scholarly journals Mineral Materials Coated with and Consisting of MnOx—Characteristics and Application of Filter Media for Groundwater Treatment: A Review

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2232 ◽  
Author(s):  
Magdalena M. Michel ◽  
Lidia Reczek ◽  
Dorota Papciak ◽  
Maria Włodarczyk-Makuła ◽  
Tadeusz Siwiec ◽  
...  
Keyword(s):  
Water Treatment ◽  
Research Needs ◽  
Groundwater Treatment ◽  
Filter Media ◽  
Manganese Ores ◽  
Metals Removal ◽  
Treatment Research ◽  
Sand And Gravel ◽  
Filter Bed ◽  
The Relationship

For groundwater treatment, the technologies involving oxidation on MnOx filter bed are beneficial, common, and effectively used. The presence of MnOx is the mutual feature of filter media, both MnOx-coated mineral materials like quartz sand and gravel, chalcedonite, diatomite, glauconite, zeolite, or anthracite along with consisting of MnOx manganese ores. This review is based on the analysis of research and review papers, commercial data sheets, and standards. The paper aimed to provide new suggestions and useful information for further investigation of MnOx filter media for groundwater treatment. The presented compilations are based on the characteristics of coatings, methods, and conditions of its obtaining and type of filter media. The relationship between the properties of MnOx amendments and the obtained purification effects as well as the commonly used commercial products, their features, and applications have been discussed. The paper concludes by mentioning about improving catalytic/adsorption properties of non-reactive siliceous media opposed to ion-exchange minerals and about possible significance of birnessite type manganese oxide for water treatment. Research needs related to the assessment of the use MnOx filter media to heavy metals removal from groundwater in field operations and to standardize methodology of testing MnOx filter media for water treatment were identified.

scholarly journals Comparison of crushed rock sand and natural river sand as filter media for rapid filtration

2020 ◽  
Author(s):  
Bruno Moreno Ramos da Silva ◽  
Rafael Kopschitz Xavier Bastos ◽  
Pedro Kopschitz Xavier Bastos
Keyword(s):  
Water Treatment ◽  
Pilot Scale ◽  
Head Loss ◽  
Crushed Rock ◽  
Filter Media ◽  
Particle Size Range ◽  
River Sand ◽  
Run Length ◽  
Acid Solubility ◽  
Filter Bed

Abstract The objective of this work was to evaluate the crushed rock sand (CRS) as a filter bed in rapid filtration for water treatment. The experiments were carried out using pilot-scale filtration units: one with a CRS filter bed and the other with natural river sand (NRS). Both filter media were prepared in accordance with typical standards for rapid sand filtration (particle size range and distribution, and filter bed depth), and were further characterized in terms of chemical composition, particles and bulk density, porosity, acid solubility and sphericity coefficient. Over four months, 14 filter runs using filtration rates of 90, 180, 270 and 360 m3 m−2 d−1 were monitored and characterized in terms of run length, head loss increase along filter bed depth, turbidity removal along filter bed depth. Overall, the performance of the CRS filter was similar to or even better than that of the NRS filter, producing filtered water with turbidity lower than 0.50 NTU along the entire run, with head loss increasing rates and run length similar to those of the NRS filter. It is concluded that CRS presents a high potential for use as filter media for rapid filtration in water treatment, without technical or operational disadvantages.

Role of filter media in an anaerobic fixed-bed reactor

1995 ◽  
Vol 31 (9) ◽  
pp. 137-144 ◽  
Author(s):  
T. Miyahara ◽  
M. Takano ◽  
T. Noike
Keyword(s):  
Anaerobic Bacteria ◽  
Fixed Bed ◽  
Methanogenic Bacteria ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Filter Media ◽  
Fixed Bed Reactors ◽  
Attached Bacteria ◽  
The Relationship

The relationship between the filter media and the behaviour of anaerobic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher than those attached to the filter media. On the other hand, the number of attached methanogenic bacteria was more than ten times as higher than that of suspended ones. The numbers of suspended and deposited acidogenic and methanogenic bacteria in the reactor operated at an HRT of 3 hours were almost the same as those in the reactor operated at an HRT of 48 hours. Accumulation of attached bacteria was promoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was higher than that in the closely packed reactor. The number of methanogenic bacteria in the sparsely packed reactor was lower than that in the closely packed reactor.

Toward better theory on the relationship between commitment, participation and leadership in unions

2012 ◽  
Vol 33 (8) ◽  
pp. 715-731 ◽  
Author(s):  
Gregor Gall ◽  
Jack Fiorito
Keyword(s):  
Design Methodology ◽  
Academic Research ◽  
Critical Assessment ◽  
Future Research ◽  
Research Needs ◽  
Union Commitment ◽  
Content Type ◽  
Extant Literature ◽  
The Relationship ◽  
Practical Implications

PurposeThe aim of this paper is to give a critique of the extant literature on union commitment and participation in order to develop remedies to identified weaknessesDesign/methodology/approachThe paper uses a critical assessment of extant literature.FindingsA number of critical deficiencies exist in the literature to which remedies are proposed.Research limitations/implicationsThe remedies need testing through empirical research.Practical implicationsFuture research needs to have different research foci and questions.Social implicationsWith a reorientation of future research on union commitment, participation and leadership, unions may be better able to benefit from academic research in the area.Originality/valueThe paper suggests that a reorientation of future research on union commitment, participation and leadership will allow more incisive and more robust contributions to be made to understanding unions as complex social organisms.

