Water filtration

[redlantern]

I'm thinking of still wanting to divert rainwater (from covered butts) to drinking purposes.

Does anyone think the Brita or similar domestic water filters are any cop for removing nasties from the water? Or are the ceramic microfilters the only things worth looking at?

Boiling would be nice, but of course it needs fuel, and I don't think solar distillation is going to cover requirements by itself.

[Bandidoz]

Does anyone think the Brita or similar domestic water filters are any cop for removing nasties from the water?

Absolutely not! Would you dare to drop pigeon faeces into a Brita filter and drink its output?

I looked into this some time ago, and decided the amount of effort required to filter and test water for drinking is really not really worth it at a single household scale. One example I've seen in use is at Earthship Brighton

They use a number of stages of filtration:
1) A WISY filter
2) A Rusco Mesh filter (45um / 20um) - like a coffee filter
3) An "American Plumber" WVC34 Charcoal filter (5um)
4) A Seagull IV filter

They also mentioned that regulations require a UV filter as well.

Try these for further information:

http://www.eng.warwick.ac.uk/ircsa/fact ... inHarv.pdf

http://www.eng.warwick.ac.uk/ircsa/factsheets.htm

http://www.wras.co.uk/

[kenneal - lagger]

You can use a slow sand filter followed by UV for potable water.

http://tilz.tearfund.org/Publications/F ... filter.htm
or
http://openlearn.open.ac.uk/mod/resourc ... ?id=109148

[Kentucky Fried Panda]

Katadyn, nuff said.

[kenneal - lagger]

If you've got mains water use it, and drainage too. You will generally put more energy into treating water yourself than your local utility will doing it for you. Economies of scale definitely work in water supply and disposal.

If, however, you are preparing for PO Doomsday you will want the simplest set up possible as even UV lamps may be difficult to get hold of in that scenario. A hand pump and a gravity sand filter would last for years with only the sand needing replacement occasionally. Keep your family silver for a final bacterial treatment of the water

[Tracy P]

My hyper husband bought us a katadyn pocket filter and we had a try drinking rain water! Takes our all bugs and parasites etc, and makes water taste of bricks! but, nice to know we have one.
The way we catch rainwater will change in the wood too, so that it doesn't come off a grubby roof and starts up slightly cleaner!
Works well!
Tracy

[redlantern]

Rainwater diversion still in the planning stage, along with the pair of trousers with one leg inside the other (not worn, obviously) for prefiltering.

But I have acquired the Pocket Katadyn filter. Hopefully I can pass it on to the next generation almost unused, given it has a 20(!) year warranty, up to 50,000L duty cycle, and built to inspire confidence. Only trick will be making sure it's properly dry before any freeze takes place, as water left in the ceramic core could crack it which would ruin the filtration.

Given that I posted the initial question before the floods, it was instructive to watch people queuing for bottled water, and interesting to think of what would happen if there weren't enough logistics corps to stage the delivery.

[Kentucky Fried Panda]

The rule of 3 always apply.

Water.
Food.
Shelter.

[kenneal - lagger]

Having done a practical on water treatment for my MSc since my last post, I would now say that for a permanent water supply post disaster/PO you would need to plan for two scenarios:

1 Immediately post disaster/PO you would require either a store of drinking water or the means to filter enough (Katadyn?) for maybe a year.

2 A permanent supply of drinking water would then have to be established. This could take up to a year. The easiest way of providing a large scale water supply is from a properly sited and safeguarded well. Clean ground is the easiest way to filter water so you have to avoid any industrial pollution or sewage contamination.

If you build a sand filter you need single size sand, i.e. all the grains the same size, so that water can flow through. If you use a building or plastering sand with an even grading water cannot flow through it very well and it clogs quite quickly. Post disaster/PO it may be difficult to source a supply of this sand. It also takes time for a sand filter to become effective as a layer of organisms, which take out the pathogens, has to be built up in the sand at the top of the filter.


The lesson from the floods is "Never ever live in a house on a flood plain" because any provision for drinking water you make will probably be contaminated. With the weather we have been having there won't be a problem, outside of flood areas, getting well water as long as we keep the ground clean. So don't allow any ground pollution near your well site.

We found in our practical that it is very difficult to clean water and, using our improvised filters, we actually managed to make treated sewage effluent dirtier! Our conclusion was that it is easier to keep water clean than it is to clean it.

[redlantern]

Kenneal, thanks for the info.

Would you recommend something like playground sand as better for a filter?

My plans are based on increasingly extreme climate, so the weather we've been having will lull us into a sense of security before the gulf stream goes N next year and gives us a bad drought

[kenneal - lagger]

Redlantern, playground sand is basically ordinary sand with the silt thoroughly cleaned out so that it doesn't stain clothes and hands. I'm not sure where you can get single size sand from. I'll make enquiries. Your sand filter would need to be about a metre deep and the surface area depends on the amount of water you want.

If the Gulf stream goes it will be so cold that a bit of drought won't matter.

Ken

[MisterE]

I'm assuming the rest of the UK like Wales really doesnt need some plan for drinking water in PO. If anything we got in wales which is in abundance is Water or am I totally off the wall? Its just that when we'd go off camping as kids for days at a time we'd never take any water, just drink what you can find lol. Also when we had droughts, we'd drink what is in the hot water cylinder

[redlantern]

Depends on how long your water has been on the surface, and whether there's a dead sheep upstream...

[Keela]

I do think it's important to remember that you can get some natural immunity to less than perfect water (conditions apply!) and that a sudden change from drinking ordinary water to a new less purified source may cause some people big problems - even if others have been drinking the alternative source for years with no problems.

My gran lived off well water for years (and we all drank it on visits) yet when we moved here and got the water tested we were told not even to wash in it!

Granted the well had been going downhill for a year or ten and we now know that run-off from the field (with cattle) was reaching the well.... but the point is we had all been drinking it totally untreated with no ill effect!

Luckily when we moved in I started boiling the water for the children .... and after the test results we got mains installed.

Now 17 years later we are hoping to re-instate the well. The field is now planted in trees (10 yrs old) and my OH cleaned the well up and found the crack in the rocks through which the water rises. Testing this has shown it to be of top quality. We await a second testing and some plumbing and basic treatment before disconnecting the mains again.

[snow hope]

Can anybody recommend a mains water filter at a reasonable cost? I would be interested in installing one as I think mains water will be one of the last utilities to be allowed to die-off.