Fluoride removal from lake water

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I am from Rwanda and we use lake water for drinking and other purposes. This lake water has high fluoride concentrations. 

As an environmental scientist, I am thinking of adopting a sustainable solution that would eliminate the negative health effects caused by high amounts of fluoride in the water. One of the adverse health effects I observed is the black teeth of residents here. 

I am thinking of making a household filter that can be used to  reduce the  fluoride concentration.

What methods could be used to reduce the fluoride concentration in households? Is there a practical household filter available on the market? 

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20 Answers

  1. The best home method is using activated alumina. It can be regenerated with sodium hydroxide.

    From Wikipedia:

    Activated alumina is also widely used to remove fluoride from drinking water. In the US, there are widespread programs to fluoridate drinking water. However, in certain regions, such as the Rajasthan region of India, there is enough fluoride in the water to cause fluorosis. A study from the Harvard school of Public Health found exposure to fluoride as a child correlated with lower IQ.[1]

     Activated alumina filters can easily reduce fluoride levels from 10.0 ppm to less than 1.0 ppm. The amount of fluoride leached from the water being filtered depends on how long the water is actually touching the alumina filter media. Basically, the more alumina in the filter, the less fluoride will be in the final, filtered water. Lower temperature water, and lower pH water (acidic water) are filtered more effectively too. Ideal pH for treatment is 5.5, which allows for up to a 95% removal rate.

    As per researches conducted by V.K.Chhabra {Chief Chemist (retd.) P.H.E.D.Raj.} Activated alumina, when used as a fluoride filter, under field conditions can best be regenerated by a solution of lye (sodium hydroxide; NaOH), sulphuric acid (H2SO4). The fluoride uptake capacity (FUC) of activated alumina can be up to 5000 mg/kg. The FUC can be determined as follows:

    V.K.Chhabra’s method (Chief Chemist retired, PHED Raj., India) : Fluoride solution: Dissolve 22.1 g anhydrous NaF in distilled water and dilute to 1,000 mL. 1 mL = 10 mg fluoride. 10 mL/L = 100 mg/L fluoride.

    Procedure: To one litre of simulated distilled water containing 100 mg/L of fluoride, agitate at 100 rpm using the jar test machine. Add 10 g of the AA under test. After one hour, switch off the machine and take out the solution. After 5 minutes, carefully decant the supernatant solution and determine the fluoride. Calculate the difference between the original and treated water fluoride concentration. Multiply the difference by 100 to give the fluoride uptake capacity of AA in mg/kg.

    Vacuum systems

  3. There is a lot of methods that you can apply in this regards, but it will treat a certain volume of water per day and it will be only for drinking purposes per households. This methods includes the following:

    1. Reverse Osmosis,

    2. Iron exchange, and,

    3. Package plant.

     

    This three is only meant for removing fluorides into water.

     

  4. The waters of the lakes and marine coastal areas not only contain fluoride but also phosphorus, nitrates, pesticides, fecal coliform. We could perform an oxidation treatment in polluted seabed to boot, producing cheap energy. Much lower than coal. I look for international partners for this and other environmental and energy solutions. 

    The  invention of the pump with two separate supply until the impeller on the suction side has allowed the invention of hydropower by recycling water in an open vessel. With this system we have, at the same time, lifting water and the production of energy, mainly by exploiting the dynamic pressure (or kinetic energy) of the water flowing from the upper reservoir.

    This invention, in turn, has inspired the present invention, which interacts positively with the environment. In fact, in pressurized systems with pumps with double separate power supply, the continuous internal recycle to the volume of water accumulated allows balance the hydrostatic pressure in inlet and outlet of the pump and therefore to circulate the water with very little energy.

    With the second separate supply until the inside of the impeller, it is possible to introduce water at low pressure in the pressurized tank. Since water cannot be compressed, the same amount is excreted in high pressure by the cushion of air through a tube that feeds a turbine, transforming the energy of static pressure into dynamic and producing electricity. The compressed air volume does not vary, therefore the air behaves like a spring, but due to of the principle of Dalton on the partial pressures of the gases and Henry on the solubilization of the gases, neglecting the effect of nitrogen that is neutral and of the other gases that are in negligible percentages, we have an important effect of the oxygen solubilization due to the pressure which increases proportionally according of the same. This involves an increase in capacity of water purifying, without increasing the cost of production of electricity. Considering that to state of the art pressurized water power does not exist, it is clear that this invention involves huge economic and environmental benefits. If with the pump with double separate supply introduce polluted water into the pressurized tank, we can produce energy while we clean instead of consuming energy. We can realize submerged pressurized water power plants in the depths of lakes and seas. But the same application can be produced in a reduced version even in small treatment plants. All the hydraulic systems, including those depurative, of the future will be able to produce energy because the power of compressed air always allows to have residual energy to be exploited in a turbine and all will be with the water recycling, because the recycling of water by the pumps with the dual separate supply allows to circumvent the force of gravity and the pressure.  The compressed air will be used as an accumulator of energy that disperses only the part of the energy due to the components that dissolve in the water chemically. This dispersion in global systems, which are also depurative, cannot be considered a loss of yield. With this invention we move towards the elimination of energy costs and multiplies environmental protection.

