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In order to design an economical and reliable LiDAR, it is necessary to quantify the influence of different factors on the attenuation of laser propagation in water. Although these factors have been widely investigated, a complete understanding is still few. In addition, a comparative analysis between the measured data and the simulation results of LiDAR to build the design of LiDAR is still lacking. For these reasons, a semi-analytical Monte Carlo method was applied to establish a simulation model of the underwater laser echo signal propagation. The control variable method was quantified with the three major types of influencing factors: 1) LiDAR system parameters, 2) water optical characteristics and 3) external conditions. The effects of these different influencing factors on laser underwater echo signal transmission were investigated. With the experimental results, the attenuation rate of laser transmission in turbid harbour was 7.1 and 19.2 times higher than that in coastal water and clean ocean. Compared with other influencing factors, the optical characteristics of water have the most significant influence on underwater laser transmission. The laser echo signals in water with different concentrations of suspended solids were investigated in a laboratory tank using a LiDAR prototype developed by our research group. The results were compared with that from the semi-analytical Monte Carlo simulation to further explore the influence of the inherent optical characteristics of water on laser energy attenuation. The experimental results showed that with increasing water turbidity, the light beam diverged by strong scattering, the size of the light spot increased, the energy of the echo signal decreased as a whole and the backscattering signal of the water changed significantly. The determination coefficients and relative errors of the measured echo signals and the normalized simulation results were 0.99 and 0.01, respectively, which demonstrate the reliability of LiDAR prototype. [ABSTRACT FROM AUTHOR]

Net cage aquaculture has a significant impact on the regional water environment, and studying the changes in water quality parameters in net cage aquaculture areas is of great practical significance for understanding the impact of regional aquaculture on the water environment. This article uses GF-1WFV data to construct an inversion model for the total suspended solids concentration in the net cage aquaculture area, which has grown exponentially in the Manwan Reservoir area in recent years. The results indicate that the model has high accuracy, with an average relative error of 9.65% between the inverted values and the measured values, and a root mean square error of 0.33mg/L. Based on the constructed inversion model and satellite imagery, the total suspended solids concentration in the Manwan net cage aquaculture area was inverted, and the variation patterns of total suspended solids concentration in the reservoir area and different net box positions were analyzed. Research has found that the variation pattern of suspended solids concentration in the Manwan reservoir area and different positions of net cages is basically consistent. The total suspended solids concentration in net cages has not shown any abnormalities due to the phenomenon of local "delineation" in aquaculture, but is lower than the overall suspended solids concentration in the reservoir area. This is mainly because the variation of total suspended solids concentration is mainly affected by precipitation, surface runoff, water flow velocity, etc. Net cage aquaculture can reduce its impact on the total suspended solids concentration in local "delineation" areas. This study has certain reference significance for understanding the changes in total suspended solids concentration in the Manwan reservoir area and net cage aquaculture area. In the future, a multi-source remote sensing data remote sensing estimation model for water quality parameters will be developed for understanding the changing patterns in water environment in the Manwan net cage aquaculture area. [ABSTRACT FROM AUTHOR]

Hydrobiogeochemical processes governing water quantity and quality are highly variable in space and time. Focusing on thirty river locations in Québec, Canada, three water quality hotness indices were used to classify watersheds as contaminant transport hotspots. Concentration and load data for suspended solids (SS), total nitrogen (TN), and total phosphorous (TP) were used to identify transport hotspots, and results were compared across hotness indices with different data requirements. The role of hydroclimatic and physiographic characteristics on the occurrence and temporal persistence of transport hotspots was examined. Results show that the identification of transport hotspots was dependent on both the type of data and the hotness index used. Relationships between temporal and spatial predictors, however, were generally consistent. Annual transport hotspot occurrence was found to be related to temporal characteristics such as the number of dry days, potential evapotranspiration, and snow water equivalent, while hotspot temporal persistence was correlated to landcover characteristics. Stark differences in the identification of SS, TN, and TP transport hotspots were attributed to differences in mobilization processes and provided insights into dominant water and nutrient flowpaths in the studied watersheds. This study highlighted the importance of comparing contaminant dynamics across watersheds even when high-frequency water quality data or discharge data are not available. Characterizing hotspot occurrence and persistence, among hotness indices and water quality parameters, could be useful for watershed managers when identifying problematic watersheds, exploring legacy effects, and establishing a prioritization framework for areas that would benefit from enhanced routine monitoring or targeted mitigation strategies. [ABSTRACT FROM AUTHOR]

The microbial fuel cell (MFC) is considered a modern technology used for treating wastewater and recovering electrical energy. In this study, a new dual technology combining MFC and a specialized biofilter was used. The anodic materials in the system were crushed graphite, either without coating (UFB-MFC) or coated with nanomaterials (nano-UFB-MFC). This biofilter served as a barrier to retain and remove turbidity and suspended solids, while also facilitating the role of bacteria in the removal of organic pollutants, phosphates, nitrates, sulfates, oil and greases. The results demonstrated that both systems exhibited high efficiency in treating kitchen wastewater, specifically greywater and dishwashing wastewater with high detergent concentrations. The removal efficiencies of COD, oil and grease, suspended solids, turbidity, nitrates, sulfates, and phosphates in first UFB-MFC were found to be 88, 95, 89, 86, 87, 75, and 94%, respectively, and in Nano-UFB-MFC were 86, 99, 95, 91, 81, 88, and 95%, respectively, with a high efficiency in recovering bioenergy reaching a value of 1.8 and 1.5 A m−3, respectively. The results of this study demonstrate the potential for developing MFC and utilizing it as a domestic system to mitigate pollution risks before discharging wastewater into the sewer network. [ABSTRACT FROM AUTHOR]

Vibrio spp. is a group of heterotrophic bacteria that are ubiquitous in marine habitats, with various ecological and clinical importance. This study investigated the environmental factors that regulate Vibrio spp. dynamics in various tropical marine habitats, including nearshore (an estuary and a coastal beach) and offshore transects located northwest and southeast of Peninsular Malaysia, while focusing on the distribution of attached and free-living Vibrio spp., population growth, and community composition. The results showed that > 85% of the Vibrio spp. in nearshore waters occurred in attached form and correlated positively to total suspended solids (TSS) and Chlorophyll a (Chl a) concentrations. On the other hand, Vibrio spp. growth rates were positively correlated to dissolved organic carbon (DOC) concentrations, but negatively correlated to total bacterial counts, likely due to resource competition. In addition, high-throughput sequencing of 16S rRNA V3-V4 region showed that Vibrio spp. in these tropical waters contributed < 1 − 18% of the whole bacterioplankton community, and the six major Vibrio spp. taxa were V. alginolyticus group, V. brasiliensis, V. caribbeanicus, V. hepatarius group, V. splendidus group and V. thalassae. db-RDA (cumulative variance explicated = 93.53%) further revealed the influence of TSS, DOC, and dissolved organic nitrogen (DON) to the Vibrio spp. community profiles. The study highlighted the importance of suspended solids (TSS and Chl a) and dissolved organic nutrients (DOC and DON) towards Vibrio spp. dynamics in tropical marine waters. [ABSTRACT FROM AUTHOR]

Recently, water has become a resource that generates controversy due to shortage alarms and high consumption by production companies. Making good use of water has become the main objective of government institutions. The food industry generates a large amount of wastewater, concentrating the largest number of contaminants originated in its processes. Wastewater from the food industry is characterized by having a large amount of organic matter, especially fats and oils, as well as suspended solids. The objective of this research is to carry out a characterization of effluents generated in a wastewater treatment plant in the food sector based on Mexican and international regulations to determine whether it is reusable. This article addresses Mexico's lag in the reuse of treated wastewater in the face of the water crisis, highlighting the urgency of adopting these practices to mitigate water scarcity. For the development of this investigation, samples were collected at the discharge point produced by the company's effluents, followed by an evaluation of their physical, chemical, and biological parameters, and finally, it was determined that the effluent follows the regulatory standards for discharge into the city sewer but outside the range for reuse in productive processes or irrigation of green areas. [ABSTRACT FROM AUTHOR]

