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Neutralizing Lime


Lime is found in all geological formations, all over the world. It plays a versatile and practical role.


Water

Drinking water is essential for life and must be of the highest quality. Scientists have carried out considerable research on water, minerals, and health. For example, the calcium in the lime is vital for bone formation. Together with magnesium, it also protects against cardiovascular disease. Lime is used in water treatment for precipitation, to raise the pH, and to adjust the hardness of the water. Adding slaked lime induces precipitation of non-desired substances, such as humus, particles, and metals. Slaked lime in combination with carbon dioxide is added to soft water from municipal sources to raise the alkalinity and the total hardness. Another method is to let the water filter through a bed of limestone CaCO3 or dolomite CaMg(CO3 )2. This protects water- and sewerage lines that require non-corrosive water.


How does having Lime in the water help?


  • Softening - In water softening, hydrated lime is used to remove carbonate "hardness" from the water. Hardness caused by other calcium and magnesium salts


  • pH Adjustment/Coagulation - Hydrated lime is widely used to adjust the pH of the water to prepare it for further treatment. Lime is also used to combat "red water" by neutralizing the acid water, thereby reducing corrosion of pipes and mains from acid waters. The corrosive waters contain excessive amounts of carbon dioxide. Lime precipitates the CO2 to form calcium carbonate, which provides a protective coating on the inside of water mains.


  • Effect on Pathogen Growth - By raising the pH of the water to 10.5-11 through the addition of lime and retaining the water in contact with lime for 24-72 hours, lime controls the environment required for the growth of bacteria and certain viruses.


  • Removal of Impurities - One of the most common methods of removing silica from water involves the use of dolomitic lime. The magnesium component of this lime is the active constituent in silica removal. Lime is also used to remove manganese, fluoride, organic tannins, and iron from water supplies.


THE NEUTRALIZING MATERIAL OF CHOICE:

Neutralization of acidic waste streams involves raising the pH, which can be achieved by adding an alkaline chemical, such as lime. There are several other chemicals that can also be used, but due to cost, handling problems, high total dissolved solids in the effluent, or mobility of heavy metals in the sludge, lime is the neutralizing material of choice. Lime sludges are heavy, low volume, easy to handle, and easy to clarify. Most metals contained in the sludge are insoluble and will not readily leach into the environment. Finally, lime is a low-cost reagent in terms of neutralizing value. This also reflects on the ability of lime to rebalance the acidity in the soil after the Sika spruce harvest. It also would potentially increase the breakdown period of the tree debris left on the ground. Applying lime, a product of nature, is the most natural method of resetting.


Too much Lime?

What is limescale in tap water?

Limescale is actually the result of hard water. Hard water is filled with minerals including calcium, carbonate, and magnesium. Hardness can be caused by several other dissolved metals; those form divalent or multivalent cations, including aluminum, barium, strontium, iron, zinc, and manganese. When scale deposits are showing on your kettle, and water glasses there is probably a “hard” problem in your home. Over time, the chalky white or green build-up of limestone surrounding your taps can become difficult to remove if it is not regularly cleaned. This residue is a result of hard water (tap water) with added minerals like calcium carbonate, calcium, and magnesium. These are left behind by hard water that contains above-average levels of dissolved minerals (TDS). This buildup will eventually cause bacterial growth in your drinking water so it is an important issue to address. Statistics reveal that 85% of European and similarly 85% of US homes are affected by such issues.


Health

Generally, it is accepted that the calcium and magnesium that makes up limescale are not unhealthy. Limescale is believed not to have any bad repercussions. The daily recommended minimum intake of calcium is 500-1200mg and magnesium 300mg. Technically if you drink two liters of water a day, you could be getting 10 to 20% of your daily calcium requirement and up to a third of your required magnesium from tap water. However, there may also be health conditions where the patients should probably avoid hard water including those with kidney stones. The hardness of water is due to the presence of carbonate and sulfate salts of calcium and magnesium. More than 3/4th of kidney stones are generally composed of calcium salt and usually occur as calcium oxalate and less commonly as calcium phosphate. Drinking hard water could add to the development. Several epidemiological investigations have demonstrated the relation between risk for cardiovascular disease, growth retardation, reproductive failure, and other health problems and the hardness of drinking water or its content of magnesium and calcium.


Types of Hardness

Groundwater that has been in contact with porous rocks containing deposits of minerals like limestone or dolomite will be very hard, while water from glaciers or flowing through igneous rocks is much softer.

Carbonate hardness is sometimes called temporary hardness because it can be removed by boiling water. Non-carbonate hardness cannot be broken down by boiling the water, so it is also known as permanent hardness. In general, it is necessary to distinguish between the two types of hardness because the removal method differs for the two. Total hardness includes both temporary and permanent hardness caused by calcium and magnesium, on the basis of which water is categorized as soft or hard and very hard. The ratio of calcium and magnesium in water is also a crucial factor indicating the hardness and in the causation of several hard water health problems. Hardness generally enters groundwater as the water percolates through minerals containing calcium or magnesium. The most common sources of hardness are limestone (which introduces calcium into the water) and dolomite (which introduces magnesium.) Since hardness enters the water in this manner groundwater generally has a greater hardness than surface water.


Why does Limewater turn milky?

Carbon dioxide reacts with calcium hydroxide solution to produce a white precipitate of calcium carbonate. Limewater is a solution of calcium hydroxide. If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white. This is why boiled lime water is cloudy and leaves deposits.

How to deal with Lime

Two of the most effective substances are lemon juice and ordinary vinegar. Lemon juice is usually the best (and will also leave a lovely smell behind). Stronger pickling vinegar and lime juice are both even more acidic and can be used for really stubborn deposits.


Both can be added to drinking water to soften.


Kettles or other drinking water boilers

  • Place a stainless steel wire scale collector in your kettle

  • Rinse plastic kettles regularly if there is limescale floating on the water surface

  • Do not leave leftover boiled water sitting in the kettle

  • Regularly descale your kettle – consult your local hardware store for advice


Hot water heating systems

Heating systems that recirculate the same water within a closed-loop are generally not affected by limescale formation. If your heating system replaces any water lost from the system with freshwater, limescale may build up over time. This can reduce the efficiency of your heating system causing your heating pipes to rattle or your radiators to take longer than usual to heat. If you are concerned you should consult a plumber.

Reducing the temperature setpoint of your water heater may reduce the level of limescale formation.


Washing machines and dishwashers

Dishwashers often have built-in water softeners. These should be used according to the manufacturer’s instructions. You can also use vinegar in your washing machine to help prevent limescale build-up.




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