  5. The easiest and I think cheapist is ion exchange. If fluoride is your only target then after your sand filtration an activated charcoal bed followed by an anion bed. The anion is regenerative so if designed and installed correctly it can last for a few years. The City of Cape Town uses something similar but they remove minerals using a cation  resin. The water works is called Witsand. Cheap and reasonably low tech.

  7. Dear Mr. Mizero,

    problem with Arsen and Fluoride at Africa is well known. By this link you find publication about examination of the situation with recommendations on sampling, behaviour and treatment. http://www.eawag.ch/en/research/humanwelfare/drinkingwater/wrq/geogenic-contamination-handbook/

    Attached please find Company description who offers Fluorid removal.

     

    Best regards

    Matthias Worst

    Bavarian Environment Agency

     

  8. http://www.spawhe.eu/the-pressurized-submerged-hydroelectric/. With these inventions, while producing energy with high output, you will also have the natural chemical exchange between the polluted water and oxygen going to purify all water which does not pass through the purifiers. Especially, those in deep water of ports and lagoon city like Venice, Amsterdam. In fact, these two new inventions allow the construction of authentic hydropower stations in the backdrops polluted lakes and seas and also in the wells with a special version. Today is a great contradiction not produce interactive energies and simultaneously spend billions of dollars in fossil energy to purify only the small amount of water passing through the purifiers. But in the same purifiers should not continue to consume energy to oxidize the water through the air diffusers. It should oxidize water, producing pressurized water power, as described in the same patent deposits, with the help of Dalton and Henry two centuries old, and the change of the circulation pumps, which must be with double separated supply until to the impeller. These innovations, which no one has ever thought of using matching the purification processes to energy production, could be born from the beginning of the industrial age because even centrifugal pumps and turbines were born before.  Even these systems may include, fully into the global environment and if the undersigned has discovered them, probably, has to thank, just those who have been silent on earlier versions of the global purification, linked to fossil energy cleaning. But who did not want to clean the fossil energy with the global purification, it is already proving that not even want the interactive hydropower. In fact, the first inventions of myself on these subjects have more than two years and the pumps with double separate power supply, over a year and have yet to find funding. However, only these inventions may scrap thermal power plants and C.C.S. system (Carbon capture and storage). Against pressurized hydropower, fossil energy is not only polluting, but also uneconomical. 

    More time spent to pass submerged compressed hydropower, the more we forgive, especially if we have to buy oil and gas. But to tell the truth, even if we were a country rich in oil and gas, the cost of extraction and refining already exceeds the submerged compressed cost of hydropower. Who does not believe it has to do no more than take up the books and get back to studying the basic principles that underpin these inventions that, for myself have no need even to prototypes to be demonstrated. We just need to be informed about science and the state of the electromechanical technologies to put them together properly.  But if the delegates of 196 countries have doubts, I do not think it's a problem to organize a small collection among the various governments to determine who is right or wrong. If theoretically, the undersigned has managed to get into the shirt of a well a pressurized tank with air and water to produce the energy needed to lift and oxygenate the water, why should it not be possible to enter the same system in the boot of a means marine or air or inland transport, only to produce energy?

    As illustrated on the same http://www.spawhe.eu/hydroelectric-power-auto-with-torque-peripheral-to-the-wheels/ website? Keep quiet about the inventions that does not come from the big powers of the world economy does not help anyone.

  10. Gee; everybody here wants to sell something! But there's no need to buy expensive filters to get flouride out of your water, because there is a really simple method to do this; simply pass the water through a large tank filled with degreased bones or antlers.

    The flouride binds to the calcium in the bones and is removed from the water; this is because of an ion exchange in which the carbonate radical of the apatite comprising bone, Ca(PO4)6.CaCO3, is replaced by fluoride to form an insoluble fluorapatite, which remains in the bone.

    Here is the citation for this: http://www.bibliotecapleyades.net/salud/salud_fluor23.htm

    It's cheap, simple, and does not involve any complex processes or expensive chemicals. And there are bones everywhere! Use the bones respectfully to make your water safer for people to use.

    Aloha, Tim............

  12. I use MgO (Magnesium oxide) prilled beads to purify drinking water in Hawaii. The prill beads come from a deep mine in Nevada. They are processed at 700 degrees which turns them into ceramic beads that do not dissolve in water.

    The beads place a positive charge in the water that shatters the magnetic bond that holds together any contaminants or pollutants (chlorine, fluoride, heavy metals: zinc, copper, lead, chromium-VI, pesticides, radiation, pharmaceuticals, mold, Ecoli, bacterias, etc) and gasses them out of the water. It raises the water pH to 8.7, high alkalinity, high oxygen, and thins the water so that can penetrate the cell membranes and flush out your toxins. As to hydration: 3 Glasses of prill water is equal to drinking 1 gallon of water. 