Calcium-nitrate-based transparent completion fluids are widely used in the oil and gas industry for well completion and stimulation operations in carbonate reservoirs. These fluids have many advantages, such as medium density, low corrosion, good temperature stability, low clay swelling, and high wettability. However, the density of calcium nitrate brine is limited by its solubility, which can be increased by the addition of alcohols. This study investigated the effects of adding different types of alcohols (G1, G2, and G3) to calcium nitrate brine on the properties and performance of the completion fluid for carbonate reservoirs. The fluid properties and performance were evaluated through a series of laboratory tests, including density measurement, corrosion test, viscosity measurement, rheology test, temperature stability test, clay swelling test, wettability test, and compatibility test. The results showed that the addition of alcohols to brine can improve or reduce the fluid density, viscosity, corrosion, temperature stability, clay swelling, wettability, and compatibility, depending on the type and amount of alcohols. The optimum fluids have been selected based on their highest density, lowest viscosity, lowest corrosion, highest temperature stability, lowest clay swelling, highest wettability change, and highest compatibility with formation fluids. The densities of the fluids CN4, CNG14, CNG24, and CNG34 were respectively 96, 101, 101.5, and 100 pounds per cubic foot (pcf). Their rates of corrosion on L80 steel were respectively 0.829, 0.589, 0.720, and 0.599 mils per year (mpy). Their apparent viscosities at 62.4 °F were respectively around 15, 120, 100, and 60 centipoise (cp). Their apparent viscosities at 176 °F were all around 10 to 25 mpy. The fluids remained clear with no evidence of suspended solid particles at 20 °F, indicating their resilience to low-temperature conditions and suitability for use in cold weather operations. The fluid CNG24 becomes cloudy at 285 °F, and the fluid CNG34 becomes cloudy from 212 °F onward, but the CN4 fluid remains clear and transparent at all temperatures. In the tested high temperatures, the effect on their pH was around the same. The fluids CN4, CNG24, and CNG34 had a lower swelling index than 5 ml per 2 g of bentonite clay. The contact angles of oil and carbonate-type thin sections after their wettabilities were affected by the fluids were also 99.5, 36.54, and 46.03°, respectively. Finally, they're all relatively compatible with formation fluids. The best completion fluid for carbonate reservoirs was CNG24, which contained calcium nitrate and G2 alcohol. This fluid had the best overall performance and safety of the fluids tested. [ABSTRACT FROM AUTHOR]

Livestock wastewater (LWW) has a complex characteristic of high organic matter content, metals, nutrients, and pharmaceutical compounds. Advanced oxidation processes (AOP) are a potential option for treating this wastewater. This study evaluated real LWW and the performance of UV/H2O2 and UV/peroxymonosulfate (UV/PMS) for its treatment. The experiments were conducted in a UV photoreactor (16 mW/m2, λ = 254 nm). The oxidant agents (Ox) tested were H2O2 and PMS, each at low, medium, and high TOC/Ox molar ratios. A pretreatment based on chemical precipitation was implemented. Annually, the LWW showed total organic carbon (TOC) values of 859 ± 13.37 mg/L, 168.85 ± 1.62 mg/L of total Kjeldahl nitrogen (TKN), and toxicity of 96% v/v. In the dry season, albendazole (ABZ) (95.3 ± 35.16 mg/L), Cu (4.3 ± 0.23 mg/L), Fe (3.8 ± 0.38 mg/L), and suspended solids (SS) (1015 ± 586.9 mg/L) were identified, so pretreatment was implemented. The UV/PMS process with the lowest molar ratio [TOC/Ox 1:0.75] removed significantly lower TOC concentrations (p < 0.05), but toxicity decreased entirely. The study of mineralization and toxicity provided insight into the changes in LWW during treatment with AOP. Furthermore, it contributed to establishing the technical basis for implementing efficient treatment processes. [ABSTRACT FROM AUTHOR]

When an artificial structure is built in a river, the river changes significantly in water quality and hydraulic properties. In this study, the effects of the weirs constructed in the middle section of a river as a four major rivers restoration project in Korea on water quality and hydrological characteristics were analyzed. For multi‐dimensional data analysis, a self‐organizing map was applied, and statistical techniques including analysis of variation were used. As a result of analysis, the cross‐sectional area of the river increased significantly after the construction of the weir compared to before the construction of the weir, and the flow velocity decreased at a statistically significant level. In the case of water quality, nitrogen, phosphorus, and suspended solids tended to improve after weir construction, and chlorophyll‐a and bacteria tended to deteriorate. Some water quality parameters such as chlorophyll‐a were also affected by seasonal influences. In order to improve the water quality deteriorated by the construction of the weir, it is necessary to consider how to improve the flow velocity of the river through partial opening or operation of the weir. In addition, in order to determine the effect of sedimentation of particulate matter due to the decrease in flow rate, it is necessary to conduct investigations on sediments around weirs in the future. Practitioner Points: Compared to before the construction of the weir, there was no significant change in the flow rate of the river after the construction of the weir.In the case of chlorophyll‐a and bacteria, the water quality was deteriorated after weir construction.To improve the deteriorated water quality, it is required to consider the fundamental management of each pollutant source and the flexible operation of both weirs.For some improved water quality parameters, further research is needed to determine whether these improvements are directly attributable to the construction of a weir. [ABSTRACT FROM AUTHOR]

This study investigates the potential impacts of future climate change on river water quality in Ardak Watershed, Northeast Iran, and proposes adaptation strategies to mitigate adverse effects. The SWAT model is calibrated and verified by Monthly water quality sampling and flow measurements. The premium SWAT-CUP model was utilized for sensitivity analysis and parameter adjustment to simulate runoff, sediment, nitrate, mineral phosphorus, and dissolved oxygen. Future catchment temperature and precipitation were projected using CMhyd statistical downscaling by incorporating four CMIP6 models under SSP scenarios for the near (2025–2049), intermediate (2050–2074), and far (2075–2099) future. The Mianmorgh River experienced increased levels of various pollutants in winter, summer, and autumn but decreased in spring for future periods. In the Abghad River, pollutant levels are expected to increase from late autumn to late winter and decrease in other months. Nitrate increased from the late summer to late winter, then decreased throughout the year. Three adaptation strategies were proposed: reducing rural swage pollutants, creating pasture on 5% of unvegetated land, and combining both. The SWAT model showed responsiveness to the mix scenario, with average reductions of 4—4.5% for suspended solids, 23—16% for inorganic phosphorus, and 16—20% for nitrate for the first strategy. The results revealed that climate change can significantly affect water quality, but its adverse effects can be mitigated with suitable actions. Combined adaptation strategies effectively reduced suspended solids and mineral phosphorus and removed pollutants. Therefore, implementing a combination of effective strategies is more beneficial than individual approaches. [ABSTRACT FROM AUTHOR]

Sand media filters are especially recommended to prevent emitter clogging with loaded irrigation waters, but their performances rely on backwashing. Despite backwashing being a basic procedure needed to restore the initial filtration capacity, there is a lack of information about the solid removal efficiency along the media bed depth. An experimental filter with a 200 mm silica sand bed height was used to assess the effect of two operation velocities (30/45 and 60/75 (filtration/backwashing) m h−1) and two clogging particles (inorganic sand dust and organic from a reclaimed effluent) on the efficiency of backwashing for removing the total suspended solids retained in different media bed slices. The average solid removal backwashing efficiency was greater with organic particles (78%) than with inorganic ones (64%), reaching its maximum at a 5–15 mm bed depth. A higher operation velocity increased the solid removal efficiency by 16%, using organic particles, but no significant differences were observed with inorganic particles. The removal efficiencies across the media bed were more uniform with organic particles (63–89%) than with inorganic (40–85%), which makes it not advisable to reduce the media height when reclaimed effluents are used. This study may contribute to future improvements in sand media filter design and management. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) and microalgae–bacteria consortia represent two renewable and promising technologies of growing interest that enable wastewater treatment while obtaining high-value-added products. This study integrates MFCs and microalgae production systems to treat animal slurry, aiming to remove and recover organic and inorganic components while generating energy and producing biomass. The MFCs effectively eliminated Chemical Oxygen Demand (COD), organic nitrogen, and a portion of the suspended solids, achieving a maximum voltage of 195 mV and a power density of 87.03 mW·m−2. After pre-treatment with MFCs, the slurry was diluted to concentrations of 10%, 50%, and 100% and treated with microalgae–bacteria consortia. The results showed a biomass production of 0.51 g·L−1 and a productivity of 0.04 g·L−1·day−1 in the culture fed with 10% slurry, with significant removal efficiencies: 40.71% for COD, 97.76% for N-NH4+, 39.66% for N-NO2−, 47.37% for N-NO3−, and 94.37% for P-PO4−3. The combination of both technologies allowed for obtaining a properly purified slurry and the recovery of nutrients in the form of bioelectricity and high-value biomass. Increasing the concentration of animal slurry to be treated is essential to optimize and scale both technologies. [ABSTRACT FROM AUTHOR]

