A Simple Reflectance Method for the Measurement of Particulate Pigment in Lake Water and its Application to Phosphorus–Chlorophyll–Seston Relationships

1980 ◽  
Vol 37 (1) ◽  
pp. 111-114 ◽  
Author(s):  
Martin Bergmann ◽  
Robert Henry Peters
Keyword(s):  
Total Phosphorus ◽  
Lake Water ◽  
Membrane Filter ◽  
New Method ◽  
Pigment Analysis ◽  
Membrane Filters ◽  
Total Pigment ◽  
Residual Variation

This paper describes a new method to measure total sestonic pigment based on the reduction in the amount of light reflected from a membrane filter after a given volume of lake water has passed through the filter. For a sample of 30 lakes, this index of "reflectance" gave a better regression on total phosphorus than did chlorophyll which suggests that part of the variation in published phosphorus–chlorophyll relationships results from the association of phosphorus with pigments other than chlorophyll. But the residual variation suggests both that the amount of pigment developed per unit of phosphorus varies among lakes and that the index does not completely represent the seston. Relationships between reflectance and concentration of chlorophyll, phosphorus, and seston are good enough to suggest that this rapid, easy analysis may find application as an adjunct to more traditional analyses whereever membrane filters are routinely used in the analysis of lake water.Key words: Total pigment analysis, seston, phosphorus–chlorophyll

Contribution of Particulate Phosphorus (> 250 μm) to the Total Phosphorus Pool in Lake Water

1984 ◽  
Vol 41 (2) ◽  
pp. 351-363 ◽  
Author(s):  
E. E. Prepas ◽  
J. Vickery
Keyword(s):  
Chlorophyll A ◽  
Total Phosphorus ◽  
Lake Water ◽  
Euphotic Zone ◽  
Particulate Phosphorus ◽  
Lake Productivity ◽  
Chl A ◽  
Relative Contribution ◽  
Residual Variation ◽  
Large Particles

Particulate phosphorus (PP) > 250 μm was concentrated in the euphotic zone of 17 lakes in central Alberta. When the euphotic zone extended below the epilimnion, PP >250 μm was concentrated deep in the euphotic zone. PP > 250 μm was a significant but variable portion of the total phosphorus (TP) pool in individual lakes; thus, samples should be collected from the euphotic zone on several dates to estimate the contribution of PP > 250 μm to the TP pool. As well, the contribution of this fraction varied among lakes: average summer values for the euphotic zone ranged from 3 to 19%. Among lakes, the contribution of large particles to the TP pool decreased proportionally as lake productivity (estimated by chlorophyll a (Chl a)) increased. The relative contribution of PP > 250 μm in summer accounted for a significant portion of the residual variation in the spring TP-summer Chl a relationship but not the summer TP-summer Chl a relationship in the study lakes. These apparently contradictory results can be explained by differences between lakes that mixed intermittently throughout the summer and those that remained permanently thermally stratified during this time.

scholarly journals Emerging Developments Regarding Nanocellulose-based Membrane Filtration Material Against Microbes

2021 ◽  
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Noor Azilah Mohd Kasim ◽  
Victor Feizal Knight ◽  
Keat Khim Ong ◽  
Siti Aminah Mohd Noor ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Membrane Filter ◽  
Healthcare Providers ◽  
Antibacterial Properties ◽  
High Specific Surface Area ◽  
Oh Groups ◽  
Membrane Filters ◽  
Wide Availability ◽  
Considerable Problem ◽  
Filtration Material

Abstract Wide availability and diversity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies had proven its usefulness in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides that, the presence of an abundant OH groups in nanocellulose allows its surface modification which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism is also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.

scholarly journals Flow and fouling in a pleated membrane filter

2016 ◽  
Vol 795 ◽  
pp. 36-59 ◽  
Author(s):  
P. Sanaei ◽  
G. W. Richardson ◽  
T. Witelski ◽  
L. J. Cummings
Keyword(s):  
Membrane Fouling ◽  
Membrane Filter ◽  
Small Particles ◽  
Porous Support ◽  
Equal Area ◽  
Membrane Filters ◽  
Membrane Pores ◽  
Dead End ◽  
Large Particles ◽  
Membrane Geometry

Pleated membrane filters are widely used in many applications, and offer significantly better surface area to volume ratios than equal-area unpleated membrane filters. However, their filtration characteristics are markedly inferior to those of equivalent unpleated membrane filters in dead-end filtration. While several hypotheses have been advanced for this, one possibility is that the flow field induced by the pleating leads to spatially non-uniform fouling of the filter, which in turn degrades performance. In this paper we investigate this hypothesis by developing a simplified model for the flow and fouling within a pleated membrane filter. Our model accounts for the pleated membrane geometry (which affects the flow), for porous support layers surrounding the membrane, and for two membrane fouling mechanisms: (i) adsorption of very small particles within membrane pores; and (ii) blocking of entire pores by large particles. We use asymptotic techniques based on the small pleat aspect ratio to solve the model, and we compare solutions to those for the closest-equivalent unpleated filter.

