The Experts below are selected from a list of 3240 Experts worldwide ranked by ideXlab platform
G A Dreitser - One of the best experts on this subject based on the ideXlab platform.
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a study of salt deposition in channels with discrete turbulence promoters carrying water of high Carbonate Hardness
Thermal Engineering, 1996Co-Authors: G A DreitserAbstract:Experimental studies for analyzing the process of salt deposition on the inner and outer surfaces of tubes with annular turbulence promoters developed at MAI were conducted. Curves were constructed showing the thermal resistance of the salt deposits as a function of the height and spacing of the turbulence promoters, the flow rate, the water Hardness, and time. A three- to fivefold decrease in the intensity of salt deposition was discovered compared to the case of smooth tubes.
Subba N Rao - One of the best experts on this subject based on the ideXlab platform.
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quality criteria for groundwater use from a rural part of wanaparthy district telangana state india through ionic spatial distribution isd entropy water quality index ewqi and principal component analysis pca
Environmental Geochemistry and Health, 2020Co-Authors: Subba N Rao, B Sunitha, Narsimha Adimalla, M ChaudharyAbstract:The present study region comprises granite and granite gneisses aquifer system constituted by Precambrian rocks. Groundwater is the primary source for drinking and other domestic purposes. Many developing regions in the world suffer from lack of safe drinking water. A rural part of Wanaparthy District in Telangana State, India, is one of them. For this reason, the groundwater samples collected from the study region were analyzed for pH, TDS, Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42−, NO3− and F− and evaluated groundwater quality criteria, using ionic spatial distribution (ISD), entropy water quality index (EWQI) and principal component analysis (PCA). The ISD maps show that some locations are not suitable for drinking purpose due to exceeding concentrations of TDS, Mg2+, Na+, K+, HCO3−, Cl−, NO3−and F−, compared to those with national drinking water quality standards. According to the EWQI, about 3%, 47%, 43% and 7% of the total area come under the excellent, good, medium and extremely poor water quality types for drinking purpose, respectively. Chadha’s diagram classified the area as Carbonate Hardness (63%), non-Carbonate alkali (17%), Carbonates alkali (13%) and non-Carbonate Hardness (7%) zones. The binary diagrams (Na+ + K+ vs TC, Na+ vs Ca2+ and HCO3− vs TC) indicate that the quality of groundwater is controlled by influences of water–rock interactions, mineral weathering and dissolution, ion exchange and evaporation as well as the impact of anthropogenic sources. The PCA transferred the chemical variables into three principal components accounts for about 81% of the total variance. The high positive loadings of PC1 (Cl−, TDS, SO42−, Na+, NO 3 − , Mg2+ and HCO3−) stand for processes of silicate weathering and dissolution, ion exchange and evaporation, and the influence of domestic waste waters, irrigation return flows and chemical fertilizers on the groundwater system, the PC2 (F− and pH) signifies the alkaline nature of groundwater, which causes fluorosis, and the PC3 (K+) is a result of potassium fertilizers. The study helps to take remediate measures at a specific site and hence suggests the treatment of water before its drinking and also the recharge of the aquifer artificially to improve the groundwater quality.
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hydrogeochemical processes regulating the spatial distribution of groundwater contamination using pollution index of groundwater pig and hierarchical cluster analysis hca a case study
Groundwater for Sustainable Development, 2019Co-Authors: Subba N Rao, Maya ChaudharyAbstract:Abstract Groundwater quality investigation has been carried out from a sub-urban area of Visakhapatnam, Andhra Pradesh, India, to find out the controlling processes of groundwater chemistry spatially, leading to groundwater contamination. The groundwater quality is characterized by fresh to brackish and hard types, with Ca2+ > Na+ > Mg2+ > K+: HCO 3 − > Cl − > SO 4 2 − > NO 3 − facies. According to the pollution index of groundwater (PIG), most of the study area (70%) comes under the insignificant pollution zone and the rest (30%) under the low pollution zone. The chemical variables from the hierarchical cluster analysis (HCA) demonstrate three distinct clusters, which measure TDS in Cluster I, HCO 3 − and TH in Cluster II, and Cl − , Na+, Ca2+, SO 4 2 − , Mg2+, NO 3 − , K+ and pH in Cluster III, representing the salinity, Carbonate Hardness and pollution processes, respectively. Groundwater samples from the HCA are categorized into three groups, which show less, moderately and highly mineralized groundwater qualities in Group I, II and III, respectively, depending upon the geogenic processes and the anthropogenic activities. The groundwater samples of Group III influenced by low pollution activity, which support the low pollution zone of PIG, establish the fact that the controlling processes of groundwater chemistry lead to groundwater contamination spatially. The present study helps taking the strategic management measures at specific sites for sustainable development of groundwater resources.
Raphael Semiat - One of the best experts on this subject based on the ideXlab platform.
