Water filters and their efficiency

In going down the Woodpile rat hole today, he mentioned a report on water filters, Water Filter Test Results | Best Choice for Backpacking, Survival & More , if you read one report on filters, you must read this one. Some of the most expensive do not filter viruses, some of the cheapest have the highest ratings, overall very well done. The test also mention that there are no official standards and while the advertising may be 100 % true, what they don't mention could kill you.

 

I haven't read it all yet , but that's about the most info I've ever seen on water filters in 1 place . Great post .

 

Very well done article, actually, it's more a 'tutorial.' I got Giardia once before because we weren't boiling our water long enough, was climbing in Nepal so wood and gas was scarce; needless to say, never want that again. It's possible, I got Hep A also from water but I will never know that for sure, that was in Bosnia, also something I never want again... So, I have lots of LifeStraw and water bottle filters. My water storage is a 1500 gallon cistern but I know that is not near enough but one never has enough. The good news is I have a very deep well, 400+ feet so as long as I can apply power and fill the cistern once a day, I'm good. The bad news is I share the well with 5 other neighbors so I don't have full control over it. Back on topic...

In my opinion, the most important bit of provided information :
1. "Purifiers and filters are technically different...Water purifiers must remove, kill, or inactivate all types of disease causing organisms from the water, including viruses, according to the EPA. Filters, on the other hand, do not have to protect against viruses."

2. The NSF standards in clear English plus a direct statement "NSF/ANSI 42 and 53 standards are not sufficient for portable water filters..."

3. The number of purifiers/filters tested and their no nonsense findings, again, presented in plain English.

I have saved this document and will refer to it when I select my next Purifier am going to look at a couple that ensure deletion of viruses like the Grayl, LifeStraw Mission or Renovo and also want to look into the Katadyn which I am not familiar with...

Thanks, Duane!

 

looks great................thanks a lot

 

Ran across this recent (2019) piece on portable water filters.

Duplicate of the above OP Post..

 

Got a Katadyn and a Berkey. You never know what is in the water.

 

I would caution folks that have a virus issue with their water that a portable filter is like shooting craps with your health. I filter (Sawyer) then treat with chlorine dioxide. 30 min later, good to go unless the water is ice cold. Then you are most likely going to boil it anyway, so good either way.

The reason iodine gets a bad rap (and is banned in the EU) for water treatment is the length of time need to kill Cryptosporidium (Protoza) and other parasites in the water.
[Efficacy of iodine water purification tablets against Cryptosporidium oocysts and Giardia cysts - PubMed] "Only 10% were inactivated after a 20-minute exposure to iodine according to manufacturer's instructions; even after 240 minutes of exposure to iodine only 66-81% oocysts were inactivated. These data strongly suggest that iodine disinfection is not effective in inactivating Cryptosporidium oocysts in water. Because this organism is common in all surface waters, it is recommended that another method of treatment be used before ingestion."

A Guide to Drinking Water Treatment and Sanitation for Backcountry and Travel Use | Camping, Hiking, Travel | Drinking Water | Healthy Water | CDC
Money quote:
If boiling water is not possible, a combination of filtration and chemical disinfection is the most effective pathogen reduction method in drinking water for backcountry or travel use. Manufacturer’s instructions must be followed.
This CDC product points out that boiling is the most effective way of treating water.

The Big Army view on iodine in water treatment (very sensitive to water temp)
https://phc.amedd.army.mil/PHC Reso... of Individual Water Purification Devices.pdf

As a side note, chlorine dioxide is now being sold as a surface disinfectant for COVID vurus.
disinfection for virus and bacteria

and in dental offices - Clinical use of Chlorine dioxide in the prevention of coronavirus spread through dental aerosols. some good data buried i the article.

Be careful out there.

 

It's my understanding that boiling, disinfection and/or UV is what's needed for viruses not filters. Filters can reduce/eliminate bacteria and protozoa depending on the size of pores in the filter.