SODIS (Solar Water Disinfection)¶
Membranes & Advanced Filtration • Est. CapEx: Low-cost / Locally fabricated
Technical Overview¶
SODIS is a simple, low-cost household water treatment method that uses solar energy to disinfect microbially contaminated drinking water. It is recommended by the WHO and suitable for low-income communities and emergency settings.
Key Specifications & Engineering Parameters¶
| Parameter | Specification |
|---|---|
| Category | Solar Disinfection / Point-of-Use |
| Capital Cost | $0 – $5 USD (Zero ongoing running cost) |
| Primary Mechanism | Transparent food-grade PET (#1) beverage bottles (0.5L–2.0L) are filled 3/4 with water, shaken vigorously for 30 seconds to oxygenate, topped up, and exposed horizontally to full direct sunlight for at least 6 hours (or 2 full days if overcast). Synergistic UV-A radiation (320–400 nm) and thermal heating (>50°C) destroy pathogenic cell membranes and DNA. |
| Turbidity Limit | Water must be < 30 NTU (able to read a headline through the bottle). Highly turbid water requires pre-settling or cloth filtration. |
| Pathogen Efficacy | >99.9% bacteria (E. coli, Vibrio cholerae), viruses, and protozoa (Giardia, Cryptosporidium). |
| Target Scale | Household Point-of-Use |
| Standard Lifespan | Plastic bottles replaced every 6–12 months as scratches reduce UV transmission. |
Official CAWST & Eawag SODIS Training Resources¶
All resources below are open-access, licensed under Creative Commons, and directly downloadable for field training:
1. E-Learning & Practical Field Manuals¶
- 💻 CAWST SODIS E-Learning Module: Explore CAWST SODIS Course — Comprehensive e-learning module detailing the biophysical mechanisms, advantages, limitations, and field monitoring procedures for solar disinfection.
- 📄 CAWST SODIS Community Poster & Field Sheet: Download Multilingual SODIS Guide — Illustrated visual guide available in Swahili, English, French, Spanish, and Khmer explaining bottle selection, roof placement, and the headline turbidity test.
2. Video Demonstrations¶
- 📺 Eawag/Sandec Official SODIS Training Video: Watch SODIS Demonstration — Step-by-step visual protocol showing 30-second bottle shaking, corrugated iron roof placement, and safe water handling directly from the bottle.
Cross-Reference & Interactive Tools¶
Need to evaluate this technology for your specific field site? Run the WhatWater.info Selector Engine to compare it against 100+ alternative solutions.