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calcium Carbonate Hardness removal by a novel electrochemical seeds system
Desalination, 2010Co-Authors: David Hasson, Georgiy Sidorenko, Raphael SemiatAbstract:Scale prevention is widely encountered in cooling water systems and is one of the main difficulties in both thermal and membrane water desalination processes. The usual scale control method applied in water desalination systems is based on the dosage of inhibiting compounds which are able to suppress scale precipitation up to a certain degree. Electrochemical scale control systems are beneficially used for Hardness abatement of cooling tower waters. The main drawback hindering their use in desalination applications is the very high electrode area requirement. The novel electrochemical system developed in this study enables drastic reduction in the electrode area requirement. This is achieved by directing the precipitation to occur in a seeds crystallization vessel rather than on the cathode. Results obtained in preliminary experiments have already yielded a reduction in the specific cathode area by a factor exceeding 10 without altering the specific energy requirement. Furthermore, the seeds system appears to be free from the restriction of an asymptotic precipitation rate limit. The outstanding advantages of the low electrode area seeds system opens possibilities for widespread applications of electrochemical Hardness removal in diverse processes requiring scale prevention measures.
M Chaudhary - One of the best experts on this subject based on the ideXlab platform.
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quality criteria for groundwater use from a rural part of wanaparthy district telangana state india through ionic spatial distribution isd entropy water quality index ewqi and principal component analysis pca
Environmental Geochemistry and Health, 2020Co-Authors: Subba N Rao, B Sunitha, Narsimha Adimalla, M ChaudharyAbstract:The present study region comprises granite and granite gneisses aquifer system constituted by Precambrian rocks. Groundwater is the primary source for drinking and other domestic purposes. Many developing regions in the world suffer from lack of safe drinking water. A rural part of Wanaparthy District in Telangana State, India, is one of them. For this reason, the groundwater samples collected from the study region were analyzed for pH, TDS, Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42−, NO3− and F− and evaluated groundwater quality criteria, using ionic spatial distribution (ISD), entropy water quality index (EWQI) and principal component analysis (PCA). The ISD maps show that some locations are not suitable for drinking purpose due to exceeding concentrations of TDS, Mg2+, Na+, K+, HCO3−, Cl−, NO3−and F−, compared to those with national drinking water quality standards. According to the EWQI, about 3%, 47%, 43% and 7% of the total area come under the excellent, good, medium and extremely poor water quality types for drinking purpose, respectively. Chadha’s diagram classified the area as Carbonate Hardness (63%), non-Carbonate alkali (17%), Carbonates alkali (13%) and non-Carbonate Hardness (7%) zones. The binary diagrams (Na+ + K+ vs TC, Na+ vs Ca2+ and HCO3− vs TC) indicate that the quality of groundwater is controlled by influences of water–rock interactions, mineral weathering and dissolution, ion exchange and evaporation as well as the impact of anthropogenic sources. The PCA transferred the chemical variables into three principal components accounts for about 81% of the total variance. The high positive loadings of PC1 (Cl−, TDS, SO42−, Na+, NO 3 − , Mg2+ and HCO3−) stand for processes of silicate weathering and dissolution, ion exchange and evaporation, and the influence of domestic waste waters, irrigation return flows and chemical fertilizers on the groundwater system, the PC2 (F− and pH) signifies the alkaline nature of groundwater, which causes fluorosis, and the PC3 (K+) is a result of potassium fertilizers. The study helps to take remediate measures at a specific site and hence suggests the treatment of water before its drinking and also the recharge of the aquifer artificially to improve the groundwater quality.
Claire Fargues - One of the best experts on this subject based on the ideXlab platform.
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Toward the reduction of water consumption in the vegetable-processing industry through membrane technology: case study of a carrot-processing plant
Environmental Science and Pollution Research, 2020Co-Authors: Céline Garnier, Wafa Guiga, Marie-laure Lameloise, Laure Degrand, Claire FarguesAbstract:The food industry consumes large amounts of clean, potable water and in turn generates a significant amount of wastewater. In order to minimize water consumption, membrane technologies represent a suitable solution for the treatment of wastewater before it is recycled as process water. Many studies have shown the effectiveness of this technology in the dairy industry, but there are few studies in the fruit- and vegetable-processing sectors. A recently developed methodology for the reduction of water consumption was tested here. Compounds to be eliminated were identified through chemical analysis of several wastewater samples from a carrot-peeling process. Drinking-water quality was selected as our target. Total suspended solids (TSS), fructose, glucose and sucrose were identified as key parameters. Salts (particularly Ca^2+ and Mg^2+), pH and Carbonate Hardness (CH) were identified as indicators for evaluating the risk of scaling and corrosion. Based on these results, sieving followed by a 0.5-μm microfiltration (MF) was chosen as the process for pre-treatment. Four nanofiltration (NF) membranes (NFW from SYNDER, DK from GE, NF270 from DOW and SR3D from KOCH) and three reverse osmosis (RO) membranes (ESPA4 from Nitto Group Company, BW30 from DOW and HRX from KOCH) were then tested for the capacity to minimize chemical oxygen demand (COD) and to principally remove sugars. These membranes were then evaluated in terms of permeability and rejection rates. High-quality water could be obtained with RO membranes at low pressure (up to 15 bar) while limiting fouling risks. Rejection rates up to 98.3, 98.0, 99.2, 99.2 and 99.4% for conductivity, COD, fructose, glucose and sucrose, respectively, were achieved. These results are very encouraging for future reuse in vegetable processing before the blanching step, after an additional disinfection treatment.