed by members international and national institutions

and international level is required toenhance its dissemination in areas suit-able for SODIS application. SODIS vio-lates the general recommendation toboil unsafe water which has beenpropagated by public health officials formany years. These people are oftenunaware of the real thermo-sensitivityof microorganisms and tend to at-tribute too much importance to waterquality. The behavioural changes, ex-pected from the communities, cannotbe sustained if policy makers and ad-ministrators do not support them. Aclear understanding of the potentialand limitations of SODIS is, therefore,required.

SODIS E-mail Conference

SANDEC (Water Supply and Sanitationin Developing Countries), a depart-ment of EAWAG (Swiss Federal Insti-tute of Environmental Science andTechnology) organised an internationale-mail conference in order to createawareness among national and inter-national agencies. Comprehensive in-formation material (a background pa-per, technical notes and a video onSODIS) were sent to the workshop par-ticipants who reviewed and discussedthis alternative water treatment option.The findings and recommendations ofthis conference are summarised in asynthesis paper (see following twopages). This paper is also available inSpanish and can be downloaded fromour homepage: http://www.sodis.ch.

New approaches and strategieshave to be applied for an effective pro-motion of SODIS. The development ofnational SODIS networks and the in-volvement of the private sector in dis-semination activities are such uncon-ventional new possibilities for themarketing of SODIS.

4S O D I S C O N F E R E N C E S Y N T H E S I S

Solar Water Disinfection –a water treatment option forthe year 2000 and beyond

Solar Water Disinfection (SODIS)�is a simple

technology using solar radiation to inactivate and

destroy pathogenic microorganisms present in

the water. The treatment basically consists in

filling plastic bottles with water and exposing

them to full sunlight for about five hours. The

Department of Water and Sanitation in Develop-

ing Countries (SANDEC) at the Swiss Federal

Institute for Environmental Science and Technol-

ogy (EAWAG) in cooperation with numerous

partners in developing countries has developed

and field tested this water treatment option. The

SODIS project has been substantially cofinanced

by the Swiss Agency for Development and

Cooperation (SDC). The participants of the

International E-mail Conference organised by

SANDEC reviewed and discussed SODIS as a

potential water treatment process. To enhance

dissemination and promotion of SODIS, they are

endorsing the following statements:

The participants agree:

� SODIS is a simple water treatment process to

improve the microbiological water quality for

use as drinking water

� SODIS inactivates or destroys most patho-

genic microorganisms present in the water

through solar radiation and thermal treatment

� SODIS requires plastic bottles which are easy

to handle and also convenient for storage

and transportation of water

� SODIS application is simple and, therefore,

ideal for use at household level

� SODIS reduces the risk of recontamination

since the water is treated and stored in the

same closed container until consumption

� SODIS does not require the addition of

chemicals and, hence, does not affect the

taste nor smell of water

� SODIS is a sustainable water treatment

method as it makes use of locally available

resources only

� SODIS is a low-cost technology since its in-

vestment costs are low and its running costs

negligible

� SODIS is a reproducible water treatment ap-

proach requiring low capital investment costs

and short construction periods

� SODIS demonstration projects have been

well-accepted by the target population in

seven developing countries

� SODIS is an environmentally sound technol-

ogy, as it reduces the demand of firewood

and charcoal, thereby, decreasing the rate of

deforestation

� SODIS uses empty plastic bottles and, thus,

enhances the recycling of solid waste.

The participants admit:

� SODIS does not improve the chemical water

quality

� SODIS requires favorable climatic conditions;

i.e., sunlight radiation and ambient tempera-

tures preferably not under 500 W/m2 and

20 °C

� SODIS should be applied to raw water of low

turbidity, preferably with less than 30 NTU

� SODIS offers limited production capacity and,

therefore, is used to treat only water for con-

sumption; i.e., 1-3 liters of water per person

and day

� SODIS is based on the use of adequate plastic

bottles not always readily available to the tar-

get population

� SODIS could cause environmental problems if

the plastic bottles have to be replaced too fre-

quently

� SODIS has been tested for inactivation of bac-

teria and viruses, however, its efficiency in de-

stroying parasites is still unknown

� SODIS improves the microbiological water

quality, however, its impact on the health situ-

ation of the users has not been evaluated so far

� SODIS shifts the burden of treatment away

from centralized systems to individual house-

holds where day-to-day behavior is often hard-

est to change

� SODIS, though a simple technology, requires

adequate training of the users

� SODIS requires the acceptance of the users

which is also influenced by their socio-cultural

background

� SODIS, as an alternative process to water boil-

ing, may not be readily accepted by public

health authorities

� SODIS is not a spectacular water treatment

process and may, therefore, not attract the

necessary public interest required for its wide-

spread dissemination

5

This Synthesis is endorsed by the followingparticipants of the SODIS E-mail Conference:

��, WB / UNDP, Washington, USA

�� , WB / UNDP, Dhaka, Bangladesh

��, WB / UNDP, Dhaka, Bangladesh

��, WB / UNDP, RWSG/AN, La Paz, Bolivia

��, WB / UNDP, RWSG/WA, Abidjan, Ivory Coast

�� , WHO, Geneva, Switzerland

�� !��, WHO, Dhaka, Bangladesh

��"��#��, UNICEF, New York, USA

��#��, UNICEF, New Delhi, India

��$��, DFID, London, England

��, IRC, The Hague, The Netherlands

�� , SDC, Berne, Switzerland

��%��&��, SDC, Dhaka, Bangladesh

��'�� , Mvula Trust, Braamfontein, South Africa

��(, ENDA Ethiopia, Addis Ababa, Ethiopia

��, Universidad del Valle, Cali, Colombia

��)�*��, Programa de Aguas, Cochabamba, Bolivia

��, Yayasan Dian Desa, Yogyakarta, Indonesia

Martin Wegelin, Programm Officer Water Treatment,

EAWAG / SANDEC, Duebendorf, Switzerland, March 1999

S O D I S C O N F E R E N C E S Y N T H E S I S

� SODIS has an excellent potential as a simple,

inexpensive alternative for improving water

quality. Nevertheless, additional research is still

required before a wide dissemination and pro-

motion of the technology can be undertaken.

