Posted: 5/8/2010 5:00:17 AM EDT
| Hi Folks, I have a 275 gal water storage tank, and have been pondering how to treat the water. Some say treated water has to be rotated every 6 mos. others say every few years. My question is this; If not treated can I just filter the water when needed? Thank you. |
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Some folks have stored water for more than a year and not had issues. I've had filtered tap water start to grow green stuff in less than a month. I'd say at least use municipal tap water as a minimum level of treatment. If you are on a well then use some chlorine to treat the water. Filtering before drinking(cooking) the water is a good idea.
Just my opinion because I do not have a tote. |
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Johnny;
A lot depends on the original source of the water and the conditions under which it was stored. The best possible source would be municiple water. It is frequently tested for quality and is pretty "sterile" right from the tap... The next thing to consider is the tote... FIrst and formost - I assume you tote is "food grade / food safe"... I think that the tote should be cleaned and rinsed/drained very well before you start... If possible, I would try to find a way to spray down the inner walls with chlorine bleach (clorox or pool chlorine liquid) - let it "soak" for about an hour and then rinse/drain throughly again... at this point the inside of the tote is essentially sterile - now the trick is to not introduce bacterial contaminants while filling the tank... I would get a length of copper tubing a bit longer than the distance from the opening of the tank to the farthest bottom corner (I assume it is open at the top). I would meticulously clean the inside of the tubing to make it "sterile" and then attach it to a hose (you will need a hose clamp)... this "wand" will be used to fill the tank and it will also be used to stir the contents of the tank to mix any chemicals you may add... Cleaning the tank - I assume that the tank is already "clean" as far as you can tell with the naked eye... If not, find a way to get the tank "naked eye" clean... THEN, sterilize the outside of the wand (use a chlorine solution at about 200 ppm) and place the wand in the tank. Turn on the water and start filling the tank... Add sufficient chlorox or pool chlorine liquid to make the final chlorine concentration 100 ppm. 1/2 gallon of pool chlorine will raise my 10,000 pool 5 ppm - that is 6.4 ounces per 1,000 gallons or 1.76 ounces per 275 gallons (to get to 5 ppm)... therefore is should take about 35.2 ounces to get to 100 ppm in your 275 gallon tote. To offset the pH rise caused by the sodium hydroxide (aka lye) in the chlorine solution, add 2 ounces of muriatic acid (for pool use) per quart of pool chlorine used. I would ballpark the muriatic acid at 2.5 ounces... add the chlorine first and then wait until the tote is at least 1/2 full before starting to add the muriatic acid. I would dilute the muriatic acid (2.5 ounces) into 1 gallon of water and add it slowly as you stir the tote with the wand. Continue adding water and stirring until the tote is full to the very top. Then miticulously clean and disinfect the lid to the tote and put the lid on. Let the tote "soak" with the chlorine solution for about 2 or 3 days and then drain the tote into a drain or your pool if you have one... At this point your tote is ready for filling with water you want to store... almost... Don't forget that you need a way to "vent" the water tank when you are removing water from it - i.e. a way to allow air to enter the tank as water leaves... you also need to consider a way to do this that will prevent any "contaminated" air from getting into the tank thus contaminating your water supply... you can use various improvised filters for this - you are basically trying to filter out any particles in the air - dust etc. as dust carries microbes. Also, remember to keep the tank sealed once you have filled it with water you want to store... Other considerations: Some of the storage conditions are worth considering at this point. (1) Algae seems to come from nowhere under the right conditions... Most algae are not harmful especially in low numbers but for my money, I like to keep algae to as low a level as possible... The majority of algae that we see requires light to grow (algae is technically a plant). If you keep the inside of your tote "dark" then most algae will find it almost impossible to grow. If your tote is translucent (will allow light to pass through it) you might consider painting the tote black. Alternatively, you can cover it (as completely as possible) in order to keep out as much light as possible in order to discourage algae growth. If your tote is not translucent (like most metal containers) , then you don't have to worry about light intrusion... (2) Next, consider temperature - Try as you may, you will not be able to get a tote full of water without any bacteria at all. You will try to kill and discourage bacteria with a sanitizing agent (chlorine) but temperature also plays a role here... Bacteria like warm conditions to grow. Human body temperature is ideal for most bacterial growth (algae also like warm water to grow in). Keeping the tank as cool as possible will be helpful... I don't mean that you have to pack the tote in ice or anything like that but storing it in as cool a place as possible will be beneficial. (3) Testing equipment - you should probably consider going to