KNW-171
Water Warnings & Purification
by KJ Anderson, kj5emp
Revised 7/2021
Water is something that Americans rarely worry about but which makes national headlines from time to time when things go bad. The average human in good shape cannot last more than about three or four days without water yet, oddly enough, most large-scale disasters on the Gulf Coast are caused by too much water. To understand what you need to know about water in a disaster situation, you need a short refresher on biology, chemistry, and the 3 very different warnings local our federal health officials may issue but let’s start with a refresher on length…
1 inch equals 2.54 cm so about 2 1/2 centimeters in each inch.
1 cm equals 10 millimeters (ten of them in one centimeter.)
That’s pretty small but there are 1,000 microns in a millimeter and…
There are 1,000 nanometers in a micron…and some viruses are no more than a nanometer or two in length!
Now on to contaminants…
Now a brief refresher on chemistry. Organic and sedimentary contaminants can be measured in microns but chemical contaminants cannot and can be virtually impossible to filter out without a secondary or tertiary chemical reagent to neutralize a large enough distribution of potentially harmful molecules. At the time of writing, there is no way to filter petrochemicals out of a drinking water supply; the water must be treated with other chemicals to render contaminants inert or filterable.
We will not discuss how contaminants get in your drinking water supply, there are too many vectors in a disaster situation to list here. We will however discuss what you can do about it and what to listen for.
There are three warnings you will hear from local health officials or the CDC. They are:
The different kinds of water contaminants we will discuss in this training are:
- Physical or Sedimentary
- Biological
- Chemical
- Radiological
Physical/Sedimentary particulate contaminants are nothing more than dirt, rust, or sand in or on your water and vary in size. None of these will harm you in any reasonable amount but are not fun to drink and can cause horrible stains on everything. Many filters will easily remove sedimentary contaminants. This should be step one in your filtration and purification system.
Biological contaminants are nasties like bacteria, protozoa, worm cysts and, sometimes, viruses that can ruin your day. These can all be killed and viruses denatured by boiling or by adding chemicals such as Chlorine or Iodine. Radiation from the sun will also accomplish this but the conditions have to be right. Check the Internet for additional information.
Now for a brief refresher on biology. Large microbes can be 750 microns which is almost a millimeter, 3/4ths to be exact and are visible to the naked eye (thiomargarita namibiensis). Then we have Giardia at 10-20 microns, Cryptosporidium at 3 to 6 microns, E. Coli at 1 micron and on down into the nanometer range. One example we are all too familiar with is COVID-19 at roughly 125 nanometers. The common Influenza (Flu) virus is between 80 and 120 nanometers and finally coming in at just 15 nanometers is the Human parvovirus B19 which causes Fifth disease (mild/non-life threatening). None of these organic visitors are welcome in any of our drinking water.
Chemical contaminants are harder to deal with. Here is a brief refresher on chemistry. Organic and sedimentary contaminants can be measured in microns but chemical contaminants cannot and can be virtually impossible to filter out without a secondary or tertiary chemical reagent to neutralize a large enough distribution of potentially harmful molecules. At the time of writing, there is no way to filter petrochemicals out of a drinking water supply; the water must be treated with other chemicals to render contaminants inert or filterable which is one reason why farm/ranch runoff can be dangerous.
We will not discuss how contaminants get in your drinking water supply, there are too many vectors in a disaster situation to list here. We will however discuss what you can do about it and what to listen for. As mentioned, runoff from farms and ranches often contain contaminants that accumulate in ponds, streams, etc. When out collecting water to drink or to use for cooking, you must be careful about your water source. The most effective way to deal with chemical water pollution is via distillation. Distillation can be problematic because chemicals with lower boiling points than water will vaporize first and can contaminate the condensed water that you want to drink. It is best to avoid chemically polluted water if at all possible.
