Department Sanitation, Water and Solid Waste for Development

Solar Water Disinfection (SODIS)

Solar Water Disinfection (SODIS) is a simple water disinfection method, making use of the sun’s energy and using PET bottles. It exploits the germicidal effect of solar radiation – especially UV-A radiation - on diarrhoea causing pathogens.

The principle of water disinfection by solar radiation was first discovered in 1984 by Prof. Aftim Acra of the American University in Beirut. In the 1990s, researchers at Eawag/Sandec launched extensive laboratory studies to evaluate the potential of solar radiation to inactivate bacteria  and  viruses.  Based on the findings of these experiments, they designed a standard procedure – the SODIS method. After successful pilot testing in low-income areas, Eawag initiated  a program in 2001 to disseminate the SODIS method through promotion projects in more than 25 low- and middle-income countries to ensure that the SODIS method becomes available to the people most in need.

The SODIS promotion activities were accompanied by various research studies to gain insight into disinfection efficiency during field application, assess the health impact in communities using SODIS for water treatment, evaluate interventions strategies supporting behaviour change for compliant application, test different containers and assess uptake and sustainability of the application.

Today, the SODIS method is recognized as one viable HWTS option. According to monitoring data from projects supported by Eawag, at least 5 million people have started using the method to improve the quality of their drinking water.

Detailed information about SODIS is available on: www.sodis.ch

Training Materials

SODIS Manual

The SODIS Manual presents an overview of the SODIS method based on 20 years of research and practice. The first part provides basic facts about solar water disinfection and guidance for application. The second part addresses the technical aspects that influence the efficacy of the SODIS method in removing pathogens from water. The third part reviews specific approaches and tools used to promote the SODIS method to target populations. It aims at supporting experts with the integration of the SODIS method into HWTS, WASH and health projects.

Here you can download the SODIS Manual

Safe Water School Manual

The Safe Water School Manual contains teaching materials to provide school lessons on drinking water treatment, hygiene and sanitation. It combines school lessons with scientific experiments, games and art activities. The lessons are based on the life-skills approach, and are inspired by the participatory teaching and learning methods PHAST and CHAST. These methods were selected be-cause they have been shown to be helpful in empowering school children to improve water, sanitation and hygiene (WASH) practices at school and at home.

