Volume Of Filtered Water Research Articles

Pressurised sand bed filtration model: Set up and energy requirements for a filtration cycle

Rapid deep bed filtration is a common process of drip irrigation systems to prevent emitter clogging. The particle retention in the porous media increases the pressure difference between the filter's inlet and outlet. Commercial operational instructions preset a threshold value of this pressure difference to define the end of a filtration cycle. Accurate particle retention models may contribute in the determination of this setpoint to improve the energy efficiency of a filtration cycle. A two-step method was developed to calibrate a phenomenological particle retention model with transient data of the filter pressure drop, and retained mass in different media slices at the end of the filtration cycle. The first step used the vertical profile of accumulated mass in the media to fit the input parameters of the specific deposit rate equation. The second step applied the pressure data to find the input parameters of the pressure drop equation. The use of constant values of the input parameters provided reasonable results for all tests. When the end of the filtration cycle was set by applying a threshold pressure drop, both particle mass accumulation and removal efficiency decreased as the flow rate increased. By using the threshold pressure drop criterion, the energy consumption in a filtration cycle also decreased as the flow rate increased, but the energy consumption per unit of filtered water volume increased. For high setpoint pressure drop values, a minimum of the energy consumption per unit of filtered water volume as a function of the flow rate was found.

Assessment and Comparison of Microplastic Contamination in Atlantic Navigation Routes with Known Uncertainty.

Microplastics (MP) have been found in various environments worldwide. However, not many studies focus on the open ocean due to logistical restraints. Between January and May 2020, the NRP Sagres sampled 123 linear paths of subsurface water of the Atlantic Ocean, passing by Cape Verde, the east coast of South America, and the west coast of Africa. The water was sampled through the ship's water system. The membranes were analyzed by the Hydrographic Institute of Portugal and the Norwegian Institute for Water Research by micro-FTIR. The contamination levels were reported with uncertainty, for 99% confidence level (CL), normalized for filtered water volume and the distance traveled during sampling. Uncertainties were calculated through a detailed ″bottom-up″ evaluation. MP were found in about a third of the stations (48 out of 123), and most of those stations (43 out of 48) presented concentrations below 1 m-3 km-1. The sites where higher concentrations were registered were the port of the island of Santiago (Cape Verde) ((5.9 ± 5.2) m-3 km-1), the Guanabara Bay in Rio de Janeiro (Brazil) ((41 ± 27) m-3 km-1), and close to South Africa ((4.9 ± 2.4) m-3 km-1). Most MP found were polyamide, polyester, polyethylene, ethylene vinyl acetate, and poly(methyl methacrylate). The estimated contamination levels cannot be directly compared with information obtained in other studies due to differences in how MP were determined and the unknown uncertainty of their measured values. This article presents a relevant and reliable contribution to understanding the MP distribution in the Atlantic Ocean.

A Novel Approach to Water Softening Based on Graphene Oxide-Activated Open Cell Foams

This work focuses on exploring a new configuration for the reduction of water hardness based on the surface modification of polyurethane (PU) open cell foams by the deposition of thin graphene oxide (GO) washcoat layers. GO was deposited by the dip–squeeze coating procedure and consolidated by thermal treatment. The final washcoat load was controlled by performing consecutive depositions, after three of which, a GO inventory up to 27 wt% was obtained onto PU foams of 60 pores per inch (PPI). The GO-coated PU foams were assembled into a filter, and the performance of the system was tested by continuously feeding water with hardness in the 190–270 mgCa2+,eq·L−1 range. Remarkable results were demonstrated in terms of total adsorbing capacity, which was evaluated by measuring the outlet total hardness by titration and exhibited values up to 63 mgCa2+,eq·gGO−1 at a specific filtered water volume of 650 mLH2O·gGO−1, outperforming the actual state-of-the-art adsorbing capacity of similar GO-based materials.