Dams and artificial reservoirs can significantly alter the dynamics of sediment transport in a watercourse. Therefore, the main objective of this study is to assess the influence of the Pandeiros Small Hydroelectric Plant reservoir on sediment transport in the Pandeiros River. The study also aims to characterize the sediment composition and assess the correlation between total and suspended solids with turbidity, flow, and precipitation variables. The study was carried out in the Pandeiros River basin, Brazil, between May 2019 and January 2023. The following variables were analyzed: flow, turbidity, precipitation, total solids (fixed and volatile), and suspended solids (fixed and volatile). The results showed that, under the conditions observed during the study, the reservoir did not affect the concentration and composition of the sediments. It was found that the solids transported by the Pandeiros River are mostly composed of inorganic material. A positive correlation was observed between the variables, which was stronger when correlated with suspended solids. The correlation analysis indicated that precipitation is one of the main factors related to sediment transport in the Pandeiros River. In conclusion, the reservoir did not significantly affect the sediment concentration in the Pandeiros River. Highlights: The Pandeiros Small Hydroelectric Plant Reservoir did not affect sediment transport. Solids are mostly composed of inorganic material. The reservoir did not significantly influence the sediment concentration and composition. Precipitation was one of the main factors associated with sediment transport. [ABSTRACT FROM AUTHOR]

Improper disposal of municipal solid waste led to the release of heavy metals into the environment through leachate accumulation, causing a range of health and environmental problems. Phycoremediation, using microalgae to remove heavy metals from contaminated water, was investigated as a promising alternative to traditional remediation methods. This study explored the potential of Scenedesmus sp. as a phycoremediation agent for heavy metal removal from landfill leachate. The study was conducted in batch, continuous, and membrane bioreactor (MBR). In the batch system, Scenedesmus sp. was added to the leachate and incubated for 15 days before the biomass was separated from the suspension. In the continuous system, Scenedesmus sp. was cultured in a flow-through system, and the leachate was continuously fed into the system with flow rates measured at 120, 150, and 180 mL/h for 27 days. The MBR system was similar to the continuous system, but it incorporated a membrane filtration step to remove suspended solids from the treated water. The peristaltic pump was calibrated to operate at five different flow rates: 0.24 L/h, 0.30 L/h, 0.36 L/h, 0.42 L/h, and 0.48 L/h for the MBR system and ran for 24 h. The results showed that Scenedesmus sp. was effective in removing heavy metals such as lead (Pb), cobalt (Co), chromium (Cr), nickel (Ni), and zinc (Zn) from landfill leachate in all three systems. The highest removal efficiency was observed for Ni, with a removal of 0.083 mg/L in the MBR and 0.068 mg/L in batch mode. The lowest removal efficiency was observed for Zn, with a removal of 0.032 mg/L in the MBR, 0.027 mg/L in continuous mode, and 0.022 mg/L in batch mode. The findings depicted that the adsorption capacity varied among the studied metal ions, with the highest capacity observed for Ni (II) and the lowest for Zn (II), reflecting differences in metal speciation, surface charge interactions, and affinity for the adsorbent material. These factors influenced the adsorption process and resulted in varying adsorption capacities for different metal ions. The study also evaluated the biomass growth of Scenedesmus sp. and found that it was significantly influenced by the initial metal concentration in the leachate. The results of this study suggest that Scenedesmus sp. can be used as an effective phycoremediation agent for removing heavy metals from landfill leachate. [ABSTRACT FROM AUTHOR]

Objective The flocculent suspended matter in fluid catalytic cracking (FCC) diesel oil from a refinery of CNOOC was separated and analyzed. Its composition, source and possible solution were deduced. Methods A scheme for separating flocculent suspended solids from an oil-water mixture was developed and characterized by Fourier transform ion cyclotron resonance mass spectrometry and Fourier transform ion cyclotron resonance spectrometry. Results The results show that flocculent suspended matter are mainly organic compounds and can be flocculated in a hydrochloric acid environment. The main body of the suspended matter is nitrogen-containing compounds about C40-C55 determined by mass spectrometry, and it shows obvious artificial synthesis characteristics. Conclusions The flocculent suspension is the compound inhibitor of amines and amides or the residue of many kinds of inhibitors. This separation and analysis method can also be used for composition analysis of similar samples, which is helpful for refineries to investigate the causes of similar faults. [ABSTRACT FROM AUTHOR]

Estuaries are one of the most productive ecosystems in the world, supporting a variety of flora and fauna. Primary productivity by phytoplankton is a rich source of organic carbon, substantial for the aquatic food web. Monitoring phytoplankton (i.e., chlorophyll-a) is essential to assess the health of estuaries and other continental shelves subjected to constant anthropogenic stress (e.g., developmental activities). In this study, a three-endmember combination Spectral Decomposition Algorithm (SDA) was developed to estimate the phytoplankton in the micro-tidal Yura estuary of Japan using Landsat-8 (30 m), and Sentinel − 2A (10 m). The endmember water, phytoplankton, and submerged aquatic vegetation (SAV) yielded the best results with both the satellite sensors (R2 > 0.80) owing to the limited influence of non-phytoplankton suspended solids (NPSS) in the estuary. Chlorophyll-a was used as the proxy for phytoplankton. The estimated root mean square error (RMSE) was relatively higher in Landsat-8 (RMSE = 0.187 µg/L) than the Sentinel-2A (RMSE = 0.162 µg/L). The results were validated using the ground truth data of the Yura Estuary (26 sampling points). Furthermore, the results indicate low chlorophyll-a concentration in the Yura estuary (< 2µg/L) except near the shorelines (~ 6 µg/L). A good fit (R2 = 0.79) between observed chlorophyll-a and turbidity indicated phytoplankton-dominated turbidity in the tide-less estuary of Japan. The estimated maximum turbidity was 1.4 FTU using both sensors, suggesting a low anthropogenic influence on the Yura Estuary. The study demonstrates a successful application of the spectral decomposition algorithm (SDA) in the coastal waters which could further be used to assess the horizontal and temporal variability in phytoplankton in estuarine water. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are being increasingly measured in water and wastewater due to emerging toxicity concerns and strict regulatory limits. Previous studies have filtered water samples to remove suspended solids before PFAS analysis. However, filtration may introduce negative bias to measured PFAS concentrations. Using a well-controlled syringe pump assembly, we evaluated retention of six perfluoroalkyl carboxylates, three perfluoroalkyl sulfonates, one fluorotelomer sulfonate, and two perfluorooctane sulfonamides by glass-fiber, glass-fiber cellulose acetate, nylon, polyethersulfone, polypropylene, polyvinylidene fluoride/ difluoride, and surfactant-free cellulose acetate filters. The impacts of water quality and operational parameters were also investigated for select filter types. We found that PFAS were retained on all filters, with the glass-fiber cellulose acetate filters demonstrating the lowest retention. For all filters, PFAS retention was linearly related to chain length and hydrophobicity above certain thresholds (i.e., log D higher than 1.5). Importantly, more PFAS were retained at low filtrate volumes, and ~ 30 mL filtrate was required before the retention efficiencies stabilized. Solution pH only affected the retention of perfluorooctane sulfonamides. Pore size (i.e., 0.20, 0.45, 0.70 µm), filtration rate (i.e., 0.5, 1.0 mL min−1), and PFAS concentration (i.e., 10, 100 µg L−1), did not exert major influences on PFAS retention. The presence of dissolved organic matter improved PFAS permeation. Based on the reported results, filtration introduces bias and is not recommended for sample pretreatment. [ABSTRACT FROM AUTHOR]

The present investigation studied the spatial and temporal variation in physicochemical parameters and ciliate community structure at three freshwater sites in Delhi, India. Samples were collected from three freshwater sites, Okhla Bird Sanctuary (OBS), Sanjay Lake (SL) and Raj Ghat (RJ) in alternate months over 1 year, from September 2018 to August 2019. The water at the OBS site exhibited the lowest pH and electrical conductivity, along with the highest concentration of ammonium. The water at RJ was higher in suspended solids, electrical conductivity, and pH than the other two sites. Ciliates belonging to classes Spirotrichea, Oligohymenophorea, and Prostomatea were dominant in these freshwater samples. Maximum ciliate diversity, richness and evenness were observed in the OBS site. The highest diversity was observed during the monsoon and post-monsoon seasons, whilst the lowest was during the winter and summer season. [ABSTRACT FROM AUTHOR]

