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Turbidity is commonly monitored as an important water quality index. Human activities, such as dredging and dumping operations, can disrupt turbidity levels and should be monitored and analysed for possible effects. In this paper, we model the variations of turbidity in Dublin Bay over space and time to investigate the effects of dumping and dredging while controlling for the effect of wind speed as a common atmospheric effect. We develop a Vector Auto-Regressive Integrated Conditional Heteroskedasticity (VARICH) approach to modelling the dynamical behaviour of turbidity over different locations and at different water depths. We use daily values of turbidity during the years 2017–2018 to fit the model. We show that the results of our fitted model are in line with the observed data and that the uncertainties, measured through Bayesian credible intervals, are well calibrated. Furthermore, we show that the daily effects of dredging and dumping on turbidity are negligible in comparison to that of wind speed. [ABSTRACT FROM AUTHOR]

Socio-economic activities along the Citarum River basin in Indonesia can induce ecological disturbances in the structure of the benthic macroinvertebrate community. This research aims to (1) identify the environmental factors responsible (2) describe the ecological disturbances using biological measurements; (3) and to develop local biocriteria using a multi-metric conceptual approach. An inventory of benthic macroinvertebrates was carried out at eight stations over a sampling period of 3 months, along with water quality monitoring. The results confirm the change in the structure of benthic macroinvertebrate communities, explained by seven environmental parameters: dissolved oxygen (DO), ambient habitat quality, turbidity, nutrient enrichment, conductivity, temperature, and embeddedness percentage. The changes were then assessed using six biological measurements. Only four have been shown to be capable as alternatives to existing biocriteria. Their implementation enabled the development of local biocriteria compatible with the multimetric concept known as the cumulative biotic index (CBI). [ABSTRACT FROM AUTHOR]

With the sustained popularity of hazy IPAs, brewers have explored multiple approaches to maximizing stable haze that will remain in suspension throughout the shelf life of the beer. Our recent investigations into yeast-dependent haze have uncovered specific brewing yeast strains that promote the formation of haze in heavily dry-hopped beer styles. These brewing strains have been termed "haze-positive" and furthermore, the timing of dry hop additions has been found to be another key factor in producing this stable haze. Classical genetics have identified YIL169C (herein referred to as HZY1) as both necessary and sufficient for the haze-positive phenotype in the yeast strain most widely used for Hazy IPAs. HZY1 encodes a candidate glycoprotein and our recent findings suggest it is localized to the cell wall through a GPI anchor. Surprisingly, using long-read sequencing data we uncovered extensive genetic variation in HZY1 across brewing strains. The haze-positive phenotype correlates with an expansion in the N-terminal serine-rich region. We propose that the Hzy1 glycoprotein is a critical component to yeast-dependent colloidal haze and the genetic variation in this locus contributes the range of haze phenotypes observed across industrial brewing strains. [ABSTRACT FROM AUTHOR]

The appearance of an extrudate formulation was monitored during hot-melt extrusion (HME) continuous manufacturing over 3 days. The formulation matrix consisted of a polymeric component, copovidone, and a low molecular weight surfactant, polysorbate 80. Based on studies prior to the continuous manufacturing, the desired appearance of the target extrudate is translucent. Although process parameters such as feed rate and screw speed were fixed during the continuous manufacturing, the extrudate appearance changed over time from turbid to translucent. For root-cause investigation, the extrudates were analyzed offline by differential scanning calorimetry (DSC) and advanced polymer chromatography (APC™). Although the polysorbate 80 content of both turbid and translucent extrudates was within target, the glass transition temperature of the turbid extrudate was 2 °C above expected value. The observed turbidity was traced to lot-to-lot variability of the polysorbate 80 used in the continuous manufacturing, where APC™ analysis revealed that the relative content of the low molecular weight component varied from 23% to 27% in correlation with the evolution from turbid to translucent extrudates. This work stresses the importance of taking feeding material variability into account during continuous manufacturing. [ABSTRACT FROM AUTHOR]

