Membrane-based methods of virus concentration from water: a review of process parameters and their effects on virus recovery

In recent years, there has been increasing talk about reverse acquisitions in capital concentration process- es. These situations are associated with the use of certain economic, tax, and other privileges by compa- nies that are often the initiator of such undertakings. The purpose of the article is, among others, to pre- sent the premises that guide economic entities when making decisions about reverse acquisitions. It is a process in which there is a specific type of acquisition of control of one entity by another. In these cases, there is a reversal of typical relationships between entities involved in the merger, because the entities that have control over the entities that acquire them are taken over. The regulations of the Interna- tional Financial Reporting Standard (IFRS) No. 3 "Business Combinations" have a very important role in accounting for these processes. They allow for the proper recognition of these relationships. Based on numerical examples, the authors present the rules for accounting for such a combination. Thus, they confirm the role of accounting, which implements the principle of faithful and reliable presentation of this process. A critical analysis of the literature and legal regulations, as well as deductive reasoning, made it possible to determine the most important motives of this type of connection.

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Effects of Water Quality on Microporous Filter Methods for Enteric Virus Concentration

Water Science & Technology ◽

10.2166/wst.1985.0169 ◽

1985 ◽

Vol 17 (4-5) ◽

pp. 665-679 ◽

Cited By ~ 2

Author(s):

M. D. Sobsey ◽

T. Cromeans ◽

A. R. Hickey ◽

J. S. Glass

Keyword(s):

Fulvic Acid ◽

Bentonite Clay ◽

Enteric Virus ◽

Fulvic Acids ◽

Virus Concentration ◽

Humic And Fulvic Acids ◽

Virus Adsorption ◽

Filter Methods ◽

High Concentrations ◽

Virus Recovery

Model enteric viruses were concentrated from seeded samples of raw, finished and granular activated carbon (GAC)-treated waters and from GAC-treated waters supplemented with humic or fulvic acid or bentonite clay particles by adsorption to electropositive (Virosorb 1MDS) filters at pH 7.5 or electronegative (Filterite) filters at pH 3.5 with and without 5 mM added MgCl2, followed by elution with 0.3% beef extract in 50 mM glycine at pH 9.5. Natural particulates in raw and finished waters had little effect on virus concentration efficiencies. Soluble organic compounds reduced virus adsorption efficiencies from both raw and finished waters compared to GAC-treated water, but the extent of interference varied with virus type and adsorption conditions. Humic and fulvic acids caused appreciable reductions in poliovirus adsorption and recovery efficiencies with both types of filters. Fulvic acid caused greater reductions in virus recovery with Virosorb 1MDS filters than with Filterite filters. Fulvic acid interference with virus recovery by Filterite filters was overcome by the presence of 5 mM MgCl2. Although humic acid reduced virus recoveries by both types of filters, its greatest effect was on virus elution and recovery from Filterite filters. Bentonite clay enhanced poliovirus retention by both filter types as much as 8-fold. However, the presence of clay often interfered with elution of retained viruses from both filter types. Under some conditions, overall virus recoveries were considerably lower from water with clay than from clay-free control water. The results of this study suggest that high concentrations of soluble organic matter such as humic and fulvic acids and suspended solids such as bentonite clay may interfere somewhat with virus recovery by filter adsorption-elution methods.

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Sewage Disposal and Viral Pollution of the Ottawa River

Water Quality Research Journal ◽

10.2166/wqrj.1979.005 ◽

1979 ◽

Vol 14 (1) ◽

pp. 45-62

Author(s):

S.A. Sattar ◽

V.S. Springthorpe ◽

S. Ramia

Keyword(s):

