Millimetric particles functionalized with biocide to improve biofouling control in RO system

2020 ◽  
Author(s):  
Ana C. Barros ◽  
Ana Pereira ◽  
Luís F. Melo
Keyword(s):  
Antimicrobial Activity ◽  
Membrane Fouling ◽  
High Performance ◽  
Negative Impact ◽  
Bulk Water ◽  
Bulk Liquid ◽  
Ammonium Compound ◽  
Membrane Systems ◽  
Biocide Release ◽  
Functionalized Particles

<p>Biofouling is responsible for more than 45% of all membrane fouling associated problems and is highly relevant for the performance of Reverse Osmosis systems (RO). Biofouling has a tremendous negative impact on the quality and quantity of permeate water and is responsible for high operational and maintenance costs associated with such systems. Current strategies targeting biofilm control on membrane systems often include the overuse of disinfectants which most of the time fail to effectively prevent biofouling build-up, can lead to the formation of dangerous disinfection by-products and represents high amounts of discharged biocides.</p> <p> </p> <p>The present work aims to study how millimetric (1-3 mm length) alumina particles, functionalized with a well-known quaternary ammonium compound biocide (benzalkonium chloride) and immobilized into a Particle Biocide Bed Reactor can effectively contribute to mitigate biofilm formation in membrane systems. For that, the functionalized particles were chemically characterized, and their antimicrobial activity was assessed in batch and recirculation assays and quantified in terms of Culturability and Propidium Iodide (PI) uptake. Special attention has been given to biocides’s (free and immobilized) mechanism of action and potential biocide release was evaluated by High Performance Liquid Chromatography (HPLC) measurements.</p> <p> </p> <p>The preliminary experiments indicate that the immobilized biocide (equivalent biocide concentration of 3 g/L) has an antimicrobial activity against Pseudomonas fluorescens (initial concentration 10<sup>8</sup> CFU/mL) by reducing 4 logs after 30 min and 8 logs after 1 h. On the other hand, the control assays (functionalized particles in water with no bacteria), also shows a biocide release between 0.8 and 1% to the bulk water after 30 min, both in batch and in the Particle Bed Reactor with recirculation experiments. No significant biocide increase is observed in the bulk liquid studies for two weeks. Nonetheless, some changes in the functionalization approach are being made to improve the biocidal anchoring to the particle.</p>

scholarly journals Biofoam of Spittlebug, Poophilus costalis (Walker): Preferential Sites, Temperature Regulation, Chemical Composition and Antimicrobial Activity

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 340
Author(s):  
Kitherian Sahayaraj ◽  
Balakrishnan Saranya ◽  
Samy Sayed ◽  
Loko Yêyinou Laura Estelle ◽  
Koilraj Madasamy
Keyword(s):  
Antimicrobial Activity ◽  
Chemical Composition ◽  
High Performance ◽  
Host Plants ◽  
Ground Level ◽  
College Campus ◽  
The Other ◽  
Mimosa Pudica ◽  
Ft Ir ◽  
Gas Chromatography Mass Spectroscopy

The foam produced by nymphs of Poophilus costalis on eleven different host plants belonging to eight families on St. Xavier’s College campus in India was studied over five months. The chemical composition and antimicrobial activity of these biofoams were investigated. The results revealed that P. costalis preferred Theporsia purpurea and Mimosa pudica for laying their eggs and producing foam, over the other tested plants. P. costalis produce their foam on either nodes or internodes on monocotyledons (30%) (p < 0.05), whereas on dicotyledons, they produce more foam on the stems (63.8%) than on the leaves (6.2%) (p < 0.01). The number of nymphs in each piece of foam from P. costalis varied from 1 to 3 (mean = 1.8 per plant). They produced their foam (5.7 to 45.2 cm) from the ground level on a plant. The length and breadth of a piece of foam ranged from 1.0 to 3.9 cm and 0.6 to 4.7 cm, respectively. The foam tended to be cooler than the environment. Qualitative profiling showed that the foam consists of carbohydrates, including maltose; trypsin; amino acids; protease. The foam was also analyzed using a spectrophotometer, Fourier transform infrared spectroscopy (FT-IR), gas chromatography–mass spectroscopy (GC-MS), and high-performance liquid chromatography (HPLC). The antimicrobial activity of the biofoam was the greatest against Staphylococcus aureus, the growth of which was reduced by 55.9 ± 3.9%, suggesting that the foam could be used as an antimicrobial product. However, no activities were observed against Fusarium oxysporum and Candida albicans.

