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Hardness
Published in Pradyot Patnaik, Handbook of Environmental Analysis, 2017
When the total hardness measured in the sample is numerically greater than the sum of both carbonate alkalinity and bicarbonate alkalinity, then Carbonate hardness=carbonate alkalinity+bicarbonate alkalinity and Noncarbonate hardness=total hardness−carbonate hardness or Total hardness−(carbonate alkalinity+bicarbonate alkalinity)
Dissolved Matter
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
The amounts of carbonate and noncarbonate hardness present are determined as follows: if the methyl orange alkalinity of the water equals or exceeds the total hardness, all of the hardness is present as carbonate hardness.if the methyl orange alkalinity of the water is less than the total hardness, the carbonate hardness equals the alkalinity.The noncarbonate hardness, under the conditions above, is equal to the total hardness minus the methyl orange alkalinity.
Water Quality
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Hardness is due to the presence of multivalent metal ions, which come from minerals dissolved in water. Hardness is based on the ability of these ions to react with soap to form a precipitate or soap scum. In freshwater, the primary ions are calcium and magnesium; however, iron and manganese may also contribute. Hardness is classified as carbonate hardness or noncarbonate hardness. Carbonate hardness is equal to alkalinity but a noncarbonate fraction may include nitrates and chlorides. Hardness is either temporary or permanent. Carbonate hardness (temporary hardness) can be removed by boiling. Noncarbonate hardness cannot be removed by boiling and is classified as permanent.
Health risk assessment in an area of dental fluorosis disease from high fluoride drinking water: a case study from southeastern Türkiye
Published in International Journal of Environmental Health Research, 2023
Benan Yazıcı Karabulut, Perihan Derin, Ayşegül Demir Yetiş, Mehmet İ̇rfan Yeşilnacar
Based on the Piper diagram, it has been determined that HCO3-Ca⋅Mg and Ca + HCO3 water types are the predominant types in the study area. The groundwater of the study area has a higher concentration of alkaline earth elements (Ca + Mg) than alkaline elements (Na + K). Moreover, weak acid roots (CO3 + HCO3) are more prevalent than strong acid roots (SO4 + Cl). Consequently, the water type in this region is indicative of waters with carbonate hardness in excess of 50%. It is believed that the length of time that groundwater interacts with anthropogenic pollutants has a role to play in the formation of different water types within the area. Furthermore, agricultural activities are known to impact water chemistry. As illustrated in Figure S2, the primary locations of groundwater sampling points in the study area were found to be located within the main hydrochemical facies of HCO3‒Ca⋅Mg.
A systematic review of the water treatment sludge toxicity to terrestrial and aquatic biota: state of the art and management challenges
Published in Journal of Environmental Science and Health, Part A, 2022
Aline Christine Bernegossi, Bárbara Luíza Souza Freitas, Gleyson B. Castro, Jéssica Pelinsom Marques, Liliane Folli Trindade, Mara R. de Lima e Silva, Mayara C. Felipe, Allan Pretti Ogura
In the retrieved studies (Table 1), the coagulants applied were Al, Fe, and Ca salts, the first two being the most reported. Al-based coagulants are less expensive and widely available, but they only work within a specific pH range and produce much gelatinous sludge.[17] On the other hand, Fe-based coagulants work over a wider pH range and remove natural organic matter more effectively than Al-based coagulants.[53] However, they are corrosive and require special piping and storage equipment.[54] Finally, Ca salt reacts with sodium carbonate and forms a calcium carbonate precipitate that can be easily removed. However, this process produces a large amount of Ca-enriched sludge,[55] significantly increasing the pH of receiving waters and soils after disposal.[56] In addition, lime is also used as a coagulant to remove carbonate hardness from water.
EUROCORR 2019: ‘New Times, New Materials, New Corrosion Challenges’ – Part 3
Published in Corrosion Engineering, Science and Technology, 2020
‘Pitting corrosion of copper in drinking water systems: an update of the current situation in Germany and an outlook on further investigations’ was reviewed by T. Jentzsch (IWW Water Centre, Muelheim an der Ruhr, Germany). Reports of damage in drinking water installations have increased since 2005. Although a plot of sulphate content (logarithmic) vs. the carbonate hardness by von Franqué identified two regions associated with (i) cold water damage, and (ii) hot water damage, there was no apparent correlation between factors affecting the probability of pitting corrosion. An electrochemical test programme, comprising rapid screening by Galvano-dynamic polarisation was conducted to re-assess the theory of a relationship between the inner surfaces of new copper pipes and the initiation of pitting corrosion to ensure that electrochemical methods are meaningful. As expected, micro-defects in oxide layers resulted in lower pitting potentials.