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The presence of impurities, microorganisms, enzymes, suspended solids, and impurities in unclarified pomelo juice negatively affected the quality and shelf-life of the product in the food industry. The objective of this study focuses on the clarification of fresh pomelo juice using an ultrafiltration (UF) process. The study examined the influence of the operating pressure (OP) on the various quality attributes of pomelo juice, such as pH, total soluble solids (TSS), turbidity, color, total phenolic content (TPC), ascorbic acid content (AAC) and fouling mechanisms and permeate flux (J) behavior. To perform the clarification of pomelo juice, a 100 kDa membrane (polymeric) was used in a dead-end system, and the process was carried out in batch mode at OP values of 1.0, 1.5, 2.0, 2.5 and 3.0 bar. The findings revealed that increasing OP led to higher flux during ultrafiltration with limiting pressure (Plim). The limiting pressure (Plim) was anticipated to be beyond 3.0 bar due to the enzymatic pretreatment. The primary fouling mechanism during the clarification process was total pore blocking. After filtration, the resulting juice showed a significant reduction in turbidity of over 97%, while TSS was lowered by 7–17% compared to fresh juice. The pomelo juice was efficiently clarified while the pH remained stable at ∼3.8. The clarified juice showed a minor decline of 10.1–13.9% in TPC and a 10.8–16.7% reduction in AAC compared to the fresh unclarified juice. In conclusion, a pressure of 3.0 bar is recommended for conducting the ultrafiltration process in order to attain desirable flux behavior and optimum properties of the juice. [ABSTRACT FROM AUTHOR]

Quantification of beer color of craft unfiltered, hazy, seltzer, and fruited beer styles can be problematic due to turbidity and unconventional ingredients. A novel integrating cavity spectrometer (ICS), designed to eliminate the effect of light scatter by the sample was employed to determine if it was able to more accurately quantify beer color compared to a conventional scanning spectrophotometer (CSS). A CSS was employed to measure the absorbance and transmission of 15 filtered and unfiltered craft brewery beer samples to determine the SRM color value and tristimulus color values. The ICS measures absorbance with a 430 nm LED to determine the single-point SRM value for each beer. The SRM values of unfiltered or 0.2 µm filtered beer samples were compared using Bland-Altman analysis and regression fits. Filtered and very clear beers showed strong agreement between the methods and Bland-Altman analysis confirmed their equivalence, particularly for SRM <25. Using the ICS alone, filtered beer versus unfiltered beer showed highly correlated values and narrow limits of agreement, successfully negating the effects of turbidity. In conclusion, SRM determination by ICS is equivalent to standard spectrophotometer single-point methods and superior in accurately determining the SRM color of hazy beers without filtration or centrifugation. [ABSTRACT FROM AUTHOR]

Remote sensing provides us with an approach for the rapid identification and monitoring of spatiotemporal changes in the urban ecological environment at different scales. This study aimed to construct a remote sensing assessment index for urban ecological livability with continuous fine spatiotemporal resolution data from Landsat and MODIS to overcome the dilemma of single image-based, single-factor analysis, due to the limitations of atmospheric conditions or the revisit period of satellite platforms. The proposed Ecological Livability Index (ELI) covers five primary ecological indicators – greenness, temperature, dryness, water-wetness, and atmospheric turbidity – which are geometrically aggregated by non-equal weights based on an entropy method. Considering multisource time-series data of each indicator, the ELI can quickly and comprehensively reflect the characteristics of the Ecological Livability Quality (ELQ) and is also comparable at different time scales. Based on the proposed ELI, the urban ecological livability in the central urban area of Wuhan, China, from 2002 to 2017, in the different seasons was analyzed every 5 years. The ELQ of Wuhan was found to be generally at the medium level (ELI ≈0.6) and showed an initial trend of degradation but then improved. Moreover, the ecological livability in spring and autumn and near rivers and lakes was found to be better, whereas urban expansion has led to the outward ecological degradation of Wuhan, but urban afforestation has enhanced the environment. In general, this paper demonstrates that the ELI has an exemplary embodiment in urban ecological research, which will support urban ecological protection planning and construction. [ABSTRACT FROM AUTHOR]

