The Environment and Public Health Organization (ENPHO), based in Nepal, is involved in testing and promotion of household water treatment technologies.

Since 2003, ENPHO has been promoting solar disinfection (SODIS). In 2007 it completed Phase-IV of the SODIS promotion project on scaling-up the institutionalisation process of SODIS technology throughout the Kathmandu Valley and one municipality in the Terai region of Nepal, and in one municipality in Sikkim State in India. In Sikkim, a health assessment survey among children under 5 years showed that SODIS users had lower occurrence of diarrhoeal diseases compared to non-users.

ENPHO has completed testing of Solvatten, a portable container for purifying drinking water utilising both the thermal effect and UV radiation of solar energy in combination with an in-built filter. The removal of faecal coliforms at different turbidity levels and in different climatic zones was tested.

ENPHO in coordination with A Vision for Clean Water distributed around 50 colloidal silver (CS) filters to the locals of Adinath, Kirtipur, Nepal. Training was provided on point-of-use drinking water treatment options and hygiene.

One disadvantage of SODIS is that can require 48 h or more for adequate disinfection in cloudy weather. American researchers have now found that a number of low-cost additives are capable of accelerating SODIS in both cloudy and sunny weather [1]. These additives included hydrogen peroxide, lemon and lime juice, and copper metal or aqueous copper plus ascorbate, with or without hydrogen peroxide. The research included laboratory experiments in the USA and field trials in Haiti and India.

[1] Fisher, M.B. … [et al.] (2008). Speeding up solar disinfection (SODIS): effects of hydrogen peroxide, temperature, pH, and copper plus ascorbate on the photoinactivation of E. coli. Journal of water and health ; vol. 6, no. 1 ; p. 35-51. doi:10.2166/wh.2007.005. Pre-publication PDF.

Related web sites: SODIS ; WHO - Household Water Treatment and Safe Storage

Contact:

• ENPHO, Nepal, rc@enpho.org, http://www.enpho.org
• Mrs. Petra Wadström, Solvatten AB, Sweden, pc.wadstrom@swipnet.se, http://www.solvatten.se
• John and Eileen Heasley, A Vision for Clean Water, USA, eheasley@wideopenwest.com, http://avisionforcleanwater.blogspot.com/
• Michael B. Fisher, Dept. of Civil and Environmental. Engineering, University of California, Berkeley, USA, mbfisher@gmail.com

Source: ENPHO E-bulletin, Dec 2007

Tags: water quality