The participantstherefore recommend:

1. Additional studies should beconducted in order to:

� ��

�� in each country / re-

gion where SODIS will be implemented.

These studies should investigate physical

property changes of the plastic material

(photoproducts) and their possible health

risk to the consumer.

Note: Comprehensive laboratory tests carried

out by Swiss research institutions reveal

that the photoproducts are formed on

the outer surface of the plastic bottles

and no substances hazardous to health

are leached into the water. These re-

search results will be published in an in-

ternational journal. However,

careful selection of the plastic

bottles for SODIS use (PET and

not PVC bottles), and determi-

nation of their durability by

simple field tests have to be

conducted at national level.

� ��

�� (e.g. Giardia and

Cryptosporidium) by SODIS.

Note: The Swiss Tropical Institute

(STI) has, in cooperation with

SANDEC, initiated laboratory

tests to study the inactivation

of Giardia and Cryptospori-

dium by SODIS. Additional re-

search focusing on these or

other organisms is welcome.

� ��

�� by epidemiological

studies.

Note: STI and SANDEC are planning

to conduct health impact

studies on ongoing SODIS de-

monstration projects in coop-

eration with local institutions.

2. Demonstration projects have to beinitiated in order to:

� ��

�� under different socio-

cultural, economic and environmental settings.

Note: Local institutions should field-test SODIS

on a pilot scale to assess the acceptance

by the target population, and to develop

approaches and material adequate for

local dissemination of the water treat-

ment method. External support agencies

should support such pilot scale studies.

� ��in the rural and urban wa-

ter sector.

Note: In general, SODIS should be viewed as a

complement to, rather than a systematic

substitute for centralized water treat-

ment. Possible applications of SODIS in-

clude the following situations:

� where central treatment is inherently

not viable (e.g. in rural areas and in

very small towns where people are

supplied by contaminated point sour-

ces or continue to use polluted surface

water for human consumption),

� where central treatment exists but has

become dysfunctional and cannot be re-

habilitated quickly (e.g. countries suffer-

ing from severe economic crises/ civil

war/ political unrest),

� where central treatment does not yet ex-

ist.

� ��

�� amongst the different actors in the

water supply sector.

Note: Practical application of SODIS is impor-

tant to acquire competence and to iden-

tify the advantages and constraints of

this water treatment method. Local insti-

tutions are invited to take up this chal-

lenge, and funding agencies to support

local initiatives.

3. SODIS requires widespreadpromotion and marketing in orderto:

� !��

��at national and international level.

Note: SODIS is not yet well-known and under-

stood by policy makers. Once efficiency,

acceptance and sustainability of SODIS

has been proven in pilot projects, large-

scale dissemination programs will have

to be initiated to attract the necessary

public attention for this technology.

� "��

�� #

�� by development agencies and lo-

cal governments.

Note: SODIS has to be discussed and as-

sessed by international leading agencies

(e.g. WB/UNDP, WHO, UNICEF, etc.). After

thorough review of this technology, rec-

ommendations on SODIS should be for-

mulated. These recommendations will

enhance its acceptance by local govern-

ments and guide them in the application

of SODIS.

6

d � f� r5

percentage of1980 forest area

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Comparison of 1980 and 1995 forest areas (in % of 1980 forest areas)

Annual forest area loss: Three times SwitzerlandThe extent of the world’s forest decreased by some 180million ha between 1980 and 1995, an area, which isabout the size of Indonesia or Mexico. This represents anannual loss of 12 million ha, about three times the size ofSwitzerland. During the 15-year period, the developingworld lost nearly 200 million ha of natural forest, mostlythrough clearing for agriculture. This was only partiallycompensated for by new forest plantations.

Developed countries: Increase of forest cover

Over the same period, forests in the developed world ex-panded slowly (by some 20 million ha) through afforesta-tion and reforestation, including natural regrowth on landabandoned by agriculture. This increase more than com-pensated for the loss of forests in developed countries duemainly to urbanization and infrastrucutre development.

G E N E R A L A S P E C T S

SODIS helps redu-cing deforestation

The two major direct causes of forest loss in Asia and thePacific are clearing for agriculture (including shifting culti-vation) and excessive cutting of timber. Other importantcauses of forest destruction include fuelwood harvesting;mining, irrigation and hydroelectric projects; and urbanexpansion.

Forest degradation is also a serious problem in the re-gion. Commercial harvesting has been more widespreadand intensive in tropical Asia and the Pacific, than in anyother tropical region. High population densities have alsoled to widespread forest degradation from fuelwood andfodder harvesting, cattle grazing, shifting cultivation, andtimber harvesting for local construction.

Situation in Africa

Forests cover an area of 520 million ha, or about one-thirdof the land area of Africa. They consist of dry tropical for-est located in the Sahel and in eastern and southern Af-rica; humid tropical forests in West and Central Africa,and various subtropical forests and woodland formationsin North Africa and in the southern tip of the continent.Land-use changes, particularly over the last 20-30 years,have been largely responsible for the extent and conditionof the forests today.

The dry tropical forests, including woodlands, savan-nah and steppe formations, are located in areas domi-nated by subsistence agriculture and rangelands whichsupport large numbers of livestock. Pressure on these for-

Situation in Asia and the Pacific

Forest cover in the temperate areas of the Asia-Pacific re-gion has essentially remained constant In contrast, the re-gion’s tropical forests have declined substantially. In thetropical counttries of Asia, deforestation amounted to 3.9million ha per year between 1980 and 1990. This repre-sented the highest annual rate of deforestation (1.2 per-cent) among the tropical regions of the world. The esti-mated rate for 1990-95 is somewhat lower (1.1 percent).