Time-Resolved Micro Liquid Desorption Mass Spectrometry: Mechanism, Features, and Kinetic Applications

2006 ◽  
Vol 59 (2) ◽  
pp. 81 ◽  
Author(s):  
Ales Charvat ◽  
Andreas Bógehold ◽  
Bernd Abel
Keyword(s):  
Mass Spectrometry ◽  
Liquid Phase ◽  
High Speed ◽  
High Performance ◽  
Kinetic Studies ◽  
Solution Concentration ◽  
Bulk Water ◽  
Laser Wavelength ◽  
Time Resolved ◽  
Desorption Mass Spectrometry

Liquid water beam desorption mass spectrometry is an intriguing technique to isolate charged molecular aggregates directly from the liquid phase and to analyze them employing sensitive mass spectrometry. The liquid phase in this approach consists of a 10 µm diameter free liquid filament in vacuum which is irradiated by a focussed infrared laser pulse resonant with the OH-stretch vibration of bulk water. Depending upon the laser wavelength, charged (e.g. protonated) macromolecules are isolated from solution through a still poorly characterized mechanism. After the gentle liquid-to-vacuum transfer the low-charge-state aggregates are analyzed using time-of-flight mass spectrometry. A recent variant of the technique uses high performance liquid chromatography valves for local liquid injections of samples in the liquid carrier beam, which enables very low sample consumption and high speed sample analysis. In this review we summarize recent work to characterize the ‘desorption’ or ion isolation mechanism in this type of experiment. A decisive and interesting feature of micro liquid beam desorption mass spectrometry is that — under certain conditions — the gas-phase mass signal for a large number of small as well as supramolecular systems displays a surprisingly linear response on the solution concentration over many orders of magnitude, even for mixtures and complex body fluids. This feature and the all-liquid state nature of the technique makes this technique a solution-type spectroscopy that enables real kinetic studies involving (bio)polymers in solution without the need for internal standards. Two applications of the technique monitoring enzyme digestion of proteins and protein aggregation of an amyloid model system are highlighted, both displaying its potential for monitoring biokinetics in solution.

Expansion of Nanosized MgSiO3/Chitosan Nanocomposite Structural and Spectroscopic for Loading Velosef by Nanomaterial Intervention

2021 ◽  
Author(s):  
amal aboelnaga ◽  
talaat Meaz ◽  
amany M elnahrawy
Keyword(s):  
Antimicrobial Activity ◽  
High Performance ◽  
Sol Gel ◽  
Polymerization Process ◽  
Absorption Bands ◽  
Structural Morphology ◽  
Crystallinity Degree ◽  
Chitosan Matrix ◽  
Antimicrobial Studies ◽  
Sol Gel Process

Abstract The aim of this study is to investigate the effect of different doses of Velosef in magnesium silica/chitosan nanocomposite in terms of structural, morphology, optical properties, and bioactivity. Loading Velosef in fine-sized magnesium silica/chitosan is an efficient engineering approach for drug delivery. The sol-gel process was used to prepare magnesium silica fine-sized before being blended into chitosan matrix, which acts as a potential morphogenetic biomaterial. The Velosef/magnesium silica/chitosan nanocomposites were characterized by XRD, TEM, SEM, FTIR, UV-absorption, and antimicrobial studies. The XRD was characteristic of the crystallinity degree of the MgO-SiO2/chitosan/Velosef nanocomposites with three maximum peaks at 26.37°, 33.34o, 36.9°. FTIR results indicated the structural change occurred with the Velosef sol-gel polymerization process. UV-absorbance reveals that the MgO-SiO2/chitosan nanocomposite appeared a high performance for loading Velosef at two absorption bands at 253 and 347 nm. The MgO-SiO2/Chitosan/Velosef nanocomposites showed considerable antimicrobial activity in opposition to the tested representative microorganisms. The maximum antimicrobial activity was obtained with MgO-SiO2/Chitosan against both Escherichia coli and Candida albicans (37 mm), while the minimum antimicrobial activity (30 mm) was recorded against B. mycoides and E. coli with control.

Optimization of the Hybrid Ship Transport Factor through Retrofitted Wave Cancelling Side-Hull Expansions and Bow Bulb

2015 ◽  
Author(s):  
Manivannan Kandasamy ◽  
Ping C. Wu ◽  
Scott Bartlett ◽  
Loc Nguyen ◽  
Frederick Stern
Keyword(s):  
High Performance ◽  
Negative Impact ◽  
Fiscal Year ◽  
Hull Form ◽  
Transport Factor ◽  
Resistance Reduction ◽  
The Us ◽  
Us Navy ◽  
Speed Range ◽  
Design Speed

The US Navy is currently considering the introduction of a Flight III variant beginning with DDG-123 in Fiscal Year 2016. The new design incorporates a new combat system and associated power and cooling upgrades. The overall system improvements increase the payload of the ship and the resulting increased displacement has a negative impact on the service life allowance for range, fuel consumption and sea-keeping characteristics. The present objective is to increase the hull displacement without resistance and sea-keeping penalty and with minimal modifications to the baseline DTMB-5415 design (open literature surrogate of the existing DDG-51 hull form) by using retrofitted blisters in the form of side hull expansions and a bow-bulb. The investigation makes use of high-performance CFD computing for analysis of wave cancellation mechanisms. A candidate modified 5415 design with both blisters and bow bulb shows a resistance reduction of ~11% w.r.t.the baseline 5415 in the design speed range of 15-19 knots, even though the displacement is increased by 8%, such that the transport factor is increased by 19%.

