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--- health:water-filtration [2017/09/21 05:20]
marcos [method]
+++ health:water-filtration [2021/11/16 04:03] (current)
marcos
@@ Line 1: / Line 1: @@
-==== method ====
+~~META:
+title = DIY Water Filtration
+~~
+====== Water Filtration ======
+===== motive =====
+https://www.ncbi.nlm.nih.gov/pubmed/30326398\\
+https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4050989\\
+https://www.ncbi.nlm.nih.gov/pubmed/26313703\\
+https://www.ncbi.nlm.nih.gov/pubmed/20183522
+===== method =====
 To filter tap water, you can buy tea bags and fill them with a mix of the following:\\
@@ Line 28: / Line 42: @@
 HOCl + NH2Cl « NHCl2 + H2O\\
 HOCl + NHCl2 « NCl3 + H2O\\
-Since these reactions are in equilibrium, it is possible that free chlorine will be present under certain conditions of pH, temperature and the ratio of chlorine to nitrogen. Free chlorine will degrade an ion exchange resin. This occurs primarily via decrosslinking in a cation resin and defunctionalization in an anion resin. In addition to the free chlorine that is formed when the equilibrium is shifted on these equations, the chloramines, while less oxidative than chlorine, will oxidize the anion resin functional group. Chloramines and free chlorine should be removed prior to ion exchange resin beds. Degradation products of these reactions include ammonia, hydrochloric acid, nitrogen, and in the case of anion resin oxidation - trimethylamine. The ionic species will likely be removed from the water by the downstream ion exchange resin and seldom have an impact on product water quality." [[https://dowac.custhelp.com/app/answers/detail/a_id/466/~/dow-ion-exchange-resins---chloramine | Source]]
+Since these reactions are in equilibrium, it is possible that free chlorine will be present under certain conditions of pH, temperature and the ratio of chlorine to nitrogen. Free chlorine will degrade an ion exchange resin. This occurs primarily via decrosslinking in a cation resin and defunctionalization in an anion resin. In addition to the free chlorine that is formed when the equilibrium is shifted on these equations, the chloramines, while less oxidative than chlorine, will oxidize the anion resin functional group. Chloramines and free chlorine should be removed prior to ion exchange resin beds. Degradation products of these reactions include ammonia, hydrochloric acid, nitrogen, and in the case of anion resin oxidation - trimethylamine. The ionic species will likely be removed from the water by the downstream ion exchange resin and seldom have an impact on product water quality."  [[https://water.custhelp.com/app/answers/detail/a_id/466/~/dow-ion-exchange-resins---chloramine |Source]]
 "If water is held in the carbon block for longer period, microorganisms can grow inside which results in fouling and contamination. Silver nanoparticles are excellent anti-bacterial material and they can decompose toxic halo-organic compounds such as pesticides into non-toxic organic products." [[http://link.springer.com/article/10.1007/s11051-005-7523-5|Source]]
@@ Line 59: / Line 73: @@
 After taking a bottle with me cycling, the ppm on both tds meters was 3!!!  That means that shaking the water up moved the molecules around sufficiently so that they eventually made contact with the media.  Also, the media had already been used in my water bottle for two weeks (although I had a larger glass bottle with a teabag filter, that I used as a first stage, pouring water from it to my drinking bottle).  The results are therefore comparable with a reverse osmosis filter.
-My original thought was that water molecules in an unshaken container were always moving around much like in a gas, but at much closer range.  This does not appear to be so much the case.  What gave me this idea, is that food coloring dropped into water disperses rather quickly.  However, this is a different phenomena.  I believe dispersion happens because of the Van-der-waals forces between the food coloring and the water.  The higher energy state and the ensuing need for entropy disperses the food coloring evenly among the water molecules.  Therefore, it appears that in order to speed up the process of getting the non-water molecules over to the tea bag to get attached to the media, some shaking is required.