your local pool store and getting one of those simple kits (to test chlorine level and pH) that are made for testing pool water. Municiple water supplies are chlorinated to a level of about 5 ppm of chlorine as the water leaves the treatment plant for distribution out into the community... It comes out of the tap at something less than 1/2 ppm in my part of the world... When you store water, I think it is a good idea to bring the chlorine level back up to about 5 ppm - this level of chlorine is relatively good at sanitizing the water and is safe for human consumption although it tastes like crap. You will need a test kit to determine if your chlorine level is where you want it. In addition, chlorine is much more effective if the pH is at or near "neutral" (pH = 7.0 to 7.4) so adjusting the pH with muriatic acid is useful. The recipe that I use in my pool is 8 ounces of muriatic acid will offset the lye in 1 gallon of pool chlorine. This recipe is a reasonably good approximation but the exact characteristics of the solutions being added may vary somewhat from time to time (the reagents are NOT exactly analytical grade) so testing the pH and the chlorine level is useful in getting these numbers where you want them... (4) Sealing the container - sealing the container well will prevent contaminants from getting into your tote and fowling the water therein. The better the seal, the longer the shelf life of the water in the tote. In addition, chlorine leaves the water by off-gassing from the surface of the water into the atmosphere above the water. If the tote is tightly sealed, the chlorine gas will not be able to escape and the water in the tote will stay "chlorinated" for a long time - this will also extent the shelf life of the water in the tote. Filling the tote to store water - again, using your best possible "sterile technique" (basically disinfecting everything that will come in contact with the water that you want to store), start to fill the tote again. This time you will be adding amount of chlorine and a corresponding amount of muriatic acid to get the chlorine level up to 5 ppm and the pH at about 7.2. I would add 1.75 ounces of pool chlorine and 2/3 of a (measuring) teaspoon (3.3 cc) of muriatic acid. Add the chlorine at the beginning and add the acid (diluted into 1/2 gallon of tap water) SLOWLY when the tank is about 1/4 full. Add water and fix well until the tank is 1/2 full and stop. Draw some water from your tote from the spigot at the bottom and test it. If the reagent concentrations are what I am used to and my calculations are correct, the chlorine level should be at about 10 ppm and the pH should be in the low 7s (7.0, 7.1, 7.2, etc.). If so, then proceed to fill the tank to almost full and retest... the pH should still be in the low 7s and the chlorine leve should be 5.something. If so, top off the tank and seal it as well as possible. CONGRATULATIONS, YOU ARE NOW STORING WATER!!! Mr. Chemistry notes: (1) The solubility of a gas (in this case chlorine) in water is inversely proportional to temperature. >>> What this means is that gases have a tendency to stay in solution in water at cooler temperatures and have a tendency to come out of solution (off-gas) at higher temperatures. We can use this principle to our advantage by keeping the tote cool, the chlorine will have a tendency to stay in the water and continue to kill (or at least prevent the growth of) microbes. When you want to drink the water - withdraw the amount that you want and test the chlorine level. If the chlorine level is easily measurable, I would feel very safe (from a microbiological perspective) drinking the water. If the chlorine level is significant, you will be able to smell or taste it when you drink the water. To get rid of the chlorine prior to drinking, simply allow the water to stand overnight in a large open container (think big pot) - protect the pot from debris falling into it and contaminating the water... If you would like to accelerate the off-gassing of the chlorine, take advantage of the gas solubility rule above and heat the water - the chlorine will go away much quicker. The higher the temp that you heat the water to, the faster the chlorine goes away. If you can bring the water to a boil, the chlorine will be gone in a few minutes (probably about 10 or 15 give or take). Alternatively, you can pass the water through an activated charcoal filter to remove the chlorine... (2) You must exercise great care when mixing solutions of chlorine and muriatic acid. If these solutions are mixed slowly and in a dilute state, you will be pretty safe. NEVER try to mix the stock solutions (i.e. solutions straight from the bottle), they are far to concentrated to mix safely. Mixing stock solutions is guaranteed to result in significant misfortune - if you bubba this up, it will kill you and maybe a few of your loved ones - DON'T DO IT. (unless of course you like ambulances, police cars, and hazmat teams) Ongoing testing: Once your tote is filled and you have determined that the chlorine level and pH are reasonable, keep the contents of the tote cool and dark as possible. Don't forget that water weighs about 8 pounds per gallon so your tote will weigh 2,200 pounds (water) plus the "dry" weight of the tote. A good place to store it is in a basement (already cool and dark-ish) and if you spring a leak, you hopefully have a floor drain. A bad place to store it is in a second story "spare room" - for obvious reasons... You should probably withdraw a small specimen