Modelling pathogen fate in stormwaters by a particle–pathogen interaction model using population balances

2012 ◽  
Vol 65 (5) ◽  
pp. 823-832 ◽  
Author(s):  
L. Vergeynst ◽  
B. Vallet ◽  
P. A. Vanrolleghem
Keyword(s):  
Settling Velocity ◽  
Interaction Model ◽  
Pathogen Removal ◽  
Solar Disinfection ◽  
Critical Effect ◽  
Layered Approach ◽  
Settling Velocity Distribution ◽  
Population Balances ◽  
Adsorption Desorption

Stormwater is polluted by various contaminants affecting the quality of receiving water bodies. Pathogens are one of these contaminants, which have a critical effect on water use in rivers. Increasing the retention time of water in stormwater basins can lead to reduced loads of pathogens released to the rivers. In this paper a model describing the behaviour of pathogens in stormwater basins is presented including different fate processes such as decay, adsorption/desorption, settling and solar disinfection. By considering the settling velocity distribution of particles and a layered approach, this model is able to create a light intensity, and particle and pathogen concentration profile along the water depth in the basin. A strong effect of solar disinfection is discerned. The model has been used to evaluate pathogen removal efficiencies in stormwater basins. It includes a population of particle classes characterized by a distribution of settling velocities in order to be able to reproduce stormwater quality and treatment in a realistic way.

Methodology of Calculation the Terminal Settling Velocity Distribution of Irregular Particles for High Values of the Reynold’s Number/Metodologia Wyliczania Rozkładu Granicznej Prędkości Opadania Ziaren Nieregularnych Dla Wysokich Wartości Liczb Reynoldsa

2014 ◽  
Vol 59 (2) ◽  
pp. 553-562 ◽  
Author(s):  
Agnieszka Surowiak ◽  
Marian Brożek
Keyword(s):  
Velocity Distribution ◽  
Settling Velocity ◽  
Random Variables ◽  
Independent Random Variables ◽  
Calculation Algorithm ◽  
Shape Coefficient ◽  
Geometrical Properties ◽  
Size And Shape ◽  
Physical Density ◽  
Settling Velocity Distribution

Abstract Settling velocity of particles, which is the main parameter of jig separation, is affected by physical (density) and the geometrical properties (size and shape) of particles. The authors worked out a calculation algorithm of particles settling velocity distribution for irregular particles assuming that the density of particles, their size and shape constitute independent random variables of fixed distributions. Applying theorems of probability, concerning distributions function of random variables, the authors present general formula of probability density function of settling velocity irregular particles for the turbulent motion. The distributions of settling velocity of irregular particles were calculated utilizing industrial sample. The measurements were executed and the histograms of distributions of volume and dynamic shape coefficient, were drawn. The separation accuracy was measured by the change of process imperfection of irregular particles in relation to spherical ones, resulting from the distribution of particles settling velocity.

The Novel Multi-layered Approach to Enhance Sorting Performance of Healthcare Analysis

2022 ◽  
Vol 11 (3) ◽  
pp. 0-0
Keyword(s):  
Big Data ◽  
Data Analytics ◽  
Large Data ◽  
The Novel ◽  
Analytical Technique ◽  
Huge Data ◽  
Costs Of Treatment ◽  
Layered Approach ◽  
New Challenges

Emergence of big data in today’s world leads to new challenges for sorting strategies to analyze the data in a better way. For most of the analyzing technique, sorting is considered as an implicit attribute of the technique used. The availability of huge data has changed the way data is analyzed across industries. Healthcare is one of the notable areas where data analytics is making big changes. An efficient analysis has the potential to reduce costs of treatment and improve the quality of life in general. Healthcare industries are collecting massive amounts of data and look for the best strategies to use these numbers. This research proposes a novel non-comparison based approach to sort a large data that can further be utilized by any big data analytical technique for various analyses.

