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Microplastics (MPs, size ≤ 5 mm) have emerged as a significant worldwide concern, threatening marine and freshwater ecosystems, and the lack of MP detection technologies is notable. The main goal of this research is the development of a camera sensor for the detection of MPs and measuring their size and velocity while in motion. This study introduces a novel methodology involving computer vision and artificial intelligence (AI) for the detection of MPs. Three different camera systems, including fixed-focus 2D and autofocus (2D and 3D), were implemented and compared. A YOLOv5-based object detection model was used to detect MPs in the captured image. DeepSORT was then implemented for tracking MPs through consecutive images. In real-time testing in a laboratory flume setting, the precision in MP counting was found to be 97%, and during field testing in a local river, the precision was 96%. This study provides foundational insights into utilizing AI for detecting MPs in different environmental settings, contributing to more effective efforts and strategies for managing and mitigating MP pollution. [ABSTRACT FROM AUTHOR]

Trajectory ensemble receptor models (TERMs) were widely used to determine the likely source locations and apportionment of air pollutants. This paper describes the development and applications of the Trajectory-ensemble Potential Source Apportionment Web application (TraPSA-Web), a comprehensive toolkit for likely atmospheric pollutant source location apportionments using TERMs and back trajectories generated with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The TERMs integrated within the TraPSA-web include Concentration Field Analysis (CFA), Concentration Weighted Trajectory (CWT), single-site and multiple-site Potential Source Contribution Function (PSCF), and Simplified Quantitative Transport Bias Analysis (SQBA). TraPSA-Web is designed as a web application with a user-friendly modern graphical user interface (GUI), which largely enhances the accessibility to the users. TraPSA-Web will provide the air quality research community with a sophisticated toolkit for (1) easy management of the research project and datasets, (2) efficient automatization for HYSPLIT configurations, calculations, and result aggregations, (3) flexible configurations for the research scenarios and TERM parameters, and (4) interactive visualizations for the pollutant pattern analysis and TERM result mapping. [ABSTRACT FROM AUTHOR]

The accumulation of significant amounts of investigation‐derived waste (IDW) from investigations of per‐ and polyfluoroalkyl substances (PFAS) contamination at active and former military installations has generated the need for viable disposal methods, which are currently limited to incineration or landfilling. Soil washing has been proposed as a more environmentally friendly alternative method to remove PFAS sorbed to IDW media, potentially allowing more cost‐effective disposal of the media as nonhazardous waste. This systematic investigation of IDW washing explored the effect of water‐, methanol‐, and salt‐based solutions, which are typically used for ion exchange (IX) resin regeneration. These solutions were tested for PFAS removal using four different field IDW solids with different pHs, total organic carbon content, and anion exchange capacity. In long washes extending to a week, distilled water was found to be effective in the removal of short‐chain PFASs (perfluorcarboxylic acids with fewer than seven fluorinated carbon atoms and perfluorosulfonic acids with fewer than six fluorinated carbon atoms) and some long‐chain PFASs including perfluorooctanoic acid, but not perfluorooctane sulfonic acid (PFOS). PFOS was only removed using water:methanol solutions with salt. Optimized 30‐min washes containing water:methanol and salt effectively removed precursors, and short‐ and long‐chain PFAS. Kinetic, soil extraction, and leaching experiments revealed that PFAS can be removed within a matter of minutes, with greater than 70% PFAS removal on the first wash; however, longer‐chain PFASs required up to three washes to be removed. Important IDW wash solution relationships influencing PFAS desorption are discussed and PFOS is proposed as an indicator species for IDW washing effectiveness. Results demonstrate that adapting components of IX regeneration solutions to IDW wash solutions facilitates an alternative means to separate PFAS contaminants from IDW, advancing PFAS remediation efforts. [ABSTRACT FROM AUTHOR]

The influence of solution electrical conductivity and ion composition on the performance of plasma reactors for water treatment applications is only partially understood. This study uses a point–point discharge over the surface of water in argon gas to determine the influence of solution conductivity, in the range of 0.3–45 mS/cm, on the physiochemical properties of spark discharges and the removal of two organic contaminants: perfluorooctanoic acid (PFOA) and Rhodamine B dye. The influence of various ions was also explored using chlorine and non-chlorine salts to adjust solution conductivity. The removal of PFOA increased with conductivity regardless of the salt type due to the salting out effect which increased PFOA's interfacial concentration. The removal of Rhodamine B dye depended on both salt type and solution electrical conductivity. In the presence of non-chorine salts, UV photolysis was the main mechanism for the dye degradation and its removal rate did not change with conductivity. The dye removal rate was the highest in the presence of chloride-based salts at the highest values of solution conductivities. In the presence of chorine salts, OH radicals are produced by the discharge generated hypochlorous acid, which is mixed into the bulk solution to react with the Rhodamine B dye. The generation rate of hydroxyl radicals appears to decrease with increasing solution conductivity, and these species are not directly involved in the degradation of the two compounds investigated in this study. [ABSTRACT FROM AUTHOR]