Radiological contamination is by far the worst because there is no way to purify irradiated water but they are, thankfully, the rarest of contamination events. If there has been a nuclear accident or attack and you are downwind of the event, DO NOT drink the water…especially during or after rain. Move at 90 degrees to the prevailing winds for as long as possible before collecting water to drink…and best of luck.
ADVISORIES:
- Boil Water Advisory
- Do Not Drink Water Advisory
- Do Not Use Water Advisory
A “Boil Water Advisory” is something most of us are familiar with. This indicates a potential biological contaminant in the potable water supply. The CDC states boiling water at a rolling boil for 1 minute at sea level will kill most contaminants. Bleach or Iodine are good alternatives. You may use the water for showering, washing dishes and even cooking, just don’t drink it until it is disinfected.
A “Do Not Drink Water Advisory” is a much more severe indication of a potential harmful chemical contaminant in the potable water supply. Boiling water will not remove chemicals from the water and, in many cases, will instead distill and concentrate the toxins in the remaining water making them even more dangerous. Use bottled water exclusively for everything. Commercially available filters will filter out these contaminants but it is advisable to buy bottled water to drink if it is available.
Finally, the very rare, “Do Not Use Water Advisory” exists to warn us about radiological contaminants or other chemical contaminants that are either extremely harmful in vaporous forms, or in any physical contact with the skin, lungs, or eyes. Again, use bottled water exclusively, do not mess around with this.
A reminder, if you get you water from the wild, i.e. lakes, ponds, streams, rivers or just from pooled rain, be careful of contaminant sources like farm fields, feed lots, fertilizer plants, etc. especially in flood or heavy runoff conditions.
When any of these advisories are issued it is recommended to turn off your water supply where it enters your house as well as water feed lines to all appliances with water or ice dispensers, your swamp coolers or misters, and your pool auto-filler until the advisory has been cleared and you have an opportunity to flush your appliances and plumbing with an adequate amount of clean water. Remember, your hot water heater can hold 30 or more gallons of potentially bad water. Some dishwashers have a “sanitize cycle” that heats the water over 150 degrees Fahrenheit and this is also sufficient to kill biological contaminants but is completely inadequate to remove chemical or radiological contaminants from the appliance. You might want to have your pool water checked by a lab after a serious event.
Filters.
An Activated Charcoal or carbon filter will be rated in particulate removal anywhere from 50 microns (which will not stop any but the very largest microbes) down to 0.1 microns- which effectively removes all bacteria but will not even slow down the average virus. Charcoal filters are suitable for filtering Giardia out of remote campsite water supplies but are wholly inadequate for disaster relief when it comes to virus removal. For newer filters that use nano-tubule filter designs, compare the filter’s ratings to a chart of virus sizes.
Newer filtration technologies like nano-tubules are orders of magnitude better than older equipment. Check specs regarding ability to filter out chemicals and compare to the virus sizes mentioned. In case you’re wondering, viruses and the smallest of chemical compounds are MONSTERS compared to the size of a water molecule.
A bit of a relevant sidebar- an N95 mask gets its “95” rating from its ability to trap 95% of all airborne contaminants larger than 0.3 microns in size (that’s 300 nanometers). An N99 mask traps 99%, and an N100 traps 99.97% of all 300 micron contaminants. “N” means Not Oil Resistant, “R” means Resistant To Oil, and “P” means Oil-Proof. Respect the P100. More on that in a different training session. Back to water…
A reverse-osmosis water filter is regarded by the CDC as the best form of water filtration, removing particulate contaminants down to 0.1 nanometers in size including all biological and sedimentary visitors. It is important to understand that this filtration comes at a cost of efficiency. A reverse-osmosis (or RO) system must continuously flush water over the dirty side of the filter membrane to keep it clear thus producing a concentrated flow of flushed contaminants which are typically routed down the sink drain.
That concludes tonight’s training. Are there any questions, comments or suggested additions to this material?
Thanks, this is (callsign) clear to net control.
Send corrections, modifications, updates or suggestions to k5prs@aol.com