In this paper, we present a mathematical model and numerical simulation for the evaporation and drying of a liquid droplet containing suspended solids, relevant to processes such as spray drying and spray pyrolysis in the food and pharmaceutical industries. The model comprises three stages: first is the evaporation of the liquid droplet consisting of solid particles, followed by the second stage starting with the formation of a porous crust around a wet-core region and, finally, the third stage with sensible heating of the dry particle. Using a finite difference method with a moving grid, we account for the moving interface between the crust and wet core. Our model incorporates spatial temperature variations and is validated against experimental data on colloidal silica droplet drying, showing good agreement. We examine model assumptions and analyze the impact of drying conditions on drying rate and final particle morphology. Along with the temperature and velocity of the drying gas, we also find that the shape of suspended solid particles inside the droplet and assuming continuum flow of vapor through the crust influence drying quality. Finally, we develop a regime map to predict whether the final particle will be solid or hollow based on operating conditions. [ABSTRACT FROM AUTHOR]

Over the past few decades, climate warming has driven alterations in both the discharge volume and biogeochemical composition of Arctic riverine fluxes. This study investigated the content of macro- and microelements in the lower reaches of the Ob River (western Siberia). Seasonal sampling was performed over a four-year period (2020–2023) during the main hydrological seasons (winter low water, spring-summer floods, and early fall low water) at three river stations. The results revealed significant seasonal variations in the elemental content of the Ob River water associated with changes in catchment inputs, physical and chemical conditions of the aquatic environment, and the amount and composition of incoming suspended sediment. During high water flow events in the Ob River, the concentration of suspended solids increased substantially. During the winter period when the Ob River was ice-covered, a two- to three-fold rise was observed in the concentration of Na, Mg, Ca, K, Si, and Mn. Having accounted for these seasonal variations in water chemistry, we were able to refine our estimates of elemental export to the Arctic Ocean. Compared to estimates from previous studies, we observed 2.3-fold higher dissolved loads of Mn, and the dissolved loads were higher by 2.1-fold for Zn, 1.6-fold for Fe, and 1.4-fold for Pb. The observed rise in elemental export is likely attributable to a confluence of factors, including permafrost thaw, enhanced water inflow from wetland catchments, and intensifying snowfall leading to increased flood runoff. [ABSTRACT FROM AUTHOR]

• Effect of fine grits (FG)/ fine debris (FD) on activated sludge system was analyzed. • FD caused a lower decline of MLVSS/MLSS ratio than FG at the same concentration. • A model to predict MLVSS/MLSS ratio of the system with FG/FD influent was developed. • MLVSS/MLSS ratio was related to the ISS/SS ratio and deposition ratio of FG and FD. This study embarks on an explorative investigation into the effects of typical concentrations and varying particle sizes of fine grits (FG, the involatile portion of suspended solids) and fine debris (FD, the volatile yet unbiodegradable fraction of suspended solids) within the influent on the mixed liquor volatile suspended solids (MLVSS)/mixed liquor suspended solids (MLSS) ratio of an activated sludge system. Through meticulous experimentation, it was discerned that the addition of FG or FD, the particle size of FG, and the concentration of FD bore no substantial impact on the pollutant removal efficiency (denoted by the removal rate of COD and ammonia nitrogen) under constant operational conditions. However, a notable decrease in the MLVSS/MLSS ratio was observed with a typical FG concentration of 20 mg/L, with smaller FG particle sizes exacerbating this reduction. Additionally, variations in FD concentrations influenced both MLSS and MLVSS/MLSS ratios; a higher FD concentration led to an increased MLSS and a reduced MLVSS/MLSS ratio, indicating FD accumulation in the system. A predictive model for MLVSS/MLSS was constructed based on quality balance calculations, offering a tool for foreseeing the MLVSS/MLSS ratio under stable long-term influent conditions of FG and FD. This model, validated using data from the BXH wastewater treatment plant (WWTP), showcased remarkable accuracy. [ABSTRACT FROM AUTHOR]

The study extended over 60 days to assess the impact of extractive species on improving water quality and enhancing GIFT fish production performance within the FIMTA system. Prior to initiating the experiment, the extraction capacities of both organic and inorganic extractives were assessed. Subsequently, based on these evaluations, GIFT fish were co-cultured with freshwater mussels and aquatic macrophytes as organic and inorganic extractive agents, respectively, within 1000 L FRP tanks. Three treatment combinations were established: GIFT fish with Lemna minor (T1), GIFT fish with Lamellidens marginalis (T2), and GIFT fish with both L. minor and L. marginalis (T3). The control treatment (C) consisted solely of GIFT fish. GIFT fish were stocked at a density of 40 m−2, while L. marginalis at 250 g per tank and L. minor covering 25% of the tank surface. GIFT fish were fed with floating commercial pelleted feed at 4% of body weight (30% CP). The results indicated that among the water quality parameters, chlorophyll a, dissolved solids, and suspended solids showed a reduction in T3. The control group exhibited elevated levels of BOD and COD, whereas the treatment groups showed significantly lower levels. Furthermore, the control group demonstrated increased conductivity levels, while T3 exhibited the lowest levels. In T3, a significant reduction was observed in both POM and POC. Growth variables like SGR and PWG were found to be highest in T3. Regarding enzyme activity, the control group exhibited lower levels of protease, lipase, and amylase, while the highest levels were observed in T3. Physiological enzyme activities such as LDH, MDH, ALP, and ACP were significantly increased (p < 0.05) in the control system, indicating elevated water pollution levels. Meanwhile, bacterial load was found to be very low in the FIMTA system (T3). These findings suggest that the integration of GIFT with L. minor and L. marginalis in the FIMTA system has the potential to enhance water quality and physiological responses, ultimately contributing to higher yields. [ABSTRACT FROM AUTHOR]

The concentration change of fine suspended solids along a sewage pipe can be influenced by different water inflow patterns, which may cause water quality issues and affect the maintenance operation on sediment management. This study was conducted to explore the migration features of fine suspended solids under the influence of the variable inflow in drainage pipes. A three-dimensional numerical model was constructed to represent a more realistic flow condition and the interaction between water flow and suspended solids. Movement characteristics of fine suspended solids under different inflow conditions were numerically investigated based on the Euler–Lagrange method. The variations of the inflow pattern, particle vertical velocity, and concentration were discussed in detail to obtain the migration-deposition characteristics of fine suspended solids in a drainage pipe. The results show that, with the increase of flow velocity in steady inflow condition, the particles gradually diffuse to the bottom and the largest concentration of suspended solids gradually moves downward. For unsteady inflow condition, the flow change would lead to the change of sectional concentration and particle mass flow. The concentration of suspended solid in the front segment of pipe was more susceptible to the variable flow than the posterior segment. The highest particle concentration and mass flow situation can be influenced for the inflow pattern scenario with advanced flow peak, which means that the front section (at least half the length) is the important area where attention is required during sewer protection and pollution control processes. Besides, advanced flow peak of rainfall may cause more pollutants to accumulate in sewers. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effect of bittern coagulant dosage and rapid stirring speed on reducing the concentrations of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and dye absorbance in batik industry wastewater, as well as to identify the optimum coagulant dosage and stirring speed. Wastewater samples were collected from a batik industry in the batik center of Sidoarjo, East Java, Indonesia. Dosage variations of 5%, 10%, 15%, and 20% were tested alongside rapid stirring speeds of 100 rpm, 130 rpm, and 160 rpm. The study was conducted on a laboratory scale using the jar test method. Initial wastewater characteristics showed BOD, COD, TSS, and dye absorbance concentrations of 185.68 ± 29.34 mg/L, 10.091 ± 363.24 mg/L, 2.231.33 ± 155.55 mg/L, and 0.212 ± 0.02, respectively. Statistical analysis using the Pearson correlation test and Two-Way ANOVA revealed that variations in coagulant dosage and stirring speed significantly impacted the reduction percentages of BOD, COD, TSS, and dye absorbance. The optimal coagulant dosage was found to be 5%, and the optimal stirring speed was 100 rpm, with reduction percentages for BOD, COD, TSS, and dye absorbance being 80.32%, 65.86%, 92.35%, and 70.77%, respectively. [ABSTRACT FROM AUTHOR]