scholarly journals Influence of Psychological Stress on Periodontal Diseases

2020 ◽  
Vol 2 (1) ◽  
pp. 1-5
Author(s):  
Larissa Marques Storto Soares ◽  
Ana Emilia Farias Pontes ◽  
Fernanda de Oliveira Bello Corrêa ◽  
Cleverton Corrêa Rabelo
Keyword(s):  
Risk Factor ◽  
Periodontal Disease ◽  
Psychological Stress ◽  
Psychological Factors ◽  
Positive Relationship ◽  
Periodontal Diseases ◽  
Psychosocial Factor ◽  
Research Needs ◽  
The Relationship

Introduction: The association between periodontal disease and stress has been questioned for a almost a century, however, it still represents an unexplored field of research with several orphaned questions of conclusive answers. Objective: To evaluate the relationship between periodontal disease and stress. Methodology: Searches were performed with descriptors related to periodontal diseases and psychological factors in the following databases: Pubmed, Embase, Lilacs. Were identified and included studies that deal with the relationship between stress and periodontal disease and /or that emphasize the role of this psychosocial factor in the progression of periodontal disease. Conclusion: Most studies have shown a positive relationship between periodontal disease and stress, however, further research needs to be developed to confirm stress as a risk factor for periodontal disease

scholarly journals Heavy Metals Removal from Water by Efficient Adsorbents

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2659
Author(s):  
Muhammad Zaim Anaqi Zaimee ◽  
Mohd Sani Sarjadi ◽  
Md Lutfor Rahman
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Water Treatment ◽  
Adsorption Process ◽  
Natural Occurrence ◽  
Toxic Heavy Metals ◽  
Major Purpose ◽  
Treatment Methods ◽  
Metals Removal ◽  
Harmful Effects

Natural occurrence and anthropogenic practices contribute to the release of pollutants, specifically heavy metals, in water over the years. Therefore, this leads to a demand of proper water treatment to minimize the harmful effects of the toxic heavy metals in water, so that a supply of clean water can be distributed into the environment or household. This review highlights several water treatment methods that can be used in removing heavy metal from water. Among various treatment methods, the adsorption process is considered as one of the highly effective treatments of heavy metals and the functionalization of adsorbents can fully enhance the adsorption process. Therefore, four classes of adsorbent sources are highlighted: polymeric, natural mineral, industrial by-product, and carbon nanomaterial adsorbent. The major purpose of this review is to gather up-to-date information on research and development on various adsorbents in the treatment of heavy metal from water by emphasizing the adsorption capability, effect of pH, isotherm and kinetic model, removal efficiency and the contact of time of every adsorbent.

Solid-Liquid Separation Process: Modelling for Design and Development of Gravity Deep-Bed Filters for Water Treatment

2007 ◽  
Vol 18-19 ◽  
pp. 563-568
Author(s):  
O.E. Ekenta ◽  
B.U. Anyata
Keyword(s):  
Water Treatment ◽  
Dynamic Models ◽  
Design Development ◽  
Quality Model ◽  
Depth Filtration ◽  
Using Data ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Development And Management ◽  
Filter Bed

This work focuses on the conception and formulation of appropriate filtration models for use by water treatment professionals for design, development and management of deep-bed (depth) filters. Performance and optimization studies were carried out using data (turbidity, filtration rate, head loss) acquired from pilot filter test runs. The curves developed from these studies were utilized for the formulation of steady-state and hydro-dynamic models of depth filtration. An effluent quality model was developed, relating depth of flow in filter bed with effluent turbidity. This model was verified and validated. The depths obtained are in good agreement with standard values from literature.

Contemporary Change: Liberalization and Epistemic Modernization

2016 ◽  
Author(s):  
David J. Hess
Keyword(s):  
Case History ◽  
Regulatory Policy ◽  
Scientific Field ◽  
Industrial Change ◽  
Research Needs ◽  
Sociological Perspective ◽  
Reflexive Modernization ◽  
Double Movement ◽  
The Relationship ◽  
Opening Up

The chapter discusses the problem of developing a historical sociological perspective on science, technology, and social movements during the period of the 1980s through 2015. It argues in favor of a historical dynamic based on liberalization and reflexive modernization that is similar to Polanyi’s double movement. The dynamic is formulated specifically for technological and industrial change based on the relationship between the liberalization of regulatory policy and the epistemic modernization of policy and knowledge production. Epistemic modernization involves the opening up of the research agendas of the scientific field to the concerns of undone science and the research needs of industrial transition movements and counterpublics. The theoretical framework is applied to a case history on the movement that supports greater access to and more research on cancer treatment based on complementary and alternative medicine. Both liberalization and epistemic modernization processes are documented for the movement.

Scared or Attached? Unraveling Important Links in Strain–Crime Relationships Among School Students

2018 ◽  
Vol 63 (8) ◽  
pp. 1175-1201 ◽  
Author(s):  
Anastasiia Kuptsevych-Timmer ◽  
Olena Antonaccio ◽  
Ekaterina V. Botchkovar ◽  
William R. Smith
Keyword(s):  
Parental Monitoring ◽  
Negative Binomial ◽  
Future Research ◽  
Adolescent Delinquency ◽  
Research Needs ◽  
School Students ◽  
Decomposition Procedure ◽  
Theory Of Crime ◽  
General Strain ◽  
The Relationship

Drawing on general strain theory of crime, the study employs the survey data from a random sample of 600 school students in Lviv, Ukraine, to examine how sanction risks and social bonds mediate and moderate the relationship between strain and adolescent delinquency. Findings from negative binomial regressions and the KHB decomposition procedure demonstrate that fear of sanctions and levels of social control mediate the relationships between strain and delinquency to a different degree, depending on the type of strain experienced. Results concerning conditioning effects are mixed, with only parental monitoring found to be a moderator of the strain–delinquency link. However, the direction of the interaction effect is unexpected. Future research needs to improve the specification of strain models and evaluate them in other sociocultural contexts.

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