Suspended Solids Samples Research Articles

Effect of Contaminated Suspended Solids on Water and Sediment Qualities and Their Treatment

Abstract Suspended solids (SS) have been discharged into water areas such as rivers, lakes, and ponds. The SS adsorb various contaminants such as heavy metals and nutrients and also form sediments by sedimentation. Therefore, contaminated SS will be able to influence not only the water quality, but also the sediment quality. In order to understand the effect of contaminated SS on the water and the sediment, SS and sediment samples were obtained from the des Hurons River in Canada. In addition, laboratory filtration tests were performed to develop a technique for removal of the SS. A downward filtration system was used with a nonwoven geotextile as a filter medium. The apparent opening size (AOS) and the thickness of the filter were 150 μm and 0.2 cm, respectively. For the investigation, the results showed that both SS and the sediments contained heavy metals with concentrations in the SS higher. In particular, zinc concentrations of the SS were approximately from two to five times higher than the Canadian guideline for sediments. In addition, it was found that SS concentrations were associated with chemical oxygen demand (COD) and total phosphorus (T-P) concentrations. Therefore, it was found that SS can play an important role in the water and the sediment qualities. The laboratory filtration tests showed the SS were reduced from 32 mg/L to 2 mg/L or less by the nonwoven filter. Thus, SS removal will improve not only the water quality, but also the quality of the bottom sediments.

Characterization of suspended solids in produced water in Daqing oilfield

The concentration and size of suspended solids (SS) in the treated produced water beyond the criteria of injection water in Daqing oilfield have raised great concerns in recent years. The SS in produced water from water, polymer and alkali–surfactant–polymer (ASP) flooding were successfully separated and characterized using some analytical techniques in this study. X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and heating method reveal that some organic compounds besides crude oil were present in the SS samples, and polyacrylamide was found in the SS from polymer and ASP flooding. X-ray diffraction (XRD) shows some crystal inorganic substances such as SiO 2, Fe 2O 3, Fe 3O 4, and BaSO 4 in the SS samples, and XPS analysis indicated that several iron compounds with different valences were present in the three SS samples. The mean diameters of three SS samples were 22.89, 11.28 and 17.61 μm, respectively. Most importantly, the aggregates formed by the SS and oil droplets as well as the small SS adsorbed on the surface of oil droplets were observed using a microscope, indicating that the SS can be removed with crude oil, and crude oil also contributes to the determination of the SS values.

Spatial and temporal variations and possible sources of dichlorodiphenyltrichloroethane (DDT) and its metabolites in rivers in Tianjin, China

Water, suspended solid (SS) and sediment samples were collected from nine water courses in Tianjin, China and analyzed for dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including o,p'-,p,p'-DDT, DDD and DDE). The average DDX concentrations in water, SS and sediment were 59+/-30 ng l(-1), 2690+/-1940 ng g(-1)dry wt. and 340+/-930 ng g(-1)dry wt., respectively. Due to the termination of the extensive agricultural application and industrial manufacture, DDXs in river sediment decreased by one order of magnitude since 1970's and low DDT fractions in these sediments were observed. Still, DDXs in the sediments near the outlets of the major manufacturers remained relatively high attributed to the historic input. DDXs in sediment were also positively correlated with organic matter content. Spatial distributions of DDXs in SS and water was different from that in sediment. For SS, a negative correlation between DDX concentration and SS content indicated a dilution effect in many rivers. Dissolved organic carbon content was the major factor affecting DDX concentrations in water phase. Wastewater discharged from dicofol manufacturers and likely illegal agricultural application were the primary reasons causing high DDT (DDE+DDD) ratios in SS and water.