7

es ta� i��0 500 1000 1500 2000 2500 3000 3500

totalroundwood

fuelwood andcharcoal

industrialroundwood developing countries

developed countriesworld

Comparison of wood consumption in developed and developing countries

1980 1990 1994 Rate [%]

Africa 330.5 443.8 502.2 3.03

Asia 675.1 816 878.2 1.90

South America 195.5 234.4 258 2.00

North/Central America 139 145.9 160.9 1.05

Europe 52.1 52.3 51.8 -0.04

Oceania 7.1 8.8 8.7 1.53

former USSR 78.9 81.1 30.6 -6.55

world 1478.1 1782.3 1890.4 1.77

Fuelwood and charcoal consumption [million m3] and annual growth rate

G E N E R A L A S P E C T S

ests due to agricultural expansion, and increasedfuelwood collection and livestock grazing is heavy inmany places. Drought and fire are major causes of degra-dation. The annual rate of deforestation in the region wasestimated at 0.7 percent, with the highest rate (1.0 per-cent) in west moist Africa, and the lowest (0.2 percent) innon-tropical southern Africa. Afforestation efforts are un-able to keep ahead the loss of natural forests.

Planting efforts in the dry areas of the region havebeen focused on meeting wood energy needs and con-trolling desertification. Dryland forest resources in the twoSahelian sub-regions continue to be exploited extensivelyto meet the energy needs of growing populatins. In spiteof the tremendous efforts in the 1970s and 1980s bycountries to increase fuelwood production and reduceconsumption, the results were not as successful as hadbeen hoped.

Situation in Latin America and the Caribbean

Almost all (95 percent) of the natural forests in the regionare tropical (852 million ha), located in Central America,the Caribbean and tropical South America. The remainingresources, covering some 43 million ha, are found in tem-perate South America, mainly in Argentina, Chile andUruguay.

The natural forest cover continues to decrease in allcountries due to: clearance for agriculture andstockfarming; construction of roads, dams and other in-frastructure; and mining. A total of 5.3 million ha of forestwas lost per year over the period 1990 to 1995. T highestaverage annual deofrestaion rate occured in CentralAmerica (2.2 percent) followed by the Caribbean (1.7percent). Deforestation was lowest in the temperate

countries of the region. Causes of forestdegradation include fire, pest infestationand extraction of timber and fuelwood.Forest fires are a major cause of forestdegradation, especially in the arid andsemi arid zone. They usually arise in as-sociation with the clearing of land foragriculture.

Fuelwood: On big demand

In developing countries, minor attentionis paid to forest condition, because re-duction in forest area is the most strikingaspect of forest change. Although theextent and degree of overharvesting offuelwood and overgrazing are difficult

to quantify, they are recognized as major causes of forestdegradation in some developing countires, particularly inarid and semi-arid zones. Especially in Africa, fuelwood ison big demand and represents more than 85% of the to-tal wood consumption in comparison to only 15% in de-veloped countries. In total, slightly more than half of thewood volume in the world is used as fuelwood.

What can SODIS do?

In some regions of the developing countries, up to 50% ofthe fuelwood consumption is used for disinfecting waterby boiling it. SODIS is an alternative method to boilingand eliminates almost all bacterias and viruses in drinkingwater, without depending on fuelwood or any other non-renewable resource. The method is designed for those ar-eas where fuelwood is a scarce commodity and whereeconomic growth has not yet introduced high-tech waterpurification systems. A widespread use of SODIS couldtherefore provide bottable water even for the poorestpeople in the world without aggravating the deforestationproblem.

Reference:The State of the World's Forests 1997 (SOFO 1997)http://www.fao.org/WAICENT/FAOINFO/FORESTRY/SOFOTOC.htm

8

Bel

ievi

ng”

SANDEC in cooperation with SDC(Swiss Agency for Cooperation and De-velopment) is supporting the develop-ment of national SODIS networks in In-donesia, Togo and Bolivia. SANDEC’scooperation partners in these countriesare acting as leading agencies and arepreparing SODIS information material,initiating new projects and establishingnetworks to enhance information ex-change. Independently, demonstrationprojects are in preparation or inprogress also in other countries such asBangladesh, Sri Lanka, Ethiopia, SouthAfrica, Cameroon and, Ecuador in or-der to study efficiency and socio-cul-tural acceptance of the process. Thefollowing two chapters summarise theprogress made in the preparation of theSODIS networks of Indonesia, Togoand Bolivia and report the experienceson SODIS received from various coun-tries.

Yayasan Dian Desa:Dissemination andpromotion in IndonesiaSANDEC’s local partner in Indonesia,Yayasan Dian Desa (YDD) is acting asleading agency in the SODIS dissemi-nation project of this country. The pro-gramme has the following objectives:1. To develop a strong and active net-

work on SODIS promotion and dis-semination in Indonesia.

2. To strengthen the capability of par-ticipant organizations of the SODISnetwork in order to enable them toeffectively disseminate the SODIStechnology to the target communi-ties. The strengthening process willinclude technical and social market-ing aspects.

3. To promote the importance to useSODIS technology as an alternativedrinking water treatment and therole of SODIS as an integral partcomponent of sustainable, social,

”Seeing is

economic, and environmental de-velopment. This will be done amongothers through the integration ofSODIS into existing water activitiesin Indonesia.

4. To assist the participant organiza-tions in obtaining support from vari-ous sources for dissemination actionin their respective locations.Since early ‘99, YDD has carried out

the following activities:The first few months were dedi-

cated to the development of supportmaterials for the dissemination ofSODIS such as leaflets, posters,manual, and comic book.

In addition, however, besides di-rectly doing some social marketing ofSODIS to different institutions, promo-tion of SODIS was also carried outthrough exhibition, workshops, meet-ings. etc.

Special efforts were made to de-velop the national SODIS Network withthe following activities:

O N G O I N G P R O J E C T S

9

Woman in Togo capturing water, naturally filtered by thesandbed. This method efficiently reduced turbidity, but doesonly partly eliminate the pathogens.

g

Irian Jaya Province

Contact was made with YPMD, a lead-ing NGO working in the Irian JayaProvince. Although there has been nodefinite plan yet, YPMD has stated in-terest to disseminate SODIS in theirarea. They really think that SODIS willprovide a very useful alternative to thepeople of Irian Jaya where the majoritystill live under very primitive and poorconditions. They have been providedwith the workshop proceedings andSODIS leaflet.

