Affordable way to remove potassium from off-grid water?

[questions8938]

TL;DR

title

I have natural spring water on my land.

I use gravity filters currently which are rated to remove the 'nasties' to make it ok to drink but the problem is they intentionally leave in minerals as they see it as a feature.

For my case though I experience side effects which feel identical to excess potassium when I intentionally tried taking it as a supplement on more than one occasion. I am guessing it is because it is getting picked up from the ground. The land is heavy clay too which is noted to have high mineral contents.

So are there practical ways to remove the minerals from the water or reduce them to lower levels? I looked up and distillation is going to be out of the question I think due to huge electricity consumption. I am in the UK too so can't rely on sun power for that as I want a year round solution.

I rely on off-grid power btw which is extremely tight during the winter months. I barely scrape through on a modest 12V system as it is during December so no chance I could add a heavy electrical burden on top of that.

Reverse osmosis I think is out too due to the huge waste of water which I read is 4:1 waste to usable. In drought times this will be unacceptable.

Ion exchange looks promising as they seem affordable from my cursory investigation.

Is this going to be the best way or some other suggestion bearing in mind the limitations above?

Rainwater I read is a natural distillation method but I am not sure I will be able to capture enough in the drought times compared to the springs which act as large catchments from the whole valley. Maybe if I got a large enough piece of plastic - I have wondered about microplastics in this case. Would that be a significant concern if the water just rolls across a tarp for a few seconds before hitting HDPE container? That will take up a large area though to gather meaningful amounts in the drought seasons, but might be doable. Testing that right now on a small scale and seeing how much I can get.

Being able to utilize the ground water still, while removing the minerals, would be best though since it is a shame to waste water that is already issuing up from the ground.

 

[.Scott]

Hello 8938:
It sounds like you have already investigated most alternatives.
I think that any option you take has to compete with simply buying bottle water - In my area, Walmart sells a 5-gallon bottle for $13.48.

I also Googled "can potassium be precipitated from water". There is a short list of chemicals that will serve this purpose. You would have to check each for toxicity. I expect that none will lead to a solution better than bottled water.

 

[Panchanan Pramanik]

Make Ice and separate the ice to melt again to water

 

[Borek]

Make Ice and separate the ice to melt again to water

Nope. Yes, for some solutions freezing out water helps in separation, and yes, "first ice" is likely to be a pure (or at least more pure) water. But I doubt this approach is economically and technically viable (if it were it would be common in desalination plants, it is not used and not without a reason I bet).

 

[Dullard]

You only need to de-K the water that you intend to consume. I don't know what fraction of your total water consumption that is, but for my house it's < 5%. A small RO system may be more practical than you think.

 

[Arne Andersen]

Ion exchange is the best way to remove potassium (and other ions). The technique is widely used to improve "hard water". In this case, an ion exchanger with sodium is often used, it can be regenerated with common table salt NaCl.
For completely pure water, combination ion exchangers with H+ and OH- are used. They cannot be regenerated, but last quite a long time. Especially if purified water is only used where it is needed, such as for food and drinks.

 

[Zaciekawiony]

As mentioned earlier, you need a water demineralization apparat. Gravity jug filters essentially do this, but they exchange ions like calcium and iron for sodium. There are filters that work on a similar principle, removing ions from water without adding anything new. We have one in our laboratory for producing demineralized water. The kit consists of a column filled with an acidic cation exchanger, which absorbs cations from the water and releases protons, slightly acidifying the water, and a second column filled with an alkaline anion exchanger, which absorbs anions and releases OH ions. After passing the same water through both columns, we obtain pure water with a neutral pH.
However, it is like a distilled water (depending on the kit's absorption strength) - is tasteless and has no other properties. To make it drinkable, it may need to be mixed with unpurified water; then the concentration of potassium and other minerals will be lower.

You can buy such demineralization kits or try to assemble them yourself with the appropriate ion exchange resins; I know the Amberlite brand, I don't know what the others are or whether they are approved for use with drinking water.

 

[256bits]

TL;DR: title

Rainwater I read is a natural distillation method

The water cycle includes atmospheric evaporation and condensation, so I suppose that can be called a natural distillation.
The adjective 'natural' does not imply purity in the sense as it is used here.

The atmosphere contains contaminates from both the natural environment as well as from human activities. These contaminants will be in the collected rain and will depend upon where the rain clouds acquired their moisture, current local conditions and extraneous variables, No two rains will have exactly the same contaminants.
Contaminants can includes dust particles, pollen, gases, bacteria. The contaminants can be picked up as the rain falls from the cloud to the ground, or from within the cloud itself as the condensation of vapour requires a nucleation site upon which the liquid can more easily form.

Rainwater can be soft as it will be of less mineralization than ground water, but not necessarily safe as is usually thought. But then again, I have never heard of anyone getting sick or dying from drinking rain water, although how many people do that is unknown - if it was a complete hazard than kids and anyone of a playfull mind collecting rain drops in their mouth would all the time be getting hospitalized.

Evidence of contamination:
- acid rain
- sediment in collected rainwater
- dark spots forming in melting snow

Just thought I should mention this as the worry about microplastics should be seen in light of other contaminants in rain water.

 

[Borek]

The atmosphere contains contaminates from both the natural environment as well as from human activities. These contaminants will be in the collected rain

Rains that fall lately in russia (after oil refinery fires) are an extreme example.