Introduction: I've maintained a salt water reef tank for more than 10 years. The following is a improvised method that I used to process water to the point where it was acceptable for use with coral and salt water fish [before it is salinated] . Coral and salt water fish are very sensitive to toxic chemicals, nitrates, nitrites, phosphates, and ammonia in some cases just .02-20 PPM would be deadly to salt water animals, so filtration quality was key.
Improvised Water Filter
Water Filtration and Storage
On the run filtration
Building a Water Filter
Collection and Storage
On the run filtration
Collect water and run through several layers of cloth; then treat water with the following process:
Add 8-9 drops of plain bleach per gallon.
Shake up container, and let sit for 30 minutes
Open container and smell for bleach. If the water does not have a light smell of bleach, then add another 8 drops, shake and wait another 30 minutes. If water does not have a light smell of bleach at that point, the water is probably too contaminated, and should not be consumed. I would not exceed 18 drops per gallon.
Remember - use plain bleach, no additives at all.
Building a Water Filter
Water Preparation Notes:
Start with chemical processing using the 'on the run filtration' method. This should kill most bacteria and parasites; if you have power, you can replace this step with a UV sterilizer, however I would wait a few days before processing due to the UV disruption the reproductive cycle through DNA corruption for many bacteria and other critters. Exposure [of very shallow water] for a day or two under direct sunlight ["the SODIS method"] could also be an alternative if someone is too sensitive to the bleach method, and you have no power.
Chlorine/bleach evaporates - so after you have treated your water with bleach to kill micro-organisms (recommended), then let the water sit open for one to two days to clear out the chemicals. By doing so, less of the activated carbon is used up filtering out your introduced chemicals.
While letting the chlorine/bleach evaporate keep in mind you are also letting particulates settle. When you are ready to move the water to the filter, try and use a secondary container for transport, and not mix up the water. The final 2-3" of water will be far more polluted than the top layers.
On a side note, if you are testing your water with a kit, chlorine can show up as ammonia. Test for ammonia after chlorine has had a day or two to evaporate.
Questionable Secondary Filter Medium
There are specific filtration material available for nitrates, nitrites, phosphates and ammonia, however since I do not know if these are 'human' safe, I will let the reader research these for themselves - all of these media are searchable under "reef tank filter media." I will say that they are fish and coral safe (if purchased for fish tank filtering), and the coral and fish that I have kept for years are very sensitive to toxic material. If I were desperate, I would consider it; but it would have to be a life or death situation with children. Be careful here, it may be a last resort.
Building the Filter Layers
Layers from top to bottom, quantity will vary depending on the size of the filter, however depth it the critical factor.
Each layer can be held in a 5 gallon food safe container with holes punched in the bottom, stacked one onto of the other. When designing the frame, make it so that each bucket can be removed for maintenance. Don't make the holes too large, you want the water to seep through the media. Starting with a few small holes is much easier to increate for flow, than plugging many large holes. This is especially true with the activated carbon. Clean buckets as though they will hold food, and use only food save material. In each layer, increasing the thickness of the media will improve the quality of the water.
Layers 1-4 with 1 being the top layer. First three layers to have 5" gap between them if possible. If not possible, touching layers would be okay in a single bucket, but this is not ideal. The key with the gaps is to allow for water to pool above the medium and slowly sink through, it also helps to self compensate for the speed that water passes through the different media.
1. Linens/Bed Sheets, cloth material; two sheets thick minimal
Details: the number of layers depend on thread count, water should seep through, not pour through. Allowing the material to sag in the center will result in more water being processed in a single pour.
Function: Initial pre-filter, to keep out large debris
Note: recommend 'natural/organic' cloth to help prevent the medium from introducing chemicals to the water.
2. Cotton Balls - 3" thick when compressed by water.
Same function as #1, however since medium will have a different texture and thickness it will pre-filter out different material. In a SHTF situation, bed sheets and cloths may be at a premium, so if need be, #2 could be the only pre-filter, or visa versa.
3. Water Polishing Pads (Here is an example )
Function: These are micro-fine polyester filters designed to remove deters and microscopic material from water.
Details: One media think layer is acceptable.
4. Activated Carbon - final layer
Details: Layered 3" to 6" deep. (Here is an example)
Function: This filtration material removes trace elements from water, along with many toxic compounds. Activated Carbon, along with the pre-filter (fabric and cotton) are the critical components.
If you will be storing the water, you may want to add 2-3 drops of bleach prior to sealing the container.
Collection and Storage
It’s important to remember that each gallon is approximately 8.35 pounds. This adds up quick if storing or collecting for a permanent location. Average water consumption in the US is 4.49 Gallons per day (Here is some data.)