This study explores the optimization of iron electrocoagulation for treating laundry greywater, which accounts for up to 38% of domestic greywater. Characterized by high concentrations of surfactants, detergents, and suspended solids, laundry greywater presents complex challenges for treatment processes, posing significant environmental and health risks. Utilizing response surface methodology (RSM), this research developed a second-order polynomial regression model focused on key operational parameters such as the area-to-volume ratio (A/V), current density, electrolysis time, and settling time. Optimal treatment conditions were identified: an A/V ratio of 30 m2/m3, a current density of 10 mA/cm2, an electrolysis duration of 50 min, and a settlement period of 12 h. Under these conditions, exceptional treatment outcomes were achieved, with turbidity removal reaching 94.26% and COD removal at 99.64%. The model exhibited high effectiveness for turbidity removal, with an R2 value of 94.16%, and moderate effectiveness for COD removal, with an R2 value of 75.90%. The interaction between the A/V ratio and electrolysis time particularly underscored their critical role in electrocoagulation system design. Moreover, these results highlight the potential for optimizing electrocoagulation parameters to adapt to daily fluctuations in greywater production and meet specific household reuse needs, such as toilet flushing. This tailored approach aims to maximize contaminant separation and coagulant efficiency, balance energy use and operational costs, and contribute to sustainable water management. [ABSTRACT FROM AUTHOR]

Industrialization and urbanization contribute significantly to environmental pollution, particularly in water bodies. The consequences of this pollution are dire, impacting both the environment and public health. A serious hazard to life on Earth, contaminated water can cause food poisoning, diarrhea, respiratory diseases, and skin ailments, among other health problems. In countries like Bangladesh, where industrial activities, particularly in the garment sector, are prevalent, waste dumping into rivers and canals has reached alarming levels. This has resulted in a drastic decline in water quality, endangering aquatic life and ecosystems. To solve this important issue, we built an innovative real-time water quality monitoring system using the Internet of Things (IoT). Our system operates at three levels, collecting data from different layers of wastewater. Key parameters, including temperature, turbidity, total dissolved solids (TDS), and pH, are continuously monitored to assess water quality. The analysis revealed that wastewater temperature varied between 25 and 37 °C across different sites, with higher temperatures observed in industrial zones, indicating potential thermal pollution. Total dissolved solids (TDS) levels exhibited substantial variations, ranging from 170 to 360 ppm, surpassing standard thresholds and posing a threat to aquatic ecosystems. Turbidity readings ranged from 1.30 to 12.89 NTU, with higher turbidity observed in areas receiving industrial discharge, highlighting the impact of suspended solids on water clarity. pH values exceeded 7.0 across all sites, ranging from 9.5 to 10.32, indicating alkaline wastewater, particularly in regions with dyeing and textile industries. By integrating these specific metrics into our monitoring system, we provide valuable insights into industrial wastewater quality and its environmental implications. These findings underscore the urgent need for real-time monitoring and targeted interventions to address water pollution. Implementing sustainable water management strategies in industrial contexts is critical to protecting public health and preserving ecosystems for future generations. [ABSTRACT FROM AUTHOR]

Biochar is a carbonaceous material with pollutant removal abilities due to its characteristics, such as high surface areas resulting from small and large pores for adsorption. Biochar can be incorporated into best management practices (BMPs) as a performance-enhancing device (PED), treating pollutants such as nutrients, heavy metals, and suspended solids in highway stormwater runoff. In this study, three (3) commercial biochar products were purchased from different manufacturers and studied. In the end, the effective one was selected based on its ability to remove pollutants from highway stormwater runoff. A batch experimental setup was utilized for each biochar product and highway stormwater runoff pollutant parameter tested. Three (3) major analyses [chemical oxygen demand (COD), color, and total dissolved solids (TDS)] were selected to represent the biochar's ability to remove oxidizable pollutants, color, and ions such as sodium (Na+), magnesium (Mg2+) and chloride (Cl−) ions from the sampled highway stormwater runoff. Among the three (3) biochars studied, the Soil Reef Biochar showed relatively high and consistent removal of COD (82%), color (66%), and TDS (28%) from the highway stormwater runoff compared to the Wakefield Biochar and the Biochar Supreme products and therefore was selected as the effective one for further studies. The pH of the highway stormwater runoff treated with the three (3) biochar products was in the low basic range (7.95 to 9.01). The Wakefield Biochar showed a conductivity of 92.3 μs/cm compared to the Soil Reef Biochar and the Biochar Supreme at 156 and 160 μs/cm , respectively. This study presented a comprehensive yet simple analytical method for selecting the effective biochar for highway stormwater runoff pollutants removal. Practical Applications: Biochar has properties that make it an efficient material for pollutant removal in highway stormwater runoff. Some of these properties include a large surface area, higher pore volume with a variety of sizes, and high carbon content, allowing pollutant removal through adsorption. The adsorption treatment process allows the attachment of solute molecules (pollutants) in the water to the biochar. The large surface area and pore volume allow for greater adsorption of pollutants and therefore greater pollutant removal. The readily available feedstock materials from waste for biochar production ensure less expensive and sustainable green material for highway stormwater runoff treatment. Biochar products in the market currently are produced using different raw materials and different production and quality assurance methods. The knowledge on selecting or screening biochar to ensure efficient highway stormwater pollutant treatment is limited. To ensure the applicability of a certain commercial biochar product in the removal of highway stormwater runoff pollutants in a specific location, traffic volume, and pollutant composition, this study provides a method of general performance testing of the biochar product before field implementation or model studies. Based on the methods developed and the results obtained from this study, stormwater managers and other stakeholders from several agencies will be able to make informative decisions on biochar product selection. [ABSTRACT FROM AUTHOR]

While 20 % of radionuclides released from the Fukushima Daiichi Nuclear Power Plant accident had been deposited in the terrestrial environment, rivers remain the long-term source for 137Cs, primarily through particulate transfer, from terrestrial to marine ecosystems. In this study, we estimated the suspended 137Cs flux to the ocean at 11 sites in the coastal area between October 2012 and December 2020 to be 17 TBq, based on our long-term monitoring data of concentrations of suspended 137Cs and suspended solids. The cumulative loss of suspended 137Cs from each site to the ocean ranged from 0.1 % to 1.7 % of initial deposition throughout the observation period, depending on the effect of dam lakes and normalized river discharge. The higher loss is also thought to be the large outflow of runoff during the typhoon. The current level of the suspended 137Cs concentrations was lowered to 1/10–1/100 of those immediately after the accident. The average value of the decreasing trend for each site was approximated using the equation: y = a1 e −k1t + a2 e −k2t. The rate constant k1 is higher in areas with intensive land use, such as pastures, bare land, and water surfaces, and k2 is lower in urban areas. [ABSTRACT FROM AUTHOR]

In micro-irrigation systems, distinct media filters and filtering materials are employed to remove suspended solids from irrigation water and thereby avoid emitter obstruction. Turbidity is related to suspended solids and dissolved oxygen depends on organic matter load. At this time, no models exist that are trustworthy enough to forecast the dissolved oxygen and turbidity at the outlet when utilising various media configurations and filter types. The objective of this investigation was to construct a model that can identify turbidity and dissolved oxygen at the filter outlet in advance. This study presents an algorithm for meta-heuristic optimisation inspired by populations termed Differential Evolution (DE) in conjunction with Support Vector Regression (SVR) (DE /SVR-relied model). This is an effective machine learning method, with seven kernel types for calculating the output turbidity (Turb o) and the output dissolved oxygen (DO o) from a dataset comprising 1,016 samples of various reclaimed water-using filter types. The type of media and filter, the height of the filter bed, the cycle duration, and the filtration velocity, as well as the electrical conductivity at the filter inlet, pH, inlet dissolved oxygen, water temperature, and the input turbidity are all tracked and analysed in order to achieve this. The best-fitted DE/SVR-relied model was constructed to predict the Turb o and DO o as well as the input variables' relative importance. Determination coefficients for the best-fitted DE/SVR-relied model for the testing dataset were 0.89 and 0.92 for outlet turbidity (Turb o) and outlet dissolved oxygen (DO o), respectively, showing a good predictive performance which are of great importance for the management of drip irrigation systems. [Display omitted] • Predictive DE/SVR models of the Turb o and DO o in granular filters are built. • The relative importance of the input variables in this process are determined. • The DE/SVR results for the Turb o and DO o are compared with the experimental values. • The correlation coefficients of the best SVR model are 0.95 and 0.96, respectively. [ABSTRACT FROM AUTHOR]