In the mineral processing engineering, ultrasound is usually used to modify reagents to improve the flotation. The study analyses the effects of the modified kerosene on the flotation of flake graphite. The outcomes demonstrate that the modified kerosene can substantially improve flake graphite's floatation efficiency. In comparison to unmodified kerosene, the dosage of modified kerosene can be reduced while the recovery of graphite remains the same. Furthermore, the effect of modified kerosene was evaluated using various detection techniques including particle size distribution measurement, contact angle tests, turbidity tests, and cryo-scanning electron microscopy (Cryo-SEM). The findings indicate that ultrasound modification significantly reduces the size of kerosene to 1–2 μm droplets and improves their dispersion in the aqueous solution. The enhanced dispersion and reduced droplets size of modified kerosene led to a better interaction between kerosene and the surface of flake graphite minerals. As a result, the consumption of kerosene was reduced, but the graphite flotation efficiency was improved. [ABSTRACT FROM AUTHOR]

In mineral processing operations, it is essential to effectively remove the fine particles in slime and tailings slurry with appropriate methods. In this study, a unique two-stage flocculation scheme was developed for achieving effective separation of fine kaolinite particles from water by polyacrylamide. The slurry turbidity and flocculation kinetic parameters were used to characterize the effect of the dosing ratio between the first and second stage on the kaolinite flocculation behavior and settling rate. The results showed that the maximum kaolinite settling rate and the minimum turbidity of slurry supernatant was achieved when 60% and 40% polyacrylamide was added in the first and second stage, respectively. Focused beam reflectometer (FBRM) and particle video microscope (PVM) results showed that the flocs formed in the first stage of dosing were large in size but small in fractal dimension and no significant sedimentation was observed. The second stage of dosing produced large size of flocs with large fractal dimension, which settled fast in slurry. Fourier transform infrared spectroscopy (FTIR) results showed that polyacrylamide was mainly adsorbed on the surface of kaolinite by hydrogen bonding and kaolinite particle flocculation was achieved by trapping and coiling of the polymer chain structure. The two-stage dosing process accomplished effective flocculation and rapid settlement of fine kaolinite particles. The findings from this study provide a feasible approach for mining companies to optimize the flocculation and sedimentation of fine particles. [ABSTRACT FROM AUTHOR]

The oxidation of sulphamethoxazole medicine (SMX) has been studied by means of UV/H2O2 conducting at a controlled pH between 2.0 and 12.0 and oxidant ratios of 500 mol H2O2/mol SMX. It is verified that operating at pH = 2.0 the highest rates of SMX degradation (74%) and loss of aromaticity (64%) are obtained. During the process, a strong brown tint and high turbidity are generated in the water depending on the pH, as it affects the chemical speciation of the dissociable compounds. The colour intensity of the water increases from pH = 2.0 (light brown, 3.5 NTU) to a maximum value at pH = 4.0 (dark brown, 42 NTU), when the neutral SMX species is almost 100%. Under these conditions, the formation of carboxylic acids (acetic and oxalic) and nitrate ion are minor. Conducting at higher pH, hue decreases, obtaining at pH = 12.0 a light yellow water (5 NTU) when the anionic SMX predominates. Thus, the maximum formation of nitrate ion occurs under these conditions. A pseudo-first order kinetic modelling is proposed for the loss of aromaticity and colour and turbidity formation in water, where the kinetic parameters are expressed as a function of the applied pH, being the pseudo-first-order rate constants (min−1): ${\rm k}_{{\rm arom}}{\rm \; } = 0.0005{\rm \; p}{\rm H}^2-0.0106\; {\rm pH} + 0.0707{\rm \; }$ k a r o m = 0.0005 p H 2 − 0.0106 p H + 0.0707 ; ${\rm k}_{{\rm colour}} = 0.0011{\rm \; p}{\rm H}^2-0.02 {\rm pH} + 0.1125$ k c o l o u r = 0.0011 p H 2 − 0.02 p H + 0.1125 and kNTU = 0.06 min−1. [ABSTRACT FROM AUTHOR]