Bandung Area

A contact was made to the Departmentof Health of West Java, Boromeus Hos-pital, and Doctors’ Association of WestJava regarding SODIS. There has beena good response from those institu-tions. In April 1999, a workshop washeld in order to introduce the idea ofSODIS to field staff of NGOs imple-menting water supply project and toofficials of governmental institutions.The one day workshop ended up withthe enthusiasm of the participants totry and disseminate SODIS in theirprojects. The government health localdepartment also gave a good supportto the adoption of SODIS. In addition,most of the participants also recom-mended that a further study related tothe decrease of diarrhoea incidence bythe SODIS intervention should be con-ducted. The St. Borromeus Hospital incooperation with the local health au-thorities and the Swiss Tropical Instituteare therefore planning to carry out sucha health impact study next year onceSODIS has been introduced toBandung area.

East Timor Province

The meeting and discussion resulted inthe agreement that a disseminationproject should be held in East Timorprovince. It is also planned that prior tothe project implementation, a one-dayworkshop will be held in Dili, the capitalof East Timor.

A further step was the writing of aproposal. The proposal was submittedto UNICEF-East Timor. Although basi-cally there has been a positive responsefrom UNICEF-East Timor, no agree-ment has been signed.

It should be noted, however, thatwe are all not sure what is going tohappen with East Timor politically, andthis means it will also affect our plan-ning program there.East NusaTenggara

Since September 1998, there hasbeen a good progress in the network-ing activities conducted in East NusaTenggara.

In October 1998, Yayasan DianDesa participated in an exhibition con-ducted by the local government. It wasreferred to as a Development Exhibi-tion. The small booth of Yayasan DianDesa exposing SODIS was quite of in-terest to many. The best thing was theinterest of the Governor himself andright away he supported that SODIS bedisseminated in EastNusa Tenggara Province.Yayasan Dian Desa whohad submitted a pro-posal to UNICEF of EastNusa Tenggara forSODIS disseminationproject through schoolsin NTT comprising fourdistricts, later addedthree more districts, andUNICEF was also willingto support the three ad-ditional districts. Theagreement was alreadysigned and preparationwas started. The dis-semination in each dis-trict is planned to bestarted with a one-daytraining workshop onSODIS for the teachersand health officers of therespective districts aspart of the disseminationand networking forma-tion in the localities.


CREPA: Preparing SODISdissemination in TogoCREPA-Togo has carried out a feasibil-ity study in order to assess the potentialand constraints for a SODIS dissemina-tion project in Togo. In a intermediatephase it is planned to field tests SODISin selected 20 villages located in the 5Regions of Togo. Socio-cultural accept-ance of SODIS by the different ethnicgroups, willingness to pay for the watertreatment method and a SODIS plasticbottle supply scheme will be studiedamong other aspects during this inter-mediate phase.

Survey in 500 households carried out

A survey covering a total of 500 house-holds (25 households per village) wascarried out by specially trained inter-viewers to assess the water treatmentneed and the interest in SODIS of thetarget population. Presently, approx.45 % of the population are supplied by

1 0

untreated surface water and hence, theneed for water treatment seems to beapparent. However, water treatmentmight be avoided in certain areas bythe development of alternative watersources such as shallow wells anddrilled boreholes. Nevertheless, the in-terviewed population is interested inwater quality improvement since thepeople already apply ingenious watertreatment methods (see photo above).

Plastic bottles in Togo arenot very easy to find

Unfortunately, plastic bottles of ad-equate quality are not easily availablein Togo. They are imported as Coca-Cola and Fanta soft drink bottles fromNigeria. CREPA-Togo is now assessingdifferent options (e.g. importation ofempty bottles from neighbouring coun-tries, modification of mineral bottlesproduced locally, start of a local PETbottle production) in order to achieve asufficient procurement of SODIS bottles.

Based on the results of the feasibilitystudy, CREPA-Togo intends to elabo-rate a detailed project proposal to besubmitted to potential external supportagencies. Contacts with UNICEF are al-ready established. SODIS disseminationprojects should be initiated towards theend of ‘99 provided the SODIS bottlesupply and the financement of theprojects are secured. Once the SODISprojects have taken off, it is planned tocarry out a SODIS efficacy study in co-

operation with the Swiss Tropical Insti-tute in order to assess the health impactof SODIS on the respective users.

Programa de Aguas:SODIS InformationMaterial for Bolivia

SODIS dissemination is also an infor-mation problem in Bolivia. Therefore,Programa de Aguas (PdA) inCochabamba as SANDEC’s local part-ner has developed different informa-tion material to address various groupsof people. Informative leaflets referringto basic health aspects and introducingSODIS are produced for the executivesof the communities, training docu-ments prepared for field staff, folders(see also Fig. X) presenting the SODISprocess printed for the users of thetreatment method and a poster as wellas a video will be used to address thelarge public.

All this information material onSODIS will be introduced by workshopsto be held in the 9 Departments of Bo-livia. Field staff from implementingagencies from governmental and non-governmental institutions are invited toattend these workshops. Furthermore,PdA as leading agency of the SODISproject in Bolivia is supposed to preparea detailed project proposal for a large-scale dissemination of the water treat-ment method in this country.


1 1

DateAir temp.

variation °CBottle temp. at the

end of the dayBottle No. Initial T.C. Initial F.C. Final T.C. Final F.C.

21 Dec 28.1 - 31.1 °C 44 °C 1G 1600 800 8 0

2G 560 80 0 0

3G 320 64 0 0

1P 900 12 14 0

2P 240 0 20 0

3P 160 12 12 8

22 Dec 29.2 - 30.8 °C 49 °C 1G 8 0 4 0

2G 0 0 0 0

3G 0 0 0 0

1P 14 0 0 0

2P 20 0 10 0

3P 12 8 0 0

23 Dec 31.1 - 33.1 °C 52 °C 4G 100 0 20 0

5G 320 32 0 0

6G 640 240 0 0

4P 120 4 32 0

5P 140 0 0 0

6P 900 40 0 0

Fig. 1: Coliform counts of samples, tested at the laboratory of National WaterSupply & Drainage Board, Sri Lanka. (TC: Total coliforms F.C.: Faecal coliforms)

Experience from Sri Lanka

J. P. Padmasiri, Chemist, NWSDB, Peradeniya, Sri Lanka

In early 80 ‘s, I was roaming through the rural communi-ties in Sri Lanka as a young, less experienced developmentworker to assist the rural folks to solve their water & sani-tation problem which was among of their major burningissues. Spring fed gravity systems and the shallow wellswere the only technical options which was offered to thevillagers from the project as we believed those are the lastlong technologies (expression of ”sustainability” wasn’texisting at that time!). All the structures of the gravitywater schemes were constructed by the stone masonryand the shallow wells were constructed by using concreterings.

