A camera and image processing system for floc size distributions of suspended particles

Shen, Xiaoteng; Maa, Jerome P.‐Y.

doi:10.1016/j.margeo.2016.03.009

Cited by 45 publications

(38 citation statements)

References 59 publications

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“…For example, the FSDs under different initial NH 4 NO 3 concentrations are modeled using the same α and

{\overset{true¯}{b_{i}}}^{(k)}

(Figure ), with the maximum FSD error E = 0.13 (Table ). It agrees with the observed FSDs in a mixing jar experiment by Shen and Maa () who use the same curve to mimic the FSDs under salinity 0.5, 1.0, 2.0, 3.0, 5.0, and 9.0.…”

Section: Resultssupporting

confidence: 89%

“…On the other hand, experimental FSD data are valuable to validate any flocculation model. To simplify the flocculation environments, clean sediments are often employed in laboratory experiments (such as in the mixing chambers or the settling columns) in a first step to investigate the FSDs under different hydrodynamic conditions (e.g., Keyvani & Strom, ; Shen & Maa, , ; Tran & Strom, ). Both unimodal (e.g., Maggi et al, ) and multimodal (e.g., Van Leussen, ) FSDs are observed in the experiments.…”

Section: Introductionmentioning

confidence: 99%

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An Approach to Modeling Biofilm Growth During the Flocculation of Suspended Cohesive Sediments

et al. 2019

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The floc size distribution (FSD) is crucial to predict cohesive sediment dynamics in aquatic environments. Recently, increasing attention has been given to biofilm effects on the FSDs of suspended particles since the presence of biofilms on particle surfaces may lead to larger flocs and thus higher settling velocities. In this study, results from a settling column experiment conducted by Tang and Maggi (2018; https://doi.org/10.1002/2017JG004165) under nutrient‐free and biomass‐free, nutrient‐affected and biomass‐free, and nutrient‐affected and biomass‐affected conditions, with different suspended sediment concentrations, shear rates, and nutrient concentrations, have been used to validate modeled FSDs that is based on the population balance equation solved by the quadrature method of moments. In addition to the processes of aggregation and breakage, the effects of biofilm are expressed in the growth term of the population balance equation. The logistic growth pattern is used to account for an increase in biomass, which is primarily controlled by the specific growth rate and the carrying capacity. In this study, the biofilm growth rate is assumed nutrient dependent, and the carrying capacity of floc size is hypothesized to be proportional to the Kolmogorov microscale. With eight size classes to interpret a simulated FSD, the predicted and observed FSDs exhibit a reasonable match for all nutrient‐free and biomass‐free, nutrient‐affected and biomass‐free, and nutrient‐affected and biomass‐affected conditions. This simplified bioflocculation model fills the gap between the simulations of the FSDs of cohesive sediments without and with biofilms and has the potential to be included in large‐scale models in the future.

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“…For example, the FSDs under different initial NH 4 NO 3 concentrations are modeled using the same α and

{\overset{true¯}{b_{i}}}^{(k)}

Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

An Approach to Modeling Biofilm Growth During the Flocculation of Suspended Cohesive Sediments

et al. 2019

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“…This is not a simple task, however, because measuring FSD/PSD at high SSCs is difficult, if not impossible. For further lab experiments, the camera system developed by Shen and Maa [1] would be used, but even that is not guarantee for a successful measurement of FSD/PSD at high SSCs, to check the PSD for YRE sediment suspension.…”

Section: Resultsmentioning

confidence: 99%

“…Suspended sediment concentration (SSC) in river, estuary, and coastal waters is an important factor to better understand sediment transport processes, e.g., flocculation [1], settling [2], erosion [3], and deposition. To accurately and efficiently measure SSCs, however, is an important and difficult task.…”

Section: Introductionmentioning

confidence: 99%

Comparisons of Different Instruments for Measuring Suspended Cohesive Sediment Concentrations

Shao

Maa

2017

Water

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Abstract:Laboratory experiments were conducted to compare the performances of four different instruments for measuring suspended cohesive sediment concentrations (SSCs). Among these instruments, two were different models of optical backscatter sensor (i.e., OBS3+ and OBS5+), one was an acoustic Doppler velocimeter (MicroADV), and the last was a laser infrared optical sensor developed at Hohai University, China (HHU-LIOS). Sediments collected from the Yangtze River Estuary and a commercially available kaolinite were selected to check the responses of these four instruments. They were placed in an aqueous solution, and the SSCs were changed within a range from about 10 mg/L to 30 g/L to demonstrate the effective measuring ranges for each instrument. For the kaolinite suspension, the results showed that the HHU-LIOS has a much larger linear response range (0.1 to 13 g/L) when compared with other devices (the MicroADV: 0.1 to 1.35 g/L; the OBS3+: 0.1 to 5 g/L; and the OBS5+: 0.1 to 1 g/L). For the sediment sample from the Yangtze River Estuary, the results showed that the HHU-LIOS has a much wider usable range (from 0.1 to 25 g/L), compared with those for the others. It also showed that a combination of using a HHU-LIOS for the quadratic increasing range up to 25 g/L and the OBS5+ for the clear decreasing output are able to measure the SSCs of the estuarine mud up to 50 g/L.

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“…Image‐based methods are applied to evaluate particle and aggregate characteristics in a variety of fields of study. Applications include particle size and shape analysis of free‐settling flocs , measurement of aggregation rate and particle size in stirred vessels , and in situ measurement in natural waters . The particle size was determined in metallic iron samples and high‐speed image analysis was applied to monitor ceramic pebble formation .…”

Section: Introductionmentioning

confidence: 99%

Analysis of In Situ Microscopy Images of Flocculated Sediment Volumes

MacIver

Pawlik

2017

Chem Eng & Technol

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An in situ microscopy method was employed to study the sediment volumes that result from batch settling of polymer‐flocculated kaolin suspensions. Statistical methods were applied including chord length distributions, perimeter‐based fractal dimension of the void areas, white area image ratio, and gray level co‐occurrence (GLCM) features. Several GLCM features have a good linear relationship with aggregation state, and the parameters of aggregate and void chord distributions can be interpreted to help explain the flocculation results. The methods applied here are suggested for the measurement of the aggregation state or relative aggregate volume on bench or industrial scale when the settled suspension interface is not available, such as in a continuous process or reaction.

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A camera and image processing system for floc size distributions of suspended particles

Cited by 45 publications

References 59 publications

An Approach to Modeling Biofilm Growth During the Flocculation of Suspended Cohesive Sediments

An Approach to Modeling Biofilm Growth During the Flocculation of Suspended Cohesive Sediments

Comparisons of Different Instruments for Measuring Suspended Cohesive Sediment Concentrations

Analysis of In Situ Microscopy Images of Flocculated Sediment Volumes

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