In this study, the functionality of liquid egg albumin pre-treated by protease was investigated to evaluate the storage stability mechanisms for field of gastronomy and gastronomist. This study aims to improve the physicochemical and functional properties such as relative whipping capacity (RWC), foam stability, color, pH, and turbidity by protease (0-control, 0.5, 1.0, and 1.5%-v/v). The protease enhanced RWC comparing to the untreated on day-0 and 27, while the control group showed lower RWC and higher values in 1% and 1.5% treatments. The effect of protease was more clearly apparent on turbidity with significantly decrease during storage (p <.05). The turbidity values ranged from 0.74 to –0.31. A considerable decrease was observed in color values of treated samples on day 27, while the best treatment was 1.0% in foam stability and 1.5% in RWC. Protease could be used in modified albumin to improve techno-functional characteristics of bakery products. [ABSTRACT FROM AUTHOR]

Wastewater generated from agricultural activities and food production is a source of environmental pollution, and its treatment is a challenging technological issue. Ozone gas (O3), and the possibility of associating it with hydrogen peroxide (H2O2), has the potential to remove persistent organic compounds in effluents. In the present work, wastewater from industrial potato processing was characterized, and its treatment with ozone combined with hydrogen peroxide was assessed. The inlet ozone concentration and the flow rate were 84.5 mg L−1 and 62.5 mL min−1, respectively. The promising conditions of temperature, pH, and H2O2/O3 proportion were determined to reduce the chemical oxygen demand, turbidity, and color, according to a central composite rotatable design. The H2O2/O3 proportions were 0.1, 0.3, 0.5, and 0.6. Additionally, the response variables were evaluated as a function of the ozone and hydrogen peroxide treatment time for up to 24 h. The conditions obtained for treating wastewater from industrial potato processing were the following: temperature = 25°C; pH = 3.0, and H2O2/O3 proportion = 0.1. For the water quality parameters adopted, the combination of ozone and hydrogen peroxide was effective at removing color and turbidity. The chemical oxygen demand, color, and turbidity reduction stabilized after 1.16 h, with cumulative applied dosages of ozone and hydrogen peroxide equal to 380 mg L−1 and 35 mg L−1, respectively. [ABSTRACT FROM AUTHOR]

In this study, the effects of the pH of tannery wastewater obtained from a local leather processing factory on the removal of COD and turbidity, and cost of theelectrocoagulation process was investigated. Studies were carried out under two different operatingconditions. The highest COD removal efficiency was obtained as 83.5% when the initial pH was set to 3, while the energy consumption at this pH was found to be 3.88 kwh m−3. In studies where pH was kept constant, the highest removal efficiency obtained was 83.33% at pH = 5. In this case, the energy consumption was determined as 2.44 kWh m−3. The total cost of the system was calculated as 1.0899 $ m−3 under controlled pH conditions and 0.8761 $ m−3with uncontrolled pH. Studies show that the COD removal kinetics are more suited to 2nd degree kinetics. The highest removal rate for uncontrolled pH was k2 = 0.0791 L g−1 min−1 at pH = 3. The highest rate for controlled pH was k2 = 0.0397 L g−1 min−1 at pH = 5. [ABSTRACT FROM AUTHOR]