Animals often moderate behaviours based on environmental and social cues to enhance their chances of survival and reproductive success. This requires reliable cues that reflect changes in ambient conditions. Environmental pollutants can increase communication costs and distort the accuracy of received information, leading to negative effects on the outcome of behavioural adjustments. Consequently, selection may reduce behavioural plasticity to avoid errors or promote more prudent decision making when certain cues become unreliable. In aquatic ecosystems, water turbidity shows high levels of natural variation, but human activities amplify its magnitude and extent by increasing algae and suspended solids in the water. Here, we investigated how elevated levels of water turbidity affected mating decisions made by female guppies in a laboratory setting. Guppies are a widespread species with a broad tolerance of polluted environments, and females rely heavily on visual cues when making mate choice decisions. We manipulated turbidity by adding suspended solids to water and tested how this affected female preference for males with more orange coloration. We found that females spent more time near males with a greater area of orange coloration in low turbidity water, but that this preference disappeared in both the mid and high turbidity water treatments. Moreover, female preferences were repeatable in low turbidity water and high turbidity water but not in mid turbidity water. Together, our results suggest that water turbidity impairs the ability of females to discern male coloration and affects the consistency of mate preferences. This could have consequences for the evolution of male coloration in turbid waters. • Male guppies have vibrant colour patterns indicating quality. • We investigated how water turbidity affects mating decisions by female guppies. • Females preferred to associate with more colourful males in low turbidity water. • Increased turbidity resulted in no preference for more colourful males. • Female mate preference was not repeatable in mid turbidity water. [ABSTRACT FROM AUTHOR]

Herbal waste produced during the manufacturing of herbal products is a potential feedstock for anaerobic digestion due to high amount of organic matter that can be transformed into biogas as an energy resource. Therefore, the present study was undertaken to convert herbal waste produced during the manufacturing of common of Ayurveda products into biogas through anaerobic digestion process using batch test study under controlled mesophilic temperature conditions of 35 °C with food to inoculum ratio of 0.75. The maximum biomethane potential (BMP) of 0.90 (gCH4COD/g CODfed) and sludge activity of 0.70 (gCH4-CD/gVSS) was exhibited by WS herbal waste owing to its high chemical oxygen demand (COD) of 4 g/g and better solubilization potential of the organic matter showing change in volatile suspended solids (ΔVSS) of 79%. On the other hand, the waste derived from the TA herb, exhibited the least biogas yield of 0.55 (gCH4COD/g CODfed) and sludge activity of 0.40 (gCH4-CD/gVSS), albeit with higher organic matter present. This was due to the possible hindrance of waste solubilization by the presence of lignin. The waste derived from VVL and PE showed intermediate BMP and sludge activity. The methane generation rate constant (k), a key indicator of the biodegradation potential, was also evaluated. The k values showed similar trend as of BMP values ranging from 0.081 to 0.15 d−1 thus indicating the influence of presence of lignin and the change in ΔVSS. The present study proves anaerobic digestion to be an alternative treatment method to be a milestone for management of herbal wastes and can be successfully implemented on real-scale systems. [ABSTRACT FROM AUTHOR]

In the Mzab, treated wastewater constitutes a fraction of water resources. This article discusses a methodology for valorizing these resources to support local sustainable development. Filtration processes constitute a simple, ecological means of treatment. Our study examines the influence of sand depth in submerged sand filters on the removal of pollution parameters in treated water from the Kaf Doukhane station, upstream of the Mzab valley. We studied the impact of four sand depths (25, 55, 85 and 110 cm) on the removal of suspended solids (SM), turbidity, NO3-, NO2-, NH4+, PO4H2, COD and BOD5. Filtration tests were carried out on a test strip at the laboratory of the University of Ghardaïa using three types of sand as filter media. Our results indicated that sand from the Metlili Valley quarry was the most effective and a sand depth of 110 cm achieved the highest performance. However, the purification efficiencies at different depths varied considerably, reaching up to 97%, and the treated waters met WHO standards for potability and irrigation. Therefore, any sand depth between 110 and 300 cm would be suitable for sizing the submerged sand filter intended for the treatment of effluents from the Kaf Doukhane STWW. [ABSTRACT FROM AUTHOR]

The development of the mountain and submontane areas of the Azerbaijan Republic in the second half of the last century caused active use of the water resources of small mountain rivers. Under present-day conditions, irrigation systems are the main components of the country's water industry ensuring the growth of economic production. The irrigation system parameters are determined by consumers' capabilities and natural factors (climate, topography, geology). In addition, they mainly depend on the water content of the rivers used. When designing and reconstructing irrigation systems, the main costs are allocated for hydraulic structures that provide the necessary volume of water of the required quality. The arrangement of the water intake facility elements in each specific case is inextricably linked with the best practices in operating similar water intake structures in similar hydrological conditions of rivers. Having analyzed the existing experience in operating such structures, we developed a more rational design of a water intake facility for mountain rivers. [ABSTRACT FROM AUTHOR]

Dissolved air flotation (DAF) is an effective method for separating suspended oil and solid particles from wastewater by utilizing small air bubbles. This study aims to investigate the impact of key factors, such as saturating pressure and water flow rate, on the separation of fine oil droplets from a water stream. The macroscopic flow patterns within the cell were analyzed using particle image velocimetry (PIV), while Digital Image Analysis (DIA) was employed to study microscopic phenomena, including oil droplet rising velocity and oil-bubble contact mechanisms. Our findings propose a safe operating window (specifically, water flow rate and saturation pressure) for the effective separation of oil droplets without any oil escaping into the clean water stream. It was found that the oil droplet rising velocity increases with the saturation pressure up to 200 kPa. However, a further increase in the pressure of the air saturating chamber leads to a decrease in oil droplet rising velocity. Additionally, we identified a peak in rising velocity at an oil droplet size of approximately 200 µm. Below this threshold, the rising velocity increases with droplet size, while for droplet sizes exceeding 200 µm, the rising velocity decreases with size. This behavior can be explained by the conflicting effects of droplet size increment according to the Stokes law for the rising velocity of oil droplets. As the droplet size increases, the average density of the bubbles/droplet aggregate rises, reducing the ∆ρ in the Stokes law and subsequently lowering the aggregate rising rate. However, as per the Stokes law, the oil droplet rising velocity increases proportionally to the square of its size. [ABSTRACT FROM AUTHOR]

This study presents a novel method for seepage control in calcareous sand using microbially induced Ca-Alginate polymeric sealant, which was achieved by the reaction between supplied alginate and microbially induced Ca2+ ions directly derived from calcareous sand. This approach includes two steps: (i) microbially induced soluble Ca2+ generated inside the pores of calcareous sand through a bio-acidification process using activated sludge and (ii) reacting with supplied alginate to form Ca-alginate polymeric sealant via the in situ gelation. With the effect of Ca-alginate polymeric sealant, the seepage rate of the calcareous sand was intensely decreased to the level of 10–9 m/s from an initial 10–4 m/s when 5 g/L of alginate was applied. In this way, a low seepage rate of calcareous sand was achieved which was able to remove heavy metal ions and suspended solids from the wastewater sludge. A model test was also carried out to assess the erosion resistance of Ca-alginate treated calcareous sand dam subjected to wave attack. Built on the current research, the proposed polymeric sealant is a promising method for the reduction of seepage, formation barriers for coastal construction on the island, and remediation of specific contaminants. [ABSTRACT FROM AUTHOR]

The superficial gas velocity (Ug) values of 1.0, 1.5 and 2.0 cm s−1 showed a diesel consumption of 59.70, 58.20 and 65.20 %, respectively. The productivity of the airlift bioreactors (ALBs) was 0.030, 0.026 and 0.034 g L−1 d−1, respectively. During 10 days of operation, the emulsification index (E24 %) values for Ug 1.0, 2.0 and 2.0 cm s−1 were 15.79, 15.07 and 12.85 %, respectively. Likewise, an increase in the degradation and suspended solids was observed when increasing the Ug from 1.0 to 2.0 cm s−1 of the ALBs, whereas a decrease in emulsification index E24 % was observed for an Ug of 2.0 cm s−1. According to the results, the Ug of 2.0 cm s−1 was the most effective for increasing the degradation of diesel and growth of the consortium among the Ug evaluated. Furthermore, the reduction of E24 % in this Ug suggests that the consortium uses a mixed form of hydrocarbon consumption, both by direct contact and in emulsified form. [ABSTRACT FROM AUTHOR]

