scholarly journals Technologies for the Removal of Water Hardness and Scaling Prevention

2017 ◽  
Vol 26 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Min Kyung Ahn ◽  
Choon Han
Keyword(s):  
TAPPI Journal ◽  
2014 ◽  
Vol 13 (9) ◽  
pp. 51-60
Author(s):  
DENNIS VOSS ◽  
HANS-JOACHIM PUTZ ◽  
SAMUEL SCHABEL

The need for deinking mills to reduce their fresh water consumption has resulted in higher loads of various contaminants in the process water. Lower recovered paper quality also leads to higher contamination levels in the mills. This higher load has an influence on achievable target brightness. The objective of the work was to determine and explain the main reasons for relatively poor deinked pulp quality or poor deinking potential based on the influence of recovered paper composition and process water quality. The process water parameters significantly affect the deinking potential of recovered paper. The test results showed the negative effects of increased water hardness. For standard recovered paper mixtures, flotation selectivity is higher with increasing flotation pH-value. Good results were realized for standard recovered paper with low hardness, low surface tension, and high pH-value. The results for recovered paper containing flexo newsprint could be slightly improved with low hardness, low surface tension, and low pH-value. The results of the test program using design of experiments showed interacting effects of pH-value and surface tension on luminosity and flotation selectivity.


Aquaculture ◽  
1987 ◽  
Vol 64 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Angelito C. Gonzal ◽  
Emiliano V. Aralar ◽  
Josefina Ma.F. Pavico

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 136 ◽  
Author(s):  
Andreas Mautner ◽  
Thawanrat Kobkeatthawin ◽  
Florian Mayer ◽  
Christof Plessl ◽  
Selestina Gorgieva ◽  
...  

Water hardness not only constitutes a significant hazard for the functionality of water infrastructure but is also associated with health concerns. Commonly, water hardness is tackled with synthetic ion-exchange resins or membranes that have the drawbacks of requiring the awkward disposal of saturated materials and being based on fossil resources. In this work, we present a renewable nanopaper for the purpose of water softening prepared from phosphorylated TEMPO-oxidized cellulose nanofibrils (PT-CNF). Nanopapers were prepared from CNF suspensions in water (PT-CNF nanopapers) or low surface tension organic liquids (ethanol), named EPT-CNF nanopapers, respectively. Nanopaper preparation from ethanol resulted in a significantly increased porosity of the nanopapers enabling much higher permeances: more than 10,000× higher as compared to nanopapers from aqueous suspensions. The adsorption capacity for Ca2+ of nanopapers from aqueous suspensions was 17 mg g−1 and 5 mg g−1 for Mg2+; however, EPT-CNF nanopapers adsorbed more than 90 mg g−1 Ca2+ and almost 70 mg g−1 Mg2+. The higher adsorption capacity was a result of the increased accessibility of functional groups in the bulk of the nanopapers caused by the higher porosity of nanopapers prepared from ethanol. The combination of very high permeance and adsorption capacity constitutes a high overall performance of these nanopapers in water softening applications.


1977 ◽  
Vol 14 (4) ◽  
pp. 571-581 ◽  
Author(s):  
Ming-Ko Woo ◽  
Philip Marsh

To evaluate the effect of tundra vegetation on limestone solution processes, the present study was carried out in a small basin in southwestern Ellesmere Island, N.W.T. A test reach was selected along the stream, and water samples were collected at regular intervals from a seepage point entering the reach, a soil water pit at the bottom of a vegetated slope along the test reach, and from the stream at the outlet of the reach. Hydrochemical characteristics of the samples were described by several measured and calculated variables including water temperature, pH, calcium and total hardness, bicarbonate concentration, equilibrium partial pressure of carbon dioxide, and indices of saturation with respect to calcite and dolomite. Throughout the growing season of 1975, all samples indicated higher concentrations in water hardness and in bicarbonate than those reported in nonvegetated areas of the Arctic. A rising trend was apparent in these data, with the concentrations reaching a seasonal maximum in late summer. These phenomena are attributed to the production of biogenic carbon dioxide, which increased the aggressiveness of the water. The partial pressure of carbon dioxide in soil water was directly increased by this process, while the addition of soil water to the stream caused noticeable downstream increase in partial pressure of carbon dioxide and a corresponding reduction in saturation with respect to calcite and to dolomite. The influence of vegetation was therefore very marked in both surface and in subsurface flows.