To provide insights into the design, optimization, and scale up of plasma reactors for water treatment, the influences of discharge energy, grounded electrode size and position, and number of high voltage (HV) discharge points on the production of reactive species and the degradation of 1,4‐dioxane and perfluorooctanoic acid in a gas–liquid electrical discharge plasma reactor were assessed. Discharge energy and plasma area largely control the treatment effectiveness. Increasing the number of discharge points lowers the voltage in the reactor and consequently the production rates of reactive species. Bench‐scale findings apply directly to large volume systems, resulting in the highest contaminant removal rates using a single HV electrode and a grounded electrode spanning the entirety of the treatment zone. [ABSTRACT FROM AUTHOR]

In this project the use of natural media filtration (NMF) was evaluated for its ability to remove colloidal particles from the aqueous phase as a function of ionic strength and filter media type by determining first-order kinetic deposition rate coefficients. Mushroom compost (MC) and leaf compost (LC) were tested as natural filter media and the results were compared to those obtained using sand and granular activated carbon (GAC). The highest deposition rate coefficients were observed for GAC, followed by LC and MC, and the lowest deposition rate coefficients were found for sand. As predicted by the Derjaguin--Landau--Verwey--Overbeek theory, higher deposition rates were obtained at higher solution ionic strengths. Overall the experiments suggest that the NMF process can efficiently remove colloidal particles from surface waters. DOI: 10.1061/(ASCE)0733-9372(2009) 135:7(544) CE Database subject headings: Colloids; Particles; Deposition; Porous media; Filtration.

In this project, the ability of natural media filtration (NMF) to remove colloidal particles and associated hydrophobic organic compounds from the aqueous phase was evaluated by performing sorption and transport experiments with leaf compost media. Phenanthrene sorption isotherm experiments for compost and model colloidal (latex) particles found that phenanthrene has a greater affinity for the colloidal particles than for the compost materials. In column experiments, the transport of phenanthrene through the NMF in the presence and absence of two colloidal particles with different hydrophobicities [sulfate (more hydrophobic) and carboxylate (less hydrophobic)] showed that the effluent phenanthrene concentration in the presence of colloids, particularly sulfate latex particles, is much higher than that in the absence of colloids. The results from a mathematical model used to evaluate data from the column experiments suggest that enhancement of contaminant transport can be significant under the following conditions: high colloidal concentrations, high partition coefficient between contaminant and colloids, or a slow desorption rate of contaminant from colloids. DOI: 10.1061/(ASCE)0733-9372(2009) 135:1 (36) CE Database subject headings: Filtration; Colloids; Organic compounds; Particles; Abatement and removal.

Current ex situ per‐ and polyfluoroalkyl substances (PFAS) remediation strategies often involve the treatment of large volumes of PFAS‐impacted water via separation processes to concentrate PFAS for subsequent treatment or disposal. This study presents a new method for concentrating PFAS that relies on colloidal gas aphrons (CGAs), unusual microstructures composed of water, multilayers of surfactants, and air, that can be used for separation via electrostatic and hydrophobic sorption. This study successfully demonstrates the efficacy of CGAs in removing ionic dyes (as PFAS surrogates) (81%–91%), as well as ultra‐short and short‐chain PFAS (60%–90%) and perfluorooctanoic acid (PFOA, 88%) within 10 min. However, poor removal of perfluorooctane sulfonic acid (PFOS, 0%) was observed within 10 min of treatment. Compared to bubbling with nitrogen alone, and nitrogen with cetrimonium bromide (CTAB) in bulk solution, CGAs demonstrate significantly higher removal of perfluorobutanoic acid, a short‐chain PFAS (0% for N2, 11% for N2 + CTAB, and 90% for CGAs). These results suggest that CGAs may serve as a promising new separation and concentration technology for removing a suite of PFAS from water, particularly for difficult to remove short‐chained compounds. [ABSTRACT FROM AUTHOR]