Phosphorus Kinetics in Lake Water: Influence of Membrane Filter Pore Size and Low-Pressure Filtration

1976 ◽  
Vol 33 (12) ◽  
pp. 2800-2804 ◽  
Author(s):  
D. R. S. Lean
Keyword(s):  
Membrane Filter ◽  
Lake Ontario ◽  
Low Pressure ◽  
Total Radioactivity ◽  
Pressure Filtration ◽  
Membrane Filters ◽  
Pressure Method ◽  
Carrier Free ◽  
Algae And Bacteria ◽  
The Difference

Radiotracer kinetics using carrier-free 32P-PO4 were conducted on samples of water from Heart Lake, Ontario. Results obtained using 0.45-μm membrane filters were compared with those for 0.1 μm at vacuums of 400 mm Hg and to those for 0.45-μm filters using very low-pressure (4 mm Hg) filtration. The difference between 0.45 and 0.1 can reach 8–20% of the total radioactivity during the first 10 min of the experiment. After 60 min the fraction removed by 0.1, but not 0.45-μm filters, declines to only 1% of the total radioactivity, but this may represent as much as 50% of that which goes through 0.45 μm. The low-pressure filtration techniques provided similar results to those for normal filtration when kinetics were monophasic. Later in the season, the low-pressure method was shown to provide confusing artifacts that were explained by the hypothesis that tiny filaments extend from the surfaces of some species of aquatic algae and bacteria and are often dislodged during filtration.

Overnight Enumeration of Vibrio parahaemolyticus In Seafood by Hydrophobic Grid Membrane Filtration

1983 ◽  
Vol 46 (9) ◽  
pp. 783-786 ◽  
Author(s):  
PHYLLIS ENTIS ◽  
PETER BOLESZCZUK
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Membrane Filtration ◽  
Membrane Filter ◽  
New Method ◽  
Overnight Incubation ◽  
Differential Medium

A method was developed for direct enumeration of Vibrio parahaemolyticus in foods by hydrophobic grid membrane filter. The method consisted of a 4–5 h resuscitation step to recover injured cells, followed by overnight incubation at 42°C on V. parahaemolyticus Sucrose (VPS) agar, a new selective and differential medium. The confirmation rate of typical colonies on VPS agar was greater than 98%. The new method produced significantly higher counts of V. parahaemolyticus than the FDA method (P<0.01) when tested with chill-, freeze- or heat-stressed samples, and was equivalent to the FDA method (P>0.05) for recovery of osmotically stressed V. parahaemolyticus.

Suitability of membrane-filter techniques to study the ultrastructure of Fusarium solani in soil

1976 ◽  
Vol 22 (11) ◽  
pp. 1628-1633 ◽  
Author(s):  
W. H. Van Eck
Keyword(s):  
Fusarium Solani ◽  
Membrane Filter ◽  
Microscopical Examination ◽  
Improved Method ◽  
Selective Effect ◽  
Electron Microscopical Examination ◽  
Membrane Filters ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Nuclepore Membrane

The suitability of two types of membrane filters for scanning and transmission electron-microscopical examination of chlamydospores formed from macroconidia of Fusarium solani from soil was tested. An improved method to incubate propagules in soil and to collect them free from soil particles for electron-microscopical observations is described. Best results were obtained if macroconidia were incubated in soil between two Nuclepore membrane filters. Both chlamydospore morphology and lysis, however, were affected to some extent in comparison with that on single membranes. This is probably due to a selective effect on the microflora colonizing the chlamydospores.

scholarly journals New method for concentration and quantitation of Mycobacterium leprae

1977 ◽  
Vol 5 (3) ◽  
pp. 326-328
Author(s):  
N Sato ◽  
A H Fieldsteel
Keyword(s):  
Pore Size ◽  
Standard Method ◽  
Membrane Filter ◽  
Mycobacterium Leprae ◽  
Glass Slide ◽  
New Method ◽  
Original Material ◽  
Polycarbonate Membrane ◽  
Standard Acid ◽  
Polycarbonate Filter

A new method of enumerating Mycobacterium leprae has been developed. Suspensions containing the organisms were filtered through a polycarbonate membrane filter (25-mm diameter, 0.4-micronm pore size, 10-micronm thick; Nucleopore) to concentrate the organisms. The membrane was then mounted on a glass slide and stained with a standard acid-fast stain. Finally, the membrane was treated with a small amount of chloroform to fix it to the slide and make it transparent. This method enabled us to detect M. leprae in quantities as small as 4.98 X 10(2) regardless of the total volume of the original material. Comparison with a standard method for enumerating M. leprae showed that both methods gave similar results when the organisms counted by the standard method were present in sufficient quantity for reproducibility. Because the least number of organisms that can be detected with the standard method is 10(4) ml and because the organisms detected with the new method could be concentrated on the polycarbonate filter from a large amount of infected fluid, a substantial number of suspensions were shown by the new method, but not by the standard method, to contain M. leprae.

