Document(s) 12 of 15

Introduction

Drawing inspiration from water treatment practices developed in India as long ago as 2000 B.C., researchers at the American University of Beirut in Lebanon developed, with IDRC support, a low-cost, practical means to provide safe drinking water in rural and urban areas in developing countries. The key to this method lies in the ability of direct sunlight to destroy bacteria. The treated water is suitable for drinking, and can also be used to prepare Oral Re-hydration Therapy (ORT) solutions to treat dehydration suffered by children with diarrhea. Solar radiation is a form of renewable energy that is abundant and accessible in most southern countries. The research focused on small quantities of drinking water, sufficient to satisfy the daily requirements of a small family. 

Sunlight with wavelengths of 315-400 nanometers (nm) on the ultraviolet (UV) range of the electromagnetic spectrum is most effective at destroying bacteria. Since colourless glass or plastic can transmit light in this near ultraviolet range, they are the best materials for disinfection. Visible light (400-750 nm) next in terms of efficiency, with the visible band of violet and blue light (400-490 nm) is the most useful within this range. As a result, violet, blue, and very light green-tinted glass follow colourless glass or plastic in order of suitability. 

More recent research carried out at Montreal's Brace Research Institute (BRI), in collaboration with international colleagues, indicates that transparent plastic bags are the best material for solar water disinfection. Researchers report that six litres of St. Lawrence River water can be disinfected in five hours during the summer. Research attention in this regard has been focused on finding or developing plastics capable of transmitting sunlight wavelengths below 400 nm. 

Impact

• Development of a simple, effective and economical method of water disinfection using solar radiation - Earlier work by researchers in Lebanon on developing suitable methods to disinfect water in developing countries is being carried on at the Brace Research Institute. Identifying simple, inexpensive plastic bags for use in disinfection has become a suitable method to use in southern contexts. BRI researchers actively promote their findings through a variety of networks, including the Global Applied Research Network (GARNET).

Prerequisites

Potential users

Contact

Dr. Aftim Acra 
Department of Civil and Environmental Engineering 
American University of Beirut 
Beirut, LEBANON 
Fax/Tel: 212-444-5813 
Telex: 20801 EL 

Resources 

Acra, A.; Jurdi, M.; Mu'allem, H.; Karahagopian, Y.; Raffoul, Z. 1989. Water disinfection by solar radiation: assessment and application. IDRC. 86 pp. 

Acra, A.; Raffoul, Z.; Karahagopian, Y. 1984. Solar disinfection of drinking water and oral rehydration Solutions - guidelines for household application in developing countries. UNICEF. 

Bingham, Annette. April 1985. Solar treatment - pure and simple. Reprinted from World Water. 

TESTING THE WATERS (information on the development of simple tests for water quality and their impact on the lives of people in remote communities in Canada and the developing world). 

Available from the Brace Research Institute (see Contact above): 

Alwand, R.; Kandpal, T. April 1966. Solar water disinfection: a field trial. 4 pp. (R.236) 

Brace Research Institute, eds. August 1988. Proceedings of the workshop on solar water disinfection. Brace Research Institute, Montreal. 300 pp. (R.207) 

Lawand, T.A.; Ayoub, J.; Gichenje, H. June 1997. Solar disinfection of water using transparent plastic bags. RERIC International Energy Journal, 19(1). 7 pp. (R.237) 

Lawand, T.A.; Papp, R.; Ayoub, J. 1994. Recent experiments in solar water disinfection. Paper presented at the SESCI 94 (Renewables 94) Conference, Ottawa, Ontario, 31 October to November 1994. (R.225; $1.50) 
 

International organizations and networks: 

Water, Engineering and Development Centre (WEDC) 
Loughborough University 
Leicestershire LE11 3TU, UK 
Tel: + 44 (0) 1509 222885 
Fax: + 44 (0) 1509 211079 
E-mail: WEDC@lboro.ac.uk 
Web site: http://info.lboro.ac.uk/departments/cv/wedc/ 

Global Applied Research Network (GARNET) 

IRC - International Water and Sanitation Centre 
PO Box 93190, 2509 AD 
The Hague, THE NETHERLANDS 
Tel: +31 (0)70 30 689 30 
Fax: +31 (0)70 35 899 64 
E-Mail: general@irc.nl 
Telex: 33296 irc nl 
Web site: http://www.oneworld.org/ircwater/ 
 

info@idrc.ca | March 13 1998

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Document(s) 12 of 15

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