Abstract Spearmint essential oil (SEO) has been widely recognized for its therapeutic properties in treating gastrointestinal, respiratory, carminative, diuretic, antispasmodic, and sedative ailments. Moreover, it is commonly utilized as a flavoring agent in various food and beverage products. However, the effectiveness of SEO for medicinal purposes is hindered by its limited water solubility. Hence, the objective of this research was to determine the optimal conditions for producing a nanoemulsion of SEO by measuring turbidity through a mixture experimental design. The study aimed to investigate the impact of different formulation variables on turbidity as the response variable. These variables included PEG-40 hydrogenated castor oil (HCO) (1%–2% w/w), Tween 80 (1%–3% w/w), Tween 20 (1%–3% w/w), propylene glycol (PG) (5%–20% w/w), and polyethylene glycol 400 (5%–20% w/w). The results of the experimental design showed that the obtained data could be adequately fitted in a second-order polynomial model for the prediction of nanoemulsion turbidity with a multiple regression coefficient of 0.9704. The particle size value at the optimum condition was 81.28 nm, which was matched with the result of transmission electron microscopy (TEM). The thermodynamic and long-term stability of the prepared nanoemulsion were investigated. Furthermore, the developed nanoemulsion exhibited better antimicrobial activity against E. coli. In vitro release testing showed that the release of the optimized nanoemulsion was significantly increased. This study demonstrated that SEO is capable of forming stable nanoemulsions for use in delivery systems of flavoring agents in the food industry. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate tear meniscus parameters in meibomian gland dysfunction (MGD) using optical coherence tomography and ImageJ software. We enrolled 66 eyes of 66 participants and measured tear meniscus parameters, including height, depth, turbidity, and percentage area occupied by particles (PAOP) in the meniscus in the MGD and control groups. Tear meniscus turbidity and PAOP were significantly higher in the MGD group, but tear meniscus height (TMH) and depth (TMD) did not differ significantly between groups. Tear meniscus turbidity and PAOP were positively correlated with each other and ocular surface parameters, including OSDI and ocular surface staining scores. Tear meniscus turbidity and PAOP were higher in the MGD group than in the control group; therefore, they can be used as significant non-invasive parameters in the prediction of MGD. TMH and TMD did not differ significantly between groups. [ABSTRACT FROM AUTHOR]

Mapping river water quality at a basin scale with satellite image data represents a tremendous technical challenge, since traditional empirical remote sensing models calibrated for specific reaches of a river cannot be applied to all the rivers and streams in the basin with an adequate prediction accuracy. In this study, we developed a multi-predictor ensemble model to map and assess water turbidity for all rivers and streams in the Tombigbee River Basin with Landsat 8 multispectral images. Coincident with Landsat 8 satellite overpass on 2 May 2019, we conducted boat-based water quality data collection in the confluence area of Tombigbee River and Black Warrior River near the city of Demopolis, Alabama. Based on the coincident satellite image and field water samples, we calibrated and evaluated the multi-predictor ensemble model, which consists four component empirical models. Our evaluations suggest that the multi-predictor ensemble model can improve turbidity estimation accuracy by 79% in comparison with the best traditional empirical model. More importantly, our multi-predictor ensemble model can be applied to other river and stream reaches across three major sub-basins with a high prediction accuracy. With the multi-predictor ensemble model, we derived a turbidity map for all rivers and streams with a width greater than 90 m in the basin, by processing three Landsat 8 image scenes. This basin-wide turbidity map indicates that the turbidity of rivers and streams exhibits longitudinal gradients and distinct spatial trends within the basin, which were related to the basin land cover/land use, hydrometeorological condition, and the spatial distribution of dams. Owing to its strong spatial transferability and high prediction accuracy, the ensemble model, in conjunction with synoptic multispectral satellite image data, is recommended as an effective and efficient tool for mapping and monitoring river and stream water quality at a large basin or regional scale. [ABSTRACT FROM AUTHOR]

Measurements of suspended sediment discharge are greatly significant and represent a basic need for the initial assessment of the effects caused by this process and for the subsequent formulation of management actions. Also, considering that obtaining direct hydrosedimentological data is not a trivial and low-cost task due mainly to the special and temporal variability of the phenomenon, substitute technologies are well employed for monitoring watersheds. Among these are turbidity measurements, described in many papers. An adaptation of this technique was designed and performed in this study for the verification and secondary use of turbidimetric data carried out by a drinking water treatment company at the closing point of the upper part of the Jundiaí river watershed, in the city of Campo Limpo Paulista, São Paulo state. Direct measurements with traditional samplers and valuations of particle size distribution throughout the hydrological year were used to establish empirical correlations between the suspended sediments concentration and turbidity. The definition of the most appropriate adjustment was carried out based on the statistical analysis of the linear regression parameters (R2, Value-p, MSPE, and PRESS) and residue statistics, thus adopting the model with piecewise regression by turbidimetric ranges (250 NTU), which in turn, presented low overestimation of the SSC for high values of turbidity. The definition of the historical series of suspended sediment discharge with hourly temporal resolution for the study site validated the main objective of reusing secondary data with hydrosedimentological purposes, highlighting the plausible applications for different places where there are insufficient resources for the installation and use of in situ turbidity equipment. [ABSTRACT FROM AUTHOR]

