Efficient Removal Of Water Research Articles

Relationships between thermal stratification in a secondarily treated wastewater reservoir that stores water for irrigation and filter clogging in the irrigation system

We studied particle distribution in relation to thermal stratification development in a secondarily treated wastewater reservoir, to learn about changes through the irrigation season that would affect the efficiency of removing water from different depths to avoid filter clogging. During an irrigation season a datalogger continually recorded temperature at 12 depths of the water column and manual measurements of the water clogging potential were carried out at relevant depths. The datalogger allowed following the development of thermal stratification, which was established during April with a 4–4.5m deep epilimnion. The epilimnion depth did not change during the irrigation season. Particles accumulated at the bottom of the epilimnion. Conclusions(1) In reservoirs that remove water from subsurface layers a manual temperature profile measured at the beginning of the irrigation season allow determining epilimnion depth, hence efficient water removal depth during most of the irrigation season. (2) Removing water for irrigation from the bottom of the epilimnion is not efficient. (3) Either if water is removed from subsurface or over-bottom layers, clogging will occur when only the particle rich epilimnion remains. (4) Removing water for irrigation from the near bottom starting before much organic matter accumulates in the hypolimnion would avoid sulfide accumulation and development of zooplanktonic organisms that could clog irrigation filters. (5) In reservoirs that remove water from subsurface layers a proper management of pumping depth should be performed to remove water from the hypolimnion to avoid clogging due to zooplankton, and from the epilimnion when required to eliminate anaerobic bacteria.

Development of new biomass-based furan/glass composites manufactured by the double-vacuum-bag technique

The present study addresses the development of new biomass-based furan resin/glass fibre composites manufactured by the double-vacuum-bag technique using a two-stage cure cycle to allow removal of water from the resin. The volumetric composition and mechanical properties of the composites are measured and analysed with focus on the porosity content. The so-called matrix correlated porosity factor is determined to be 0.096, meaning that the furan matrix itself contains 8.8% porosity. In the optimal case of no matrix porosity, stiffness of the composites compares well with the stiffness of conventional thermosetting/glass composites, but with lower strength. The findings of the present study show that a more efficient water removal during manufacturing, a lower porosity content and a less brittle stress–strain behaviour of the furan matrix are to be addressed to further improve the properties of the composites.

Physicomechanical characterization of monodisperse multivesiculated polyester particles

This work describes physicomechanical properties of low-density polyester particles with multi-alveolar inner morphology, obtained via a water/oil/water double emulsion process. Monodisperse particle diameters were produced thanks to the use of a microchannel T-junction device for droplet generation. The drying conditions tested showed that rapid water evaporation at 120°C, combined with slow diffusion towards the exterior, causes internal fracture and particle deformation. Interestingly, all particles present virtually identical internal damage and external deformation features under these drying conditions, demonstrating the uniformity in internal structures. Drying at 70°C allows for efficient water removal with no damage. Thermomechanical transitions and thermal stability were analyzed by dynamic mechanical analysis (DMA in single-particle compression mode), dynamic scanning calorimetry (DSC) and thermogravimetry (TG). The effectiveness of curing conditions was evaluated by FTIR and DSC, allowing to identify the need of a thermal post-treatment for consumption of residual styrene. The consequent increase in degree of crosslinking produced a positive shift in glass transition temperature measured by DMA. Finally, mechanical reinforcement of the multivesiculated polyester particles was obtained by loading the polymer with surface-modified fumed silica, yielding 75% increase in storage modulus.

Drainage Bed: A Natural System for WTP Sludge Dewatering and Drying with Different Coagulant Chemicals in Tropical Countries

This study seeks to evaluate the mechanisms for dewatering sludge from Water Treatment Plants (WTP) in a natural system that uses nonwoven polyester geotextile blankets named Drainage Bed (DB). Dewatering mechanisms are divided into two stages: Drainage and Drying Phases. For the Drainage Phase, the results showed that the solids content of the Aluminum Sulfate sludge reached 8.9% to 18.3% and the PACl sludge 1.8% to 6.5%, the volume reduction on this phase exceeding 50% and 74%, respectively. The final solids content, after the Drying Phase, was greater than 28%, reaching 90%. In the Drainage Phase the lower the Surface Application Rate—SAR [kg/m2] is, the greater the drainage flow will be. In the Drying Phase, moisture and insolation were key factors in drying sludge. Thus, the Drying Phase in the DB takes special attention for being virtually nonexistent in dewatering technologies in a closed system (confined) without exposure to solar energy. The use of the DB as a natural system for dewatering WTP sludge in tropical countries proved to be a promising alternative, because of its efficient removal of water from sludge coupled with operational simplicity and low costs, provided there is area available.

