The following exchange might be of assistance to anyone looking at setting up clean water supplies in rural parts of Africa
We received the following email:
“Thank you for your very helpful website https://www.uk-water-filters.co.uk which has given me a lot of thoughts about the possibilities of water purification.
I am a UK Surgeon volunteering at a rural Mission hospital in the East of Rwanda for the next five years. I am wondering about the possibility of using a UV water filtration system with pre-filters for two separate projects here.
One is providing purified water to the sinks in our operating theatre – this would be essentially for mains-supplied water pumped up to and stored in a header tank in order to provide the necessary pressure. We currently use mains water, but I am unconvinced of the water quality in the system (rural Africa!).
The second project would be for use in our own house here. Again, there is mains water (which we store in a tank and then filter before drinking), but the supply is unreliable and we are reliant on rainwater harvesting for some periods of the year. While I would not necessarily want to drink purified rain water, some form of filtration would probably be useful when using this water for showering, etc.
Looking at your Ultraviolet filters https://www.uk-water-filters.co.uk/types/ultra_violet_water_filters.html I think your 19W UV system would probably suffice for our theatres, but your 30W UV system might be needed for the house (although we use very little water due to its scarcity). Ideally this would run on solar power. The main issue for us would be getting the replacement filters and UV bulbs. My query is therefore about how bulky these items are – i.e. could the needs for a year fit into personal luggage on return from a UK visit each year? and also whether you would be able to send overseas to Rwanda if needed?
A quote for the cost of the two systems including pre-filters would be very helpful, along with the yearly costs of replacement filters/bulbs.
After a fair amount of back and forth we got the following update on the solution:
“I already had two 1000 litre rubber bladder tanks at ground level which fill from the mains water when it is on and the pressure is high enough (often not for several months at a time in the dry season!). I also have 5000 litre and 2000 litre rainwater harvesting tanks at ground level.
I now also have a 750 litre water tank at 3m high. This can be filled from the mains water tanks via an existing pump (that used to provide water pressure to the house, but the pressure switch no longer works).
This will be the main water source when it can be. The new tank can also be filled with rainwater using an existing submersible pump which pushes this water through a pre-filter (Atlas Hydra self-cleaning 100micron polyester filter).
Water from the new tank then passes through a 370W pump, controlled by a pressure switch to provide 1-2 bar of water pressure at all times. From the pump it passes through two So-Safe 10 & 1 micron Polypropylene Yarn filters, followed by a Sita UV filter before entering the house. The pump and filter run from a voltage-protected 2000W modified sine wave inverter UPS/Car battery for when mains power is off.
I have also fitted bypass taps to enable any part of the system to be removed should it not be needed or be serviceable in future – the realities of having something that will work for a while in Rwanda.
I am currently still boiling water for drinking and passing it through a ceramic water filter, until I can get a water sample tested. However, I feel a lot safer when my young daughter is bathing in water that has now had some sort of filtration, rather than being previously unfiltered.
As far as potential assistance in future goes, I am hoping to have some time over the next few months to look at the water system in our hospital. We have significant water difficulties there (not ideal in a hospital), but we do collect rainwater and have something of a mains water supply.
There are a couple of plans to bring a more reliable water supply – the national water company want to bring us a dedicated pipeline from their spring 5 km away (although this was done before, and now has so many people taking water from the pipe before it reaches us that there is frequently none left!).
Another proposal is for a borehole on-site (although apparently a nearby school has a borehole and the water quality is poor), and a third proposal is to pump water 2km & 500m up from the local lake.
Discussions are ongoing here, and it is important for us to support a project that has a chance of succeeding, but also that is developed and owned by the local people, otherwise it won’t be maintained.
At present there is only about £20000 available for what is expected to cost £50000, so it may take some time… Meanwhile I hope to sort out a smaller-scale plan for getting rainwater/lakewater filtered for use in our operating theatre. I’ll get in touch when I have a better idea of what is possible/sensible!