The dynamic water–sediment system: results from an intensive pesticide monitoring campaign

To gain insight into the dynamics of pesticides in the different compartments of a river system, an intensive monitoring campaign was set up. An extensive dataset is useful when planning to model the fate of pesticides in river systems. In this study we focus on the Nil, a small, hilly basin situated in the central part of Belgium. Two automatic samplers were placed in the river basin, i.e., one at the mouth and one upstream, taking composite samples of water and suspended solids. Undisturbed sediment samples were taken by means of a macro-core and immediately frozen with CO2-ice. The samples were sliced and analysed for pesticides in pore water and on sediment. The results of the study revealed the dynamics of the different compartments of a river system. The water compartment showed hourly variations in pesticide peak concentrations, regularly exceeding the standards. The amount of pesticides transported by suspended solids increased after a rainfall event. The concentration of pesticides in pore water, measured on a monthly basis, followed the trends of the water compartment remarkably well, but in a significantly lower concentration. These observations may be explained by combined diffusion, biodegradation and chemical reactions occurring in the water column and the sediment. Further insight into the importance of each of these processes can be gained by dynamic modelling, an approach that is currently being followed.

Dynamic behavior of fractional suspended solids and particle-bound polycyclic aromatic hydrocarbons in highway runoff

A long-term continuous runoff monitoring was carried out in a highway in Winterthur, Switzerland. The total suspended solids (TSS) samples were fractionated into fine (<45 μm) and coarse (>45 μm) fraction and their washoff behavior was studied. The fine and coarse fraction showed different washoff behaviors. During the runoff the concentration of the fine fraction was less fluctuated compared to coarse. The fluctuation of the coarse fraction was more influenced by TSS concentration. The PAH content measurement in fine fraction showed less fluctuation compared to the coarse fraction. The PAH content in the coarse fraction was found decreasing with increasing the coarse fraction contribution to TSS.

Determination of sixteen polycyclic aromatic hydrocarbons in aqueous and solid samples from an Italian wastewater treatment plant

A robust procedure for the determination of 16 US EPA PAHs in both aqueous (e.g. wastewaters, industrial discharges, treated effluents) and solid samples (e.g. suspended solids and sludge) from a wastewater treatment plant (WWTP) is presented. Recovery experiments using different percentages of organic modifier, sorbents and eluting solvent mixtures were carried out in Milli-Q water (1000 mL) spiked with a mixture of the PAH analytes (100 ng/L of each analyte). The solid phase extraction (SPE) procedures applied to spiked waste water samples (1000 mL; 100 ng/L spiking level) permitted simultaneous recovery of all the 16 PAHs with yields >70% (6–13% RSD). SPE clean up procedures applied to sewage and stabilized sludge extracts, showed percent recoveries in the range 73–92% (7–13% RSD) and 71–89% (7–12% RSD), respectively. The methods were used for the determination of PAHs in aqueous and solid samples from the WWTP of Fusina (Venice, Italy). Mean concentrations, as the sum of the 16 PAHs in aqueous and suspended solid samples, were found to be approx. in the 1.12–4.62 μg/L range. Sewage and stabilized sludge samples contained mean PAH concentrations, as sum of 16 compounds, in the concentration range of 1.44–1.26 mg/kg, respectively. Extraction and clean up procedures for sludge samples were validated using EPA certified reference material IRM-104 (CRM No. 912). Instrumental analyses were performed by coupling HPLC with UV-diode array detection (UV-DAD) and fluorescence detection (FLD).

ひ沼川流域における平水時河川水の懸濁物質による主要元素濃度

Samples of water and suspended solids (SS) collected from the Hinuma river system over one year were analyzed by PIXE (Particle Induced X-ray Emission) to determine elemental concentrations.The average SS concentrations at the 11 sampling sites ranged from 1.4 to 12.7mg·l-1 during ordinary water discharge. The SS concentrations were the highest in the upstream reaches of the Hinuma River, but were lower from the middle to downstream reaches, suggesting that the SS may have settled to the riverbed. All of the SS samples contained relatively high concentrations of Al, Fe, Ca, K and Mg, suggesting that the SS consist of particles from the earth's crust. Variations in elemental ratios to Al of Na, Mg, K, Ca and Cu in the SS among the sampling sites may have been due to differences in geology, land use, drainage from quarries, or brackishness of the water. Moreover the highest Fe: Al ratio was observed at a site where a large microbial mat had developed; the Cu: Al ratio was remarkably high at another site where intensive pig farming was practiced.