As a custom or rather a practice we were used to con-struct the reservoirs buried in the soil and only the en-trance to the tanks were exposed. Similarly all most all theshallow wells were either covered on top and ahandpump was fixed or else there was a opening on thecover slab so that people can draw water by using abucket and rope. We were always insisted on coveredstructures and the maximum precautions were takenagainst contamination as the project was very much con-cerned on the quality of the drinking water. But very of-ten, in most of the projects there was always someone, avillager who would approach me politely and say they donot like the coveredstructures as they hadserious doubts aboutthe quality of the waterin covered structuressince stored water is notexposed to the sunlight.As a person who hailsfrom a rural village, Iknew that in rural com-munities of Sri Lanka,they feel comfortable(or traditionally believe)to fetch water from theopen wells which are lo-cated in sunlit places.No one of them had ascientifically provedtheory but surprisinglywas it their ”basic in-stinct” which convincedthem that the sunlightcan kill pathogens? Orwas it a something

complete different reason, I do not know yet.However, I used to convince them explaining the rate

of probability of contamination and the algael growth inun-covered structures, in addition to the better tastewhich derives from the coolness of the water in covered(against the sunlight) reservoirs. They trusted me sincethey thought (most likely) ”this guy is an expert in his joband he knows better than us”, the usual acceptance orthe humble respect from a Sri Lankan villager. Did I know(or even do I) better than them or have I misled them incertain elements? The question was well answered inearly 90’s when I heard about SODIS for the very firsttime and met Martin Wegelin of SANDEC in a latter year.

In Sri Lanka, there are many rural and even peri-urbancommunities who do not have access to safe drinkingwater due to many number of reasons which are com-monly known in many developing countries. There aresubstantial investments and serious attempts by variousagencies in order to find solutions to this burning problembut the sustainability in water supply & sanitation is yet adistant goal. Insufficient funds for operation and mainte-nance and the weak & intermittent management struc-tures at community level will not be simple issues whichcan be dealt with overnight. Whilst working towards thislong term achievements, it’s also worthwhile to look foralternative strategies which can positively contribute to-wards the same objective. In Sri Lankan context SODISwill be such an alternative which is effective, practical and

simple enough to beapplied by individualsor households. How-ever, SODIS technol-ogy itself will not be”the solution” but itcould be ”a solution”to improve the qualityof drinking water. Foran instance, in an anygiven community in SriLanka, raw water(stream or irrigation)could be treated by anefficient, effectiveroughing filter at com-munity level and laterSODIS could be appliedat household levelwhich will definitelyminimize the burdenon issues like O&M andthe community man-agement compared

E X P E R I E N C E S F R O M T H E F I E L D

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with other treatment technologies.COSI Foundation, which is an active organisation in

the water and sanitation sector has already identified theneed and the necessity of dissemination of SODIS tech-nology in Sri Lanka. In near future, COSI expects to tryout SODIS in selected 80 communities with the help ofCBOs/NGOs as research partners who are working invarious geographical areas where SODIS will have ahigher degree of demand. During the one year researchperiod, it is expected to study the socio-cultural, technical,economical, environmental aspects related to SODISwhich may facilitate the dissemination of SODIS laterthroughout the island. Recently, as a trial, SODIS hastechnically tested at the laboratory of National WaterSupply & Drainage Board at Peradeniya which gave suc-cessful results (see Fig. 1).

SODIS Test: Down to zero

A set of glass bottles and a set of plastic bottles with acapacity of 750 ml were taken for the trials. One half ofeach bottle was painted in black to preserve the heat fall-ing on to the bottle. The bottles were filled with rain waterand kept in sunlight for six hours with the clear side facingthe sun. At the end of the each day all the samples weresubjected to micro biological examination. Rain water wasselected for these trials because its micro biological qualityis somewhat similar to that of ordinary shallow wells. Thefirst set of samples disinfected by sunlight on 21st Decem-ber 98 were further subjected to solar disinfection on thenext day.

The results clearly showed that faecal coliform countscould be brought down to zero level in both glass andplastic bottles, thus indicating SODIS as a sucessfulmethod to do the disinfection of water in many communi-ties in Sri Lanka. To which extent the Sri lankan communi-ties are going accept SODIS is yet to be researched.

Experience in Ethiopia

Desalegn Eyobe, Desalegn News Agency, Addis Ababa.

Half the world cooks daily meals over fires. For one out ofevery three people in the world wood is becoming scarceand cooking is difficult. In recent years wood shortages inmany developing countries have added hardships to al-ready burdened families, particularly in Eastern andSouthern Africa. The annual wood consumption for cook-ing in most parts of the world is about 3 tons per family ofsix people.

The World Health Organization says 40,000 childrendie from water borne-diseases each day. About 80% ofthe hospital cases in Ethiopia are related to water borneand/or water related diseases. Families are less able toheat/pasteurize their water and milk to reduce waterborne diseases, the major killers of children.

Ethiopia is a country with a per capital income beingone of the lowest in the world. For too many, fuel is tooscarce to even heat water to kill germs. Two of the world’spressing problems- growing scarcities of cooking fuels andthe sourage of water-borne diseases can be helped withsolar water treatment. Solar energy easily pasteurize wa-ter. Ethiopia is a thirteen months of sunshine country. Themain ingredient of solar water treatment is sunshine,which is free.

FORUM FOR ENVIRONMENT was established in June1997 with an aim to create links between all those whoare concerned with the Environment in Ethiopia. Withthese respect the FORUM held a half day meeting onSODIS. It was organized with the aim to create awarenesson different options and give basics about the SODIStechnology. Before the meeting, four well-water sampleshad been analysed in around Addis Ababa. Two of rawwater and two of the same water after 5 hours exposureto the sun in plastic bottles. The results were convincing.One of the sample was so infected with pathogens, that ithad not been possible to make a count of the pathogens.The Number of pathogens after the SODIS treatment wasnil.

