Hard water is one of the most common water problems besides alkaline water (iron contaminated water). So what are the signs, how to classify hard water and how to treat hard water to ensure that the water source meets the standards? Let’s find out with Scimitar Vietnam through the article below.
What is hard water?
Hard water is water that exceeds the permissible standards for the content of dissolved minerals in water, mainly salts containing Ca 2+ and Mg 2+ ions . According to the clean water standards of the Ministry of Health, if the total calcium and magnesium content is over 300mg/liter, the water becomes hard water. In other words, the hardness of water is said to be temporary in the presence of calcium carbonate and bicarbonate salts. This type of water when boiled will produce salt precipitates CaCO 3 and MgCO 3 .
Hard water
Hard water contains many ions Mg2+, Ca2+
Hard water classification
Based on the ionic composition, hard water is classified as follows:
Temporary hard water
Temporary hard water is water containing ions: Ca 2+ , Mg 2+ , HCO 3 – . To soften temporary hard water, you can use boiling water (thermal method) to create salts that precipitate CaCO 3 , MgCO 3 and remove the precipitate. In addition, temporary hard water softeners such as NaOH, Ba(OH) 2 , Na 2 CO 3 , Na 3 PO 4 can also be used by putting these softeners in water to form a precipitate then remove precipitate.
Everlasting hard water
Permanent hard water is water containing ions: Ca 2+ , Mg 2+ , HCO 3 – , Cl – , SO 4 2- . Permanent hard water cannot be softened by boiling like temporary hard water, but permanent hard water softeners (chemical method) must be used.
Totally hard water
Total hard water is water that includes both temporary hard water and permanent hard water. Means total hard home pure water purifier price in bd water including salts Ca(HCO 3 ) 2 , CaCl 2 , Mg(HCO 3 ) 2 , MgCl 2 , etc. To soften total hard water, you can use the same methods. temporary hard water softening and permanent hard water above.
How is hard water formed?
From the headwaters, water flows through different terrains, dissolving trace elements in the rock, including calcium and magnesium. In particular, when water flows through areas with mineral deposits or limestone mountains, the water will dissolve a large amount of magnesium and calcium, causing Ca2+ and Mg2+ ions in the water to exceed the allowable threshold and turn that water into hard water. limestone water.
Signs of hard water
Hard water has a significant impact on the daily life and health of users. So how to identify hard water is also a question that many people are interested in. To identify hard water is not too difficult. Here are a few ways you can use to identify hard water:
Water pipes, faucets, washing machine bins, kitchen utensils, bathroom items are often covered with a white powder like chalk
Detergent, soap dissolved in hard water creates very little foam, when in contact with this solution, hands will be very viscous and difficult to wash off.
Boiled kettle settles a lot of thick plaque on the bottom
Clothes after washing feel rough and quickly decayed, damaged by residual soap residue on the fibers of clothes.
Dry skin and stiff hair after a period of using hard water because hard water needs soap and shampoo to create lather, but then not completely washed off
Freezing hard water is difficult and takes longer than normal water
Effective hard water treatment methods
Treat hard water by boiling
Boiling water is a common method used by many households. Under the influence of great heat, hard water will be softened by a chemical reaction.
Ca(HCO 3 ) 2 → CaCO 3 + H 2 O + CO 2
Mg(HCO 3 ) 2 → MgCO 3 + H 2 O + CO 2
Also in this process, CO 2 is released, the salt is insoluble CaCO 3 and MgCO 3 sediment at the bottom of the warm, long days heater easily damaged, degraded. With this method, water is recommended to be used within 24 hours, the longer it is left, the higher the hardness, which affects health.
Hard water treatment with ion exchange filter media
Ion exchange methods are used to treat water for many different purposes, including water softening. Currently on the market there are a number of specialized ion exchange filter materials used to soften water (hard water treatment) such as cation resins. These materials are used in the column filter system with other filter materials such as Support Gravel, Quartz Sand, Activated Carbon, ODM, Corosex, Manganese Sand, Birm and Pyrolox…
Water softener ion exchange filter column
Water softener ion exchange filter column
The principle of this method is to use polymer materials containing insoluble ion exchange resins. For hard water, we use ion exchange resins containing Na + ions bonded with another anion (negative ion), that anion has a stronger affinity (binding capacity) for Ca 2+ and Mg 2+ than Na. + . When water passes through a column containing ion exchange materials, Ca 2+ and Mg 2+ in the water will exchange Na + to bond with an anion radical and will be trapped in the column, and at the same time will release Na + into the water. .
The polymer materials after the end of exchange capacity can be treated and regenerated their filtering capacity. If the treatment water requires to completely remove the minerals present in the water, continue the treatment by passing the water through the ion exchange column with the resin containing H + (which will remove the cation) and then through the column with resin containing OH ions – (removal of anions). H + and OH – will then combine to form water (H 2 O).
Chemical hard water treatment
People use a sufficient amount of necessary chemicals that are not harmful to water to mix with water, these chemicals will combine with Ca 2+ , Mg 2+ ions to create insoluble compounds and then filtered. leave them. Chemicals commonly used to soften water are NaOH, Na 2 CO 3 , Na 3 PO 4 , Ba(OH) 2 , BaCO 3 , Ba(AlO 2 ) 2 … With this method, we need to determine Accurately determine the state of the water and calculate to ensure the reaction is just enough, not redundant, and avoid affecting the quality of the water.
Treat hard water with a water purifier
Water purifiers are a fairly simple and effective method for treating household and semi-industrial hard water. Not only treating hard water, the water purifier also handles all other water problems such as water with a lot of sediment, contaminated water, alum, water contaminated with heavy metals…
Cation Core 10 inch
Cation Core
RO Membrane
RO Membrane
RO water purifier takes advantage of the above advantages of the ion exchange method itself to soften hard water thanks to the Cation prefilter core with ion exchange resin beads, which helps to remove Ca 2+ and Mg 2+ ions in the water. Next, the RO membrane with micro pore size continues to completely remove the salts containing calcium and magnesium in the water, yielding 99.9% pure water.
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