Micro-particles in recirculating aquaculture systems: microscopic examination of particles

In order to determine the composition, shape and structure of micro-particles in a cold water recirculating plant raising juvenile Atlantic salmon to the smolt stage, samples of suspended solids, collected on classification meshes, and samples of particles in the culture water were examined microscopically. Concurrent gravimetric tests were attempted which method proved unusable due to clogging of the meshes by a viscid material, especially for particles under 40 μm. It was determined that this viscid material, also evident on the classification screens, constituted a major portion of the less dense particles (1050 kg/m3) by floccing fine particles. Staining indicated that the viscid material was primarily mucus with some gelatinized starches from the feed. Undigested feed stirred in distilled, filtered water were also examined microscopically. Again a viscid coating was found on the filter media, but in this case the primary source appeared to be gelatinized starches. The lighter fraction was essentially absent. In both the culture water and the feed samples, the heavier fraction, 1150 kg/m3, appears to originate primarily from the heavy, brown, indigestible cellulose fraction of the ground wheat in the feed.

Multi-residue Analysis of 66 Biocides in River Water, River Sediment and Suspended Solids Samples by Gas Chromatography-Mass Spectrometry

A multi-residue method for the screening and analysis of 66 common pesticides from hydrological samples, including sediment, suspended solids and water is presented. The investigated pesticides belong to the following chemical classes: polychlorinated organic compounds, triazine- and chloroacetanilide herbicides, organophosphorous insecticides and miscellaneous. The method includes fluidized-bed and microwave-assisted extraction for solid samples and solid-phase extraction on C 18 -cartridges for water samples, followed by a combined purification-separation step on adsorption chromatography using open silica gel columns. Two fractions were eluted separating the 66 analytes into the non-polar and the more polar compounds. All analytes were identified and quantified by gas chromatography coupled with mass spectrometry in selected ion monitoring mode. The method was characterized by recovery experiments and statistical methods and finally applied to environmental river samples during a one-year monitoring program. This method allowed the screening and measurement of the contaminants in all parts of Liao-He and Yangtse rivers (Eastern China) at levels as low as 0.07 ng/L resp. 0.7 ng/L for hexachlorobenzene, with a precision better than 20%.

Preference ratios for mercury and other chemical elements in the Madeira River, Brazil

Samples of water, suspended solids, and bottom sediments from the Madeira River, Rondônia state, Brazil, were physically and chemically analyzed to investigate the actual Hg mobilization in the aquatic environment and compare it with that of other heavy metals and elements in the area. Two dimensionless Hg preference ratios were defined, expressing (1) the ratio of Hg and other elements in the liquid phase divided by the ratio of Hg and other elements in bottom sediments ( P l.phase) and (2) the ratio of Hg and other elements in the particulate matter divided by the ratio of Hg and other elements in bottom sediments ( P s.solids). These preference ratios are useful for comparing Hg transport in three different phases (liquid, particulate matter, and bottom sediments). They also were applicable to any analyzed element in the area studied, because they generated an almost constant value when the maximum calculated was divided by the minimum ( P l.phase=2931; P s.solids=84) and because of their sensitivity to the dominance of sorption processes by Fe oxides and hydroxides. Mercury could be transported preferentially to other analyzed elements in the particulate phase only if its concentration reached values at least 10 4-fold higher than those expected or quantified in the area.