+My original thought was that water molecules in an unshaken container were always moving around much like in a gas, but at much closer range.  This does not appear to be so much the case.  What gave me this idea, is that food coloring dropped into water disperses rather quickly.  However, this is a different phenomena.  I believe dispersion happens because of the Van-der-waals forces between the food coloring and the water.  The higher energy state and the ensuing need for entropy disperses the food coloring evenly among the water molecules.  Therefore, it appears that in order to speed up the process of getting the non-water molecules over to the tea bag (to get attached to the media), some shaking is required.
+My solution was to get a small 3 watt submersible fish-tank pump for $3 on ebay, which I put into a gallon glass jar (the kind used for pickles) along with the tea bag.  I measure the PPM after the water filters overnight.  Now I can tell when the filter material is used up, because the lowest PPM attainable quickly increases.  The lowest attainable has shown anywhere from 0 to 2 ppm.  When it gives up the ghost, the lowest quickly increases to 7-15ppm.  I think this happens after about 10 gallons / 40 liters, but I haven't been keeping track.
+In hoping to have the filtration take less time, and possibly use the media more uniformly, I've wanted to try putting the pump in line with a [[https://www.google.com/search?tbm=isch&q=refillable+filter+cartridge | refillable filter cartridge]], such that the water is forced through the media.  However, I can't seem to find one that is less than the standard 10 inch length, and that will not fit well in a glass jar.  It would have to be a very big glass jar and I'm not sure where to find such a beast.
-==== demineralization controversy ====
+On ebay I saw some very small funnels for a dollar, that I hope will fit on the intake of the water pump.  The idea is that the tea bag will get stuck in the funnel and the water will be forced through it.  So far, I've been having the tea bag circle along in the current created by the pump, by placing the pump at a higher level than the tea bag.  The tea bag floats around close to the bottom.  Without the funnel, if the tea bag gets caught on the intake of the pump, the small surface area of the intake, covered by the tea bag paper, does not allow a sufficient amount of flow.
+What Does a TDS Meter Not Measure?  [[https://www.hydroviv.com/blogs/water-smarts/tds-meters-and-testers | source]]
+" Because TDS is an aggregate measure of charged compounds in water, uncharged things like motor oil, gasoline, many pharmaceuticals, and pesticides do not contribute to a TDS measurement.  For example, the glass on the left in this article's header image contains deionized water with Malathion (an organophosphate pesticide) dissolved into it at 100 times higher concentration than allowed by the EPA for drinking water, and the TDS probe reads 000. "\\
+I thought the whole point of anything being able to dissolve in water, was that it needed to be ionic: that's why oil and water don't mix?  Well, I'm wrong.  From wikipedia:\\
+" Dissolved organic solids, such as sugar, and microscopic solid particles, such as [[https://en.wikipedia.org/wiki/Colloid | colloids]], do not significantly affect the conductivity of a solution, and are not taken into account. "
+Again, one of the other reasons I'm using activated carbon is to [[https://www.omicsonline.org/open-access/bpa-free-waters-essential-to-perform-laboratory-studies-2157-7064-1000295.php?aid=61493 |help remove plastics]].  Yet when I put a tea bag of carbon in my [[https://en.wikipedia.org/wiki/CamelBak | camelback]], the water still tastes like plastic.  I need to try and see if the [[https://www.homebrewtalk.com/forum/threads/beer-line-tests-solution-to-the-plastic-taste.60380/ | tube]] or bladder causes the most effects.  In any case, it appears that the plastic overwhelms the tea bag.  They have inline carbon filters for the hose line, that may help, but I'm going to accept some plastic on my hikes for now.  The carbon does keep the plastic taste from forming in my cycling water bottle, however.
+Update: I spent a week in Somersworth, NH, and the tap water quality is horrible, in terms of a TDS reading of 150ppm, compared with nyc 40ppm.  A single tea bag filter (working with the pump) was only good for purifying 6 liters of water to 1ppm.  After that, the next 6 liters went no lower than 82ppm.  I continued filtration with an unused filter.
+Update: If you want to remove flouride, a TDS meter will not be that helpful, because flouride is added to water at 1ppm.  The TDS meter does not have enough resolution to estimate the percentage of flouride that is removed by your filter.