The presentation was followed by questions and dis-cussions, which helped to see SODIS from different direc-tions. All in all, participants felt the technique should bepromoted in Ethiopia but a proper package has to be pre-pared, including wider test results using different types ofbottles and clean instructions, in a language understand-able by any layman, on how to use the technique.


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Mail from and to Somalia

Dear Mr. Wegelin,I have read your article in a recent Waterlines onSODIS and earlier this month I had to go to Somalia fora mission with SAWA-Netherlands a dutch foundation.My job was to look for viable, approrpiate ways toimprove the waterquality for rural areas. People thereare nomadic and catch (scarce) rainwater ingroundtanks, thus it becomes very contaminated. Oneof the only options there was to do something withSODIS, because it is very hot and plastic jerrycans areavailable. I did some tests with black jerrycans (10 liter)in a wind free location for 4 - 5 hours and found aftertesting with Del Aqua kit that almost all faecalcoliforms were gone (couple of times we had measure-ments from > 2500 FC / 100 ml initially down to < 50or a couple of times even 0. This is a bit contrary towhat you are saying in your articles (I have also copiesfrom your earlier publications). You mention that UV-Aradiation is required to get 99.99% reduction. Or itshould be pasteurized in 70 degrees Celcius. I have afeeling from the few experiments we have done that2 hours above 50 degrees also kills (almost) all Faecalcoliforms. ALso a question was raised that even whenthe FC are killed, what about other pathogens..? Fromreading other publications I gathered that FC are almostthe most resistent, meaning that Vibrio Cholera, Shig-ella, Ascaris, etc should also be removed. Did you doany more tests since the Waterlines article? Maybe wecold keep in touch with each other on this facinatingsubject.

Yours sincerelyFoort Bustraan

Dear Mr. Bustraan,Thank you for your letter which reveals very interestinginformation. Your tests jerry cans of 10 liters volumedemonstrate the temperature effects on the inactivationof microorganisms. Due sunlight radiation the watertemperature rose to more than 50 0C andwas kept above this level for more than 2hours. You observed a substantial inacti-vation of Faecal coliforms in your tests.This is in agreement with the literature(see also Table X which was alreadypublished in SODIS News No. 1). As youcan see, also Vibrio Cholera, Shigella andAscaris eggs are destroyed when exposedto a water temperature of 45 - 57 °C forone hour. The Table also indicates that

longer exposure times reduce the necessary temperaturefor 100 % destruction. The Swiss Tropical Institute (STI)has embarked on a research to study the inactivation ofGiardia cysts and Cryptosporidium oocysts by SODIS.Storage (time), light (UV-A irradiation) and energy(heat) can be used individually or in combination toimprove the microbiological quality of drinking water.SODIS makes use of all three processes which areenhanced by synergies. By these physical water treat-ment processes, the microbiological quality is alwaysimproved. Hence, any storage, sunlight exposure orwater heating will have a positive effect and produce asafe or at least improved water quality.

I look forward to hearing from you again.With kind regards. Martin Wegelin

A Village in Cameroon

Chris Hochstrasser, SIL, Yaoundé

The village (Mekomba) is situated near the town of Mfou,at about 30 km from Yaoundé. We probably encounteredthe worst conditions to introduce a new water treatmentmethod. We had actually analysed their water two yearsago since a drinking water protection programme wassupposed to be introduced in the region. However, thisprogramme was finally never implemented. We pre-sented them with a more simple treatment method. How-ever, the water in the village had always been consumeduntreated since the population was under the impressionthat it was clean. We, therefore, confronted them with anunexpected request. Furthermore, it was the rainy seasonand the sky was cloudy.


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We visited the village three times. On our first visit, weinformed the villagers about their water quality andtaught them how to use the SODIS bags. Thanks to thepresence of their health officer, we received a warm wel-come in spite of our long absence. We gave the partici-pants of this meeting about ten SODIS bags or one bagper household and told them to use them the next day.

Two days later, we returned to the village and askedthe persons who had been given the bags how they hadused them. They had perfectly followed our instructions.We also sampled water from their bags to analyse it.

On our third visit, we brought Petri dishes to demon-strate the change in water quality before and after SODIStreatment. We taught the villagers how to reuse PET bot-tles and left them a few bottles, including a can of water-resistant black paint and a brush.

It can conclusively be stated that the treatment systemand its use had been well understood by the villagers.However, the conditions for its acceptance in a villagewhere drinking water had never been treated are ratherunfavourable a priori. We plan to return to the village inApril to find out whether the bottles are still used!

As regards SODIS, the questions most frequentlyasked referred to the possibility of using containers hold-ing more than 1.5 litres and its costs rather than the boil-ing of water (this question was always asked by the menand never by the women). The only question we couldn’tanswer referred to the possibility of producing a SODISbottle by tying a black cloth around one of its sides. Wetold the villagers that we would consult the researchersabout this question.

A continuing education course for persons in charge ofdispensaries was held during our stay at Mfou. Dr Mangasfrom the Mfou hospital asked us to present the SODIStechnology at this course. The participants understoodand seemed interested in the treatment method, how-ever, we don’t know whether they will implement it. Justafter the course we were informed that a member of theMinistry of Health was also present. He came to ask us afew questions and seemed interested, but again, we arenot sure if and how he will make use of the informationreceived.

SODIS in Ecuador

Brigitte Hintermann, Guayaquil, Ecuador

After a day of frustrating meetings in Berne, I came tomeet Martin Wegelin in the train. This was in August1998 when I first heard of SODIS. We decided that Iwould disseminate the SODIS method during my stay inEcuador.

As graduate nurse specialised in tropical medicine, Ihad already worked for a year with the Ecuadorian HealthService in 1994/1995. Although my second mission to Ec-uador was to be entirely devoted to my newprofession of midwife, I was highly mo-tivated to take the necessary SODISdocuments to South America. TheSODIS leaflet is now also available inSpanish.

Within the frame of an Interna-tional Nursing Congress at the Univer-sity Católica Santiago de Guayaquil, I wasinvited to give a lecture on “New Alternatives in PrimaryHealth Care” in mid-November 1998. It was clear that thetopic was going to be SODIS!