This adds up to 37.49 lbs per person, per day. That’s 262 lbs per person per week. Yes, showers will be more limited, but with lots of dehydrated food to prepare, and reserves for gardening, the numbers would be ½ the current average at best and most likely close to the same. Since the amount of water per person needed will be highly personalized, it is best to plan for the maximum possible water storage.
For those with a well or spring fed pond, storage is still a critical component. Droughts happen, wells run dry, pumps break. Besides, transporting water to a garden in 5 gallon containers is bound to get old soon.
We should also keep in mind that you can smell water when thirsty. Just like cooking food caries smells for miles, water does too. This should not be overlooked. Ponds, lakes, rivers carry the smell of water far, but a dehydrated person will still be able to smell a exposed rainwater cistern much further than you like.
Like any good defense there should be layers to water storage. Each layer kept in a different location. So, have a plan and cover story.
In my area, we have a few community wells pumping to our subdivision. Since water can get interesting during the summer, when everyone is watering their lawns, it is easy to explain my 8 x 24 bottle cases of water per person. It’s not much, but will help during natural disasters where power, and water pressure is temporarily unavailable.
Until I purchase a few cisterns my plan B is as follows:
Leverage plastic garbage cans, using reef safe silicone to plug any holes at the time and to dry a thin layer around the lid to seal in water from evaporation. One good thing about this is that no one has ever asked my why I have two extra garbage cans. Of course this will need to be cleaned with bleach, and collected water will need to be filtered. Yes, human safe is a question here, but it’s a SHTF plan.
Creating the seal. Apply silicone bead around the area of the plastic trashcan, where the lid comes in contact. Make sure the silicone bead is dry before closing. The intent is to create a barrier that will seal when the lid is shut, similar to the seal on an ammo can. Also use the silicone to plug any minor holes in the can, if you are forced to use a used trashcan. This is necessary for two main reasons: 1. It keeps bugs from crawling into the water, and 2. Keeps down evaporation.
For a location, I have an area near my gutter down spouts that I’ve cleared of major rocks and can dig our and bury the trash can with out too much effort. This area has plants, so yard work is always a good cover story. In a SHTF situation, the plastic can will be buried at night, a wood cover placed over it to allow for camouflage placement, and the plastic water re-direction tube on my gutter down spouts can be kept pointing at my plants until rain comes. Keep the location within a reasonable distance to a door/window for quick in home transport, and away from high traffic areas. Just a few minutes saved in accessing your water source could be the difference between a secret and a major neighborhood conversation.
If I had to dig a secondary location for water in a SHTF condition (which I most likely would), and someone saw the digging, I expect to use the ‘digging the next outhouse location’ as a good answer to keep away prying eyes.
The best way is to purchase several cisterns approved for storing drinking water. Once I can purchase the cisterns, I plan on putting on in the same location described for the trashcan. I won’t be able to hide the install so, since I have a few ‘green happy’ neighbors, I’m going with that approach. Telling them that I am collecting rainwater for use with plants around the house, and a secondary location for the garden, is far more neighborhood acceptable than saying I’m preparing for TEOTWAWKI.
Supplemental Tools: In addition to the storage, a hand pump is critical here. The pump must have a garden hose attachment. For my case, I have about 300 feet of garden hose, which just happens to be the depth of my neighbors well. (another item for my to-do list).
I’ve been looking at a Dayton Brand Hand Pump, Rotary 15 GPM, but will need to do more research. (The Grainger web site also has less expensive pumps that I might get first as a backup before getting the $100-$200 pumps. Not the best way, but I have other priorities to purchase first, and this would get me something while I save up for the better quality one. In the end I’ll have two hand pumps.
Note: even though the intent is to collect rainwater, do not be misled. This water still needs to be filtered. Roof top runoff water is exposed to your roofing material, let alone what the birds leave behind on the roof, and improvised storage medium may contain chemicals. Water filtration is critical, for health and safety.
On a side note: The more I plan, the more I kick myself for moving to a populated area. It’s no city here, but if there were a major event something as simple as having water would put me in a no-win situation. JWR, feel free to insert an ‘I told you so’ comment.
Testing the results
I would recommend testing the water pre and post processing. You may need to tune the depth of the material, and the number of holes in the buckets. Places like Petco have many fresh water testing kits.
Focus on the following kits:
Nitrate, Nitrite, Phosphate, and Ammonia. If the water is in the same range or better than for freshwater fish (guidelines describing the range acceptable for fish are almost always included in the test kits) it should be well within human tolerances. Note, that when I was processing city tap water for my tank, I almost always had to pre-process the water before using it with fish, since they need a higher quality of water than we do.