Here you can download the Safe Water School Manual and Teaching Materials

Publications

Disinfection

Bosshard, F.; Riedel, K.; Schneider, T.; Geiser, C.; Bucheli, M.; Egli, T. (2010) Protein oxidation and aggregation in UVA-irradiated Escherichia coli cells as signs of accelerated cellular senescence, Environmental Microbiology, 12(11), 2931-2945, doi:10.1111/j.1462-2920.2010.02268.x, Institutional Repository
Bosshard, F.; Bucheli, M.; Meur, Y.; Egli, T. (2010) The respiratory chain is the cell's Achilles' heel during UVA inactivation in Escherichia coli, Microbiology, 156(7), 2006-2015, doi:10.1099/mic.0.038471-0, Institutional Repository
Bosshard, F.; Berney, M.; Scheifele, M.; Weilenmann, H.-U.; Egli, T. (2009) Solar disinfection (SODIS) and subsequent dark storage of Salmonella typhimurium and Shigella flexneri monitored by flow cytometry, Microbiology, 155(4), 1310-1317, doi:10.1099/mic.0.024794-0, Institutional Repository
Berney, M.; Weilenmann, H.-U.; Egli, T. (2006) Flow-cytometric study of vital cellular functions in Escherichia coli during solar disinfection (SODIS), Microbiology, 152(6), 1719-1729, doi:10.1099/mic.0.28617-0, Institutional Repository
Berney, M.; Weilenmann, H. -U.; Simonetti, A.; Egli, T. (2006) Efficacy of solar disinfection of Escherichia coli, Shigella flexneri, Salmonella Typhimurium and Vibrio cholerae, Journal of Applied Microbiology, 101(4), 828-836, doi:10.1111/j.1365-2672.2006.02983.x, Institutional Repository
Berney, M.; Weilenmann, H.-U.; Ihssen, J.; Bassin, C.; Egli, T. (2006) Specific growth rate determines the sensitivity of Escherichia coli to Thermal, UVA, and solar disinfection, Applied and Environmental Microbiology, 72(4), 2586-2593, doi:10.1128/AEM.72.4.2586-2593.2006, Institutional Repository
Dejung, S.; Fuentes, I.; Almanza, G.; Jarro, R.; Navarro, L.; Arias, G.; Urquieta, E.; Torrico, A.; Fenandez, W.; Iriarte, M.; Birrer, C.; Stahel, W. A.; Wegelin, M. (2007) Effect of solar water disinfection (SODIS) on model microorganisms under improved and field SODIS conditions, Journal of Water Supply: Research and Technology. Aqua, 56(4), 245-256, doi:10.2166/aqua.2007.058, Institutional Repository
Wegelin, M.; Sommer, B. (1998) Solar Water Disinfection (SODIS) - destined for worldwide use?, Waterlines, 16(3), 30-32, doi:10.3362/0262-8104.1998.013, Institutional Repository
Sommer, B.; Mariño, A.; Solarte, Y.; Salas, M. L.; Dierolf, C.; Valiente, C.; Mora, D.; Rechsteiner, R.; Setter, P.; Wirojanagud, W.; Ajarmeh, H.; Al-Hassan, A.; Wegelin, M. (1997) SODIS—an emerging water treatment process, Journal of Water Supply: Research and Technology. Aqua, 46(3), 127-137, Institutional Repository
Wegelin, M.; Canonica, S.; Mechsner, K.; Fleischmann, T.; Pesaro, F.; Metzler, A. (1994) Solar water disinfection: scope of the process and analysis of radiation experiments, Journal of Water Supply: Research and Technology. Aqua, 43(3), 154-169, Institutional Repository

Material assessment

Schmid, P.; Kohler, M.; Meierhofer, R.; Luzi, S.; Wegelin, M. (2008) Does the reuse of PET bottles during solar water disinfection pose a health risk due to the migration of plasticisers and other chemicals into the water?, Water Research, 42(20), 5054-5060, doi:10.1016/j.watres.2008.09.025, Institutional Repository
Wegelin, M.; Canonica, S.; Alder, A. C.; Marazuela, D.; Suter, M. J. -F.; Bucheli, T. D.; Haefliger, O. P.; Zenobi, R.; McGuigan, K. G.; Kelly, M. T.; Ibrahim, P.; Larroque, M. (2001) Does sunlight change the material and content of polyethylene terephthalate (PET) bottles?, Journal of Water Supply: Research and Technology. Aqua, 50(3), 125-133, doi:10.2166/aqua.2001.0012, Institutional Repository

Health Impact

Graf, J.; Togouet, S. Z.; Kemka, N.; Niyitegeka, D.; Meierhofer, R.; Pieboji, J. G. (2010) Health gains from solar water disinfection (SODIS): evaluation of a water quality intervention in Yaoundé, Cameroon, Journal of Water and Health, 8(4), 779-796, doi:10.2166/wh.2010.003, Institutional Repository
Graf, J.; Meierhofer, R.; Wegelin, M.; Mosler, H.-J. (2008) Water disinfection and hygiene behaviour in an urban slum in Kenya: impact on childhood diarrhoea and influence of beliefs, International Journal of Environmental Health Research, 18(5), 335-355, doi:10.1080/09603120801966050, Institutional Repository
Gara, A.; Tobler, M.; Meierhofer, R. (2010) Reducing diarrhoea with SODIS and promoting hygiene in Ng’ombe Slum, Zambia, Sandec News, 11, 22-23, Institutional Repository