Preceding the congress I took the opportunity topresent SODIS in the media. Two articles on the SODISmethod appeared in the newspapers, one in Guayaquil’slargest daily paper “El Universo” (Guayaquil, the largestcity in Ecuador, 2.5 million inhabitants).

I also presented SODIS at a local TV station whichtransmitted it live in a morning show. Two weeks later Iwas asked by the University Católica de Ibarra to holdSODIS lectures in the North of Ecuador at the Universityof Ibarra, Otavalo, San Gabriel and Tulcan. My presenta-tion varied depending on the age of the pupils and stu-dents attending the lectures. The Spanish video on SODISproduced by EAWAG is an important audiovisual aid indisseminating information. Unfortunately, I am not in aposition to check whether the disseminated informationhas also led to its practical application. Unluckily, copyingof the leaflet was regarded as too expensive by the boardof the nurse’s training school. Moreover, the list of pro-spective users also got lost.

Since I have been in Guayaquil I drink tap water everyday which I previously expose to the sun in blacked PETbottles. The SODIS methods works as I have never beenill. You have to apply this method yourself before you canrecommend it.


1 5E X P E R I E N C E S F R O M T H E F I E L D

SODIS in South Africa

Edward D. Breslin and Erik Harvey, The Mvula Trust,South Africa

The Mvula Trust is a South African NGO which concen-trates on rural water supply and environmental sanitationdevelopment. In recent months, the Trust has effectivelyintroduced SODIS at a number of project sites throughoutthe country. This has been done through a “revisiting ini-tiative” designed to evaluate projects for sustainabilityand develop strategies to overcome problems identified atlocal level.

SODIS and the “Revisiting Initiative”

The Mvula Trust is currently managing a national pro-gramme to re-evaluate existing water projects forsustainability. The “revisiting initiative” is being con-ducted in partnership with the Australian Agency for In-ternational Development (AusAID) and the South AfricanDepartment of Water Affairs and Forestry (DWAF). A to-tal of 78 projects will be evaluated by the end of April1999.

The evaluations focus on issues of operation and main-tenance (O&M), cost recovery/affordability, communica-tion, water for production, and health. Plans of action aredeveloped at project site to address sustainability prob-lems which become apparent during the evaluations.

One of the more disturbing issues to emerge from theevaluations is the high levels of fecal contamination ofwater in existing project sites. The reasons for this arecomplex, but are primarily related to poor O&M at projectlevel. To illustrate, in one project site in the NorthernCape, the project was specifically designed to address is-sues of water quality. The purification plant is poorly man-aged, and the economic conditions in the area mean that

the District Council’s ca-pacity to sustain the pu-rification plant are sus-pect.

The evaluations areclearly suggesting thatthe potential beneficialhealth impact of im-proved water supply isbeing threatened bypoor water quality atproject site.

To address this prob-lem, the evaluators areintroducing the conceptof SODIS through a par-

ticipatory process known as PHAST (�articipatory �y-giene �nd �anitation �ransformation). The overall meth-odology, known as SARAR, was originally developed byLyra Srinivasan, together with Ron Sawyer and Jake Pfohl,and adapted specifically to the water supply and environ-mental sanitation sector through PROWWESS and thePHAST initiative.

The approach is designed to promote health/hygiene,sanitation and community management of water supplyand sanitation facilities. PHAST is an adaptation of theSARAR methodology of participatory learning, whichbuilds on people’s innate ability to address and resolve�� . The methodology aims to empowercommunities to manage their water supply and to controlsanitation-related diseases.

Discussions on what can be done about poor waterquality at project site are initiated using PHAST. Commu-nity members explore a range of treatment options – in-cluding boiling andchlorinating water –that are commonly con-sidered at local level.SODIS is introduced us-ing the picture depictedbelow, usually withoutany explanation. Par-ticipants rapidly figureout how solar disinfec-tion works.

Community mem-bers discuss what ��believe are the advan-tages and disadvan-tages of each option.Boiling, for instance, isoften considered time consuming, costly (in terms of fuel)and somewhat difficult to manage. Chlorination, with alocal product called Jik (household bleach), is also expen-sive and leaves a bad taste in the mouth (especially if toomuch Jik is used). SODIS is often a new concept but peo-ple readily claim that it would not cost them anything. Butdoes “SODIS water” taste alright? And, isn’t “SODIS wa-ter” hot?

Participants are asked if they want to test these as-sumptions through a SODIS experiment. A 2 liter plasticcoke bottle is filled with water that had been tested as“contaminated” the previous day. The plastic bottle iskept in the sun for 24 hours, and then tested again. Aftera further 24 hours (when the water quality tests can beanalyzed by villagers), community members see that thewater is clean as the test results show that contaminationhas been eliminated.

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Participants are then asked to taste the water. Com-munity members involved in the test indicate that thewater “tastes fine”. The issue of “hot water” is resolvedby storing the water in a cool place overnight.

SODIS uptake and foreseen obstacles

In a number of project sites, SODIS is now being used bymany households as a means to improve water quality.The Mvula Trust will, in the near future, try to quantify theuptake at a number of these villages, but observations atcommunity level suggest that the SODIS experimentshave had an impact on household water management.

There are, nevertheless, a number of factors which willthreaten the spread of SODIS in South Africa. First, 2 literplastic bottles are not as accessible nationwide as manywould hope. Moreover, households do complain thatthey need bigger containers so that larger amounts of wa-ter can be disinfected by the sun. The most common wa-ter collection bucket is 25 liters, but many of these plasticcontainers are PVC rather than PET containers. In isolatedvillages in KwaZulu/Natal, where PET containers are read-ily available, then the issue of volume is not such a prob-lem (see picture below of child fetching water from astream to conduct a SODIS experiment).

In other areas, like Mpumalanga and the NorthernProvince, this is a bigger problem as supplies of PET con-tainers is somewhat limited.

Another problem encountered is that communitymembers claim that they should not have to be concernedwith water treatment. Many argue that the water fromnew taps should be treated if new supplies of water havebeen provided through a donor or government scheme.People in the cities get clean water from their taps, so whyshould rural people be treated any differently?

The size of a community may also present obstacles.The history of water supply in rural South Africa has leftmany communities disillusioned and apathetic. It is moredifficult for community structures to effect change in suchcommunities, especially larger communities. Recommen-dations from future participatory evaluations will providethe scope for more in-depth interventions in such commu-nities.

