Imagine some great disaster strikes (asteroid, solar flare, whatever) and shuts down the power grid and greatly disables road travel. Water service is unavailable because of the lack of power. You can survive on only the things within your walking distance. Your neighborhood has a community swimming pool and it is the only viable water source.
How would you go about making the swimming pool water drinkable? As for equipment, assume this is a normal, surban neighborhood. The normal household items would be available (pots, pans, garage tools, etc). There would be a plentiful supply of wood around for fuel. How could you create a neighborhood water purification system from normal household items?
All that cholrine and urine? I wouldn’t drink it unless it were distilled.
The easiest way? Figure out how to boil the water where there is no wind. Then, take a large sheet of glass, or metal and put it above the pot of water, so the flat surface is facing the water and the sheet is angled at about 45°.
Get the water boiling. When the steam hits the glass/metal it will condense. Put a pot under the low end of the sheet to catch the drippins. That’ll probably be good enough to drink. And probably as good as you’ll do in a post apocolyptic scenario.
Unless you’ve really overchlorinated it, it is already drinkable. The chlorine should have knocked out any fecal bacteria of significance (significant virulence and significant concentration of said bacteria), & dilute urine is not harmful.
I agree with the distilling as both the easiest and safest way to make it drinkable. If you’re in a relatively sunny and warm climate, you could even use the sun to distill the water which may be a good idea if you need to conserve firewood for some reason or another.
Really? I hadn’t realized that. Well, that’s no fun. So imagine that I’m not sure how the pool is treated. Maybe it’s treated with salt. Or maybe I don’t know if it’s been shocked recently. Actually, since the power has been out for a week and the pumps aren’t running, the pool has turned a lovely shade of slimy green and smells awful.
And if you don’t like the chlorine, just wait a while. If it were me, I’d fill every container I could; capping some for longer storage and leaving a few uncovered to naturally dechlorinate for short-term use. Becuase eventually the pool will dissapate all it’s chlorine and sooner or later get nasty.
Wouldn’t heating the water to boiling point get rid of most of the chlorine, and kill and bugs that the chlorine hadn’t killed, so that water would be safe to drink (if not all that tasty)?
Chlorine will evaporate out of a pool in a matter of a day or two - pools need a feeder to maintain an active supply. Furthermore, sunlight denatures the chlorine. When I managed an apartment complex swimming pool, our chlorine would reach 0 by mid-afternoon without a feeder to keep adding more. The amount of chlorine in a pool (assuming you’re within the 3-5 ppm required by health regulations) poses no risk to you, even if you drink the water.
The problem is as others have pointed out - within a week, you could be growing algae and mosquitoes.
My recommendation would be to keep a healthy supply of chlorine around (granules, tablets or bleach - for pool owners, these are household supplies) and treat the water that way. I’m not sure the exact amounts needed to make water safe for drinking, but it doesn’t take very much (10-20 parts per million is used for “shocking” the water). If you know basic algebra, you can use the instructions on the chlorine container to calculate the dosage. Dose the water about a day before you need it and leave it open in the sun. It may taste awful, but it will be safe.
The military has water treatment tablets that might be even better, but you specified household supplies.
These dont sound like likely scenarios to me. In the event of a disaster the first things stolen or hoarded will be chlorine and bottled water. You wont be able to walk into the local pool store and get chlorine or bleach.
Distilling by using heat or even evaporation is how people in extreme circumstances survive. By the time you spend two hours walking to the pool store only to find it empty or some guy with a shotgun telling you to get lost, your neighbor has already started siphoning and distilling your pool water to keep his family from dehydrating. He wont share any with you. Heck, he’ll probably keep people away from the pool with a shotgun too.
Ditilling is safe and simple, but takes time. Perhaps I have a more realistic view of the average suburbanite, but I wouldnt be surprised that giving the task of turning green water into drinking water via chemicals to a random guy will just lead to either unsafe water or chlorine poisoning.
This is one of my pet peeves. When fiction writers describe disasters it seems everyone is a McGyver and everyone has a can-do selfless spirit. Thats the exception, not the rule. In situations where water or food is scarce, guns and violence rule, not quick thinking and community spirit.
Bleach (the washing kind), at least in my house, doesn’t have enough concentration. You’d be pouring inordinate ammounts, even compared to liquid chlorine.
If your neighbor who doesn’t have a pool is siphoning off your pool water, where is he storing it? If he doesn’t have a pool himself the only place to put your pool water is in your pool.
You don’t need to distill pool water to make it safe to drink. It’s already safe to drink. It’s not like it’s going to turn into a swamp in a day, and even if it has algae the algae isn’t toxic. What you have to worry about is animal feces and dead animals.
So the most important thing is to put a cover over the pool to keep out leaves and dirt and animals and minimize evaporation. But the amount of water needed for drinking purposes is very small compared to the volume of a swimming pool.
And if you have household bleach you don’t need to sanitize the whole pool, just the stuff you’re going to drink that day. You haul out a jug of water, put in a few drops of bleach, and leave the jug to sit for a day, and drink it the next day.
So even if the water goes bad why couldn’t you just hang a tarp over a section (all) of the pool? Raise the center of the tarp so it’s tent-shaped and manage the edges so that the water that condenses runs down to one of the corners and into a collection vessle?
And drink on that while you hunt down a Fresnel lens (from the back window of someone’s conversion van) or other magnifying lens to create a solar-powered water boiling thing.
And then head for the hills while society completely disintegrates.
I’m not so sure about this. At Caltech, we were told (by those who have to think about these things) that in the case of a severe earthquake, much of our drinking water would be dechlorinated water from the gym’s swimming pool.
First, imagine this is the community pool and all neighbors are working together to make it drinkable. If it’s drinkable as is, then they’d just come with buckets. If it needs to be processed, the neighbors would work together to make it drinkable.
Second, I would be very concerned about the non-chlorine chemicals in the water. I know our community pool uses salts instead of chlorine. I would imagine the salt alone would make it unsuitable in terms of drinking water regardless if there were any bugs in it.
Perhaps the fire dept above said pool water was unusable because it would take more effort than would be an appropriate in a normal disaster. That is, in a normal disaster the authorities will come by relatively quickly and distribute aid. But if it was clear that aid was not coming in the foreseeable future, the pool water may mean the difference between life and death.
So say it’s been a week. The last of the suitable water left in the houses (water heater, toilet tank, etc) was gone 3 days ago. No one thought to store water because they all thought the authorities would be by with aid, which is not coming. Now you and your neighbors are looking at the only water source: 20000+ gallons of slimy pool water with an unknown amount of unknown pool chemicals. You will die if you don’t get water soon. Is there a way to make that water safe to drink?
No. If there’s no wind, eventually your surface will heat up and water will no longer condense. What you need is a large flexible hose, some rope, and a blanket. And some wind. Coil the hose so the input is at the top and the output at the bottom. Hang the coiled hose from a tree or something. Soak the blanket (in water or urine) and drape it over the coil. The steam from your kettle or whatever goes in the top of the coil and the energy of first heating then evaporating the water in the wet blanket cools the steam giving you potable water out the other end of the coil.
Bromine is virtually identical to chlorine in most respects. You need about twice as much of it for the same sanitizing effect, though.
The main reason bromine is used instead of chlorine is that it won’t form chloramines, which are the actual compounds that cause most of the classic chlorine smell and irritation.