Precision of larval herring abundance and body length assessments when sampling with BONGO nets for spawning site mapping

Data on the abundance and size structure of larval and juvenile fish are commonly used in environmental research. Knowledge about the repeatability of the results of a given sampling tool is an important part of planning sample collection schedules. The aim of this research was to evaluate the variance in the abundance and length of herring larvae (6.9–24.4 mm SL) collected with 505 bongo nets during 12 cruises conducted during April-June at 6–9 stations in the Pomeranian Bay, Baltic Sea, from 2015 to 2018. The differences (mean value of % deviation from the mean) between the left and right bongo nets (compared during 17 tows) were 21.6% for larval abundance and 3.6% for the SL measurement. When three tows were subsequently conducted at the same station (compared at 6 stations), the differences were 19.7% and 10.1% for abundance and the SL assessment, respectively. When samples were collected at the same stations on consecutive days (compared for 75 paired days), the error was 33.4% for abundance and 6.1% for SL. Several factors (filtered-water volume, larval abundance, larval size, wind strength, and station location) were tested for their effect on the magnitude of the variations, but only sampled larvae abundance was found to be significant with lower precision for low abundance. Although the above low precision level did not significantly affect the overall assessment of larval abundance and SL within the investigated geographical area within a given year, it should be considered that differences of ca. ± 10% (for SL) and ca. ± 33% (for abundance) are within the sampling method errors, which correspond to ca. thirteen percent (for SL) and 200% (for abundance) of the absolute differences expressed as % of the lower value. While the present results were obtained for herring, we believe that the conclusions are also applicable to early life stages of other fish species, especially clupeids such as sprat, menhaden, and smelt.

How many replicates to accurately estimate fish biodiversity using environmental DNA on coral reefs?

Quantifying fish species diversity in rich tropical marine environments remains challenging. Environmental DNA (eDNA) metabarcoding is a promising tool to face this challenge through the filtering, amplification, and sequencing of DNA traces from water samples. However, because eDNA concentration is low in marine environments, the reliability of eDNA to detect species diversity can be limited. Using an eDNA metabarcoding approach to identify fish Molecular Taxonomic Units (MOTUs) with a single 12S marker, we aimed to assess how the number of sampling replicates and filtered water volume affect biodiversity estimates. We used a paired sampling design of 30 L per replicate on 68 reef transects from 8 sites in 3 tropical regions. We quantified local and regional sampling variability by comparing MOTU richness, compositional turnover, and compositional nestedness. We found strong turnover of MOTUs between replicated pairs of samples undertaken in the same location, time, and conditions. Paired samples contained non‐overlapping assemblages rather than subsets of one another. As a result, non‐saturated localized diversity accumulation curves suggest that even 6 replicates (180 L) in the same location can underestimate local diversity (for an area <1 km). However, sampling regional diversity using ~25 replicates in variable locations (often covering 10 s of km) often saturated biodiversity accumulation curves. Our results demonstrate variability of diversity estimates possibly arising from heterogeneous distribution of eDNA in seawater, highly skewed frequencies of eDNA traces per MOTU, in addition to variability in eDNA processing. This high compositional variability has consequences for using eDNA to monitor temporal and spatial biodiversity changes in local assemblages. Avoiding false‐negative detections in future biomonitoring efforts requires increasing replicates or sampled water volume to better inform management of marine biodiversity using eDNA.

Effects of filtration methods and water volume on the quantification of brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) eDNA concentrations via droplet digital PCR

AbstractThe quantification of the abundance of aquatic organisms via the use of environmental DNA (eDNA) molecules present in water is potentially a useful tool for efficient and noninvasive population monitoring. However, questions remain about the reliability of molecular methods. Among the factors that can hamper the reliability of the eDNA quantification, we investigated the influence of five filtration methods (filter pore size, filter type) and filtered water volume (1 and 2 L) on the total eDNA and the fish eDNA concentrations of two species, brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) from tanks with known number of individuals and biomass. We applied a droplet digital PCR (ddPCR) approach to DNA extracted from water samples collected from two cultivation tanks (each of them containing one of the targeted species). Results showed that the quantification of fish eDNA concentrations of both species varies with filtration methods. More specifically, the 0.45‐µm Sterivex enclosed filters were identified to recover the highest eDNA concentrations. Difficulties to filter 2 L water samples were present for small pore size filters (≤0.45 µm) and likely caused by filter clogging. To overcome issues related to filter clogging, common in studies aiming to quantify fish eDNA molecules from water samples, we recommend a procedure involving filtration of multiple 1 L water samples with 0.45‐µm enclosed filters, to recover both high quality and high concentrations of eDNA from targeted species, and subsequent processing of independent DNA extracts with the ddPCR method.

