Sciencemadness Discussion Board

Drinking water - filtration methods & re-introducing "minerals" for taste

RogueRose - 7-7-2016 at 17:09

Skip to after the quoted part if you already know why, in places, household water (especially drinking water) should be filtered.
Quote:

Water provided to homes either via local municipality, home well/spring or rain water can greatly vary in their quality from having varying levels of chlorine or fluoride (city water usually), salt/brine (near ocean/bay), calcium or magnesium carbonates and in some of the worst cases toxins like lead, sewage, old medications passed through waste treatment facilities and god only knows what else (some say natural gas is leaking into water tables in areas...). The contents of the water usually depends upon the soil and the geologic formations (rocks) under the pumping stations. Waters can also be basic or acidic and that can lead to corrosion of the pipes. Finally sediment is one of the most noticeable pollutants as it can make the water cloudy and leave stains on the sink/toilet.





My plan is to pass my well water (soft water, slightly acidic) through a very large 10 micron filter, then normal 10" x 2.5" 5 micron. Then drinking/cooking water will go through the following 1 micron then it will pass through a very "high end" (read very thorough) activated carbon filter finishing with a .1micron filter to remove any carbon dust (may move this to immediately before faucet..?).

I think this should give me fairly good tasting water but it will still be acidic and lacking in most any minerals or electrolytes as far as the test have revealed.

What I was thinking was adding a last filter that contained both CaCO3 and MgCO3 and possibly some KCl, NaCl and MgCl (IDK if there are others that would contribute to a better taste or give health benefits). The biggest problem here is how to add these in appropriate amounts. The only conclusion I can see is the following:

Each compound will have its own pipe filled with the pure compound.
A hose barb will allow attachment to the pipes and each pipe is fed from the same main line (so there are many T connections to connect each all pipes). Now I will assume that the water in each pipe is a saturated solution. The way to control the about of each compound will be done with varying the size of the out-flow orifice
which all feed tubes leading to one main outflow pipe to the faucet. I may consider moving the .1 micron to right before the faucet instead of after the charcoal but would that remove any of the added compounds.?

So the way it is described above, with hole size governing flow rate of each compound the following could be theoretical results

In a 100ml water sample the following amounts may be obtained:
50ml CaCO3
30ml plain water
19.1ml MgCO3
.4ml KCl
.3ml MgCl
.2ml NaCl

Obviously this would have to be adjusted to taste or even dietary requirements. If people need more calcium, then adding CaCO3 inline with the drinking water may be a good idea.

Does anyone think that this type of a setup would or would-not be successful (never-mind if necessary or not, that isn't up for debate as you don't know my water quality).

I would think that this type of setup would be very beneficial to people who use reverse osmosis systems as I have heard the taste of that water can sometimes be bad and even leave a "dry" feeling in the mouth:o (could that be due to lack of electrolytes?)

BromicAcid - 7-7-2016 at 17:23

I would think that the final carbon filter would introduce some metals, usually activated carbon has metals present in it, we don't use it for instance in high purity (with respect to metals) applications. Otherwise your setup sounds like the first several steps of a standard water purification system, lacking the usual reverse osmosis on the backside.

Regarding minerals, you're certainly not the first to think to put them back in there. The key phrase you are looking for is 'mineralization cartridge' which will bring up plenty of hits on google. Some even have MSDS specs attached which show they are mostly calcium carbonate (which makes sense, it's vanishingly low solubility in non-acidic solutions means it's going to last a very long time).

RogueRose - 7-7-2016 at 18:53

Quote: Originally posted by BromicAcid  
I would think that the final carbon filter would introduce some metals, usually activated carbon has metals present in it, we don't use it for instance in high purity (with respect to metals) applications. Otherwise your setup sounds like the first several steps of a standard water purification system, lacking the usual reverse osmosis on the backside.

Regarding minerals, you're certainly not the first to think to put them back in there. The key phrase you are looking for is 'mineralization cartridge' which will bring up plenty of hits on google. Some even have MSDS specs attached which show they are mostly calcium carbonate (which makes sense, it's vanishingly low solubility in non-acidic solutions means it's going to last a very long time).