The main objective of this work is to analyze the possible use of banana peel waste as a natural coagulant and also to improve its coagulation effectiveness using an eco-friendly modification methodology the removal of synthetic water turbidity and river water purification. In this case, the modified banana peel powder hasan average particle size and diameters are 571 and 360 nm respectively. While the normal banana peel powder's size of particles and diameter were 978 and 602 nm, respectively. The effectiveness of the coagulation was examined at various pH values, dosages, sedimentation periods, and NaCl concentrations. With up to 90% turbidity removal, the ideal dose for modified banana peel was discovered to be 0.4 g/L. At small concentrations of less over 0.4 g/L, NaCl somewhat improved the coagulation performance; however, the activity decreased at higher concentrations, even when using the modified powder. In river water, banana peel powder act significantly hence reduced the color of the water, the total amount of dissolved and suspended solids, as well as the chemical and biochemical oxygen demand. However, for non-modified and modified powders, the turbidity reduction was only 75 and 83%, respectively. To look into and validate the coagulation mechanism, SEM and FT-IR analysis were done. Banana peel powder modified in this environmentally friendly way has a lot of potential as a cheap and accessible bio-coagulant and can likely help to decrease wastages. [ABSTRACT FROM AUTHOR]

New Zealand's agricultural sector faces the challenge of maintaining productivity while minimizing impacts on freshwaters. This study evaluates the cost-effectiveness of various green infrastructure systems designed to reduce diffuse agricultural sediment and nutrient loads. Utilizing a quantitative economic and contaminant reduction modeling approach, we analyze the impacts of five interceptive mitigation systems: riparian grass filter strips, constructed wetlands, woodchip bioreactors, filamentous algal nutrient scrubbers, and detainment bunds. Our approach incorporates Monte Carlo simulations to address uncertainties in costs and performance, integrating hydrological flow paths and contaminant transport dynamics. Mitigation systems are assessed individually and in combination, using a greedy cyclical coordinate descent algorithm to find the optimal combination and scale of a system for a particular landscape. Applying the model to a typical flat pastoral dairy farming landscape, no single system can effectively address all contaminants. However, strategic combinations can align with specific freshwater management goals. In our illustrative catchment, the mean cost to remove the full anthropogenic load is NZD 1195/ha for total nitrogen, NZD 168 for total phosphorus, and NZD 134 for suspended solids, but results will vary considerably for other landscapes. This study underscores the importance of tailored deployment of green infrastructure to enhance water quality and support sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Abrasion occurs on the concrete surfaces of irrigation canals because of the flow of water and sand. Abrasion increases the roughness of the concrete surface. Increased roughness reduces water flow function. Underwater ultrasonic roughness measurements estimate roughness from the peak-to-peak strength of reflected underwater ultrasonic waves. However, the effect of turbid water flowing in a canal on peak-to-peak strength has been unclear. The objective of this study was to evaluate the effect of turbid water on underwater ultrasonic roughness measurements. The characteristics of the attenuation of the peak-to-peak strength of underwater ultrasonic waves were investigated as a function of the particle size and concentration of suspended solids. The suspended solids used in the experiments were kaolin with a particle size of 0.5 µm and alumina with particle sizes of 2, 4, and 8 µm. Peak-to-peak strength was measured as a function of the concentration of each particle size. The experimental results indicated that peak-to-peak strength was attenuated only with increasing concentrations of suspended solids and was not affected by particle size. A proposed correction equation for peak-to-peak strength took into consideration the concentration of suspended solids in turbid water. The coefficient of determination R2 between this equation and measured data was as high as 0.98. Using this correction equation, peak-to-peak strength without turbidity could be calculated from peak-to-peak strength measured in turbid water. It is thus possible to make effective use of underwater ultrasonic roughness measurements in turbid water. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study intended to detect the inherent deficiencies of prescription‐type empirical design procedures often adopted for nitrogen ‐removal activated sludge systems. Principles of process stoichiometry and kinetics were used to identify a series of hotspots that were likely to impair and disrupt system performance and efficiency. Available data, derived from an existing plant subject to a similar design approach, were utilized to numerically assess significant hotspots and to define a sustainable remedial action in compliance with applicable scientific principles. RESULTS: Critical appraisal of the implemented design exposed a large spectrum of deficiencies affecting system efficiency and performance, including nitrification efficiency, denitrification potential, anoxic volume and sludge age, internal recycling and nitrate removal. The major role of the inorganic suspended solids as a design parameter was also ignored. The remedial strategy adopted for retrofitting corrected all the observed discrepancies and it devised a sustainable approach of flipping around the existing reactors so that they could be operated as a series of carousel/fast recycle reactors, each including anoxic and aerobic volume fractions to provide full nitrification. CONCLUSION: The merit of the proposed remedial strategy was justified by offering two additional options of equally effective system operation with either reduced reactor volume or increased sewage flow. The study presented conclusive evidence to show why prescription‐type design should be avoided, providing numerical proof that this methodology is incompatible with stoichiometric and kinetic characteristics of sewage under local conditions. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Aging oil is a common pollutant in petrochemical enterprises due to its severe emulsification and flocculation, poor settling performance, low oil recovery rate, and high difficulty in treatment. This article adopts the method of mechanical, ultrasonic, and chemical coupling demulsification to treat aging oil, with the water content and oil recovery rate of the treated aging oil as the inspection indicators. The experiment shows that when the oil-water ratio is 1:4, the heating temperature is 50°C, the stirring speed is 180rpm, the ultrasonic frequency is 25kHz, the power is 40W, the ultrasonic time is 25min, and the pH is adjusted to 3-4. The additional amount of FeSO4 is 160mg/L, the additional amount of H2O2 is 0.11%, and the heating stirring reaction is 40min. When the dosage of cationic PAM with an ion degree of 50 is 35mg/L, the centrifugation speed is 3200rpm. The centrifugation time is 20 min, the crude oil recovery rate after aging oil treatment can reach over 94.6%, and the water content of the treated crude oil is less than 0.5%, meeting the standards for crude oil gathering and transportation in China. The oil content in the water generated after aging oil treatment is about 150 mg.L-1, the suspended solids content is 200 mg.L-1, the oil content in the residue is 6%, and the water content is 53%. By analyzing the appearance of aging oil before and after treatment, it was found that when using this process to treat aging oil, the original spatial cross-linking network structure of the aging oil was broken, allowing the water droplets wrapped in the oil to be released, thereby significantly reducing the water content in the recovered oil and improving the oil recovery rate. [ABSTRACT FROM AUTHOR]

The present research evaluates the performance of the Nile tilapia (Oreochromis niloticus) (initial weight 11.5 ± 0.07 g) with biofloc technology. For this purpose, spent grains (malted barley) from the brewing industry after aerobic fermentation were used, as both a carbon source (suspended solids) and partial substitute for the diets at 0, 10, 20, 30, and 40% levels (settleable solids). The partial 20% substitution of the diet did not have significant effects on the biological parameters: final body weight, weight gained, average body weight, specific growth rate, daily growth index, condition factor, feed conversion ratio, protein efficiency rate, and viscerosomatic and hepatosomatic indices. However, the dietary substitution showed a significant effect on the final biofloc chemical composition. Nitrogen compounds, NH4+, NO2−, and NO3−, were adequate for tilapia cultivation in all the treatments. No clear effect of partial dietary substitution was observed on meat quality parameters: pH, color, water holding capacity, and amino acid and fatty acid profile of fillet. The results suggest that a 20% substitution of the diet for malted barley is suitable for satisfactory biological parameters and Nile tilapia fillet quality. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are a widespread group of organic contaminants whose presence in water bodies is cause of severe concern. With few exceptions, the majority of PAHs is hydrophobic, presents a high adsorption affinity, and is thus primarily transported within river systems during high-flow events together with suspended particulate matter (SPM). Evidence exists of analytical challenges related to the incomplete extraction of PAHs adsorbed to solids and thus to a potential negative bias in the chemical analysis of PAHs in bulk water samples with high SPM content. Despite this, partly due to the elevated efforts required to collect representative samples containing sufficient SPM for the separate PAH analysis in this matrix, several investigations rely on the analysis of aqueous samples. This study tests the hypothesis that surveys based exclusively on bulk water may lead to a systematic underestimation of the real contamination level and transport of PAHs in rivers. Six high-turbidity events were examined in three Austrian rivers applying time-integrated sampling and simultaneously analyzing PAHs in total bulk water, filtered water, SPM, and supernatant. Despite an unavoidable degree of uncertainty in such challenging sampling scheme, the results indicate that measurements performed with best available standard methods in bulk water samples determined in average only about 40% of the theoretically expected total PAHs concentrations derived from the analyses in SPM. Such deviation has important implications for the reliable assessment of the compliance with environmental quality standards as well as for surveys aimed to estimate riverine loads, validate emission models, and understand the transport dynamics of PAHs in rivers. Whereas the first objective, e.g., in European countries, is alternatively achieved via monitoring in biota, the latter ones require efforts directed to complement monitoring campaigns with separate sampling of SPM, with monitoring of suspended solids transport to appropriately select and interpret the results of water samples and to improve the chemical analysis of PAHs in bulk water samples with high solids content. [ABSTRACT FROM AUTHOR]

