Two-step system

Construction

Each system consists of two large tanks and one bucket. The tanks hold 1000 and 200 litres and the small holds ten litres. The 1000 litres tank is filled with water, preferably rainwater, while the 200 litres tank is filled with sand. The 1000 litres tank has a pipe with a tap attached, which able the user to turn off the water flow when there is enough water in the 200 litres tank. The bucket used is placed upside down in the bottom of the 200 litres tank and is covered with a filter cloth. Two centimetres from the top of the bucket 30 holes are made where water can seep through. The bucket is connected to a pipe that leads the purified water up from the bucket. The output of this pipe should be placed about ten centimetres from the top of the 200 litres tank and be fitted with a tap on the outside of the tank. The sand should be filled as high as possible in the tank to permit usage of the sand for as long time as possible before it has to be replaced completely.



Function

When the 1000 litres tank is filled with water sedimentation starts and all larger particles fall to the bottom of the tank. About three inches from the bottom a pipes carrying water to the smaller tank is placed. When the sediment that has landed on the bottom of the big tank reaches this height it shall be emptied of sediment to avoid pollution in the smaller tank. In the smaller tank the water is filtered through a sand layer of 80 cm. The sand purifies the water by prevent particles from passing through, but also by a natural creation of a biological skin in the top layer, which degrades the unwanted bacteria in the water (Mangold, 2012). When the water is filtered to the bottom it flows through the filter cloth and is pressured through the pipe and up to the tap, where the result is purified water. The filter cloth is to prevent the sand in the tank to enter the small bucket and plug the pipe.

Maintenance of the system

Where the two-step system is built, the challenge will be to convey the importance of a proper use of the system. The sand must de kept hydrated at all times for the purification to work, if not the bacterial degradation will stop (Mangold, 2012). Depending on the water source the time needed for sedimentation differs. During the seasons when river water is used, more maintenance and attention for decreasing quality in the water produced is demanded from the women responsible for the systems due to more polluted source water. Of this reason it is important to give the users of the system good knowledge about how long time the sedimentation process takes, for how long time the sand is of good quality and how often sediment has to be removed from the tank (Brauer, 2013).

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Bibliography

Brauer, I. (january 2013). Engineer. (J. Ringsby, & K. Blad, Intervjuare) Leticia, Amazonas, Colombia.

Mangold, M. (den 20 October 2012). Postgraduate, PhD. (J. Ringsby, Intervjuare) Gothenburg, Sweden.