Characterisation of retention tank water quality: particle settling velocity distribution and retention time

2013 ◽  
Vol 48 (4) ◽  
pp. 321-332 ◽  
Author(s):  
Thibaud Maruéjouls ◽  
Peter A. Vanrolleghem ◽  
Geneviève Pelletier ◽  
Paul Lessard
Keyword(s):  
Velocity Distribution ◽  
Retention Time ◽  
Settling Velocity ◽  
Oxygen Demand ◽  
Combined Sewer Overflows ◽  
Particle Settling ◽  
Wastewater Systems ◽  
Receiving Waters ◽  
Settling Velocity Distribution ◽  
Settling Performance

Retention tanks (RTs) are commonly used to reduce combined sewer overflows, management of which is an important way of reducing the impacts of urban development on receiving waters. However, overflow characteristics and the processes affecting them are not yet fully understood. In a context of integrated urban wastewater systems, the management of RTs is mainly done to satisfy hydraulic constraints even if the idea behind such structures is to limit the discharge of pollutants to the environment. This study reports new insights in the settling processes and the pollutant behaviour occurring in an off-line RT. The authors first focus on the total suspended solids (TSS) and the total chemical oxygen demand (CODt) dynamics at the inlet and the outlet of a RT. Secondly, they focus on the possible relationship between the variation of the particle settling velocity distribution of particles and the TSS concentration dynamics. Finally, analyses of the TSS and CODt concentration evolution during tank emptying give information on the interaction between wastewater retention time and the settling performance.

scholarly journals Photocatalytic Enhancement for Solar Disinfection of Water: A Review

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
J. Anthony Byrne ◽  
Pilar A. Fernandez-Ibañez ◽  
Patrick S. M. Dunlop ◽  
Dheaya M. A. Alrousan ◽  
Jeremy W. J. Hamilton
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Waterborne Diseases ◽  
Safe Drinking Water ◽  
Developing Regions ◽  
Water Supplies ◽  
Semiconductor Photocatalysis ◽  
Solar Disinfection ◽  
Clean Drinking Water

It is estimated that 884 million people lack access to improved water supplies. Many more are forced to rely on supplies that are microbiologically unsafe, resulting in a higher risk of waterborne diseases, including typhoid, hepatitis, polio, and cholera. Due to poor sanitation and lack of clean drinking water, there are around 4 billion cases of diarrhea each year resulting in 2.2 million deaths, most of these are children under five. While conventional interventions to improve water supplies are effective, there is increasing interest in household-based interventions to produce safe drinking water at an affordable cost for developing regions. Solar disinfection (SODIS) is a simple and low cost technique used to disinfect drinking water, where water is placed in transparent containers and exposed to sunlight for 6 hours. There are a number of parameters which affect the efficacy of SODIS, including the solar irradiance, the quality of the water, and the nature of the contamination. One approach to SODIS enhancement is the use of semiconductor photocatalysis to produce highly reactive species that can destroy organic pollutants and inactivate water pathogens. This paper presents a critical review concerning semiconductor photocatalysis as a potential enhancement technology for solar disinfection of water.

Measurement of soil aggregate settling velocities. 1. A modified bottom withdrawal tube method

Soil Research ◽  
1988 ◽  
Vol 26 (1) ◽  
pp. 55 ◽  
Author(s):  
CJ Lovell ◽  
CW Rose
Keyword(s):  
Entire Range ◽  
Settling Velocity ◽  
Soil Aggregates ◽  
Soil Aggregate ◽  
Natural Sediment ◽  
Polydisperse Suspension ◽  
Modified Method ◽  
Sediment Types ◽  
Settling Velocity Distribution ◽  
Sediment Settling

Sediment eroded by water consists largely of soil aggregates. The settling velocity of such aggregates and primary soil particles is of fundamental importance to the processes of sediment transport and deposition in water. A modified bottom withdrawal tube method is presented for the direct measurement of the settling velocity distribution of soil aggregates or particles of different sizes that settle together in a polydisperse suspension. The modified method overcomes experimental error and analytical deficiencies present in the initial method and is suitable for measuring settling velocities up to 0.5 m s-1. The method employs the bottom withdrawal principle; new exact theory is presented for interpretation of sedimentation data thus measured. By complementing the pipette or hydrometer methods which measure settling velocities less than 10-3 ms-1, this modified method allows analysis of the entire range of settling velocities encountered in natural sediment. Settling velocity distributions measured for a variety of sediment types are illustrated.