Wood nanocelluloses: fundamentals and applications as new bio-based nanomaterials

Nanocelluloses, which include nanofibrillated celluloses (NFCs) and cellulose nanocrystals (CNCs) with high and low aspect ratios, respectively, are promising new bio-based nanomaterials, prepared from wood and other plant celluloses by mechanical shearing in water with or without pretreatments. Low degrees of enzymatic hydrolysis, carboxymethylation, acetylation, oxidation, and other position-selective modifications on cellulose microfibril surfaces have been applied as pretreatments to wood celluloses to reduce energy consumption in the mechanical shearing process and to improve the nanofibrillation level of the obtained NFCs. NFCs are convertible to nanocellulose sheets, films, hydrogels, foams, and aerogels with fibril network structures or close-packing structures using coating on base films or filtration process like papermaking, which is advantageous for efficient removal of water predominantly present in the NFC/water dispersions. NFC-containing self-standing films, coated films, and NFC/matrix nanocomposites in most cases show explicitly high mechanical strength and ductility despite being lightweight and having optical transparency, thermal stability, and gas-barrier properties. Because NFCs have aspect ratios and molecular weights higher than those of CNCs, the most promising and challenging end products are NFC-containing nanocomposite materials having higher functionalities than those of the conventional fiber-reinforced composite materials.

The role of molecular adsorbent recirculating system dialysis for extracorporeal liver support in children

The majority of children with acute, acute-on-chronic, and progressive chronic liver failure require liver transplantation. Since organ availability is limited, extracorporeal liver support systems are increasingly applied to bridge the time until transplantation. At present, four different devices are available: the molecular adsorbent recirculating system (MARS), Prometheus dialysis, plasma exchange combined with hemodialysis (PE/HD), and single-pass albumin dialysis (SPAD). Randomized trials in adults have demonstrated efficient toxin removal, improved portal hypertension, hemodynamic stability, and improved hepatic encephalopathy compared with standard medical therapy. None of the liver support systems has yet been evaluated systematically in children. Knowledge of the specific indications and technical features of the different devices is essential if applied in children. MARS combines albumin dialysis with conventional hemodialysis and allows for efficient removal of water and protein-bound toxins without exogenous protein delivery and the associated infectious and allergic risks. It has successfully been applied in children with otherwise intractable cholestatic pruritus and with liver failure. The benefits, however, need to be balanced against the costs and the risk of volume and nitrogen overload if repeated plasma infusion is required. In cases of active bleeding, plasma exchange in combination with hemodialysis should be preferred.

A techno‐economic comparison of various process options for the production of 1,1‐diethoxy butane

AbstractBACKGROUND: Acetals can be considered important bio‐based diesel additives. The production of most of these compounds, from an alcohol and an aldehyde, suffers from low conversion due to thermodynamic limitations. These limitations can be overcome through the removal of the by‐product water. Previous studies showed that the in situ dehydration options of reactive distillation and pervaporation membrane reactor integration offer little advantage or at least not at reasonable unit dimensions. The aim of the present work is the development of a membrane based process and comparison with other alternatives (based on experimental data).RESULTS: Three different membrane processes were developed. The one in which the reaction mixture is recycled over a first dehydration membrane module and subsequently through a simple distillation column, was found to give the highest overall conversion (100%) at low recycle rates and reasonable membrane area. This process was techno‐economically compared with other possible alternatives: (1) a process based on a conventional tubular reactor and several distillation columns; and (2) a process based on reactive distillation.CONCLUSIONS: Efficient water removal by membranes avoids possible azeotropes in downstream distillation units making them much simpler, reducing considerably the unit sizes and the energy demand (40% lower). Copyright © 2012 Society of Chemical Industry

Are Wet-Induced Wrinkled Fingers Primate Rain Treads?

Wet fingers and toes eventually wrinkle, and this is commonly attributed by lay opinion to local osmotic reactions. However, nearly a century ago surgeons observed that no wrinkling occurs if a nerve to the finger has been cut. Here we provide evidence that, rather than being an accidental side effect of wetness, wet-induced wrinkles have been selected to enhance grip in wet conditions. We show that their morphology has the signature properties of drainage networks, enabling efficient removal of water from the gripped surface.