Radionuclides in the Loire river estuary (France) : Sources, transport and fate

Anthropogenic radionuclide inputs in the Loire estuary (French Atlantic coast) consist of radioactive releases from 14 nuclear reactors located along the Loire river basin, and of fallout from nuclear weapon tests and from the Tchernobyl accident. To estimate to what extent radionuclides associated with sediment accumulate in the estuary, three complementary approaches were used: field surveys, laboratory experiments and numerical modelling. Sampling of bottom sediments, water and suspended solids was carried out at 8 different dates over a 15 month-period. Analysis covered 14C, 90Sr, 3H, the naturally occurring gamma-emitters (uranium and thorium decay chains, 7Be and 40K), and the artificial gamma emitters (mainly cobalt and cesium isotopes). Processes of radionuclide transport and exchange between dissolved and particulate phases were included in a previously developed estuary specific 2D-hydrodynamic model. Equations of sorption and desorption kinetics were derived from laboratory experiments conducted at different salinities. Simulations carried out for two river discharge conditions (low summer flow, high winter flow) allowed to follow radionuclide desorption in the estuary. For long term simulations, a simplified model was developed. It provided estimates of the amount of radionuclides expelled out of the estuary under dissolved and particulate forms, of the transit time for both forms and of the variations in radionuclides concentrations in the fluid mud. Based on computed results and observations, contributions from different origins (natural, military, industrial) to the inventory of radioactivity in the estuary are presented.

Radionuclides in the Loire river estuary (France): Sources, transport and fate

Anthropogenic radionuclide inputs in the Loire estuary (French Atlantic coast) consist of radioactive releases from 14 nuclear reactors located along the Loire river basin, and of fallout from nuclear weapon tests and from the Tchernobyl accident. To estimate to what extent radionuclides associated with sediment accumulate in the estuary, three complementary approaches were used: field surveys, laboratory experiments and numerical modelling. Sampling of bottom sediments, water and suspended solids was carried out at 8 different dates over a 15 month-period . Analysis covered I4 C, 90 Sr ,3H, the naturally occurring gamma-emitters (uranium and thorium decay chains, 7 Be and 40 K), and the artificial gamma emitters (mainly cobalt and cesium isotopes). To gain information on the contamination history of the estuary, sediment cores were also collected at different locations inside and outside the estuarine zone. Processes of radionuclide transport and exchange between dissolved and particulate phases were included in a previously developed estuary specific 2D-hydrodynamic model. Equations of sorption and desorption kinetics were derived from laboratory experiments conducted at different salinities. Simulations carried out for two river discharge conditions (low summer flow, high winter flow) allowed to follow radionuclide desorption in the estuary. For long term simulations, a simplified model was developed. It provided estimates of the amount of radionuclides expelled out of the estuary under dissolved and particulate forms, of the transit time for both forms and of the variations in radionuclides concentrations in the fluid mud. Based on computed results and observations, contributions from different origins (natural, military, industrial, marine, continental) to the inventory of radioactivity in the estuary are presented.

Forms of particulate phosphorus in suspension and in bottom sediment in the Danube Delta

AbstractIn the summer of 1995, samples of suspended solids and bottom sediments were collected from the lower course of the Danube, downstream from potential pollution sources such as tributaries draining industrialised and densely populated watersheds (the Jiu, Olt, Arges and Ialomita rivers) or big cities on the border of the river (Tulcea, Galati, Braila), and from the Danube Delta. Chemical and toxicological analyses were carried out on these samples. In the present paper, the results of the measurements of the forms of particulate phosphorus are discussed. Phosphorus occurring in the bottom sediments and the suspended solids has various origins and chemical forms. These forms may be operationally defined as: organic phosphorus (OP), apatite inorganic phosphorus (AP) and non‐apatite inorganic phosphorus (NAIP). The AP shows low variability, ranging from 350 to 400 p.p.m. for suspended solids and from 425 to 500 p.p.m. for bottom sediments. This is essentially due to the detrital origin of this form. These values are typical for freshwater sediments in European rivers. The NAIP, which originates both from natural sources and from human pollution, shows a high variability. This indicates that the nutrient pollution is derived from both point and non‐point sources in the watershed. The NAIP concentrations of 800 p.p.m. (Vadul Oii) and 850 p.p.m. (Oltenita) are very high (fourfold the average for European rivers), indicating that strong anthropogenic sources of phosphorus are present in the lower Danube watershed. As the NAIP is potentially bioavailable, its high concentration may contribute to eutrophication in the lower Danube and the Danube Delta.