Estimation of Recycled Concrete Aggregate's Water Permeability Coefficient as Earth Construction Material with the Application of an Analytical Method.

Creating models based on empirical data and their statistical measurements have been used for a long time in the economic sciences. Increasingly, these methods are used in the technical sciences, such as construction and geotechnical engineering. This allows for reducing the costs of geotechnical research at the design stage. This article presents the research carried out on Recycled Concrete Aggregate (RCA) material with is reclaimed crushed concrete rubble. Permeability tests were carried out using the constant head method. Tests were conducted on blends of RCA with the following particle size ranges: 0.02–16 mm, 0.05–16 mm, 0.1–16 mm, and 0.2–16 mm. The gradients used during the tests were between 0.2 to 0.83, which corresponds to gradients encountered in earth construction and are below the critical gradient. Directly from the tests, the flux velocity for the range of tested gradients were calculated based on filtered water volume measurements. The values of the permeability coefficient (k) were then recalculated. Finally, statistical methods were used to determine which physical parameters of the tested material affect the permeability coefficient. The physical parameters selected from the statistical analysis were used to create a model describing the phenomenon. The model can be used to determine the permeability coefficient for a mixed RCA material. The article ends with conclusions and proposals concerning the use of models and the limits of their applicability.

Improving eDNA yield and inhibitor reduction through increased water volumes and multi-filter isolation techniques

To inform management and conservation decisions, environmental DNA (eDNA) methods are used to detect genetic material shed into the water by imperiled and invasive species. Methodological enhancements are needed to reduce filter clogging, PCR inhibition, and false-negative detections when eDNA is at low concentrations. In the first of three simple experiments, we sought to ameliorate filter clogging from particulates and organic material through a scaled-up, multi-filter protocol. We combined four filters in a 5 mL Phenol-Chloroform-Isoamyl (PCI) procedure to allow for larger volumes of water (~1 L) to be filtered rapidly. Increasing the filtered water volume by four times resulted in 4.4X the yield of target DNA. Next, inhibition from organic material can reduce or block eDNA detections in PCR-based assays. To remove inhibitory compounds retained during eDNA isolation, we tested three methods to chemically strip inhibitors from eDNA molecules. The use of CTAB as a short-term (5–8 day) storage buffer, followed by a PCI isolation, resulted in the highest eDNA yields. Finally, as opposed to a linear relationship among increasing concentrations of filtered genomic eDNA, we observed a sharp change between the lower (70–280 ng) and higher (420–560 ng) amounts. This may be important for effectively precipitating eDNA during protocol testing.

Optimizing environmental DNA sampling effort for fish inventories in tropical streams and rivers

Environmental DNA (eDNA) metabarcoding is a promising tool to estimate aquatic biodiversity. It is based on the capture of DNA from a water sample. The sampled water volume, a crucial aspect for efficient species detection, has been empirically variable (ranging from few centiliters to tens of liters). This results in a high variability of sampling effort across studies, making comparisons difficult and raising uncertainties about the completeness of eDNA inventories. Our aim was to determine the sampling effort (filtered water volume) needed to get optimal inventories of fish assemblages in species-rich tropical streams and rivers using eDNA. Ten DNA replicates were collected in six Guianese sites (3 streams and 3 rivers), resulting in sampling efforts ranging from 17 to 340 liters of water. We show that sampling 34 liters of water detected more than 64% of the expected fish fauna and permitted to distinguish the fauna between sites and between ecosystem types (stream versus rivers). Above 68 liters, the number of detected species per site increased slightly, with a detection rate higher than 71%. Increasing sampling effort up to 340 liters provided little additional information, testifying that filtering 34 to 68 liters is sufficient to inventory most of the fauna in highly diverse tropical aquatic ecosystems.