Determination of dimethyl sulfoxide and dimethyl sulfone in urine by gas chromatography–mass spectrometry after preparation using 2,2‐dimethoxypropane

A method for routinely determination of dimethyl sulfoxide (DMSO) and dimethyl sulfone (DMSO(2)) in human urine was developed using gas chromatography-mass spectrometry. The urine sample was treated with 2,2-dimethoxypropane (DMP) and hydrochloric acid for efficient removal of water, which causes degradation of the vacuum level in mass spectrometer and shortens the life-time of the column. Experimental DMP reaction parameters, such as hydrochloric acid concentration, DMP-urine ratio, reaction temperature and reaction time, were optimized for urine. Hexadeuterated DMSO was used as an internal standard. The recoveries of DMSO and DMSO(2) from urine were 97-104 and 98-116%, respectively. The calibration curves showed linearity in the range of 0.15-54.45 mg/L for DMSO and 0.19-50.10 mg/L for DMSO(2). The limits of detection of DMSO and DMSO(2) were 0.04 and 0.06 mg/L, respectively. The relative standard deviations of intra-day and inter-day were 0.2-3.4% for DMSO and 0.4-2.4% for DMSO(2). The proposed method may be useful for the biological monitoring of workers exposed to DMSO in their occupational environment.

Farmland birds and resource protection in the UK: Cross-cutting solutions for multi-functional farming?

Farmland bird declines in Europe are well documented. In the UK, agri-environment schemes are key mechanisms for reversing the declines of birds and other farmland biodiversity, but recent reviews suggest that wet habitats might be a gap in provision by these schemes. Important resources provided by wet habitats include: (i) damp soil, for probing species; (ii) permanent water to provide water-dependent invertebrates, as a source of food; (iii) bare or sparsely vegetated ground in the draw-down zone, to improve access to food; (iv) rank emergent vegetation for nesting. However, wet habitats have been lost from farmland as a result of loss of ponds and filling of ditches, as well as the effective removal of water from fields by surface run-off, itself affected by soil compaction, and extensive under-field drainage. The efficient removal of water from fields can cause problems downstream, both through flooding, and diffuse pollution. Regular farmland pollutants include pesticides, nitrogen, phosphorus and sediment, leading to environmental problems such as eutrophication and reduced quality of drinking water. Major new political instruments, such as the Water Framework Directive, will aim to reduce the impact of this diffuse pollution from agriculture. A variety of solutions to diffuse pollution, such as conservation tillage, buffer strips at field edges, and small constructed wetlands, could simultaneously provide some of the resources required by farmland birds. We suggest that future agri-environment schemes, to be truly multifunctional, could focus on bringing these diverse objectives together.

Solvent-free production of 1,3-diglyceride of CLA: Strategy consideration and protocol design

Enzymatic production of a homogeneous 1,3-diglyceride of polyunsaturated fatty acids (PUFAs) was carried out using Novozym 435 as biocatalyst and conjugated linoleic acid (CLA) as a model fatty acid. Three different operation modes, namely, magnetic stirring under vacuum, vacuum-driven N 2 bubbling and incubation with molecular sieves, were examined to find an efficient protocol for the enzymatic production. Studies on the effects of mass transfer showed that the occurrence of mass transfer limitation was strongly dependent on the operational modes. Vacuum-driven N 2 bubbling proved to be capable of eliminating mass transfer resistance, creating effective interaction for a multiple-phase reaction system and yielding an efficient water removal and a faster reaction rate. Hence, vacuum-driven N 2 stirring was considered as the best choice among the tested strategies for the production of pure 1,3-diglyceride of PUFAs with industrial interests, because it gave a higher yield of the desired product, higher productivity and lower impurity content due to its suppression of the acylmigration of 1,3-diglyceride to 1,2-diglyceride. The yield of 92–96% 1,3-dCLG could be obtained when 5 mmol of glycerol were incubated with 10–12 mmol CLA for about 3 h at 45–55 °C and a pressure less than 10 mbar, with enzyme loading of 40–70 g l −1. Among the operational parameters, temperature and reaction time were found to have profound effects on the acylmigration and yield of 1,3-diglyceride. Moreover, the enzyme showed excellent operational stability in this protocol under the optimized conditions (little activity loss of enzyme was observed after 10 consecutive batch reactions), indicating the potential of this technology for industrial application.