Relating stream-bank erosion to in-stream transport of suspended sediment

We seek an improved and quantitative understanding of the sources and transport of sediment and attached phosphorus in upland catchments and downstream reaches of the Namoi River in New South Wales, Australia. Study of the sources of phosphorus and related sediment was motivated by severe problems with blooms of blue-green algae and toxic by-products in the Darling and Namoi Rivers. Using atmospheric fall-out of radionuclides as tracers, Olley et al. (1996) concluded that much of the sediment deposited in the lower reaches came from subsoil rather than topsoil. With this insight, we focus on quantifying sediment sources from stream bank erosion, especially in seasonally erosional reaches of Cox's Creek and the Mooki River. The approach presented here integrates interdecadal aerial photography, interseasonal field measurements of bank erosion processes, continuous monitoring of stream flow and turbidity and event sampling of suspended solids and phosphorus, with an analytical model of in-stream suspended sediment transport. We compare a lateral source term in the calibrated transport model with field-based and aerial measurements of stream bank erosion. Calibration of the in-stream model is illustrated for two reaches of the Mooki River, with the changes in parameter values being related to aspects of the hydraulic geometry and particle size. The processes of stream flow and bank erosion due to undercutting, desiccation, block failure and mass wasting of aggregated particles interact to produce instream fluxes of suspended sediment that are transported and redeposited downstream. The combined approach demonstrated here has potential for predictive spatial modelling of sediment concentrations and loads. Copyright © 1999 John Wiley & Sons, Ltd.

Relating stream‐bank erosion to in‐stream transport of suspended sediment

We seek an improved and quantitative understanding of the sources and transport of sediment and attached phosphorus in upland catchments and downstream reaches of the Namoi River in New South Wales, Australia. Study of the sources of phosphorus and related sediment was motivated by severe problems with blooms of blue-green algae and toxic by-products in the Darling and Namoi Rivers. Using atmospheric fall-out of radionuclides as tracers, Olley et al. (1996) concluded that much of the sediment deposited in the lower reaches came from subsoil rather than topsoil. With this insight, we focus on quantifying sediment sources from stream bank erosion, especially in seasonally erosional reaches of Cox's Creek and the Mooki River. The approach presented here integrates interdecadal aerial photography, interseasonal field measurements of bank erosion processes, continuous monitoring of stream flow and turbidity and event sampling of suspended solids and phosphorus, with an analytical model of in-stream suspended sediment transport. We compare a lateral source term in the calibrated transport model with field-based and aerial measurements of stream bank erosion. Calibration of the in-stream model is illustrated for two reaches of the Mooki River, with the changes in parameter values being related to aspects of the hydraulic geometry and particle size. The processes of stream flow and bank erosion due to undercutting, desiccation, block failure and mass wasting of aggregated particles interact to produce instream fluxes of suspended sediment that are transported and redeposited downstream. The combined approach demonstrated here has potential for predictive spatial modelling of sediment concentrations and loads. Copyright © 1999 John Wiley & Sons, Ltd.

Heavy metals in freshwater ecosystems introduced by urban rainwater runoff - monitoring of suspended solids, river sediments and biofilms

Sediments, suspended solids and biofilm samples at different locations of the River Alb near Karlsruhe were analysed for their heavy metal content (Pb, Cu, Cd). The main task of this study was to validate the biofilm method by comparing the measured pollution with the results of long term monitoring programs based on sediments and suspended solid samples. All compartments of the surveyed systems showed increasing heavy metal concentrations towards highly urbanised areas. The translation of data into pollution classes detected similar pollution situations for sediments and biofilms. The presented biofilm method recommends itself as a practicable instrument for assessing the heavy metal pollution in freshwater ecosystems. The easy sampling-technique, the low variability in the detected values and the ecological relevance of biofilms are the obvious advantages of this biofilm monitoring.