When olive mill wastewater is given directly to nature without being treated, natural waters become coloured, aquatic life is adversely affected, surface and underground waters are polluted, bad odours occur, and soil quality deteriorates. For these reasons, waste water is not allowed to be poured into soil and water without being discharged. This problem has become a problem that needs to be solved for the Mediterranean countries. With this study, acid cracking and chemical treatability studies achieved the conversion of the physicochemical pretreatment process of olive black water to an automation system. With the applied processes, removal efficiencies of 85% for Chemical Oxygen Demand, 99% for suspended solids, 97% for oil grease and 92% for phenol were obtained. Since the mixing processes of the tanks in the chemical additions are long, the heating chamber in the acid cracking process is designed larger than the tanks. Thus, when there is a black water density in the system, the heating tank in this system can be used as a heating and resting tank in sudden densities in this system. This waste separation process includes producing raw materials, protecting natural resources, and increasing sustainability. In particular, separating the phenol material and making it usable have been essential gains. [ABSTRACT FROM AUTHOR]

Gravity settling is a widely employed technology that removes oil from produced water in oilfields. However, with the transition of reservoir development to low-permeability reservoirs, conventional produced water settling tanks face limitations in the treatment efficiency and coagulant dosage. This study presents an innovative approach that optimizes sedimentation tank structures and integrates micro-vortex flow technology to enhance coagulation and flocculation. Through chemical dosage experiments, comparative experiments, and long-term observation, the micro-vortex flow reactor demonstrates a 9.4% increase in oil removal efficiency while reducing the coagulant dosage by 30.0%. The MOR equipment achieved a 20.5% higher oil removal efficiency than conventional methods while maintaining effluent oil and suspended solids below 20 mg/L. The long-term observation experiment of MOR equipment further highlights oil removal efficiency of 94.2% and the micro-vortex reactor's excellent anti-pollution performance. The MOR equipment significantly reduces the land occupancy area by over 50% compared to conventional methods, thanks to the implementation of micro-vortex flow technology that effectively addresses the limitations associated with traditional settling tanks. This study contributes to advancing efficient and sustainable practices in waterflooding reservoirs, particularly for meeting stringent standards of water injection in low-permeability oilfields. [ABSTRACT FROM AUTHOR]

Despite over two decades since the EU Water Framework Directive have passed, achieving the desired water quality in German surface waters remains challenging, regardless of efforts to reduce phosphorus inputs and associated environmental impacts. This study aims at analyzing the characteristics governing the concentrations of four key water quality parameters (total phosphorus, orthophosphate, particulate phosphate, and suspended solids) in two lowland catchments: the 50 km2 catchment of the Kielstau, Germany, and its 7 km2 tributary, the Moorau, which are dominated by agricultural land use. To this end, different sampling methods, particularly high-resolution precipitation event-based sampling and daily mixed samples, are conducted and evaluated, and their effectiveness is compared. The identification of sources and characteristics that affect phosphorus and suspended sediment dynamics, both in general and specifically during heavy precipitation events, is one focus of the study. Over a 15-year period, increasing concentrations of these parameters were observed in daily mixed samples, exhibiting distinct seasonal patterns—higher in summer and lower in winter—consistent with lowland catchment behavior. Particularly during heavy precipitation events, the smaller catchment exhibits a more complex and less predictable response to chemical concentrations compared with the dilution effect observed in the larger catchment. The results underline the complexity of phosphorus dynamics in small catchments and emphasize the importance of event-based sampling for capturing short-term concentration peaks for all four parameters, particularly beneficial regarding measuring suspended solids. While daily mixed samples capture average phosphorus concentrations, event-based sampling is crucial for detecting short-term spikes, providing a more comprehensive understanding of phosphorus dynamics. [ABSTRACT FROM AUTHOR]

Fruit consumption guarantees the supply of most of the necessary nutrients for a complete and balanced diet, as it is a relevant source of vitamins, minerals, and antioxidants. In particular, pomegranate has very interesting medicinal properties, such as an anti-inflammatory effect and the protection of the cardiovascular system, among others. During pomegranate juice production, it appears cloudy and must be clarified to remove suspended solids such as colloids and high-molecular weight tannins. The membrane clarification process is a cost-effective alternative to the conventional methods, resulting in a high-quality product. In this work, the clarification of pomegranate juice using the Triple System Model F1 membrane module was carried out for the Mollar and Wonderful varieties with early and late maturity. Three ultrafiltration membranes with different molecular weight cut-off and different chemical compositions were used. The rejection coefficient and permeate flux (which represent the selectivity of the membranes and the process efficiency, respectively) were measured. GR-40PP showed the best results in terms of membrane selectivity and process efficiency, achieving adequate physicochemical juice parameters. Regarding the comparison of the maturity degree, in general terms, the Mollar variety showed better results. Ripe pomegranates showed greater selectivity, while the process efficiency was higher for the early samples. [ABSTRACT FROM AUTHOR]

To address the issue of insufficient carbon sources in urban sewage, which leads to poor nitrogen removal performance in sewage treatment systems, an anaerobic/anoxic/aerobic (AAO) pilotscale reactor was established. The reactor aimed to treat low C/N (chemical oxygen demand; COD/total nitrogen; TN) municipal wastewater (C/N<5). To enhance nitrogen removal and investigate the mechanism in the AAO process, a Pall ring modified biological suspended filler was introduced to the aerobic zone after achieving partial nitrification and denitrification (PND). The results revealed that the activated sludge-biofilm composite system can be successfully formed within 40 days, with a stable loaded biomass on the membrane at 40.06 mg/g (measured by volatile suspended solids (VSS)/filler). The aerobic zone of the activated sludge-biofilm composite system demonstrated an increase in nitrite accumulation rate (NAR) and simultaneous nitrification and denitrification efficiency (SND), from 60.46% and 19.42% in the initial stage (stage 1) to 69.62% and 46.47% in the stable forming stage (stage 3), respectively. By promoting both PND and SND pathways for nitrogen removal, the effluent from the system exhibited decreased concentrations of ammonia nitrogen (NH4+-N) at 0.11 mg/L and total nitrogen (TN) at 4.55 mg/L, indicating the significant synergistic effect of the biofilm on nitrogen removal. 16S rRNA amplification and sequencing analysis revealed that Proteobacteria was the dominant microorganism in the 60-day biofilm, accounting for 76.12% of the relative abundance. The main ammonia oxidizing bacteria (AOB) were Nitrosomanas (1.77%) and Nitrosococcus (1.69%). Meanwhile, denitrification microbial species were found to have a substantial proportion (29.11%), along with a small amount of Anammox bacteria (Anammoxoglobus, 0.35%) within the biofilm. These sequencing results were consistent with the macroscopic performance of the reactor. Overall, these findings establish a theoretical foundation for enhancing nitrogen removal in the AAO system. [ABSTRACT FROM AUTHOR]

This study aimed to examine the performance of an anaerobic hybrid reactor (AHR) and an anaerobic continuous stirred tank reactor (CSTR) for treating high-strength fresh leachate. As the organic loading rate (OLR) was increased in both systems, the pH decreased, with the lowest pH corresponding to an OLR of 25-30 kgCOD/m³.d. The AHR system demonstrated instability in total volatile fatty acids when the OLR increased to 20 kgCOD/m³.d. The highest methane (CH4) content was achieved when the OLR was 15 kgCOD/m³.d. Moreover, the AHR showed excellent sediment retention. When the OLR increased, volatile suspended solids (VSS) in the system increased. The CH4 content tended to increase as the OLR increased up to 20 kgCOD/m³.d. The highest CH4 content in the AHR was 68%, which was higher than that of the CSTR. The CSTR could not produce biogas when the OLR was 20 kgCOD/m³.d. The optimal OLR for the operation of AHR and CSTR treating fresh leachate was found to be 15 and 10 kgCOD/m³.d respectively. [ABSTRACT FROM AUTHOR]