This study aimed to develop and validate an ultrasonication-aided UV-Vis spectroscopy method for quantifying black seed oil (BSO) in alginate beads. The method utilized sonication at 10% power rate for 120 seconds to stabilize the emulsion droplet size of 10 mL of the emulsion diluents derived from breaking BSO-alginate beads in phosphate buffer. Absorbance measurements were taken at 400 nm, which was found to be the optimal wavelength for measuring the absorbance of turbid emulsion diluents. The method showed excellent linearity between 0.8 - 5 mg/mL (R2 = 0.9977), with Limit of Detection (LOD) and Limit of Quantification (LOQ) values of 0.082 and 0.249 mg/mL, respectively. The method also exhibited good accuracy and precision, with recovery percentages ranging from 98.02 - 101.9% (RSD = 0.15 - 1.24%) and intra-day/inter-day precision with RSD less than 2%. These findings suggest that the ultrasonication-aided spectroscopy method is a quick, accurate, and precise way to quantify encapsulated oils and could be useful for oils analysis during R&D, In Process Quality Control (IPQC), and Quality Control (QC) tests, as well as in other applications such as industrial manufacturing and academic research. [ABSTRACT FROM AUTHOR]

In this study, a neural network-based Secchi depth retrieval model (NNSD) was developed using observations obtained during 2003–2012 in the Bohai, Yellow, and China East Seas (Eastern China Coastal Seas, ECCS). Based on the results of the analyses, the NNSD model produced less than 25% uncertainty in quantifying the Secchi depth in the optically complex ECCS. The slope of the linear relationship between the field-measured and NNSD model-derived Secchi depth varied from 0.98 to 1.08 among the datasets. However, the corresponding determination coefficients were not any lower than 0.91. To determine the effectiveness of the NNSD model in deriving the Secchi depth in the ECCS, the performances of the three existing models were also evaluated, and the results are presented in this study. By comparison, using the NNSD model decreased the uncertainty by 26% when compared with the three existing models in deriving the Secchi depth in the ECCS. Finally, the NNSD model was further applied to the MODIS data over the ECCS to briefly illustrate its applicability to general oceanographic studies. The NNSD model could produce 24.62% MRE and 0.14 RMSE values in deriving the Secchi depth from the ECCS, which was > 26% MRE and > 0.07 RMSE values better than all the BGSD, KDSD and SASD models. In regards to the spatial distribution pattern of the Secchi depth, the eastern and northern sections of the ECCS were much higher than the western and southern areas. Additionally, the temporal distribution mode indicated that the winter season was higher than the summer season. These spatiotemporal characteristics were caused primarily by the regional climate, river discharges, and strong tidal currents and winds, among other factors. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing oil- and gas-produced water is frequently highly impaired. While it is often deep well injected, there is a great deal of interest in treating and recovering this water for beneficial uses. However, multiple-unit operations are needed if these wastewaters are to be recovered. Electrocoagulation is considered a promising pretreatment technology. Herein, we have investigated the use of aluminum electrodes for electrocoagulation as a pretreatment operation. The effects of electrode arrangement, applied current, reaction time, pH and inter-electrode distance on the quality of the treated water have been investigated. The results obtained here indicate that electrocoagulation can obtain good removal of turbidity (95%), total suspended solids (TSS) (90%) and total organic carbon (TOC) (69%) by carefully choosing the reaction conditions. Sedimentation was used to separate the treated water from the sludge. The performance of the electrocoagulation process depends strongly on the quality of the feed water. The viability of a practical continuous electrocoagulation process will depend on the volume (footprint) of the reactor, which in turn will depend on operating conditions and the quality of the feed water. [ABSTRACT FROM AUTHOR]