FEM-Modelling of Open Stormwater Detention Ponds

Stormwater in urban areas is polluted with suspended materials which transport heavy metals and degrade the quality of the receiving waters. Since open detention ponds improve water quality, an investigation of a constructed pilot-scale detention pond was carried out. Measurements of inflow and outflow were performed and two flow-weighted samplers were used to collect representative samples of suspended solids and heavy metals. The particle size distribution was analysed to allow an estimation of the settling of suspended solids. Particle removal from a rain event was defined as two different phases where the first phase occurs during the rain event and the second phase after the event. In this paper only the first phase is considered. A FEM-software package (FIDAP) was used to calculate the three dimensional velocity flow field for one rain event. A sedimentation approach was applied to the flow field where paths were calculated through the detention pond for different particle sizes. The results from four different particle sizes show satisfactory agreement between FEM-calculated and observed particle removal. The results show that FIDAP is a useful tool to predict pollutant removal for open detention ponds with arbitrary geometry.

Heavy metals in freshwater ecosystems introduced by urban rainwater runoff — Monitoring of suspended solids, river sediments and biofilms

Sediments, suspended solids and biofilm samples at different locations of the River Alb near Karlsruhe were analysed for their heavy metal content (Pb, Cu, Cd). The main task of this study was to validate the biofilm method by comparing the measured pollution with the results of long term monitoring programs based on sediments and suspended solid samples. All compartments of the surveyed systems showed increasing heavy metal concentrations towards highly urbanised areas. The translation of data into pollution classes detected similar pollution situations for sediments and biofilms. The presented biofilm method recommends itself as a practicable instrument for assessing the heavy metal pollution in freshwater ecosystems. The easy sampling- technique, the low variability in the detected values and the ecological relevance of biofilms are the obvious advantages of this biofilm monitoring.

Absorption spectra of inorganic particles in the Irish Sea and their relevance to remote sensing of chlorophyll

Abstract Mineral suspended solids contribute significantly to the total suspended sediment load in shelf seas and estuaries. Even in moderate concentrations, mineral suspended solids affect algorithms for retrieving chlorophyll concentrations from remotely-sensed colour data. Brown and Simpson (1990) showed empirically that the slope of a log-log graph of chlorophyll against the blue-green reflectance ratio increased as the concentration of mineral suspended solids increased. In an attempt to explain this, we have measured the absorption spectrum of over 100 samples of mineral suspended solids collected from the Menai Strait in the Irish Sea. The absorption spectra of the mineral suspended solids particles on filters consistently show an exponential decrease with increasing wavelength across the visible spectrum. The absorption coefficient at a single wavelength is proportional to the concentration of mineral suspended solids. This spectrum has been incorporated into a simple model of the blue-green ratio in the presence of both chlorophyll and mineral suspended solids. The results are in qualitative agreement with Brown and Simpson's observations and can be made to be in quantitative agreement by correcting the absorption of mineral suspended solids on filters to in situ absorption using a pathlength correction factor β = 4. The main effect of mineral suspended solids is to decrease the sensitivity of the blue-green ratio to changes in chlorophyll in shelf seas and we conclude that the blue-green ratio may not be the best remote sensing tool for measuring chlorophyll in case 2 waters.

Studies of the dynamic behaviour of a primary sedimentation tank

This study concerns the dynamic behaviour of a primary sedimentation tank in a municipal WWTP. It is a part of the effort to estimate the varying biological load on the activated sludge stage under different operating conditions. The primary settlers have been investigated with several methods: (i) cross sectional sampling of suspended solids; (ii) tracer tests with lithium-solution; (iii) finite element method (FEM); (iv) flow measurement with a turbine-type sensor; and (v) cross-sectional flow measurement with a cross-bar metering device. The choice of measurement positions, the number of samples and the methods selected for analyses have all been guided by the ambition to avoid erroneous conclusions due to odd single measurement data. The study demonstrates how modern graphical computer methods like Finite Element Method and MATLAB Toolboxes can be used to increase our understanding of the settler.