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Water Treatment and Purification
Published in P.K. Tewari, Advanced Water Technologies, 2020
Ice is manufactured in several food industries and cold storage plants. The water used in ice making should be absolutely clear, odorless, colorless, tasteless and free from iron and manganese. Bicarbonate hardness is objectionable, as both calcium and magnesium are precipitated on freezing. The water treatment process selected mostly depends on the quality and composition of the raw water. If total salt content in raw water is low, the sodium cation-exchange process is employed for treatment. The cold lime process is used to reduce bicarbonate hardness. For water high in sodium bicarbonate, hydrogen cation exchange is used, as it removes the bicarbonate. Ion-exchange demineralization is also used to obtain excellent quality ice. Where surface water is used as the raw water, coagulation, settling and filtration is carried out followed by chlorination as required.
Water Quality Interpretation
Published in Arthur W. Hounslow, Water Quality Data, 2018
Step 6. Compare bicarbonate with silica. Bicarbonate is formed when carbon dioxide and water react with various minerals in a process called acid hydrolysis. Carbonates dissolve without releasing silica, whereas albite (plagioclase) releases considerable silica. Other silicates release a much lower amount (Table 4.2). An arbitrary division of bicarbonate/silica of <5 is used to indicate silicate vs. carbonate weathering and a ratio >10.
2+ process
Published in Ai Sheng, Energy, Environment and Green Building Materials, 2015
Bicarbonate and carbonate are widely present in natural water bodies. There is a balance between HCO3- and CO32-, and HCO3- is considered to be the main existing form at neutral pH value (Zhao et al. 2006). The effect of HCO3- on the removal of phosphorus with Fe/Mn oxide formed in situ by KMnO4-Fe2+ process at different pH was illustrated in Fig. 2.
Groundwater suitability zonation with synchronized GIS and MCDM approach for urban and peri-urban phreatic aquifer ensemble of southern India
Published in Urban Water Journal, 2018
The principal sources of calcium in groundwater are silicate minerals like feldspars, pyroxenes and amphiboles of igneous and metamorphic rocks and limestone, dolomite and gypsum among sedimentary rocks (Elango and Kannan 2007). In addition, disposal of sewage and industrial waste are the main sources of calcium. Calcium ion concentration (Figure 7) of a few groundwater samples were beyond the desirable limit of 200 mg/L and the value decreased from pre-monsoon to post-monsoon. The concentration of bicarbonate ions in the study area is shown in Figure 7. Bicarbonates represent the major form of alkalinity in natural waters; its source being the partitioning of CO2 from the atmosphere and the weathering of carbonate minerals in rocks and soil (Sawyer and McCarty (1978). The chloride ion is the most predominant natural form of the element chlorine and is extremely stable in water. The chloride in groundwater may be from diverse sources such as weathering, leaching of sedimentary rocks and soil, and domestic and municipal effluents (Prasanth et al. 2012). As per the Stuyfzand (1989) classification, the majority of the samples fall in the oligohaline class followed by freshwater type in the study area. In the post-monsoon period, some fresh water type areas are transformed to oligohaline water type. Groundwater in the coastal zone is fresh-to-brackish to brackish type with a small area in the urban cluster having a hyper-saline category and these samples exceed the highest desirable limit for drinking water. It may be due to domestic sewage percolation and saline water intrusion. The study area has an average 13.8 mg/L of sulphate in the pre-monsoon period and 12.12 mg/L in the post-monsoon period. The sulphate concentration for a groundwater sample from the urban cluster which lay near to the coastal line reached a maximum value of 119 mg/L during pre-monsoon and106 mg/L in post-monsoon.
Critical review on lanthanum-based materials used for water purification through adsorption of inorganic contaminants
Published in Critical Reviews in Environmental Science and Technology, 2022
Koh Yuen Koh, Yi Yang, J. Paul Chen
The stability of La-based adsorbents is another concern for the applications. A series of studies has shown that, La is vulnerable under strongly acidic condition, leading to a decline in the adsorption capacity. Thus, a better control in the solution pH is of great importance. Such buffering agents as sodium carbonate and bicarbonate are useful in the pH control.
Supervise the physicochemical quality of ground water using soft computing technique
Published in Environmental Technology, 2021
Sunil Kumar Sharma, Vivek Sharma, Hassan Ibrahim Mohamed, Hasim Khan, Sameh S. Ahmed
Sulphate gets affected by the release of industrial wastes and domestic sewage [19]. According to WHO guidelines SO42−concentration in groundwater is to be ≤250 mg/L. Bicarbonate (HCO3−)