scholarly journals Pressure, Performance and Prestige: Dilemmas for Contemporary Professionals

2016 ◽  
Vol 23 (79) ◽  
pp. 539-552
Author(s):  
Ana Heloisa Costa Lemos ◽  
Leila Sharon Nasajon Gottlieb ◽  
Alessandra de Sá Mello da Costa
Keyword(s):  
Professional Growth ◽  
High Performance ◽  
Negative Impact ◽  
Well Being ◽  
Excessive Pressure ◽  
Performance Practices ◽  
Personal Lives ◽  
Work Intensification ◽  
Working Day ◽  
Mental Nature

Abstract Recent changes in the world of work have resulted in a greater level of work intensification. Whilst there have been gains in productivity, workers have been subject to increasing demands of both a physical and mental nature, which tend to have a negative impact on their well-being. Our interest in understanding this phenomenon has led to a qualitative study that seeks to analyse the experiences of professional graduates working in organizations that use high-performance practices, which tend to generate work intensification. The respondents revealed both the negative implications of work intensification, such as an increase in the working day, excessive pressure and sacrifices in their personal lives, as well as other aspects considered positive, such as learning, professional growth, autonomy and financial gains. These latter aspects deserve attention, since they can help us understand what leads qualified workers to accept intensified working practices.

scholarly journals Removal Characteristics of N-Nitrosamines and Their Precursors by Pilot-Scale Integrated Membrane Systems for Water Reuse

2018 ◽  
Vol 15 (9) ◽  
pp. 1960 ◽  
Author(s):  
Haruka Takeuchi ◽  
Naoyuki Yamashita ◽  
Norihide Nakada ◽  
Hiroaki Tanaka
Keyword(s):  
Membrane Fouling ◽  
Water Reuse ◽  
Pilot Scale ◽  
Feed Water ◽  
Water Reclamation ◽  
Size Distributions ◽  
Membrane Systems ◽  
Chemical Cleaning ◽  
Ro Membrane ◽  
Feed Water Temperature

This study investigated the removal characteristics of N-Nitrosamines and their precursors at three pilot-scale water reclamation plants. These plants applies different integrated membrane systems: (1) microfiltration (MF)/nanofiltration (NF)/reverse osmosis (RO) membrane; (2) sand filtration/three-stage RO; and (3) ultrafiltration (UF)/NF and UF/RO. Variable removal of N-Nitrosodimethylamine (NDMA) by the RO processes could be attributed to membrane fouling and the feed water temperature. The effect of membrane fouling on N-Nitrosamine removal was extensively evaluated at one of the plants by conducting one month of operation and chemical cleaning of the RO element. Membrane fouling enhanced N-Nitrosamine removal by the pilot-scale RO process. This finding contributes to better understanding of the variable removal of NDMA by RO processes. This study also investigated the removal characteristics of N-Nitrosamine precursors. The NF and RO processes greatly reduced NDMA formation potential (FP), but the UF process had little effect. The contributions of MF, NF, and RO processes for reducing FPs of NDMA, N-Nitrosopyrrolidine and N-Nitrosodiethylamine were different, suggesting different size distributions of their precursors.

On the conditions of labor productivity growth in agriculture of the Sverdlovsk region

2020 ◽  
pp. 35-45
Author(s):  
E. Potaptseva ◽  
S. Smirnykh
Keyword(s):  
Labor Productivity ◽  
Productivity Growth ◽  
High Performance ◽  
Agricultural Sector ◽  
Negative Impact ◽  
Federal State ◽  
Technical Equipment ◽  
Labor Costs ◽  
Labor Productivity Growth ◽  
City District

Agricultural production is one of the most labor-intensive in the world. In our country, at the same time with large labor costs, the agricultural sector is characterized by low wages. This state of affairs in the industry makes relevant research on the identification of factors of labor productivity growth. In addition, it is necessary to develop methods for creating high-performance jobs. The data of the Federal State Statistics Service and the Ministry of Agriculture of the Russian Federation formed the informational basis of this study. There were also used information officially distributed by the Ministry of Agriculture and Food of the Sverdlovsk region. The research is based on the results of the author's survey of managers and specialists of agricultural enterprises located in the Talitsky city district of the Sverdlovsk region. The study focuses on the study and analysis of the dynamics of the development of the agricultural sector in the region. In conclusion, the conclusions are formulated, and the main factors of labor productivity growth in agriculture of the Sverdlovsk region are identified. The results of the study showed that outdated technical equipment of production has a negative impact on the productivity of labor in the agricultural sector.

