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Sub-Sand Intakes

A picture commonly used to illustrate the plight of African refugees is that of a woman or child scooping water from a dirty hole dug in a dry river bed. The picture suggests not only a scarcity of water, but the little that there is is likely to be polluted.

There is something of an irony in this situation, because many African rivers have deep sandy beds which are actually a marvellous reservoir of water throughout the dry season. Not only that, but the water in the beds would be clean if only it could be extracted hygienically. The well jetting techniques developed by SWS Filtration allow well points to be inserted as deep as six metres into the sand quickly and economically and then connected to either a hand or mechanical pump to be used to draw water from deep in the bed before it is contaminated.

Water drawn in this way is likely to be suitable for drinking immediately and it will certainly be infinitely better than water scooped from unprotected holes which are often visited by animals.

For maximum security and the best quality water the intake should be inserted as deep as possible in the bed but even if the sand there is not especially deep, it is still possible to create a pre-filtered intake by using a device such as the SWS Filter Unit.

If sufficient labour is available long horizontal trenches may be dug and perforated pipes wrapped with geotextile may be laid at the bottom of these trenches to act as the take-off.

To summarise, SWS Filtration can supply both know-how and materials to exploit the sandy beds of rivers to give both easier access to and better quality of the water than would otherwise be available.

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© 1997 SWS Filtration | Page maintained by RHC
Last updated 18.04.01 | Contact details
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