scholarly journals The Dyadic Interaction Model of Relationship Quality and the Impact of Attachment Orientation and Empathy on Infertile Couples in China

2020 ◽  
Author(s):  
Kun Du ◽  
Yue-zhi Dong
Keyword(s):  
Relationship Quality ◽  
Interaction Model ◽  
Psychological Services ◽  
Dyadic Interaction ◽  
Infertile Couple ◽  
Attachment Orientation ◽  
Infertile Couples ◽  
The Impact ◽  
The Relationship

Abstract Background: The study was conducted to examine the effect of attachment orientation and empathy on the relationship quality of infertile couples and assess the interdependency model of these factors.Method: In this study, 168 infertile couples (336 individuals) were enrolled and asked to finish he following questionnaires: the revised Adult Attachment Scales, the Interpersonal Response Index questionnaire, and the Relationship Quality subscale of the Fertility Quality of Life (FertiQol).Results: The attachment orientation of infertile couples can influence their relationship quality, and empathetic wives and husbands have actor and partner effects on the infertile couples’ relationship quality.Conclusion: Empathetic infertile couples are conducive to the harmony of the relationship. In order to provide better psychological services for patients, the clinical personnel should consider the infertile couple as a team both experiencing the stress of infertility together, and then should evaluate their ability for empathy systematically.

scholarly journals Parameter identification of the interaction body model using available measurements

2020 ◽  
Vol 40 (3) ◽  
pp. 1-12
Author(s):  
Qingwen Zhang ◽  
Zheng Li ◽  
Yu Zhang ◽  
Tianjian Ji
Keyword(s):  
Curve Fitting ◽  
Interaction Model ◽  
Continuous Model ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Interaction Models ◽  
Identification Process ◽  
The Masses ◽  
Better Than

This paper determines the parameters of the interaction models based on available published experimental measurements. The masses, damping ratios and stiffnesses of body models are identified by the curve fitting of the measured apparent mass curves from shaking table tests in published biomechanics studies. Then the extracted data are used to identify the parameters of the interaction models. Finally, the eigenvalue analyses of the human-structure models are calculated for comparison. In this identification process, it was identified that the quality of the curve fitting for the interaction model is as good as and even slightly better than the published results. One or two additional conditions for the interaction models would lead to several sets of parameters, but with the result of the continuous model, reasonable parameters have to be applied which can be identified and these parameters could be used in further calculations.

scholarly journals Characterisation of floc size, effective density and sedimentation under various flocculation mechanisms

2020 ◽  
Vol 82 (7) ◽  
pp. 1261-1271
Author(s):  
Yuping Fan ◽  
Xiaomin Ma ◽  
Xianshu Dong ◽  
Zeyu Feng ◽  
Yingdi Dong
Keyword(s):  
Settling Velocity ◽  
Structural Characteristics ◽  
Effective Density ◽  
Floc Size ◽  
Floc Structure ◽  
Trivalent Cations ◽  
Coal Tailings ◽  
Better Than ◽  
Flocculation Mechanisms

Abstract Floc structure plays an important role in the separation of coal wastewater. In this study, a camera-based method is used to evaluate quantitatively the structural characteristics of flocs generated by different coagulants and flocculants. The correlations between particle size, settlement velocity and effective density of coal tailings flocs are analysed. The results show that the statistical settling velocity increases linearly with floc size, while the effective density decreases with increase in floc size. Different flocculation mechanisms lead to diverse growth abilities of flocs. When the flocculant is used alone, the quality of the flocs generated by the flocculants, cationic polyacrylamide (CPAM) and non-ionic polyacrylamide (NPAM), is better than that generated by anionic polyacrylamide (APAM). However, the combination of trivalent cations and APAM yields a much better effect than that obtained using CPAM and NPAM. Flocs become larger and more compact when treated with a coagulant combined with a flocculant.

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