Water Samples ◽

Tap Water ◽

Point Sources ◽

Virus Concentration ◽

Viral Agent ◽

Sewage Disposal ◽

Ottawa River ◽

The Impact ◽

Virus Isolates

Abstract The quality of water in the Ottawa River is being affected by the disposal of increased volumes of sewage into it. Some of the sewage disposal points are situated upstream of beaches and intake points for water purification plants. The aim of this study was to assess the impact of such waste disposal on the virological quality of recreational and drinking waters for the Ottawa area. A total of 132 weekly samples of raw sewage, chlorinated secondary effluents, raw and finished surface waters were examined for viruses from June to December 1977. In addition to these, ten samples of tap water, collected during the first two weeks of April 1978, were also included in this study. Virus concentration from these samples was carried out using the talc-Celite technique developed in the laboratory. Primary human embryonic kidney (HEK) cells and BS-C-1 cells were used for the detection and quantitation of viruses present in the sample concentrates. Virus isolates were identified by their cytopathology, examination under the electron microscope and serology. When 6 1. volumes were processed, nearly all the samples of raw sewage and 54% chlorinated effluent samples were found to be positive for virus. Approximately 50% of the surface water samples were also shown to contain virus using 40 1. sample volumes. Concentrates of some of the potable water samples showed virus-like degeneration in cell cultures. Although this degeneration was found to be transmissible, at this stage it is not possible to say if this effect was in fact due to a viral agent. The following major conclusions were drawn from this study: (a) All three major enteric virus groups were represented in the virus isolates. However, inherent limitations of sample concentration and virus isolation techniques may have resulted in the detection of only a small fraction of the viruses present in the samples. (b) There was no apparent correspondence between the numbers of indicator bacteria and the presence or absence of detectable virus in the samples. (c) Viruses detected in the recreational and raw water samples may be due to the presence of point sources of raw sewage discharge upstream. This could result in the dissemination of human pathogenic viruses through recreational and potable waters.

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Fine hydraulic screening for staged separation of titanium-magnetite concentrate

Obogashchenie Rud ◽

10.17580/or.2021.01.02 ◽

2021 ◽

pp. 8-14

Author(s):

A. E. Pelevin ◽

N. A. Sytykh

Keyword(s):

Process Parameters ◽

Mass Fraction ◽

Process Efficiency ◽

Separation Technology ◽

Concentration Process ◽

Process Indicators ◽

Operating Modes ◽

Magnetite Concentrate ◽

Concentrate Grade ◽

Titanium Magnetite

This article covers the applications of fine hydraulic screening for the staged separation of titanium-magnetite concentrates upstream of the last grinding stage and provides an evaluation of its process efficiency options for the Kachkanarsky GOK. In all screen operating modes tested, the mass fraction of iron in the undersize was higher than its mass fraction in the oversize, but failed to reach the target value for the concentrate of 61 %. Therefore, the undersize must be subjected to additional magnetic concentration. Staged separation of the concentrate by fine screening allows either to improve concentrator performance (by up to 10 %) or to increase the concentration process indicators without changing the grinding equipment volume. In this case, the undersize yield averages 55 %. The use of the staged concentrate separation technology with fine screening at constant process parameters and steady factory performance allows reducing the tertiary mill volume in relative terms, not exceeding half of the undersize yield from the operation, which shall be 65–70 %. The minimum permissible values of the mass fraction of iron and of the –0.071 mm class in the screen feed and the undersize must be ensured for obtaining the required concentrate grade. The values of these indicators depend on the material composition of the ore and the concentration process used.

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Developments in Methods for the Detection of Viruses in Large Volumes of Water

Water Science & Technology ◽

10.2166/wst.1983.0040 ◽

1983 ◽

Vol 15 (5) ◽

pp. 59-67 ◽

Cited By ~ 2

Author(s):

Naomi Guttman-Bass

Keyword(s):

Recent Literature ◽

Virus Concentration ◽

Membrane Filters ◽

Recent Developments ◽

Virus Recovery

The purpose of this review is to summarize recent developments in virus concentration methodology. Evaluations of virus recovery by electronegative and electropositive membrane filters, as well as other methods of virus concentration reported in recent literature are discussed.

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Optimisation of the PEG reconcentration procedure for virus detection by cell culture or genomic amplification

Water Science & Technology ◽

10.2166/wst.1997.0777 ◽

1997 ◽

Vol 35 (11-12) ◽

pp. 455-459 ◽

Cited By ~ 8

Author(s):

Ph. Vilaginès ◽

A. Suarez ◽

B. Sarrette ◽

R. Vilaginès

Keyword(s):

Cell Culture ◽

Virus Detection ◽

Second Step ◽

Virus Concentration ◽

Rt Pcr ◽

Genomic Amplification ◽

Field Samples ◽

Group A ◽

Virus Recovery ◽

Higher Sensitivity

A double reconcentration procedure was developed for virus detection in tapwater concentrates obtained by conventional adsorption-elution techniques suitable for cell inoculation as well as for genomic amplification. Using 7.5% PEG 6000 and 2.5% NaCl, a 15min contact time under agitation at room temperature followed by centrifugation (first step: 3,500xg, 90min, 4°C; second step 10,000xg, 20min, 4°C) were the conditions to obtain overall average virus recovery efficiencies of 71% for poliovirus from 900ml eluates and 88, 83 and 75% for poliovirus, coxsackie B2 and rotavirus respectively (400ml eluates). Direct extraction of viral RNA from the first PEG pellet with TrizolTM was efficient for RT-PCR assays without any further treatment. Primer pairs were selected to amplify rotavirus group A and poliovirus in seeded tapwater concentrated by adsorption elution through glass wool. A positive signal was obtained for theoretic virus concentration of 1 PFU. Analysis of field samples (1001) by cell culture and genomic amplification resulted in a higher sensitivity with the latter.