Managing Human Resources in Family Businesses

2014 ◽  
pp. 96-112 ◽  
Author(s):  
Santiago Gutiérrez-Broncano ◽  
Mercedes Rubio-Andrés ◽  
Pedro Jiménez Estévez
Keyword(s):  
Human Capital ◽  
Human Resources ◽  
High Performance ◽  
Negative Impact ◽  
Business Owners ◽  
Family Businesses ◽  
Future Research ◽  
Research Directions ◽  
Positive Effects ◽  
Future Research Directions

Although a lot of research has been carried out in the field of family businesses in recent years, not much of it has focused on human resource management. After compiling the major studies, both negative aspects (e.g. nepotism) and positive ones (e.g. employee commitment) have been identified. Therefore, the authors propose high-performance human resources practices to reduce the negative impact of family in business and boost the positive effects, increase their human capital, and achieve a competitive advantage in this field. Finally, the authors provide key insights for practitioners, family business owners, and managers, and they propose future research directions.

scholarly journals Analysis of aristolochlic acids and evaluation of antibacterial activity of Aristolochia clematitis L.

2019 ◽  
Vol 70 (4) ◽  
pp. 323-329 ◽  
Author(s):  
Gergely Sámuel Bartha ◽  
Gergő Tóth ◽  
Péter Horváth ◽  
Eszter Kiss ◽  
Nóra Papp ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Antimicrobial Effect ◽  
Aristolochic Acids ◽  
Microdilution Method ◽  
Stem Leaf ◽  
Ethyl Acetate Extracts

Introduction Several Aristolochia species were used as medicinal herb across Europe and in recent years, their antimicrobial activity has also been investigated. Materials and methods In this study, A. clematitis was selected to evaluate the aristolochic acids I and II (AA I and AA II) concentrations and the antimicrobial activity of methanol, hexane, butanol, and ethyl acetate extracts of the root, stem, leaf, root, and fruit. AA I and AA II contents were measured by a validated high-performance liquid chromatography–ultraviolet method. Results Each fraction of the plant contained AA I and AA II and the root was found to have the highest contents of AA I (1.09%) and AA II (0.7454%). The minimum inhibitory concentrations of all extracts were determined by standard microdilution method. The fruit’s extracts showed the most efficient antimicrobial effect against both methicillin sensitive and resistant Staphylococcus aureus strains. Conclusion Correlation between the AA I and AA II concentrations and the antimicrobial effect was not found.

scholarly journals Recycling of Reverse Osmosis Concentrates to the Membrane Bioreactor in the MBR-RO Process for Water Reuse: effect on mbr performances

2017 ◽  
Vol 30 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Thi Thu Nga Vu ◽  
Manon Montaner ◽  
Christelle Guigui
Keyword(s):  
Organic Matter ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Water Reuse ◽  
High Performance ◽  
Membrane Bioreactor ◽  
Membrane System ◽  
Size Exclusion ◽  
Ro Concentrate ◽  
The Impact

Wastewater effluents can be treated by an integrated membrane system combining membrane bioreactor (MBR) and reverse osmosis (RO) for effective removal of micropollutants in the field of high-quality water reuse. However, discharging the RO concentrate waste stream directly into the natural environment could lead to serious problems due to the toxic components contained in the concentrates (micropollutants, salts, organic matter). A possible solution could be the recirculation of RO concentrate waste to the MBR. However, such an operation should be studied in detail since the recirculation of non-biodegradable organic matter or high concentrations of salts and micropollutants could directly or indirectly contribute to MBR membrane fouling and modification of the biodegradation activity. In this context, the work reported here focused on the recirculation of such concentrates in an MBR, paying specific attention to MBR membrane fouling. Lab-scale experiments were performed on a continuous MBR-RO treatment line with RO concentrate recirculation. The main goal was to determine the recovery of the RO unit and of the global process that maintained good process performance in terms of biodegradation and MBR fouling. The results demonstrate that the impact of the toxic flow on activated sludge depends on the recovery of the RO step but the same trends were observed regardless of the organic matter and salt contents of the concentrates: the concentration of proteins increased slightly. Size-exclusion high performance liquid chromatography (HPLC-SEC) was employed to study the effects of RO concentrate on the production of protein-like soluble microbial products (SMPs) and demonstrated a significant peak of protein-like substances corresponding to 10-100 kDa and 100-1 000 kDa molecules in the supernatant. Thus a significant increase in the propensity for sludge fouling was observed, which could be attributed to the increased quantity of protein-like substances. Finally, the effect of the concentrate on sludge activity was studied and no significant effect was observed on biodegradation, indicating that the return of the concentrate to the MBR could be a good alternative.

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