    I also puify rain catchment systems. 

    Let me know if you would like to test this personally in a 3 gallon glass or BPA free plastic or ceramic container with spigot at bottom.

    Great for acid conditions: acid-reflux, heartburn and acne. Richard Fishman PrillyPureWater@outlook.com or PrillyPureWater.net

  13. It sounds like you have a challenge as you would be looking to have a maximum amount of 1mg/L which is the Health Department recommendation. From a treatment perspective, the most appropriate and effective treatment is using reverse osmosis however in remote areas it is not always practical.

    Following is an extract from the Degremont Water Handbook which is available on line free of charge and offers various methods of eliminating fluoride (fluorine). I hope it is useful.

    Eliminating fluorine: 

    Some natural waters contain more than 10 mg · L–1 of fluorine. This concentration has to be reduced to approximately 1 mg · L–1 (the acceptable residue falling as the average annual temperature rises); the European standard has set 1.5 mg · L–1. The following processes are used :

    filtration through activated alumina

    This is the most widely used process. Fluoride ion fixing is reversible and regeneration is carried out with aluminium sulphate or, preferably, with sodium hydroxide and sulphuric acid. Screening-out capacity can vary considerably: depending on the water’s initial fluorine content,  pH  and overall salinity, the material’s particle size and operating conditions, 0.3 to 4.5 g of F–ion can be fixed per litre of product. We recommend carrying out preliminary tests in the laboratory in order to identify optimum conditions and the consequences for the composition of the treated water.

    coagulation-flocculation

    The aluminium sulphate treatment constitutes another way of using fluorine’s affinity for alumina but the coagulant demand will be very high (50 to 150 g per g of F– to be eliminated); therefore, it can only be used on raw water that requires sedimentation and that has a low fluoride content.

    lime used to soften water

    This method can be used but with a  pH  >10 and providing that the water has a sufficiently high magnesium level because it is the magnesium oxide that will adsorb the fluorine. It is felt that approximately 50 mg · L–1 of magnesium will be required to remove 1 mg · L–1 of fluorine.

    using tricalcium phosphate

    The affinity of fluorine for this compound has long since been noted because significant levels of fluorine have always been found in natural phosphates such as apatites, phosphorites (2 to 5%) and even in bones. Consideration has been given to using the following :

    • either natural products: bone ash (animal charcoal) or powdered bone;
    • or synthetic apatite that can be produced within the water through the controlled combination of lime and phosphoric acid.

    other processes

    When the fluoride ion has to be eliminated at the same time as excessive water mineralization, then reverse osmosis may provide the answer.

    Electro dialysis can also be considered.

     

    Regards

    Kim

  14. If the presence is exceeding Safe Limits as prescribed in the Drinking Water Standards of WHO it needs very special care.Many cases witness Bone Distortion and Infants are found adversely affected relating Bone Formations.

  17. Dear sir;  I neither think nor advise that you filter Fluoride from drinking water.

    Fluoride has more pros than cons for the teeth. On the pros side,  it reduces cavities, reduces tooth decay and reduces pain due to tooth decay.

    The only negative that is supported by scientific background is what is called ; dental fluorosis; a condition that causes changes in the appearance of the teeth.

    Moe to the point, most communities add Fluoride into drinking water. 

    1 Comment

    1. This ​statement is ​blatantly false.​ Flouride is ​only useful in ​LOW doses ​administered ​ topically ; it should ​not be ingested.​ When ingested ​it replaces ​iodine in ​Thyriod ​hormones which ​affect and/or ​control several ​other hormones ​in the body. ​The flouridated ​version of the ​molecule does ​not perform the ​purpose of the ​hormone, only ​the correctly ​formed molecule ​with iodine can.​ Most people ​are low in ​iodine intake ​to begin with ​and flouride ​will displace ​even that ​iodine. Even if ​flouride is ​wanted for ​dental health, ​it is available ​in almost all ​dentifrice and ​mouthwashes. ​This is  a ​MUCH better way ​to get the tiny ​amount needed ​since it ​is not ​swallowed. ​

      The fact that ​many municipal ​water treatment ​plants add the ​highly ​poisonous ​sodium flouride ​(a byproduct of ​the aluminum ​industry and ​very effective ​rat poison)​ to tap ​water is no ​assurance of ​either the ​efficacy nor ​prudence of ​doing so. ​

      The best way ​to get flouride ​out of water is ​to use high-​calcium bone ​char carbon ​preceded by KDF ​55 (a copper ​alloy), or the ​bone char ​carbon followed ​by activated ​alumina. ​This will get ​out 90+%.  ​

      1 Comment reply

      1. I aggree,  fluoride with attack bones making them weak. I see fluoride being pulled back in permits to 10 ppm max! To treat fluoride the use of lime with  aluminum on the back side is used.