Printable View for Presentation #78 (See also "Manual on a String").

CLEAN WATER FROM AN EMERGENCY WELL

Considerations about safe drinking water at home in case of regular flooding
Flooding may occurs regularly and remain within limits where evacuation is not needed. In such a case a source of water for drinking and washing can be arranged at one's own yard, as during such a flooding normal access to drinking water may become interrupted. There is the temptation to use the water that has flooded the surrounding. But this is a dangerous practice, as there is a mayor chance that excrements of human or animal source contaminate this water. This can cause cholera and other illnesses.
In the next illustrated pages a possible solution is proposed, that will give the wanted amount of water and that is located at one's own yard. Time for construction is about two days, the cost involved is that of sand (often for free), a small piece of plastic sheet and about 15 liters of cement.

Author: Demotech, design for self-reliance
Version: Juli 27, 2008 Feedback email info@demotech.org
Postal: Biesenwal 3, 6211 AD Maastricht, the Netherlands

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1. Excavating the filter bed

Dirt is excavated from a hole 1.5 meter deep and 2 meter wide. Throw the top layer composed out of sand and clay with organic matter on one heap. It is unsuitable for later use as a filter.

If at a layer deeper then 1 meter sand is found, then throw this sand on a heap well separated from the first. This sand will later be used to filter the instreaming water.

2. A circular barrier is made to guide the flow of water through the sand

This barrier has the shape of a wide tube and is made of plastic sheet.
It is suspended from sticks, crossing the dugout. The sheet plastic tube, 0,6-m diameter and 1-m height is placed in the center, 20 cm free from the bottom of the dugout.

The dugout is then filled with clean sand (no clay or organic parts). The sand must be evenly distributed on the inside and the outside of the plastic barrier during filling back.

3. Construction of the top part

Access to filtered water can be made with a brick or concrete tube, extending well above the expected highest water level during flooding.

This pipe is stabilized in a concrete slab at ground level. Utmost care should be given to ensure a leak free interconnection between the plastic barrier and the up going pipe.

Safe water can be collected in a suitable way from the reservoir that forms inside the pipe. Adding a few drops of bleaching-liquor ensures the water is safe for household purposes.

4. Additional info on sand filters

The biosand filter can make a difference, providing safe drinking water, right where it's needed most: at household level, because it effectively purifies contaminated water. Cheap and simple, yet effective. WASH believes this filter can make a difference, save lives, where other technology fails or is too costly.
Check out the technical pages, photo construction guides, project evaluations, scientific reports proving the intrinsic effectiveness of the filter. Build your own filter or start your own sand filter project and read about past projects.

Author: Demotech, design for self-reliance Version: Juli 27, 2008	Feedback email info@demotech.org Postal: Biesenwal 3, 6211 AD Maastricht, the Netherlands
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