scholarly journals Phosphate Mine Tailing Recycling in Membrane Filter Manufacturing: Microstructure and Filtration Suitability

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 318 ◽  
Author(s):  
Mohamed Loutou ◽  
Wafa Misrar ◽  
Mohammed Koudad ◽  
Mohammed Mansori ◽  
Liga Grase ◽  
...  
Keyword(s):  
Mine Tailings ◽  
Textile Industry ◽  
Ceramic Membrane ◽  
Membrane Filter ◽  
Mercury Porosimetry ◽  
Industrial Effluent ◽  
Ceramic Membranes ◽  
Effluent Treatment ◽  
Membrane Filters ◽  
Phosphate Mine

Ceramic membrane filters based on industrial by-products can be considered to be a valorization alternative of phosphate mine tailings, even more so if these ceramic membranes are used in the industrial wastewater treatment due to their good mechanical, chemical, and thermal resistance. The depollution of textile industry rejections with this method has not been studied in detail previously. In this work, ceramic membrane filters have been manufactured from natural clay and phosphate mine tailings (phosphate sludge). Blends of the abovementioned materials with a pore-forming agent (sawdust, up to 20 wt. %) were investigated in the range 900–1100 °C using thermal analysis, X-ray diffraction, scanning electron microscopy, and mercury porosimetry. Ceramic properties were measured as a function of firing temperature and sawdust addition. Filtration tests were carried out on samples with advantageous properties. The results showed that gehlenite together with diopside neoformed from lime decomposed carbonates and breakdown products of clay minerals, while calcium phosphate derived from partial decomposition of fluorapatite. Both quartz and fluorapatite resisted heating. The results of the experimental design showed that the variations of physical properties versus processing factors were well described by the polynomial model. Filtration results are quite interesting, allowing these membranes to be used in industrial effluent treatment.

Direct Enumeration of Coliforms and Escherichia coli by Hydrophobic Grid Membrane Filter in 24 Hours using MUG

1990 ◽  
Vol 53 (11) ◽  
pp. 948-952 ◽  
Author(s):  
P. ENTIS ◽  
P. BOLESZCZUK
Keyword(s):  
Escherichia Coli ◽  
Conventional Method ◽  
Validation Study ◽  
Membrane Filter ◽  
Food Products ◽  
New Method ◽  
E Coli

An improved 24-hour hydrophobic grid membrane filter HGMF method for coliform and Escherichia coli enumeration was developed. The new method, which uses a buffered MUG agar for the E. coli portion of the test, was subjected to a precollaborative validation study against the 3-tube MPN procedure encompassing 375 naturally contaminated and inoculated samples representing 25 food products. The HGMF/MUG method produced coliform and E. coli counts equivalent to the conventional method. The confirmation rate of MUG-positive colonies in this study was 98.1%.

scholarly journals Analysis of Biogenic Secondary Pollution Materials from Sludge in Surface Waters

2019 ◽  
Vol 16 (23) ◽  
pp. 4691 ◽  
Author(s):  
Laima Česonienė ◽  
Edita Mažuolytė-Miškinė ◽  
Daiva Šileikienė ◽  
Kristina Lingytė ◽  
Edmundas Bartkevičius
Keyword(s):  
Organic Matter ◽  
Total Phosphorus ◽  
Lake Water ◽  
Organic Phosphorus ◽  
State Monitoring ◽  
Biogenic Substances ◽  
Secondary Pollution ◽  
Secondary Sludge ◽  
Biogenic Material ◽  
The Impact

Many countries of the world, including Lithuania, are making an effort to reduce surface water pollution. State monitoring data show that almost 80% of the lakes in Lithuania have an increased amount of sludge. One of the reasons for this increase in sludge is an excessive amount of biogenic material in the water. It is known that even after the source of pollution is removed, the condition of the lake water does not improve; rather, the condition of the lake water worsens due to the secondary pollution of sludge in the water. A study was conducted to determine the impact of secondary sludge pollution on water. For this study, 5 sludge samples were taken from different lakes in Lithuania. Fresh water was poured on the sludge samples, the concentrations of Nt, NO2-N, NO3-N, NH4-N, PO4-P, Pt, the pH and the changes in the electric conductivity (C) were measured in the water within 28 h. Research has shown that the thickness of the sludge layer influences the total amounts of nitrogen, phosphorus, and organic matter present in the sludge. As the thickness of the sludge layer increases in a lake, the total concentrations of nitrogen, total phosphorus and organic matter increase. Studies have also shown that the concentrations of all biogenic substances in water increase, with the exception of total phosphorus. This finding shows that organic phosphorus is "locked" in sludge, and no secondary pollution occurs from this source. Moreover, the electrical conductivity values of the water influence the release of biogenic substances from sludge in the water.

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