+\\
+\\
+===== consumer products =====
+==== zero water filter ====
+" The problem with the Zero unit, you see, is that pure water seeks to become contaminated. It will hungrily absorb CO2 from the atmosphere, forming carbonic acid, as well as any contaminants in the air. More dangerous is the fact that the Zero Water Filter removes 100% of the chlorine form the water. If your municipality did that, your community would suffer another yellow fever, legionella or other bacterial/viral disease outbreak.
+Bacteria will grow in water that has no chlorine in it. If you use the Zero Water Filter remember that the filtered water is chlorine free. Also remember, ion-exchange resin is also a great medium for growing bacteria. The TDS meter on this device measures electrical resistivity or conductivity. It has no capacity to measure algae, fungi and microorganisms in your water.
+The purification technology in this unit itself is sound, but the product has no technology to keep the water pure once it is made so. In water treatment science it is more expensive to keep water pure than it is to make it pure. I am willing to bet that if you do not sterilize your pitcher daily, you have bacteria growing in the system. " [[http://wateristhenewgold.com/zero-water-filters-danger-will-robinson |source]]
+==== bacterial load ====
+In order to reduce the bacterial load on a filter cartridge, it's best to have a large family that will use up its filtering capacity quickly (so that the water filter gets replaced frequently).
+Comparing the "zero water filter" with the "ion-exchange + carbon tea bag" (see section "method" above):\\
+Since you will more often discard a tea bag than a larger filter cartridge, maintaining sanitation of the filter media is easier with tea bags.  A glass jar is also easier to maintain sanitary, compared to a plastic carafe.  The only weakness in filtering with a tea bag is the need for a small water pump.
+\\
+\\
+===== maintaining water purity after filtration =====
+Pure water will strongly attract any impurity, including contaminants in the air.  In order to keep purified water pure, after being transferred out of the filter, you should continue to keep it in a glass container with a sealed lid.  Another option is to dirty the water so it is no longer pure!  Add some lemon juice, tea, cinnamon sticks or cloves.
+==== boiling pure water ====
+It's not advisable to boil pure water, because it will become contaminated quickly.  If you must, you can use a stainless steel tea kettle to boil the water, as stainless steel is [[https://www.quora.com/How-do-metals-react-with-distilled-water |highly unreactive]].
+\\
+\\
+===== demineralization controversy =====
 Demineralized water has been claimed to have negative health effects because of a reduction in beneficial minerals.
@@ Line 101: / Line 164: @@
 The recommended daily intake for magnesium is 400mg.  A liter of drinking water in the U.S. has about [[https://www.ars.usda.gov/ARSUserFiles/80400525/Articles/NDBC32_WaterMin.pdf | 10mg/L of magnesium]].  It's recommended to drink [[https://authoritynutrition.com/how-much-water-should-you-drink-per-day | 2 liters a day]].  That's 20mg of Magnesium from drinking water.  Um... that's significant?  There was a study that showed people drinking demineralized water urinated 20% more.  Maybe they liked the water better?  I guess I'm going to keep taking my multivitamin and magnesium supplement, and I hope I'll be ok.  That along with my raw milk ;-)
-==== fluoride controversy ====
+\\
+\\
+===== fluoride controversy =====
 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491930\\
@@ Line 215: / Line 281: @@
    chemicals, or the dissolution of metals in water systems because of a
    substantial depression in the pH of the water.
+\\
+\\
+===== water pH =====
-==== water pH ====
+Should drinking water be at a certain pH?  Well, I'm taking the pH out and making it completely neutral with the ion exchange resins.  There is some marketing fad to sell alkaline water.  If it's supposed to be basic, then I've got that covered because I brush my teeth with baking soda.  The food you eat will have so much more ions in it than the trace amounts in water.  Does it matter that it goes in with the wrong pH, if it quickly gets mixed up with the food in your belly?
-Should drinking water be at a certain pH?
+Related article: [[https://www.healthline.com/health/food-nutrition/alkaline-water-benefits-risks |Alkaline Water: Benefits and Risks, healthline.com 20190530]]

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