Prediction of Scale Formation in Calcium Carbonate Aqueous Phase for Water Treatment and Distribution Systems

2010 ◽  
Vol 45 (3) ◽  
pp. 379-389 ◽  
Author(s):  
Alireza Bahadori
Keyword(s):  
Calcium Carbonate ◽  
Water Treatment ◽  
Ionic Strength ◽  
Distribution Systems ◽  
Scale Formation ◽  
Accurate Estimation ◽  
Predictive Tool ◽  
Simple Method ◽  
Calcium Cation ◽  
Reported Data

Abstract Accurate estimation of scale formation in distribution systems for drinking water and water treatment technologies is of utmost importance. A novel and simple method is presented here to predict the formation of calcium carbonate scaling as a function of pH, temperature, ionic strength of the solution, calcium cation, and bicarbonate anion concentrations, in order to evaluate the effect of solution conditions on precipitation tendency. The proposed simple method covers concentrations of calcium cations and bicarbonate anions up to 10,000 mg/L, temperatures up to 90°C, pressures up to 500 kPa, total ionic strength up to 3.6, and pH values ranging between 5.5 and 8. The predicted values are found to be in good agreement with the reported data with average absolute deviations being less than 2.6%. Predictive tool presented in the paper can be of immense practical value for engineers and researchers to have a quick check on the formation of calcium carbonate scaling at various conditions without opting for any experimental measurements. In particular, personnel dealing with water treatment and distribution systems would find the proposed method to be user-friendly with transparent calculations involving no complex expressions.

Effect of Electronic Water Treatment System on Calcium Carbonate Scale Formation in Landfill Leachate Collection Piping

2019 ◽  
Vol 145 (9) ◽  
pp. 04019052 ◽  
Author(s):  
Bishow N. Shaha ◽  
Daniel E. Meeroff ◽  
Kevin Kohn ◽  
Timothy G. Townsend ◽  
John D. Schert ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Water Treatment ◽  
Landfill Leachate ◽  
Scale Formation ◽  
Treatment System ◽  
Water Treatment System ◽  
Leachate Collection ◽  
Calcium Carbonate Scale

scholarly journals Theoretical Estimation of Energy Balance Components in Water Networks for Top-Down Approach

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1011
Author(s):  
Surachai Lipiwattanakarn ◽  
Suparak Kaewsang ◽  
Natchapol Charuwimolkul ◽  
Jiramate Changklom ◽  
Adichai Pornprommin
Keyword(s):  
Energy Balance ◽  
Water Loss ◽  
Distribution Systems ◽  
Minimum Energy ◽  
Head Loss ◽  
Water Networks ◽  
Top Down ◽  
Pressurized Water ◽  
Simple Method ◽  
Energy Balance Approach

The energy balance calculation for pressurized water networks is an important step in assessing the energy efficiency of water distribution systems. However, the calculation generally requires mathematical modelling of the water networks to estimate three important energy components: outgoing energy through water loss (El), friction energy loss (Ef) and energy associated with water loss (EWL). Based on a theoretical energy balance analysis of simplified pipe networks, a simple method is proposed to estimate El, Ef and EWL with minimum data requirements: input energy, water loss (WL) and head loss between the source and the minimum energy point (ΔH). By inclusion of the head loss in water networks into the estimation, the percentages of El and EWL are lower and higher, respectively, than using only the percentage of WL. The percentage of Ef can be a function of the percentage of ΔH. By demonstrating our analysis with the simulation results from the mathematical models of 20 real water networks, the proposed method can be used to effectively estimate El, Ef and EWL as a top-down energy balance approach.

Experiments on Substrate Selection by Corophium Species: Films and Bacteria on Sand Particles

1964 ◽  
Vol 41 (3) ◽  
pp. 499-511
Author(s):  
P. S. MEADOWS
Keyword(s):  
Ionic Strength ◽  
Sea Water ◽  
Distilled Water ◽  
Substrate Selection ◽  
Corophium Volutator ◽  
Simple Method ◽  
Substrate Preferences ◽  
Solutions Of Electrolytes ◽  
Sand Particles ◽  
Micro Organisms

1. A simple method is described for determining the substrate preferences of Corophium volutator (Pallas) and Corophium arenarium Crawford. 2. If offered a choice of its own substrate with that of the other species each prefers its own. 3. Level of illumination and colour of substrate have little effect on choice. An animal's size and hence its age has little effect on its substrate preferences. 4. C. volutator prefers a substrate previously maintained under anaerobic conditions, C. arenarium vice versa. 5. Treatments which kill, inactivate, or remove micro-organisms render sands unattractive to Corophium. These include boiling, acid-cleaning, drying, and soaking in fixatives or distilled water. Attempts to make these sands attractive again failed. 6. Distilled water, and solutions of the non-electrolytes sucrose and glycerol at the same osmotic pressure as sea water, induce many bacteria to desorb from sand particles; smaller numbers are desorbed in the presence of solutions of electrolytes at the same ionic strength as sea water (NaCl, Na2SO4, KC1, MgSO4, MgCl2, CaCl2). Of all these, only distilled water and solutions of MgCl2 and CaCl2 reduce the attractive properties of sands. Hence the loss of bacteria from the surface of sand grains, though related to the ionic strength and composition of the medium, is not necessarily associated with a substrate becoming unattractive.

