Dynamics of filter feeding in Corbicula fluminea (Bivalvia: Corbiculidae)

1990 ◽  
Vol 68 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Carl M. Way ◽  
Daniel J. Hornbach ◽  
Christine A. Miller-Way ◽  
Barry S. Payne ◽  
Andrew C. Miller
Keyword(s):  
Particle Concentration ◽  
Suspended Particle ◽  
Corbicula Fluminea ◽  
Suspended Particles ◽  
Particle Removal ◽  
Filter Feeding ◽  
River Population ◽  
Significant Difference ◽  
Riverine Habitats ◽  
Deposit Feeding

Filtration rates of Corbicula fluminea were measured using 2-μm microspheres from three riverine habitats which differed in ambient suspended particle concentration; rates were measured at particle concentrations spanning the range for the three habitats. Filtration rates were significantly different across the three habitats, and were inversely correlated with the mean ambient suspended particle concentrations: 66.4 mL/h for 11 mg/L, 100.2 mL/h for 7 mg/L, and 144.9 mL/h for 4 mg/L for the Tombigbee, Ouachita and Tangipahoa rivers, respectively. However, the weight of particles filtered by clams from the three rivers was not significantly different. These results indicate that C. fluminea can make physiological adjustments to its filtration rate to achieve some "optimal" rate of particle removal. Within each habitat, particle concentration had a significant effect on filtration rates for the Tombigbee River and Tangipahoa River populations; maximal filtration rates were observed in the range of ambient particle concentrations for each habitat. The effects of particle size and type on filtration rates were examined for clams from the Tombigbee River. Filtration rates were measured with microspheres of various sizes, natural suspended particles, and Chlorella. Filtration rates were highest with natural suspended particles; these particles were also the smallest in size (3 × 5 μm). Rates were also highest when measured with particles representative of the size range encountered in the field. There was no significant difference in filtration rates measured with similar-sized microspheres and Chlorella. Pseudofeces were produced by all sizes of clams from each population at particle concentrations greater than 12 mg/L. For the Tombigbee River population, pseudofeces were produced by all sizes of clams at particle sizes greater than or equal to 16 μm. These data indicate that there are potential morphological constraints on the clam gill that limit the range of particle concentrations and sizes that can be processed. Laboratory observations also demonstrated the capacity for deposit feeding in C. fluminea. Our data indicate that filter feeding in C. fluminea is a complex phenomenon, requiring an understanding of how the physiological process of feeding is influenced by morphological constraints imposed upon gill functioning and by the temporal effects of environmental variables. In addition, the plasticity in the filter-feeding response and the capacity for alternative feeding modes contribute to the success of C. fluminea as an invasive species.

scholarly journals Test of precoat filtration technology for treatment of swimming pool water

2017 ◽  
Vol 77 (3) ◽  
pp. 748-758 ◽  
Author(s):  
Morten Lykkegaard Christensen ◽  
Morten Møller Klausen ◽  
Peter Vittrup Christensen
Keyword(s):  
Removal Efficiency ◽  
Particle Concentration ◽  
Swimming Pool ◽  
Maximum Efficiency ◽  
Particle Removal ◽  
Sand Filter ◽  
Technical Performance ◽  
Pool Water ◽  
Significant Difference ◽  
Swimming Pool Water

Abstract The technical performance of a precoat filter was compared with that of a traditional sand filter. Particle concentration and size distribution were measured before and after the filtration of swimming pool water. Both the sand and precoat filters could reduce the particle concentration in the effluent. However, higher particle removal efficiency was generally observed for the precoat filter, especially for particles smaller than 10 μm in diameter. Adding flocculant improved the removal efficiency of the sand filter, resulting in removal efficiencies comparable to those of the precoat filter. Three powders, i.e., two types of perlite (Harbolite® and Aquatec perlite) and cellulose fibers (Arbocel®), were tested for the precoat filter, but no significant difference in particle removal efficiency was observed among them. The maximum efficiency was reached within 30–40 min of filtration. The energy required for the pumps increased by approximately 35% over a period of 14 days. The energy consumption could be reduced by replacing the powder on the filter cloth. The sand filter was backwashed once a week, while the powder on the precoat filter was replaced every two weeks. Under these conditions, it was possible to reduce the water used for cleaning by 88% if the precoat filter was used instead of the sand filter.

Influence of floc structure on membrane permeability in the coagulation-MF process

2005 ◽  
Vol 51 (6-7) ◽  
pp. 143-150 ◽  
Author(s):  
M.-H. Cho ◽  
C.-H. Lee ◽  
S. Lee
Keyword(s):  
Fractal Dimension ◽  
Membrane Permeability ◽  
Hybrid System ◽  
Concentration Ratio ◽  
Particle Concentration ◽  
Specific Resistance ◽  
Suspended Particle ◽  
Ion Concentration ◽  
Operating Parameters ◽  
Floc Structure