Addressing these legitimate worries at field sitesthroughout the country remains a critical challenge for theTrust.

Promoting SODIS in South Africa

The Mvula Trust is involved in a number of initiatives thatshould help promote the spread of SODIS in South Africa.

First, the Radmaste Center at the University of theWitwatersrand (Johannesburg), is actively involved in thedevelopment of the field-based water quality testing pro-

gramme outlined above. A central part of this programmeis SODIS.

Second, the Mvula Trust, Danida, the Department ofWater Affairs and Forestry (KZN) and Glover Develop-ment Engineers have been running a child-to-child pro-gramme in rural KwaZulu/Natal centered around waterquality issues. The children in the participating villages arepromoting SODIS as a cost-effective, simple way to treatwater effectively.

Finally, SODIS will be a key section in a forthcomingmanual for field workers involved in health, water supplyand sanitation. The manual, being produced by Soul Cityin South Africa, will highlight low-cost, effective ways toaddress water- and sanitation-related health problems incommunities that will continue to rely on unprotectedsources of water supply for the foreseeable future. SODISwill be presented as an important option in these commu-nities trying to find ways to improve water quality athousehold and community level.

Will plastic bottles help tomitigate the arsenic problem inBangladesh?By tradition, pond water has been a major raw watersource for the rural population in Bangladesh. In order tosupply a source of water free from bacteria and virus, theuse of groundwater has rapidly expanded since the1970s. At present, about 95 % of the rural population aredrinking groundwater. However, skin diseases and cancerhave been recently reported and in the following, in nu-merous wells in various parts of the country high levels of

arsenic have beendiscovered. This seri-ous threat to thehealth of over 50 mil-lion people throughconsumption of ar-senic-rich well waterin Bangladesh callsfor immediate actionon various levels. Thedevelopment and useof alternative rawwater sources such assurface water (e.g.from ponds, lagoonsor rivers) and rainwa-ter are proposed.However, surfacewater is exposed to


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Bangladesh Arsenic Mitigation

Water Supply Projecttreat surface water by

treat groundwater by

S DIS

pollution and, therefore, generally requires treatment.SODIS is a simple method used at household level to im-prove the microbiological quality of drinking water.SODIS has been field tested in various developing coun-tries for its socio-cultural acceptance and affordability.

Another option to respond to the Arsenic problem isthe development of low-cost and simple arsenic removalmethods appropriate and affordable for household use.Currently existing small-scale arsenic removal proceduresrequire chemicals that are either not easily available and/or affect water taste and odor. With major financial sup-port of the Swiss Agency for Development and Coopera-tion (SDC), EAWAG is in progress to develop a simple so-lar oxidation and removal of arsenic (SORAS) method thatuses irradiation of water with sunlight in PET- or otherUV-A transparent bottles to reduce arsenic levels from>500 mg/L to levels below 50 mg/L.

SDC initiated and funds the WATSAN PartnershipProject (WPP) in the project area of Rajshahi and ChapaiNawabganj districts with the aims toimprove user’s sustainable access and use of afford-

able water and sanitation- build on experience learned in the project toward an

incremental integration into the nationwide Bangla-desh Arsenic Mitigation Water Supply Project(BAMWSP)

SODIS as well as SORAS are being field tested withinWPP. For SODIS, this treatment method is introduced to15 villages by the Partner NGOs (PNGO) under the lead

of CARE and with theassistance ofYayasan Dian Desa,Yogyakarta in Indo-nesia acting as a con-sultant to the project.EAWAG has a back-stopping mandatefor this project andconsiders to carry outa SODIS Health Stu-dy in cooperationwith the Swiss Tropi-cal Institute (STI). Im-plementation of SO-DIS at village levelstarted in March ‘99and it is planned torun the field studyover period of oneyear.

The target popu-lation is interested in SODIS as the water treatmentmethod helps to reduce the demand on firewood which isoften scarce in the project area. Quite often the womenuse cow dung as energy source for cooking. However, asuccessful application of SODIS mainly depends on theusers’ acceptance to return to unsafe and polluted surfacewater sources. Pond water is often turbid and, therefore,requires the separation of the suspended solids and algaeby sedimentation possibly supported by flocculation usingalum sulfate or Moringa oleifera seeds. Furthermore, thegroundwater wells equipped with a handpump and usu-ally located within the owner’s compound are nearer tothe users than the ponds proposed as alternative watersource. The ongoing field studies in Bangladesh will revealwhether SODIS will be accepted by the Arsenic affectedpopulation or whether SORAS will efficiently reduce theArsenic concentration found in the groundwater.


1 8O U T L O O K

Information exchange remains an important issue in the development and promotion of new technologies. SODIS has gained worldwide momentum and different actors are gaining their own experience with this fascinating

water treatment process. The practical knowledge acquired in different projects may prevent other field staff from making the same mistakes or may allow the same approach to be successfully applied

elsewhere. SODIS News plans to play an important role in this information exchange. We, therefore, invite all our readers to use this communication platform which may in future be

replaced by a mail box on the Internet. The electronic information exchange will certainly be faster and more interactive.

Hence, new approaches for the dissemination of information will be announced electronically. However, SANDEC intends to also keep on

using the traditional communication channels. We plan to prepare a SODIS Manual containing information collected during the

different phases of the SODIS project; i.e., results obtained in the laboratory, field tests and in the

demonstration projects, including the practical experience gained in the implementation of

SODIS. Furthermore, SODIS will be presented at forthcoming events

such as the 9th Stockholm Water Symposium in

Sweden or the 25th WEDC Confere-

ce in Ethio-pia.

T h e i d e a

of using solar ener-

gy to impro-ve the micro-

biological quality of the water is very

attractive and fasci-nating. Development of

the technology was simple compared to the task

o f c o n -v i n c i n g p e o p l e about the potential of this water treatment process. A change of perceptions and atti-tudes takes time - SANDEC will continue to work on these changes.

EAWAG / SANDEC No. 4 May 1999 S DIS · Paper signed by members of international and national...

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Transcript of EAWAG / SANDEC No. 4 May 1999 S DIS · Paper signed by members of international and national...