Electroforming of metallic bipolar plates with micro-featured flow field

In addition to mechanical properties, uniform fuel dispersion, efficient removal of water and high electric conductivity are also important functions of a bipolar plate. The capillary effect of micro-featured flow field may attract water from the carbonic diffusion layer and promote more evenly dispersion of fuels into the diffusion layer. Thus, it may improve the performance of proton exchange membrane (PEM) fuel cells. In this research, the Lithography Galvanik Abformung (LIGA) manufacturing processes with electroforming technology are investigated for the production of micro-featured flow field of the metallic bipolar plates. The micro-features are designed in conjunction with the existing flow channel to form an integrated flow field system. Instead of silicon wafer, a 4 in. wafer size SS304 stainless steel plate is used as the substrate. The LIGA processes of photo masking, spin coating, exposure and development are employed to create electric conducting die with flow field pattern. Electroforming of this metallic plate coated with flow field patterned photo resist will result in the main flow channel on the SS304 plate. The same processes were conducted for the second iteration to form micro-features. Thus, metallic bipolar plates with micro-features are produced using the electroforming technology. A single cell with total cell area of 16 cm 2 and reaction area of 4 cm 2 was produced. It has micro-features of 100 and 200 μm width and of 50 μm depth. The dimensions of the main flow channel were 300 μm in width and 200 μm in depth. Single cell tests were conducted to evaluate its performance. The cell performance of the single cell with SS304 metallic bipolar plates exceeds similar size single cell with silicon or glass fiber substrates. The electroforming is a promising technology for metallic bipolar plates with micro-features and micro-fuel cell.

‘Making water’: the hydrogeological adventures of Britain’s early mining engineers

Abstract The earliest detailed technical descriptions of British mining practices still in existence (which date from the late 17th and early 18th centuries) dedicate many paragraphs to the problems posed by the unwanted ingress of ground water into underground workings. Excessive water in working areas seriously hinders production. More importantly, sudden inrushes of ground water to underground workings are a significant mortal hazard. In view of the problems experienced with water ingress to workings, the main preoccupations of the early mining engineers were utterly practical, focusing on the efficient removal of water which could not be prevented from entering the workings (by simple bailing, by adit drainage or by pumping), and on efforts to minimize water ingress in the first place (by the use of tubbing in shafts and the use of rock barriers and dams in working areas). Occasionally, the mining engineers took time to reflect upon the origins of the water they encountered in their work. In their writings we find some of the earliest accurate conceptualizations of issues of ground water origin, driving heads, hydraulic gradients (including vertical upward gradients) and natural heterogeneities in water quality. So successful were these early mining engineers in their endeavours that they bequeathed most of the technological basis for the development of large-scale public-supply ground water abstractions, and much of the basis for the geotechnical control of ground water during construction projects, from about 1820 onwards. By the late 19th Century, mining engineers concerned with ground water management became gradually isolated once more within their own specialist domain, where they went on to develop a vernacular hydrogeology of their own, replete with its own key concepts and vocabulary. Nevertheless, occasional interchanges of experience between mining and the water industry have continued to enrich both sectors down to the present day.

Efficient water removal in lipase‐catalyzed esterifications using a low‐boiling‐point azeotrope

High conversions in lipase-catalyzed syntheses of esters from free acyl donors and an alcohol requires efficient removal of water preferentially at temperatures compatible to enzyme activity. Using a lipase B from Candida antarctica (CAL-B)-mediated synthesis of sugar fatty-acid esters, we show that a mixture of ethyl methylketone (EMK) and hexane (best ratio: 4:1, vo/vo) allows efficient removal of water generated during esterification. Azeotropic distillation of the solvent mixture (composition: 26% EMK, 55% hexane, 19% water) takes place at 59°C, which closely matches the optimum temperature reported for CAL-B. Water is then removed from the azeotrope by membrane vapor permeation. In case of glucose stearate, 93% yield was achieved after 48 h using an equimolar ratio of glucose and stearic acid. CAL-B could be reused for seven reaction cycles, with 86% residual activity after 14 d total reaction time at 59°C. A decrease in fatty-acid chain length as well as increasing temperatures (75°C) resulted in lower conversions. In addition, immobilization of CAL-B on a magnetic polypropylene carrier (EP 100) facilitated separation of the biocatalyst. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 31–34, 2002; DOI 10.1002/bit.10084

Efficient water removal in lipase-catalyzed esterifications using a low-boiling-point azeotrope.