Technical Note: Common Water Treatment Chemicals and Calcium Carbonate Saturation

2017 ◽  
Vol 109 ◽  
pp. 38-43
Author(s):  
R. Rhodes Trussell ◽  
John D. Kenny ◽  
David R. Hokanson
Keyword(s):  
Calcium Carbonate ◽  
Water Treatment ◽  
Technical Note

scholarly journals Waterborne outbreaks in the Nordic countries, 1998 to 2012

2015 ◽  
Vol 20 (24) ◽  
Author(s):  
B Guzman-Herrador ◽  
A Carlander ◽  
S Ethelberg ◽  
B Freiesleben de Blasio ◽  
M Kuusi ◽  
...  
Keyword(s):  
Water Treatment ◽  
Water Supply ◽  
Distribution Systems ◽  
Water Source ◽  
Nordic Countries ◽  
Surveillance Systems ◽  
Water Supplies ◽  
Treatment Regimens ◽  
Supply And Distribution ◽  
Household Water

A total of 175 waterborne outbreaks affecting 85,995 individuals were notified to the national outbreak surveillance systems in Denmark, Finland and Norway from 1998 to 2012, and in Sweden from 1998 to 2011. Between 4 and 18 outbreaks were reported each year during this period. Outbreaks occurred throughout the countries in all seasons, but were most common (n = 75/169, 44%) between June and August. Viruses belonging to the Caliciviridae family and Campylobacter were the pathogens most frequently involved, comprising n = 51 (41%) and n = 36 (29%) of all 123 outbreaks with known aetiology respectively. Although only a few outbreaks were caused by parasites (Giardia and/or Cryptosporidium), they accounted for the largest outbreaks reported during the study period, affecting up to 53,000 persons. Most outbreaks, 124 (76%) of those with a known water source (n = 163) were linked to groundwater. A large proportion of the outbreaks (n = 130/170, 76%) affected a small number of people (less than 100 per outbreak) and were linked to single-household water supplies. However, in 11 (6%) of the outbreaks, more than 1,000 people became ill. Although outbreaks of this size are rare, they highlight the need for increased awareness, particularly of parasites, correct water treatment regimens, and vigilant management and maintenance of the water supply and distribution systems.

scholarly journals Ammonia/ammonium dissociation coefficient in seawater: A significant numerical correction

2007 ◽  
Vol 4 (3) ◽  
pp. 183 ◽  
Author(s):  
Thomas G. Bell ◽  
Martin T. Johnson ◽  
Timothy D. Jickells ◽  
Peter S. Liss
Keyword(s):  
Ionic Strength ◽  
Natural Waters ◽  
Ammonia Toxicity ◽  
Acid Dissociation ◽  
Gaseous Ammonia ◽  
Accurate Estimation ◽  
Environmental Processes ◽  
Climate Regulation ◽  
Natural Temperature ◽  
Ammonia Exchange

Environmental context. Quantifying ammonia concentrations in natural waters is important for our understanding of environmental processes that relate, in particular, to aquaculture toxicity and to the transfer of gaseous ammonia into the atmosphere where it plays a role in new particle formation and climate regulation. The proportion of ammonia present in natural waters is determined in part by variations in temperature and salinity. This work identifies that a previous equation for predicting ammonia concentrations over natural temperature and salinity ranges is incorrect and suggests alternative, more appropriate equations. A more accurate estimation of environmental ammonia concentrations is essential if improved estimates are to be made of the flux of ammonia into the atmosphere and the level of ammonia toxicity within aquacultures. Abstract. The equilibrium between ammonia (NH3) and ammonium (NH4+) in aqueous solution is a function of temperature, pH and the ionic strength of the solution. Here we reveal a 30-year-old error in published work on the thermodynamics of ammonium dissociation in seawater, which has propagated throughout the literature. The work in question[1] [K. H. Khoo, C. H. Culberson, R. G. Bates, J. Solution Chem. 1977, 6, 281] presents an incorrect expression for the variation of the acid dissociation coefficient (Ka) of ammonium with temperature and ionic strength. We detail the error and reveal that it can lead to as much as a 500% overestimation in calculated NH3 concentration under environmental conditions. This finding is highly relevant, particularly for studies of ammonia toxicity and air–sea ammonia exchange. In addition, we recommend two expressions that better reproduce previous experimental work: (i) taken from the work of Johansson and Wedborg,[2] and (ii) our own derivation using the dataset of Khoo et al.[1]

Top-down model of calcium carbonate scale formation in turbulent pipe flows

2021 ◽  
pp. 101141
Author(s):  
L. Moriconi ◽  
T. Nascimento ◽  
B.G. B. de Souza ◽  
J.B.R. Loureiro
Keyword(s):  
Calcium Carbonate ◽  
Scale Formation ◽  
Top Down ◽  
Pipe Flows ◽  
Calcium Carbonate Scale

Virtual Ground Fence: A Simple Method for Protection against High Frequency Simultaneous Switching Noise

2012 ◽  
Vol 2012 (1) ◽  
pp. 001081-001084 ◽  
Author(s):  
Jesse Bowman ◽  
A. Ege Engin
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Power Efficiency ◽  
Printed Circuit Board ◽  
Supply Voltage ◽  
Circuit Board ◽  
Voltage Source ◽  
Accurate Estimation ◽  
Simple Method ◽  
Power Distribution System

When integrating sensitive RF analog devices with complex VLSI digital components, simultaneously switching drivers cause supply voltage fluctuations which can propagate both horizontally and vertically between the power/ground planes. The same voltage source on a printed circuit board can be shared to increase power efficiency and reduce space used. In order to accomplish this, on board filtering is needed to isolate the noise between these two types of devices for proper operation. Hence, accurate estimation and improvement of the performance of power/ground planes is critical in a mixed-signal system. We present a new method to minimize the noise transfer at high frequencies to the power distribution system, called the Virtual Ground Fence. At its basic level, the Virtual Ground Fence consists of quarter-wave transmission-line stubs that act as short circuits between power and ground planes at their design frequency. We will present various configurations of Virtual Ground Fence for different coupling scenarios.

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