As climate change affects weather patterns, scientists predict more intense storms, or lengthening droughts. Access to clean drinking water is a widening issue. Even during a monsoon rain, normally clean drinking water can easily become contaminated by flood waters. And in dry areas, limited ground water resources are often polluted with salts.
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In Sri Lanka, the NGO Practical Action aims to provide sustainable solutions that people can self-manage. They have helped install solar distillers to purify salty water along the coast. The construction of a distiller is simple and cheap – a galvanised steel tray covered by a slanting glass lid. The sun evaporates water lying in the tray, which rises as steam but condenses on the sloping lid, and is collected into a pipe. A well-placed distiller in full sun, can produce 8-10 litres of water a day. Practical Action had water distilled in this way tested at the University of Moratuwa, Sri Lanka and it was found free of salts, microbes and nitrogen compounds.
Other research done by UNICEF in the 1980s showed that just exposing water to sunlight can help purify it. While not as 100% effective as boiling water, if relatively clear (not too muddy) water is exposed for at least six hours (temperature to at least 55ºC), solar treatment is about 99.9 per cent effective against micro-pathogens.
Practical Action have tested this system, SODIS, in places with high sunlight hours, including Colombia, Bolivia, Burkina, Togo, Thailand and Indonesia, and it has proved effective against infectious diarrhoea, dysentery, and even cholera.
An incredibly simple process, SODIS requires four large (two litre) recycled PET plastic bottles per family member. Two for processing, and two for the day’s drinking water. PVC releases chemicals into the water, and glass deflects some UV rays, so PET bottles are preferred. Bottles are simply filled and laid horizontally on a tin roof or other flat surface where they are exposed to a full day of sunlight, or two days if slightly cloudy. If the underside of each bottle can be painted black, the process is even more effective.
There is no fuel required, so almost no costs, and a realistic solution for self-managed water purification for low-income groups. Boiling is still recommended for any family member with sensitive immune systems who have been ill, very small children or those with HIV.
Designs for these concepts are easily available on the internet, through the Global commons, so NGOs and social enterprises can easily access the latest ideas with the highest efficiency and lowest costs. Designs aim for self-managed solutions that can usually be built or created by local people with basic training.
Chocosol, “socially just chocolate”, is a Canadian/Mexican social enterprise using solar power to roast cacao beans. Designed by Fraser Symington in Canada, and tried and tested in Mexico by Michael Sacco, the system allows communities to roast cacao beans themselves, at very low cost.
Chocosol have in addition created a social enterprise experimenting with Horizontal trade (beyond Fair Trade, Horizontal trade goes beyond a simple exchange of money for product, with an emphasis on exchange of information, ideas and cultures, connecting farmers with each other and the wider world). They buy the chocolate directly from about 500 Indigenous farmers in Southern Mexico, and sell this solar-roasted chocolate in Canada, where they have a rooftop garden to produce many of the herbs used as ingredients for their products.
In much of Africa, clean ground water is available, but is expensive to pump to the surface as the water table is dropping and wells must be deeper. In Uganda, where they receive solar radiation of about 4-5 kWh/square meter/day, only one per cent of rural areas had electricity served by the national power grid. The Energy for Rural Transformation project rolled out extensive solar PV projects, to increase access to clean water. Costs of drinking water dropped dramatically too as previously pumps were diesel-driven, an ongoing and increasing outlay now avoided.
This provision of technical support has enabled thousands of people in deprived areas who previously had little access to electricity and clean drinking water, to live better and healthier lives. They’ve been taught how to set up the technology and in most cases are able to maintain the systems themselves.
“Give a man a fish, and you feed him for a day. Teach a man to fish, and you feed him for a lifetime” – and if you can teach him to harness the power of the sun, you surely enrich him for a lifetime too.
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PHOTO CREDITS: Trey Ratcliff on flickr