Hard Water
Hard Water How can water be hard? Well, it can, but maybe not in the sense that one would think. Hard water refers to water with dissolved calcium and magnesium ions in it. Rainwater is naturally soft, but when the water runs through the ground or over rocks causing erosion, calcium and magnesium ions can be easily picked up. Most people prefer hard water to soft water for drinking, because the ions are good for you, and because soft water leaves a “dry” taste in one’s mouth (1,2). Big businesses and even everyday water users are concerned about the hardness of their water. It takes more soap to create suds in hard water, which contributes to “scaling in industrial equipment”(4). Hard water can be both a benefit and a burden in different areas.
Water hardness is usually measured in grains per gallon (gpg), on a scale from 0 to more than 10.5, or in ppm (mg/L), from 0 to more than 1,000. About 85% of the United States has hard water (more than 120 ppm), with the hardest water in Texas and New Mexico, and the softest waters in New England (2, 3). Extreme water hardness has not been found to have any ill health effects, but some people are still concerned about their water hardness. These people might invest in a water softening system.
There are two ways to soften water: chemically, and mechanically. Chemically, there are four main ways to neutralize the calcium and magnesium ions: lime softening, chelate softening, phosphate softening, and polymer softening. In Lime softening, slaked lime (calcium hydroxide) is added to the hard water to precipitate the calcium and magnesium, to be easily filtered out later. Then, soda ash is added to precipitate an non-bicarbonate hardness (3). For phosphate softening, mono-, di-, or trisodium phosphate are added to the water. The added phosphates keep the pH levels constant, with less variation, and “precipitate calcium and magnesium into a soft deposit rather than a hard scale”(3). Chelates are mainly used for water with a
Water hardness is usually measured in grains per gallon (gpg), on a scale from 0 to more than 10.5, or in ppm (mg/L), from 0 to more than 1,000. About 85% of the United States has hard water (more than 120 ppm), with the hardest water in Texas and New Mexico, and the softest waters in New England (2, 3). Extreme water hardness has not been found to have any ill health effects, but some people are still concerned about their water hardness. These people might invest in a water softening system.
There are two ways to soften water: chemically, and mechanically. Chemically, there are four main ways to neutralize the calcium and magnesium ions: lime softening, chelate softening, phosphate softening, and polymer softening. In Lime softening, slaked lime (calcium hydroxide) is added to the hard water to precipitate the calcium and magnesium, to be easily filtered out later. Then, soda ash is added to precipitate an non-bicarbonate hardness (3). For phosphate softening, mono-, di-, or trisodium phosphate are added to the water. The added phosphates keep the pH levels constant, with less variation, and “precipitate calcium and magnesium into a soft deposit rather than a hard scale”(3). Chelates are mainly used for water with a
Cited: 1. Errico, Daniel, and Ernst, Joseph. Hard Water Lab. 16 April 2013. Raw data. Ravenwood, Brentwood, TN. 2. "Hard vs Soft Water Explained." Hard and Soft Water Explained. FreeDrinkingWater.com, n.d. Web. 17 Apr. 2013. 3. Snyder, Kent. Email interview. 15 Mar. 2013. 4. "Water Hardness and Alkalinity." Water Hardness and Alkalinity. USGS, 28 Dec. 2012. Web. 17 Apr. 2013.