Filtering / sterilising larger amounts of water

[Kirsty]

Our water is from a borehole and this has been affected by a number of faults leaving us with no supply, plus we have had a number of multi-day power outages in recent years which would quickly result in it running dry. I could trek up the hill to a spring but wouldn't have time or want to do it on a daily basis. There is a very small stream flowing past the house, no human/chemical pollution, quite possible dead deer and definitely livestock poop contamination, e-coli variants quite likely. How would you prepare that water for drinking, cooking, teeth cleaning, in a way that could be sustained for longer periods? Thanks

 

[HorseGuy]

Filtering and boiling are the best options but could be difficult over longer time periods.

Another option is to use calcium hypochlorite (swimming pool cleaner). Not something you would choose if better alternate methods of water purification are available but if you need to disinfect large quantities of water over long periods of time it is a viable option to consider as a backup.

It's also cheap to buy too. Just be extremely careful where it's stored though. If water gets into the bottles of calcium hypochlorite powder it will produce a toxic, potentially deadly, chlorine gas during the chemical reaction which will seriously burn your eyes and lungs. Keep it in a sturdy air tight container, well away from any sources of moisture and preferably in a well ventilated room.

 

[Kirsty]

Thanks @HorseGuy. That sounds like serious stuff!

I could establish a spring supply, with a storage tank on the hill. I have permission and I have been eyeing a spring that seems to be reliable, but there would be about 400m of pipe - which is quite normal in these parts but what the heck would that cost? I would feel better to have a gravity fed system even if it didn't pass official standards without filtering it would be acceptable for own use. I need to go price pipe.

 

[HorseGuy]

That sounds like serious stuff!

Oh yeah chlorine gas is not to be messed with!
God knows how many millions of men it killed during in World War 1.

 

[Broch]

Hi Kirsty, I have just been through a whole load of borehole supply and quality problems. Finally, we have now returned to crystal clear, untainted, water. Apologies for the long response and detail but it may be of value depending on your circumstances.

After 32 years of pure water from our borehole we first had a problem at the end of summer last year when our water smelled and tasted foul. I assumed it was bacterial contamination in the pressure vessel so changed the bladder and flushed the whole system with a shock chlorine system. That appeared to work.

In January this year our pump failed (after over 32 years of operation) and we had a new pump put in - we then found that our borehole is 68m deep.

This summer, again, after the drought the water was foul. I now suspected that our 2025 solution was a red herring and it was the water table drop that was enabling water from different ground water fissures to enter the borehole. However, upon testing, our water was only 1.5m from the head. It may still be dropping faster when in use and hence being filled by other fissures. On top of that I found that the company that had fitted the new pump had cracked and left a gap in the borehole sleeve that appeared to have allowed a small rodent in (we had small mammal hairs in the water!!).

So, what I have done is:
a) repair the borehole sleeve.
b) sent samples off to be analysed to see what we were dealing with (the water was definitely not fit to drink)
c) carried out a calculated volume shock chlorine treatment circulating through the borehole only and testing the free chlorine after 1 hr of circulation
d) circulated the chlorinated water throughout the house system and left it in tanks and pipes for 12 hours
e) tested the free chlorine (the amount of chlorine in mg/L remaining in the system)
f) flushed the whole system out with water running from all tanks and taps for 1 hour.
g) fitted a 4 stage filter system (spin down filter, 20 micron sediment filter, iron & manganese filter, 5 micron carbon filter)
h) Fitted a 25W Ultra violet sterilising unit

Result - clean, drinkable, tasteless water - but not cheap.

We also have rights to draw water from a well about 100m up hill from us (only about a 15m head) that I intend to draw from in emergencies (such as if our pump fails again). I would not drink that without treatment so I am looking into teeing that into the pre-filter supply.

 

[Broch]

Blue potable water 25mm piping is about £100/100m at the moment.