Author(s):  
A. B. Shashmurina ◽  
O. L. Mishutina ◽  
V. R. Shashmurina

Relevance. Dental caries is a leading dental disease in children. Aim – to study the quality of drinking water in Smolensk and its region to provide evidence for implementing dental caries preventive measures in children.Materials and methods. We took tap water samples from ten water intake points in seven districts of Smolensk and six Smolensk regions. An accredited testing laboratory of the Center for Hygiene and Epidemiology in the Smolensk Region carried out water chemical analysis. The study analyzed standard parameters of drinking water quality: pH 6.5-8.5, fluoride content 0.60-1.2 mg/l; water hardness 7.0-9.0 (Sanitary Regulations and Standards 2.1.4.1116-02). The parameter was considered normal if its 95% confidence interval was within the reference range.Results. In Smolensk, the hydrogen ion concentration in centralized drinking water supply systems is within normal limits and amounts to 7.39 (95% CI: 7.32-7.46; р < 0,05) pH units. The mean fluoride concentration in the Smolensk water is 0.19 (95% CI: 0.14-0.23; р < 0,05) mg/l, which is below the normal range. In most Smolensk districts, water hardness is within normal limits, 8.21 mmol/l (95% CI: 7.03-9.39; р < 0,05). However, the upper limit of the confidence interval of 9.39 mg/l and the maximum of 12.0 mg/l exceed the normal range. In the Smolensk region cities, the hydrogen ion concentration is 7.2 (95% CI: 7.02-7.38; р < 0,05) pH units in the centralized drinking water supply. The fluoride concentration in the Smolensk region water is 0.45 mg/l (95% CI: 0.23-0.68; р < 0,05), which demonstrates the fluoride deficiency in water. In the Smolensk region cities, mean water hardness is 6.66 mmol/l (95% CI: 6.00-7.03; р < 0,05), which is below the normal values. However, the CI upper limit of 7.03 mmol/l and the maximum of 7.05 mmol/l are within normal limits.Conclusions. The water of the centralized drinking water supply system in Smolensk and the Smolensk region is low in fluorides. Urgent community and individual preventive measures should be taken to expose children to fluoride.


2012 ◽  
Vol 377 (1) ◽  
pp. 1-6 ◽  
Author(s):  
V.B. Fainerman ◽  
S.V. Lylyk ◽  
E.V. Aksenenko ◽  
N.M. Kovalchuk ◽  
V.I. Kovalchuk ◽  
...  

2009 ◽  
Vol 24 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Slavica Vukovic ◽  
Dusanka Indjic ◽  
Vojislava Bursic ◽  
Dragana Sunjka ◽  
Mila Grahovac

Simultaneous occurrence of different harmful species in agricultural practice necessitates that different plant protection chemicals be applied at the same time (tank mix). Mix components differ in purpose, mode of action and/or formulation, while addition of no pesticide components (complex fertilizers, adjuvant and wetting agents) is widely practiced today. However, data concerning the effects of water quality used for preparation of working liquids on the biological effects of pesticides is still scarce. Therefore, the objective of this study was to determine insecticidal effects as depending on components used in mixes and water hardness. The effects of mixtures of thiametoxam (Actara 25-WG 0,07kg/ha) with azoxystrobin (Quadris 0.75 l/ha), mancozeb (Dithane M-70 2.5 kg/ha), a complex fertilizer (Mortonijc plus 3 kg/ha) and a wetting agent (Silwet L-77), depending on the components and water hardness (slightly hard (15.4 d?) - tap water from Novi Sad, and very hard (34.7 d?) - well water from Adica, a Novi Sad suburb), were determined in a bioassay based on adult mortality rate of the first generation of Colorado potato beetle (Leptinotarsa decemlineata Say). The mixtures were applied by a flooding method. The trial was set up to include four replications. Insecticidal effects were determined 24 h and 48 h after exposure. Thiametoxam effectiveness 24 h and 48 h after application in slightly hard water was 100% when the insecticide was applied alone and in double and triple mixes with the fungicides, complex fertilizer and wetting agent, showing no dependency on mix components. The tested adult population of Colorado potato beetle demonstrated high susceptibility to thiametoxam, while the other components had no impact in slightly hard water. In very hard water, 24 h after application, the insecticidal effect had the same level of significance to thiametoxam in double and triple mixes, with an exception of thiametoxam+mancozeb+Mortonijc plus and thiametoxam+mancozeb+wetting agent combinations, which showed significantly lower efficacy. After 48 h, substantially lower effectiveness, in comparison with the sole insecticide and other combinations, was only observed in thiametoksam+mancozeb+Mortonjic plus combination. Significantly lower efficacy of that combination is probably due to an incompatibility of the macozeb preparation and the complex fertilizer containing boron (B), which was evidenced only in very hard water.


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