The relation between floc structure and membrane permeability was studied in a coagulation-MF hybrid process. The floc structure changed with operating parameters in the coagulation process and was quantified with fractal dimension (dF). The concentration ratio between suspended colloids and injected coagulant had an essential effect on dF of coagulated flocs. Larger flocs with low fractal dimension were produced for ALT (aluminum ion concentration dosed/suspended particle concentration) between 0.4 and 0.8. Flocs maintained stable characteristics at the coagulation period of over 20 minutes. Membrane permeability was improved with coagulated flocs of lower fractal dimension, which tend to have higher porosity and aggregate relatively loosely. These more porous flocs reduce specific resistance of coagulated flocs. The relation between membrane filterability and fractal dimension of flocs was explored in a submerged MF hybrid system as well as in a batch unstirred cell filtration.

scholarly journals Nanoparticle Number Concentration in the Air in Relation to the Time of the Year and Time of the Day

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 523
Author(s):  
Jáchym Brzezina ◽  
Klaudia Köbölová ◽  
Vladimír Adamec
Keyword(s):  
Web Application ◽  
Annual Variation ◽  
Suspended Particle ◽  
Relative Number ◽  
Absolute Number ◽  
Suspended Particles ◽  
Number Concentration ◽  
Size Fractions ◽  
The Difference ◽  
The Individual

The paper analyzes suspended particles number concentrations of 61 size fractions (184 nm to 17,165 nm) in the air at a traffic location. The average course of the individual fractions was analyzed at various intervals – daily, weekly, monthly and annually, in the period between 2017 and 2019. The data was then used to calculate the arithmetic mean for all the fractions (MS Excel, R) and then using a proprietary web application, heatmaps were constructed. The obtained results showed significant differences in both the annual and daily variation of number concentrations between the individual fractions differing in particle size. In the case of the annual variation, one can see a greater variability of smaller particles, which is most likely due to the source of the actual suspended particles. Meteorological and dispersion conditions are found as important factors for suspended particle concentrations. These can lead to significant differences from year to year. However, a comparison between 2018 and 2019 showed that even though the average absolute number concentrations can differ between years, the actual relative number concentrations, i.e., the ratios between the individual fractions remain very similar. In conclusion it can be said that the difference between the number concentration variation of the size fractions depends on both the actual pollution sources (especially in the long-term, i.e., the annual variation) and the actual size of the particles, which plays a role especially in the short-term (daily, weekly variation).

Study of the Particle Separation Performance of a Dust-settling Hopper

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Bofu Wu ◽  
Jinlai Men ◽  
Jie Chen
Keyword(s):  
Fluid Dynamics ◽  
Particle Concentration ◽  
Separation Efficiency ◽  
Simulation Analysis ◽  
Numerical Study ◽  
Particle Separation ◽  
Separation Performance ◽  
Particle Removal ◽  
Airflow Velocity ◽  
Calculation Results

This paper presents a numerical study to predict the particle separation performance of a dust-settling hopper using computational fluid dynamics. The Euler-Lagrange approach was employed to analyze the particle separation efficiency and the outflow particle concentration of the dust-settling hopper under different inlet airflow velocities. The calculation results obtained reveal that the overall particle separation efficiency and the outflow particle concentration decrease with the increase of the inlet airflow velocity, and the particle grade efficiency increases with particle size. Since there is a paradox between the particle separation performance and the particle removal performance for a street vacuum sweeper, it is necessary to counter-balance the effects of the inlet airflow velocity on them. According to the simulation analysis, an appropriate inlet airflow velocity is provided for the design of the dust-settling hopper.

The size range of suspended particles trapped and ingested by the filter-feeding lancelet Branchiostoma floridae (Cephalochordata: Acrania)

2000 ◽  
Vol 80 (2) ◽  
pp. 329-332 ◽  
Author(s):  
Edward E. Ruppert ◽  
Troy R. Nash ◽  
Allison J. Smith
Keyword(s):  
Colloidal Particles ◽  
Size Range ◽  
Suspended Particles ◽  
The Body ◽  
Phytoplankton Production ◽  
Branchiostoma Floridae ◽  
Filter Feeding ◽  
Experimental Conditions ◽  
Tracer Particles ◽  
Different Diameters

Lancelets of the genus Branchiostoma (amphioxus) are widespread and locally abundant filter-feeding animals in shallow coastal waters of the south-eastern US (up to 5000 ind/m2) and in temperate and tropical seas worldwide (up to 9000 ind/m2). Lancelets are consumed by bottom-dwelling fish and humans. As part of a larger project to aquaculture lancelets, an experiment was conducted to determine the range of diameters of suspended particles filtered and ingested by the Florida lancelet, Branchiostoma floridae (Chordata: Cephalochordata). After a period of starvation, animals were exposed to a suspension of tracer particles of seven different diameters (range 90–0.062 μm) and the protein, ferritin (0.012 μm) and their faeces were examined subsequently for the presence or absence of tracer. Particles ranging from 90–0.062 μm, but not ferritin, were filtered and ingested. Many of the 90 μm diameter particles, however, were excluded from entering the body by the oral cirri. Under experimental conditions, B. floridae filters and ingests particles in the range of ∼100–0.062 μm (microplankton to colloidal particles). This result suggests that the lancelet diet, like that of appendicularians, includes microbial as well as phytoplankton production.

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