Comparative studies on the feeding behavior of two heterotrophic nanoflagellates: the filter-feeding choanoflagellate Monosiga ovata and the raptorial-feeding kinetoplastid Rhynchomonas nasuta

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 22:243-249 (2000) - doi:10.3354/ame022243 Comparative studies on the feeding behavior of two heterotrophic nanoflagellates: the filter-feeding choanoflagellate Monosiga ovata and the raptorial-feeding kinetoplastid Rhynchomonas nasuta Jens Boenigk*, Hartmut Arndt Department of General Ecology and Limnology, Zoological Institute, University of Cologne, 50923 Cologne, Germany *E-mail: jens.boenigk@uni-koeln.de ABSTRACT: Even though bacterivorous flagellates have been recognized as being able to structure the bacterial community, their behavioral basis for food selection is hardly known. We investigated the feeding behavior of the filter-feeding choanoflagellate Monosiga ovata and the raptorial-feeding kinetoplastid flagellate Rhynchomonas nasuta feeding on a bacterial community dominated by Pseudomonas putida and compared it to that of interception-feeding flagellates. M. ovata handles several food particles simultaneously. In contrast, R. nasuta handles only 1 particle at a time. The handling time for 1 prey particle is in the range of 3.7 s for R. nasuta but more than 300 s for M. ovata. The speed of food particles within the feeding current of M. ovata was only 9.3 ± 5.7 μm s-1 but due to the large surface of the collar the filtered water volume was 6.4 nl h-1 and therefore comparable to that of interception-feeding flagellates of a similar size. Bacteria ingested by M. ovata were significantly smaller compared to the bacteria in the medium (p = 0.001). Size selection of food particles occurs during the processing of food items. This is in contrast to raptorial-feeding R. nasuta, which shows passive food size selection for bigger particles during the contact phase. Attachment of bacteria proved to be an efficient protection mechanism, defending them from being grazed by flagellates. There are significant species-specific differences in the processing of food particles which explain the coexistence of various bacterivorous nanoflagellates in the size range of 3 to 5 μm and indicate the existence of specific predation pressure on different bacteria. KEY WORDS: Protozoa · Microbial food web · Feeding ecology · Nanoflagellate Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 22, No. 3. Online publication date: October 26, 2000 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2000 Inter-Research.

ネットの目詰りがろ水計によるろ水量測定に与える影響

This paper deals with the effect of net clogging on measurement for filtered water volume with a flowmeter placed at the center of a net frame. Experiments were carried out using a sampler which had two cyclinder-corn nets: one with fine mesh (0.100×0.100mm, F-net), the other with coarse mesh (0.140×0.170mm, C-net), with a ratio of mesh aperture to mouth area of 10. The sampler was towed horizontally 151 times at a speed of about 1.25m/s for 7 min. In most of the tows, the distances which the C-net flowmeter travels (Lc) and which the F-net flowmeter travels (LF) almose reached the expected value (525m). However, on some of the tows, LF was much shorter than the expected value and LF/Lc was under 0.9. On these tows, the settling volume caught with the F-net was over 100ml and the number of fish eggs caught with the F-net per 25m3 (DF), calculated with the filtered water volume estimated from the revolution of the flowmeter's impeller, tended to be a little more than the number of fish eggs caught with the C-net per 25m3 (Dc). The correlation between DF and Dc are indicated by a regression line of DF=1.128 Dc. This suggests that net clogging has an effect on measurement with a flowmeter for filtered water volume.

開閉式動物プランクトン採集器の試作

A new, opening-closing, paired zooplankton sampler for horizontal or oblique towing was built and tested. Two nets, which have cylinder-cone filtering section and canvas collar, are at-tached to a frame constructed with two acrylic pipes (23.4cm I. D.). The nets are opened and closed by means of a double releaser (General Oceanics). The sampler is simple to consturct and easy to use, and furthermore it is very light (6.5kg in air). In 151 tows, the sampler fuctioned 97 percent of the time. A depth of the sampler changes scarcely even when the nets are opened. The revolution number of a flowmeter attached in the pipe is little during the nets closing. Consequently the revolution number of a flowmeter can give the correct filtered water volume.

Organics isolation from fresh and drinking waters by macroporous Nonionic sorbents

In this paper the results on the isolation of organic water pollutants by nonionic sorbents are presented. Polish active carbon Z4S, Amberlite XAD‐2, XAD‐4, XAD‐7 and Polish nonionic macroporous sorbents were used. Adsorption effectiveness, as influenced by organics polarity and concentration, by contact time and by filtered water volume was examined. The best parameters for isolation with macroporous nonionic sorbents were established. For the desorption of organic substances, a Soxhlet extraction for 12hrs with dichloromethane is proposed. The investigated sorbents give total recoveries very close to those obtained by Amberlite XAD resins.