High conversions in lipase-catalyzed syntheses of esters from free acyl donors and an alcohol requires efficient removal of water preferentially at temperatures compatible to enzyme activity. Using a lipase B from Candida antarctica (CAL-B)-mediated synthesis of sugar fatty-acid esters, we show that a mixture of ethyl methylketone (EMK) and hexane (best ratio: 4:1, vo/vo) allows efficient removal of water generated during esterification. Azeotropic distillation of the solvent mixture (composition: 26% EMK, 55% hexane, 19% water) takes place at 59 degrees C, which closely matches the optimum temperature reported for CAL-B. Water is then removed from the azeotrope by membrane vapor permeation. In case of glucose stearate, 93% yield was achieved after 48 h using an equimolar ratio of glucose and stearic acid. CAL-B could be reused for seven reaction cycles, with 86% residual activity after 14 d total reaction time at 59 degrees C. A decrease in fatty-acid chain length as well as increasing temperatures (75 degrees C) resulted in lower conversions. In addition, immobilization of CAL-B on a magnetic polypropylene carrier (EP 100) facilitated separation of the biocatalyst.

Integrated hybrid membrane systems—membrane extraction and pertraction coupled to a pervaporation process

The processes of membrane extraction (ME), and pertraction of metal cations with simultaneous pervaporation (PV) of water from an organic phase, were examined and compared. The continuous membrane extraction (CME) system comprised two contactors containing the cation exchange membranes (CEMs) and a liquid organic phase circulating between them. The pertraction process was performed in a system composed of two CEMs separating the flowing liquid membrane (FLM) from the external aqueous solutions. The organic phase of CME or FLM was additionally circulated through a PV module with a hydrophilic polymer membrane. The CME–PV and FLM–PV systems were tested with the use of Zn 2+ extractants such as di-(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4-trimethylpenthyl) thiophosphinic acid (Cyanex 302). According to the experimental findings, coupling the ME or pertraction to the PV process allows the continuous and efficient removal of water from the organic liquid membrane phase. The studied systems were found to work steadily with maintaining their integrity and high selectivity.

Catalysis of the Knoevenagel reaction by γ-aminopropylsilica

The Knoevenagel reaction can be catalysed by γ-aminopropylsilica. Reactions are rapid and essentially quantitative with small amounts of catalyst. A range of aldehydes and ketones can be reacted successfully, the only exceptions being very bulky ketones. The reaction is very dependent on the efficient removal of water, which leads to faster reaction rates and to much higher conversions. The choice of solvent is also extremely important, with nonpolar solvents such as cyclohexane being optimal. Less polar, higher boiling solvents are significantly less effective, even at much higher reaction temperatures. Catalyst poisoning is slow and appears to be due to amide formation on the surface.

A study on dynamic separation of silica slurry using a rotating membrane filter 1. Experiments and filtrate fluxes

The microfiltration performance of an axially rotating filter was in vestigated experimentally with an aqueous slurry containing fine silica particles. The effects of the rotating speed of the inner filter, gap size, feed concentration and feed rate on the filtrate flux were examined. Since Taylor vortices generated in its annular gap reduce the cake formation on the surface of the inner filter medium, an efficient removal of water from the slurry was achieved to a certain degree. The results show that continuous filtration is possible in turbulent Taylor-vortex regimes. By dividing the experimental data into two groups, transient and pseudosteady, empirical correlations for the dimensionless filtrate flux were obtained in terms of the Taylor number and the ratio of the annular gap to the inner cylinder radius, respectively.

Effect of Vacuum Degassing on Mechanical Properties of Two Rapidly Solidified Al–Fe Alloys for Elevated Temperature Applications

The use of powder metallurgy in the aluminium industry offers many advantages, e.g., improved homogeneity, refined microstructures, novel alloy compositions, etc. However the presence of an 'aluminium oxide surface layer on the powder particles is the cause of some concern. This aluminium oxide is prone to hydration. The mechanical properties of powder metallurgical aluminium alloys can be improved by uniformly distributing the aluminium oxide throughout the matrix. This successful distribution depends on the efficient removal of water from the hydrated oxide. Vacuum degassing has been used to achieve this objective. The present paper reports on the search for a suitable degassing temperature for two high temperature Al-Fe-Ce alloys consolidated by hot extrusion

Structural analysis of poly(tetramethyl-p-silphenylenesiloxane)-poly(dimethylsiloxane) copolymers by silicon-29 NMR

A method for measuring composition and sequence lengths in these copolymers is presented. The technique has been used to study the relationship between the block length in the copolymer and the degree of oligomerization of the starting disiloxanol, and to study the redistribution reaction of the polymer. It has been shown from 29 Si NMR studies of the polymerization reaction that efficient water removal is necessary to minimize redistribution of siloxane bonds in the polymer