The SODIS method has been proven to be a simple and low cost method of purifying bacterial contaminated water in rural areas. My proposal here is to up-scale and streamline the SODIS method in the form of large water stations positioned at central locations within the communities. The entire system consists of the following 4 main points:
1. WATER COLLECT POINT: a floating weir is positioned in the lake or river where the water is drawn from. The floating weir collects the top water film which is usually the clearest water section, since all solids settle downwards to lake/river bottom. A pipe is connected between the weir and the pump station.
2. PUMP STATION: Standard pre-assembled boxed pool type pump-filter (2 off in parallel) is placed next to the river/lake below the water level. The sand filters removed solids/dust and also reduce turbidity to prepare water for the SODIS plant. The pump shall be carefully selected for the particular site. The pool pump-filter is well known by many, easy to learn and operate and easy filter backflush of water back to the river. Timers and solar sensors shall control the pumps. Pumps can be solar powered. 1.5 L/s.
3. PIPELINE: 75mm black HDPE pipeline to transfer water to the SODIS station, installed above ground. Sunlight will warm up the pipe and warm water increase the SODIS efficiency.
4. SODIS Water Station: clear rectangular glass type tubes are fitted ontop of the black painted corrugated sheetmetal roof. Rectangular tubes together with the steel roof which helps heat the water improves the SODIS efficiency. After 3 hours purified water is fed to the two 5000 L tanks under the roof. After the SODIS tubes is filled, the pump shall continue to feed non-drinkable but filtered water to the other 4 tanks. Clear sign boards shall be installed to indicate which tanks holds drinkable and non-drinkable water. The station footprint is 5 x 6.5meters.
This system is designed to produce about 3000 Litres of solar disinfected water per day and 20,000 Litres of potable water for other uses per day. I estimate the total cost of this system (with 1km pipeline) installed at R220k ($20,000 USD) excluding import of materials to countries. An appointed local water community leader shall easily learn and perform the maintenance required for this system.