from the spigot on your tote about once a month and test it for chlorine and pH. As long as the chlorine level is above 2 ppm, you can have a high level of confidence regarding its safety (from a microbial POV). When the chlorine level falls to an almost unmeasurable level, you should probably consider rotating it out and replacing it with a new batch... If you make it to a year with perceptable levels of chlorine, I would suggest pulling off a specimen and sending it off for analysis just to see what comes back... I would have it tested chemically and microbiologically. If I thought the results of the analysis were "favorable" I might be tempted to keep the water for up to another year. ...but at 2 years, I would dump and replace it... Whatever you do, keep accurate notes so that you can learn from past experiences to further refine your technique... Disclaimer: I HAVE NEVER ACTUALLY DONE THIS IN THE REAL WORLD. But I do have a few advanced degrees with an emphasis on chemistry, biochemistry, microbiology, biology, physiology, etc... The descriptions above did not come from any place other than my head (i.e. there was no cutting/pasting involved) - they are based on my own knowledge, experience, and training. The principles are sound although may require some tweeking to get it right - what I described above is how I would attempt to do it if I were so inclined. I would keep accurate records of everything that I did and the results of all testing in order to refine the technique into a workable solution for SHTF potable water needs... I would also search the web looking for "tips and tricks"... Discussion: I hope that I didn't snow everyone with the details and minutia above but, when it comes to the drinkable shelf life of stored water - the devil is in the details... There are simply too many variables for anyone to reasonably predict the "safe to drink" shelf life of water stored in a tote. I would guess it to be in the 6 month to 2 year ballpark but that is just my guess based on some background but no real world experience. If I had a tote and the inclination, I'd do exactly as above and see what the actual shelf life was in my particular "real world" and would rotate my water accordingly. In my part of the world, 275 gallons is not all that expensive so if testing indicated that the practical shelf life was 9 months, I'd rotate my stock every 6 months. In a worst case, I would be using 550 gallons per year to water my lawn or replace water lost from my pool... but even if it were going down the drain, it wouldn't be much of a problem (in terms of cost). I hope you found this helpful... I wish you luck on your project... If you are a really nice guy, you will update this thread periodically with test results and other observations so that others may benefit from this interesting experience/experiment... Hasta... 
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Shibumi's Survivalist Water Storage Primer:
People just starting out go through a lot of effort to figure out how to store water and keep it drinkable. They make it a lot more work and a lot more expensive than it needs to be. They try to sterilize it before storage and spend endless time debating the best methods. IT DOESN'T NEED TO BE THAT COMPLICATED! Really simple: Figure out how much water you need for your drinking (not cooking, not washing, DRINKING) needs per person per day for a week or so. In Indiana that'll be 1/2-1 gallon per person per day (washing and cooking water will be on top of that) for about a week. Then buy as many 5 gallon containers as you need to fill that requirement. Fill them from your regular water source. Store them in a dark location. Rotate that water out every six months or so. That takes care of drinking water. Don't bother treating it with anything. Now figure bulk storage, however much you want to store for however long you plan on needing water. Figure 1-2 gallons of water per person per day. Fill that up (whether it's a pallet of 5 gallon containers or larger tanks, whatever), don't bother treating it. Then if SHTF, you can treat/filter the water you actually DRINK. You don't need to bother treating it if it used for cooking or washing. That's it. It's that simple. Always remember you have 30-80 gallons of fresh water in your water heater. Figuring out how to drain it before SHTF is a good prep idea. |
| Thank you guys. Let me clarify some of the details. It is food grade plastic (make just for water storage), my water will be municipal water, and will be stored inside, in a cool, dry place. The tank is from surewater tanks. Thank you for your time and information. I will keep everyone updated with my progress. |
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Quoted:
Thank you guys. Let me clarify some of the details. It is food grade plastic (make just for water storage), my water will be municipal water, and will be stored inside, in a cool, dry place. The tank is from surewater tanks. Thank you for your time and information. I will keep everyone updated with my progress. You're probably good to go already. City tap water, as has been said (mine comes out of the tap reeking of chlorine). If the tank is translucent, cover it. Keep it cool, keep it closed, it should last a good long time. Simple unscented Chlorox is a grand water treatment that costs dirt, and seldom even needs to be added until you're ready to actually use the water. You're far more likely to contaminate the water as you're dispensing it than you are in storage. |
