Aeration and disinfection of drinking water ponds from rainwater
A client of ours is funding water storage facilities for individual allotments in the Sudan. It is a matter of creating a lined pond and then covering same so that the owners can draw drinking water from rainfall over the dry season.
The problem is how do you keep it aerated and how do you disinfect same in a low technology way.
Do you know anything about this or perhaps someone who would have the necessary experience of low tech approaches to such matters.
I've told him as bit about them typical operation of hafirs in the area and at the time that I was in Sudan.
4 Answers
Sounds to me like a modern version of the standard cistern or a small scale hafir. I do not see the point of aeration. Provided it is really well protected, and facilities for drawing the water designed so that there is no puddling around or possibility of back flow into the pond, you may get away with washing it with a chlorine solution when dry.
Of course, protection measures apply equally to getting the water into the cistern. If additional treatment needed: filtering +/ boiling water would be too difficult/expensive. I came across reference to a tree with flowers/seeds used in Sudan to precipitate sediment - at the same time removing some bacteria..
Harriet
I have seen some of these small rainwater harvesting facilities in Ethiopia - lined ponds with corrugated iron roofs. The government was promoting the widespread construction of these things for small scale irrigation with little regard to the economic viability of building them. I am sure that they are also used for drinking water and would have a few suggestions to make in that respect;
- Ensure the catchment area is a clean as possible from faecal contamination
- Build some sort of sediment trap/ simple sand/gravel filter to pass the water through before it enters the tank
- Keep interior of the tank dark to avoid algal growth
- Use fixed bucket to extract water so that it is not so subject to pick up dirt in the house/yard
Even with these precautions, the water will probably still not be pure. Disinfection by boiling, chlorination or solar radiation UV disinfection may be the best low cost/low tech. way forward.
Similar structures in Palestine are disinfected with chlorine from time to time but that may be too expensive or difficult for parts of Ethiopia and Sudan.
An excellent website that deals with many issues relating to Rainwater Harvesting and low-cost tanks is https://www2.warwick.ac.uk/fac/sci/eng/research/dtu/rwh/
Martin
An excellent website that deals with many issues relating to Rainwater Harvesting and low-cost tanks is https://www2.warwick.ac.uk/fac/sci/eng/research/dtu/rwh/
Regards, Brian
It would be useful to know where people are drawing water from currently and how they store/treat that water. Also further technical details of the project would be useful – is it for instance surface or roof run-off, how big are the tanks, how many people will use each one and is it only for drinking… I am assuming we are in southern Sudan….. I believe the seeds Harriet is referring to are Moringa seeds, see for instance https://www.echotech.org/mambo/images/DocMan/MorWaterTreat.pdf
Regards,
Tim
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