Upcoming Tech in sourcing clean water

Howdy Yall,

With the multiple water treatment facility failures in the news I was digging into water purification/desalination and came across some interesting papers I thought I'd share here.

Yoon et. al. (2022) have now started field studies for a filterless desalinator! From what I've read it was designed to run off a little ($50) solar panel and only weighs 10kg. Looks like it currently only produces about .3L/hour, but with with additional solar panels and a battery backup that would be 7.2 Liters/day while off-grid. From related articles and interviews it sounds like the researchers are intending to create a desalination kit that would be available to consumers, likely at a reasonable cost as they target low-income families in coastal nations. While a bit too heavy for hiking, it sounds like it would be great for bugout vehicles and off-grid structures with access to non-potable water sources.

Guo et. al. (2022) looks further from market, but is more intriguing imo. Its a gel film that essentially acts like a powerless dehumidifier, just pulling water from the air but with no electricity! And its not just for the humid swamps, one report was saying that 1kg of the gell could pull 6L/day in humidities lower than 15%, and 13L/day with humidities up to 30%. In interviews the researchers are envisioning this gel as (eventually) available in hardware stores. Now it looks like the gel has to be heated to release the water, and the lifespan of the material hasn't been reported yet, but I still think its exciting.

At the moment I'm mostly geared for distillation over an open flame. What are yall's favorite current and future potential methods for water deslination/purification?

Papers:
Yoon, et. al. (2022) 'Portable Seawater Desalination System for Generating Drinkable Water in Remote Locations'. Environ. Sci. Technol. 2022, 56, 10, 6733–6743
https://pubs.acs.org/doi/pdf/10.1021/acs.est.1c08466 (Sadly there is a paywall).

Guo, el al. (2022) 'Scalable super hygroscopic polymer films for sustainable moisture harvesting in arid environments'. Nature Communications volume 13, Article number: 2761
https://www.nature.com/articles/s41467-022-30505-2 (No Paywall!).

There are really 2 different types of water purification discussed in this post which are used to purify different 2 types of water.

If your water contains pathogens, then you need some sort of a filter which removes all solid materials from the water. This is used for water than comes out of dirty creeks and rivers.

If your water comes from the ocean, then you need desalination. This is when you remove the salt from the water. It's a complicated process, and it always requires an energy input. Desalination is completely unnecessary for water that comes out of a creeks or rivers.

Most preppers would have little interest in desalination as a technique for getting water when SHTF. Unless your bugout plan is to go to an ocean beach somewhere that's also a desert, it's going to be much easier to just find a freshwater source such as a creek, than to try and desalinate ocean water. For homesteading/gardening, desalination isn't of much use either. Unless you happen to live very close to the ocean, your available water source isn't going to require desalination.

Just a simple, $20 portable filter that fits in a backpack is really all you need. It's slow, you need a lot of patience and a lot of time, but it gets the job done if you need drinkable water while camping outdoors.

C. Nygren wrote:Howdy Yall,

With the multiple water treatment facility failures in the news I was digging into water purification/desalination and came across some interesting papers I thought I'd share here.

Yoon et. al. (2022) have now started field studies for a filterless desalinator! From what I've read it was designed to run off a little ($50) solar panel and only weighs 10kg. Looks like it currently only produces about .3L/hour, but with with additional solar panels and a battery backup that would be 7.2 Liters/day while off-grid. From related articles and interviews it sounds like the researchers are intending to create a desalination kit that would be available to consumers, likely at a reasonable cost as they target low-income families in coastal nations. While a bit too heavy for hiking, it sounds like it would be great for bugout vehicles and off-grid structures with access to non-potable water sources.

Guo et. al. (2022) looks further from market, but is more intriguing imo. Its a gel film that essentially acts like a powerless dehumidifier, just pulling water from the air but with no electricity! And its not just for the humid swamps, one report was saying that 1kg of the gell could pull 6L/day in humidities lower than 15%, and 13L/day with humidities up to 30%. In interviews the researchers are envisioning this gel as (eventually) available in hardware stores. Now it looks like the gel has to be heated to release the water, and the lifespan of the material hasn't been reported yet, but I still think its exciting.

At the moment I'm mostly geared for distillation over an open flame. What are yall's favorite current and future potential methods for water deslination/purification?

Papers:
Yoon, et. al. (2022) 'Portable Seawater Desalination System for Generating Drinkable Water in Remote Locations'. Environ. Sci. Technol. 2022, 56, 10, 6733–6743
https://pubs.acs.org/doi/pdf/10.1021/acs.est.1c08466 (Sadly there is a paywall).

Guo, el al. (2022) 'Scalable super hygroscopic polymer films for sustainable moisture harvesting in arid environments'. Nature Communications volume 13, Article number: 2761
https://www.nature.com/articles/s41467-022-30505-2 (No Paywall!).

Nathan said, "If your water contains pathogens, then you need some sort of a filter which removes all solid materials from the water. This is used for water than comes out of dirty creeks and rivers.

Does the $20.00 filter remove pathogens?

Does the water still need to be boiled to remove parasites?

Can you give an example of this $20.00 filter?  

A picture or maybe an Amazon link?

Anne Miller wrote:

Nathan said, "If your water contains pathogens, then you need some sort of a filter which removes all solid materials from the water. This is used for water than comes out of dirty creeks and rivers.

Does the $20.00 filter remove pathogens?

Does the water still need to be boiled to remove parasites?

Can you give an example of this $20.00 filter?  

A picture or maybe an Amazon link?

The water will not have to be boiled. Here is an example of an approximately $20 filter that can be purchased that does all this and takes up very little space in a backpack:

https://www.walmart.com/ip/Sawyer-Products-MINI-Water-Filtration-System-w-One-16oz-0-5-Liter-Pouch-Single-Blue/29273210

And yes, this simple model removes the pathogens you're typically concerned with. The listing says that "It can filter out particulates as well as bacteria and protozoa like Giardia and Cryptosporidium, but not viruses. It works in many configurations. "

Pump filters such as this are slow and take a lot of time and patience.

There are other types of filters besides those with a pump. Gravity feed purifiers are especially handy because you can set them up and walk away, then come back later when the filtering is done.

REI has put together a pretty good list all all the different types of water purifiers and filters that are available and the pros and cons of each. Their page also links some gravity feed filters.

https://www.rei.com/learn/expert-advice/water-treatment-backcountry.html