Thank you for pointing me to the cartridge. that would save a lot of work!

As far as the metals in the Act Carbon, I'm wondering if boiling it in a pressure cooker, rinse, repeat, (maybe 3x) would do anything to help this situation. I have seen some carbons advertised that it is specifically for drinking water and it is made of coconut shells. Maybe it doesn't use metal salts in the production? I'll have to look into this further to see what the best options are.

I was trying to stay away from RO system as the system I described above I can make in it's entirety (except the micron filters, although I have made some that get below 10 micron and last a LONG time like 30x the standard 10" x 2.5")

Lots to think about!

On another note, about drinking water, does anyone have a favorite bottled water brand which they can recognize without the label? I know I can specifically taste one brand bottled by a HUGE soda company. It is my favorite and seems to have a specific identifying "taste" IMHO. I have never tried the high end imports like France Pierre (or whatever it is) or Fiji as I can't justify shipping water that far but I would like to try a new Icelandic glacier water - it just sounds good!

Argentum - 8-7-2016 at 03:27

You should research about Lifestraw. It is a plastic tube with three filtration stages. The first one is a mechanical filter, the second one is a carbon filter and the third one is some kind of iodine which kills bacteria. It's similar to your idea

Now, I cannot see why you should add minerals into the filtered water. I mean, I don't think the filter will absorb them.
If not, you would have cheap, homemade deionized water.

jsc - 13-7-2016 at 13:39

Carbon filters do not do much unless the water is contaminated with solid particles. Dissolved solids are the main problem.

The best option is a 5-stage reverse osmosis system which will make the water very pure.

The whole "pure water tastes bad" thing is nonsense. Pure water tastes a lot better than water with salts or other contaminants in it. I use a 5-stage system and store drinking water in glass bottles in my frig to keep it cold. It tastes great and is crystal clear and pure. When it is boiled it leaves no residue.

macckone - 14-7-2016 at 12:23

A tiny amount of mineral in water has been shown to taste better to most people.
magnesium, calcium, sodium, and potassium ions as well as chloride, sulfate and carbonate ions.
iron shows a negative taste as does sulfur. Surprisingly lead has a positive taste.
which just shows your taste buds can't be trusted. I would have to find the paper on this.

unionised - 14-7-2016 at 12:45

Not quite the same outcome, but have you heard of this?
http://finnhillbrewing.blogspot.co.uk/2011/01/how-to-burtoni...

macckone - 14-7-2016 at 19:19

Quote: Originally posted by unionised  
Not quite the same outcome, but have you heard of this?
http://finnhillbrewing.blogspot.co.uk/2011/01/how-to-burtoni...

That is the general direction that the OP desired, although probably not that hard.
A tiny amount of lithium carbonate will help the flavor and is a mood enhancer.
Most likely everyone will have their own prefered flavor profile.
Tiny amounts of iron and copper will make it more natural.

Praxichys - 15-7-2016 at 04:47

Have you had your water tested? You might not need to spend the money on all this equipment.

I have well water where I live and I don't use a softener. I get it tested yearly to make sure it's safe, but otherwise I drink it straight out of the ground. I even have to remove sand grains that get stuck in the shower heads regularly. It crusts up the plumbing fixtures and it definitely tastes different, but after 5 years of living here, I've come to enjoy the mineral taste. If the quality test is OK, I don't see why I'd ever do anything to it.

When the power goes out, I resort to drinking the distilled water I buy in bulk for the lab. It's virtually tasteless.

When I visit other people who have city tap water, I can really taste the softness and the chloramine they put in it.

[Edited on 15-7-2016 by Praxichys]

"Lab grade" purified water - De-ionized then: Actv Carbon filter then distill - or - distill then AC filter?