 

[slowworm]

Our water is from a spring. Currently we filter it in a Lifesaver Cube and boil for cooking and hot drinks.

It does need sorting out, the water seems quite clean but fishing the odd dead snail out the header tank for the ram pump would probably fail some tests...

I do need to replace our ram pump though, and then fence off the catchment area as we get deer passing through and the occasional flock of stray cows.

And I need to replace the house supply pipe as it's getting old, but I think it's around 300m and needs to be buried so not a small job.

My main worry though is how long the spring will last. The source isn't much higher than us, we've had numerous droughts in recent years and the farms that all draw water from bore holes havd doubled in size in the last decade so I expect the water table is somewhat strained.

 

[Kirsty]

@Broch I'm so glad you solved your problem and have clean water again, may it remain fixed for another 32 years. Thanks for the detailed reply.
I feel uneasy that there are so many ways for a borehole system to have a problem with quantity and quality. My childhood system was simple, and though we once drank an entire sheep before detecting a fleece and barely connected skeleton floating in the open concrete tank, corrugated iron cover having blown off, it was all accessible, gravity fed, and anyone could repair it. With a borehole it might be the power supply or a sensor or one of many possibly subterranean concerns...

@slowworm thanks, I just happened across the Lifesaver Cube, how are they to use? Hopefully it will continue to run, especially if you got through this years heatwave (didn't occur in my area but it looked like it was the ultimate water supply test).

 

[slowworm]

@slowworm thanks, I just happened across the Lifesaver Cube, how are they to use? Hopefully it will continue to run, especially if you got through this years heatwave (didn't occur in my area but it looked like it was the ultimate water supply test).

Initially our cube leaked a fraction around the tap/filter housing but adding a length of tube to the tap stops any risk of contamination and makes it much easier to use. Our spring water is pumped to a storage tank and we use the water from that to fill the filter. Most of the fine particles in the water settle out and we've used the same filter cartridge for 18 months and its still supplying water. As with any filter, you can't say if it works unless you get the water tested, but we've had no ill effects and don't notice any taint in the water.

I will say it is not quick, it's fine for the two of us but it's a stopgap until we sort out a new pump and filter.

 

[Kirsty]

Brilliant, I am going to get one of these cubes to have on stand-by. Thanks!

 

[Silverclaws2]

Has one thought about metal purification for I am aware both silver and copper are bactericides, in fact there is a method of purification that can be achieved by combining two metals side by side, usually copper and zinc

Connecting Two Metals Purifies ANY Water

And if this does not suit one can at least find amusement in the lousy AI illustration

 

[Broch]

Yes, the carbon 5 micron filter we have is silver impregnated.

 

[Watch-keeper]

We have a shack in the woods where we stay sometimes, it has a very basic well consisting of concrete rings sunk in to the ground to about 2.5 m deep where there is a spring. We tested the water and it was OK other than E.coli being 2 points over what is acceptable for human consumption. All we have done is run a pipe down hill from the well/spring to the shack and then use a large electric kettle to boil the drinking water, everything else like washing etc is done with the raw water, so far we haven't had any issues with illness. We did have a problem with foul smelling water so we did the same chlorine shock thing as Broch and drained as much water out as we could and that solved it for us. I have been advised to buy a microfilter for any sediment and a UV light to kill any bugs but it costs so it will have to wait.

 

[Toddy]

Interesting conversation on the topic here.....not quite practical, I agree, but interesting nonetheless.

https://chemistry.stackexchange.com/questions/179448/can-adding-alcohol-create-potable-water

 

[Kirsty]

Interesting conversation on the topic here.....not quite practical, I agree, but interesting nonetheless.

https://chemistry.stackexchange.com/questions/179448/can-adding-alcohol-create-potable-water

I will try, in the interests of science, with a 14 year old Ardbeg...

 

[Broch]

I will try, in the interests of science, with a 14 year old Ardbeg...

NO!! well, only a drop of water if you must