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Downstairs
Published in Michael Allaby, Conservation at Home, 2019
Domestic water softeners use one of two common processes. Some filter the water through a bed of ‘zeolite’, a hydrated aluminosilicate from whose crystals the water has been driven by heating. This leaves an open crystal structure that captures the salts. This is the technique used, for example, by Permutit. The alternative is to filter the water through polysulphates, such as Calgon, which trap calcium. Eventually the filter medium becomes saturated and must be replaced or regenerated. Domestic water softeners are effective, and remove substances from water rather than adding anything, so they are quite harmless. While soft water is most useful for washing, hard water is probably heathier for drinking (see hardness and softness of water, page 38).
Water Supply Systems
Published in Monzur A. Imteaz, Urban Water Resources, 2019
Water softening is the process of removing hardness; however, this is not an essential element of water treatment as hard water is not harmful for human consumption. Water softening reduces soap consumption and reduces maintenance costs for plumbing. Treatment processes for water softening are: 1) Precipitation and 2) Ion exchange. Precipitation involves adding lime and soda ash to the water, which react with Calcium and Magnesium salts and form insoluble precipitates, which are removed by sedimentation. Ion exchange is basically the exchange of cations with the help of ion-exchanging resin. In this process, Calcium and Magnesium cations are exchanged for Sodium cations as Sodium salts do not cause hardness.
Water Quality Parameters
Published in Joseph Cotruvo, Drinking Water Quality and Contaminants Guidebook, 2019
Many people do not understand the meaning of hard water and some believe that it is a contamination of harmful chemicals. The term “hard water” generally refers to water that has high mineral content, but specifically water that is high in calcium and/or magnesium ions. Barium, strontium, copper, lead, zinc, cadmium, and radium can also be minor components. Hard water forms precipitates of metal carbonates that are very insoluble and it causes problems by forming scale deposits, accumulating in pipe and in cooling systems where they reduce the heat transfer capability. When combined with soap the metal components interfere with lathering and rinsing and cause the precipitated “bathtub ring.” Hard water is probably the most common and noticeable water quality problem that occurs. It has been said that about 80–85 percent of the United States has hard water as defined. The good news is that hardness is not known to cause any human health concerns, and it may have some health benefits, but it can certainly have negative aesthetic and economic consequences.
Water quality assessment of Mansbal Lake in Kashmir
Published in Water Science, 2022
Daawar Bashir Ganaie, Anirudh Malhotra, Irfan Ahmad Wani
The presence of high mineral content in a water describes it as hard water and water with low content as soft water. Hard water becomes as soon as water seeps over deposits of limestone, chalk, or gypsum which are basically made up of calcium and magnesium carbonates, bicarbonates, and sulfates. In the present study, the total hardness of water was high at all the sites of the lake, ranging between 212 mg/L and 90 mg/L. The maximum values were recorded all over during June. The highest values of total hardness at Kondabal site 2 seem to be related to the percolation of Ca2+ and Mg2+ ions into lake waters due to the presence of stone quarries and lime kilns in the adjoining area. The hardness of water may also happen due to the occurrence of cations of Ca2+, Mg2+, Fe3+, etc. (Lodh et al., 2014). The lake is also surrounded by the human settlements and the sewage outlets possessing soap and detergent wastewaters and agricultural run-off directly drain into the lake which can also increase the hardness of the water. According to (Satya & Narayan, 2018), the hardness of water may be due to the entrance of direct pollution from settlements and industrial discharge. The water of Manasbal lake is placed in the category of very hard waters, because of the values of hardness exceed the value of 180 mg/L, according to the hardness scale of Water Quality Association, a hardness value below 17 mg/L is soft water, 17 mg/L to 60 mg/L is slightly hard, 60 mg/L to 120 mg/L is moderately hard, 120 mg/L to 180 mg/L is hard and above 180 mg/L is very hard.
Synthesis and hard water resistance mechanism of polycarboxylate dispersant for pesticide water dispersible granules
Published in Journal of Dispersion Science and Technology, 2020
Qingmei Tian, Yanyan Zhang, Zhiyu Jia, Qiang Zhang
Hard water is usually defined as underground water that contains a higher concentration of calcium and magnesium ions, and water hardness is used to describe the sum of the calcium and magnesium content.[12] In the practical application of pesticide WDG, hard water would greatly reduce the dispersion and suspension stability of WDG, which affect the performances of WDG remarkably. How to improve the hard water resistance of WDG received too much attention during the past decade.[13–15] The dispersion and suspension stability of pesticide WDG in hard water have already been studied to a certain extent, but the problems of pesticide WDG performance after hot storage deteriorating rapidly in water with high hardness have not been solved.
Assessment of some physicochemical parameters and determining the corrosive characteristics of the Karnaphuli estuarine water, Chittagong, Bangladesh
Published in Water Science, 2020
Md. Ripaj Uddin, Md. Moazzem Hossain, Shakila Akter, Muhammad Edris Ali, Md. Aminul Ahsan
Hardness is a chemical parameter of water, which scaling the corrosive characteristic of water that represents the total concentration of calcium and magnesium ions. Investigation showed that the Total hardness of the Karnaphuli river varied from 50.1 to 2308.4 ppm. Sampling station RK1 showed highest Total hardness during the winter season and sampling station RK3 showed lowest Total hardness during the rainy season. The higher Total hardness at RK1 is due to the cement industry, soap, and detergent plant (Tables 6 and 7) effluents discharged here. The nature of Karnaphuli river water can be considered according to Table 12 as hard water. Hard water is not suitable for domestic use such as washing, bathing, cooking as well as other purposes. Hard water is also not suitable for industrial and agricultural use. It damages the delicate machineries and affects the quality, stability and glossiness of the final product. According to the Environmental Conservations Rules (ECR) guideline, the range of Total hardness should be 200–500 ppm (ECR, 1997). Table 8 shows that most of winter and all rainy seasonal observed values exceeded the acceptable limit which is listed in Table 10 and also shown in Figure 3.