RogueRose - 18-7-2016 at 11:21

I want to make some ultra pure water - as pure as I can make it with what I have on hand. I have some gallons of de-ionized (from dehumidifier). I have activated carbon filters as well as 5 and 1 micron cylinder filters (for home water filtration units) and .45 and .22 micron bottle-top vacuum filters (these are slow and a last resort as they are expensive and can't do large quantity). The carbon filter has a very tightly packed cotton filter that removes visible carbon dust (if a gallon of carbon filtered water settles in a milk jug, no carbon is seen on the bottom after months, so it is pretty good).

I was wondering if it makes a difference to use the carbon filter before distillation or after.?

Should I use one of the micron filters after the distillation or carbon filter?

AJKOER - 1-8-2016 at 04:45

I would consider adding to your filtered water fine powdered ZnO and MgO. Then, further treat with sunlight and pass air through it.

Logic: Both metal oxides are solar light active producers of reactive oxygen species (ROS). See comments relating to nanoparticles ZnO at http://link.springer.com/article/10.1007/s40820-015-0040-x along, pending further research, I would not personally consume any nanoparticles.

Apparently, ROS can provide powerful disinfecting abilities even against the likes of a virus. Also, toxic pesticides can be mineralized (broken down). Inherently, Zn and Mg are also good minerals, in limited amounts, for human health.

Aeration can cause the precipitation of heavy metal oxides, remove H2S and volatile undesirable organic compounds.

I would test your water for nitrate levels which may increase as a function of drought conditions moving water table levels. The introduction of ROS (especially the hydroxyl radical) may form volatile organic nitrates (assuming the introduction of ROS prior to filtering) that may be removed with aeration, but best to test water quality post treatment.

Also, avoid copper pipes if there is any bromide in your water as apparently Cu facilitates the conversion of bromide to very problematic bromate.

My take on how the bromate formations occurs in copper pipes:

First, an equilbrium reaction of residual chlorine in water:

Cl2 + H2O = HOCl + H+ + Cl-

The action of CuO on removing HCl (this is actually an old preparation path for hypochlorous acid via the action of a metal oxide on chlorine water) and moving the equilibrium to the right via:

CuO + 2 HCl = CuCl2 + H2O

Next, the action of HOCl on a bromide:

HOCl + Br- → HOBr + Cl- (See, for example, http://pubs.acs.org/doi/abs/10.1021/ic00263a030?journalCode=... )

Followed by:

3 HOBr → HBrO3 + 2 HBr

where the CuO could further catalyzed the above disproportionation. Here is a source, see "Enhanced Bromate Formation during Chlorination of Bromide-Containing Waters in the Presence of CuO: Catalytic Disproportionation of Hypobromous Acid - ...", at https://www.google.com/url?sa=t&source=web&rct=j&... .

[Edited on 1-8-2016 by AJKOER]

semesa - 1-8-2016 at 14:30

Quote: Originally posted by macckone  
Surprisingly lead has a positive taste.


Lead acetate was used as a sugar substitute in Rome a few thousand years ago. Supposedly most lead salts have a sweet taste(wouldn't recommend trying them given toxicity!)

careysub - 1-8-2016 at 15:21

What make water "taste good" is very individual, and is largely a learned preference.

When I was a child I had a copper drinking cup (a birth present) which I always drank water from, liking the metallic taste. Now I prefer distilled water, which is tasteless (Aquafina is essentially distilled water, almost no TDS). I dislike water with minerals "added for taste".

I remember reading about a study trying to find the "optimum" salinity for taste from a large taste panel. They started at zero, and kept increasing the salinity, and at some point the panel split into two, with part liking it more and part less as the salinity increased. Finally a point was reached where on group liked the water the most, while the other found it undrinkable.

Herr Haber - 6-8-2016 at 22:01

As a youngster in the Boy Scouts I remember us setting up camp for a few days inside a refuge where we had running water.
In the boy scouts, running water is always welcome.

I remember clearly that there were large red stickers above the sinks mentioning that the water was disease free, drinkable but had almost no minerals. As a consequence it was ok for cooking, washing your teeth but it was ice cold and almost devoid of minerals.

Half of us ended up running out with the roll of toilet paper to find some peace and quiet in the woods.