Application and sustainability

Hering, J. G.; Hoffmann, S.; Meierhofer, R.; Schmid, M.; Peter, A. J. (2012) Assessing the societal benefits of applied research and expert consulting in water science and technology, GAIA: Ecological Perspectives for Science and Society, 21(2), 95-101, doi:10.14512/gaia.21.2.6, Institutional Repository
Tamas, A.; Wehrle, F.; Wojtalla, K.; Meierhofer, R. (2011) Assessing long-term sustainability of former Eawag HWTS projects, Sandec News, 12, 8-9, Institutional Repository
Meierhofer, R.; Landolt, G. (2009) Factors supporting the sustained use of solar water disinfection - experiences from a global promotion and dissemination programme, Desalination, 248(1–3), 144-151, doi:10.1016/j.desal.2008.05.050, Institutional Repository
Lantagne, D.; Meierhofer, R.; Allgood, G.; McGuigan, K. G.; Quick, R. (2009) Comment on "Point of use household drinking water filtration: a practical, effective solution for providing sustained access to safe drinking water in the developing world", Environmental Science and Technology, 43(3), 968-969, doi:10.1021/es802252c, Institutional Repository

Behaviour change

Mosler, H. J.; Kraemer, S. M.; Johnston, R. B. (2013) Achieving long-term use of solar water disinfection in Zimbabwe, Public Health, 127(1), 92-98, doi:10.1016/j.puhe.2012.09.001, Institutional Repository
Tamas, A.; Meyer, J.; Mosler, H.-J. (2013) Predictors of treated and untreated water consumption in rural Bolivia, Journal of Applied Social Psychology, 43(7), 1394-1407, doi:10.1111/jasp.12096, Institutional Repository
Kraemer, S. M.; Mosler, H.-J. (2012) Effectiveness and effects of promotion strategies for behaviour change: solar water disinfection in Zimbabwe, Applied Psychology, 61(3), 392-414, doi:10.1111/j.1464-0597.2011.00475.x, Institutional Repository
Tamas, A.; Mosler, H.-J. (2011) Why do people stop treating contaminated drinking water with solar water disinfection (SODIS)?, Health Education and Behavior, 38(4), 357-366, doi:10.1177/1090198110374702, Institutional Repository
Kraemer, S. M.; Mosler, H.-J. (2011) Factors from the transtheoretical model differentiating between solar water disinfection (SODIS) user groups, Journal of Health Psychology, 16(1), 126-136, doi:10.1177/1359105310370630, Institutional Repository
Kraemer, S. M.; Mosler, H.-J. (2010) Persuasion factors influencing the decision to use sustainable household water treatment, International Journal of Environmental Health Research, 20(1), 61-79, doi:10.1080/09603120903398301, Institutional Repository
Tamas, A.; Tobias, R.; Mosler, H.-J. (2009) Promotion of solar water disinfection: comparing the effectiveness of different strategies in a longitudinal field study in Bolivia, Health Communication, 24(8), 711-722, doi:10.1080/10410230903264022, Institutional Repository
Murinda, S.; Kraemer, S. (2008) The potential of solar water disinfection as a household water treatment method in peri-urban Zimbabwe, Physics and Chemistry of the Earth, 33(8–13), 829-832, doi:10.1016/j.pce.2008.06.025, Institutional Repository
Moser, S.; Mosler, H.-J. (2008) Differences in influence patterns between groups predicting the adoption of a solar disinfection technology for drinking water in Bolivia, Social Science and Medicine, 67(4), 497-504, doi:10.1016/j.socscimed.2008.04.002, Institutional Repository
Heri, S.; Mosler, H.-J. (2008) Factors affecting the diffusion of solar water disinfection: a field study in Bolivia, Health Education and Behavior, 35(4), 541-560, doi:10.1177/1090198108321248, Institutional Repository
Altherr, A.-M.; Mosler, H.-J.; Tobias, R.; Butera, F. (2008) Attitudinal and relational factors predicting the use of solar water disinfection: a field study in Nicaragua, Health Education and Behavior, 35(2), 1-14, doi:10.1177/1090198106288251, Institutional Repository