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Electropositive Filter Membrane as an Alternative for the Elimination of PCR Inhibitors from Sewage and Water Samples

Applied and Environmental Microbiology ◽

10.1128/aem.67.10.4614-4618.2001 ◽

2001 ◽

Vol 67 (10) ◽

pp. 4614-4618 ◽

Cited By ~ 33

Author(s):

A. P. S. Queiroz ◽

F. M. Santos ◽

A. Sassaroli ◽

C. M. Hársi ◽

T. A. Monezi ◽

...

Keyword(s):

Water Samples ◽

Environmental Samples ◽

Virus Concentration ◽

Immunoperoxidase Method ◽

Rt Pcr ◽

Pcr Inhibitors ◽

Filter Membrane ◽

Creek Water ◽

Organic Extraction ◽

Seminested Pcr

ABSTRACT PCR is the best method for the detection of enteric viruses present at low concentrations in environmental samples. However, some organic and inorganic compounds present in these samples can interfere in the reaction. Many of these substances are cytotoxic, too. The ZP60S filter membranes used in addition to fluorpentane treatment are quite efficient for virus concentration and simultaneous elimination of cytotoxicity from environmental samples. In this study, both procedures were used to promote the elimination of reverse transcriptase PCR (RT-PCR) inhibitors from sewage and sewage-polluted creek water. Samples were subjected separately to each of the following procedures: filtration through electropositive filter membranes (ZP60S), organic extraction with Vertrel XF, and filtration through ZP60S followed by organic extraction. Afterwards, aliquots were experimentally inoculated with rotavirus SA-11 RNA and subjected to RT-seminested PCR for amplification of the VP7 gene. Results showed that the ZP60S membranes efficiently eliminated the RT-PCR inhibitors from water samples. The sample processing method was also applied to 31 in natura sewage and creek water samples for detection of naturally occurring rotavirus. A duplex seminested PCR was used for the quick detection of couples of the four rotavirus genotypes (G1 to G4). Eight samples (25.8%) were positive, and rotavirus sequences were not detected in 23 (74.2%). Results were confirmed by direct immunoperoxidase method. In summary, the use of electropositive filter membrane is appropriate for the elimination of substances that can interfere with RT-PCR, obviating additional sample purification methods.

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Performance evaluation of virus concentration methods for implementing SARS-CoV-2 Wastewater-based epidemiology emphasizing quick data turnaround.

10.1101/2021.05.29.21257950 ◽

2021 ◽

Author(s):

Md Ariful Islam Juel ◽

Nicholas Stark ◽

Bridgette Nicolosi ◽

Jordan Lontai ◽

Kevin Lambirth ◽

...

Keyword(s):

Membrane Filtration ◽

Municipal Wastewater ◽

Turnaround Time ◽

Optimal Choice ◽

Virus Concentration ◽

Emf Method ◽

Municipal Wastewater Treatment ◽

Filtration Time ◽

Concentration Method ◽

Virus Recovery

Wastewater based epidemiology (WBE) has drawn significant attention as an early warning tool to detect and predict the trajectory of COVID-19 cases in a community, in conjunction with public health data. This means of monitoring for outbreaks has been used at municipal wastewater treatment centers to analyze COVID-19 trends in entire communities, as well as by universities and other community living environments to monitor COVID-19 spread in buildings. Sample concentration is crucial, especially when viral abundance in raw wastewater is below the threshold of detection by RT-qPCR analysis. We evaluated the performance of a rapid ultrafiltration-based virus concentration method using InnovaPrep Cp Select pipette tips and compared this to the established electronegative membrane filtration (EMF) method. We evaluated the sensitivity of SARS-CoV-2 quantification, surrogate virus recovery rate, and sample processing time. Results suggest that the Cp Select concentrator is more efficient at concentrating SARS-CoV-2 from wastewater compared to the EMF method. 30% of samples that tested negative when concentrated with the EMF method produced a positive signal with the Cp Select protocol. Increased recovery of the surrogate virus control using the Cp Select confirms this observation. We optimized the Cp Select protocol by adding AVL lysis buffer and sonication, to increase the recovery of virus. Sonication increased BCoV recovery by 19%, which seems to compensate for viral loss during centrifugation. Filtration time decreases by approximately 30% when using the Cp Select protocol, making this an optimal choice for building surveillance applications where a quick turnaround time is necessary.

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