Analysis of the suitability of water colour products for the reliability of subsequent applications, or improvements of the algorithm at later stages, is important. We used three types of water bodies: Type 1 (Southern Ocean and Qinghai Lake) clean oceanic water bodies dominated by chlorophyll and clean inland water bodies dominated by chlorophyll and coloured dissolved organic matter; Type 2 (Taihu Lake and Chagan Lake) turbid inland water bodies dominated by suspended matter and chlorophyll and Type 3 (Xiaoxingkai Lake and Daxingkai Lake) turbid inland water bodies dominated by suspended matter. The accuracies of two Chl a concentration products data for synchronous Sentinel-3 OLCI Neural Network (NN) and ocean colour 4 band ratio (OC4Me) algorithms were verified using two metrics combined with in situ data (to compare the applicability of Chl a concentration algorithms for the three types of water bodies). The optimal Chl-a concentration algorithm was selected to analyse the spatial and temporal variation characteristics of monthly concentrations of Chl a. Based on the analysis, (1) the NN algorithm had better applicability to Type 1 water bodies ; the NN algorithm had better applicability to Type 2 water bodies, ; and both algorithms had poor applicability to Type 3 water bodies, (2) Limitations: An overall low derivation value was obtained for the Sentinel-3 OLCI NN algorithm with water concentrations of Chl a, higher than 25 mg m−3. The OC4Me Chl a concentration product only applies to the concentrations of Chl a in Type 2 during the summer. (3) When the Sentinel-3 OLCI Chl a concentration product was compared with the moderate-resolution imaging spectroradiometer (MODIS) and visible infrared imaging radiometer (VIIRS) Chl a concentration products, the distribution trends of the Chl a concentrations were consistent. Furthermore, the Sentinel-3 OLCI Chl a concentration product was more dominant in spatial resolution. [ABSTRACT FROM AUTHOR]

A combination of discrete sampling using autosamplers triggered by area-velocity metres and continuous water quality monitoring using YSI datasondes enabled us to evaluate the dynamics of both stormwater runoff and dry weather water quality associated with an urban park and WSUD treatment train in Singapore. The WSUD treatment train consisted of a raingarden and sedimentation ponds. A first flush phenomenon was observed for total suspended solids (TSS) in three of four discrete-sampled events, but there was a less pronounced first flush characteristic for nutrients. Mean TN concentrations associated with runoff from the park (upstream of the WSUD treatment train) were in the range that would be associated with eutrophic conditions, while mean TP levels were in the mesotrophic/eutrophic boundary range. The raingarden reduced nutrient and TSS levels by 7–62% and loads by 65–93%, although nitrate levels were higher in the effluent compared to the influent. The sedimentation ponds successfully reduced sediment levels by 56%, based on continuous turbidity measurements. The dissolved oxygen levels in the sedimentation ponds were lower during drought periods, which has implications for aquatic organisms. The WSUD treatment train generally improved runoff quality from the park and such features can be easily integrated into the park design. [ABSTRACT FROM AUTHOR]

Sludge-recycling enhanced flocculation (SEF) is an effective method for enhancing flocculation. In the conventional SEF process, the settled sludge is recirculated into the flocculation process without any further treatment. However, studies have shown that the efficacy of the SEF process could be improved by pre-treating the sludge. In this work, the acid activation of sludge was performed using a range of pH values (1.0–6.0) and charge states, with and without long-chain bridging. The resulting residual turbidities, floc fractal dimensions and floc morphologies were then analyzed, to examine the effects of sludge activation on the efficacy of SEF. In the absence of long-chain bridging, it was found that flocculation was enhanced by pH values between 2.0 and 5.0 in the electrostatic patch (EP) and near charge neutrality (NCN) states. In the EP state, the optimal pH for SEF enhancement was pH = 2.0; in the NCN state, the optimal pH was pH = 3.0. In terms of floc morphology, pH values between 2.0 and 5.0 resulted in larger average floc sizes and lower floc fractal dimensions than conventional SEF. However, in the presence of long-chain bridging, sludge activation did not enhance flocculation; residual turbidity increased with decreases in pH, in both the EP and NCN states. Based on these results, it may be surmised that the acid activation of sludge is suitable for cases without long-chain bridging. [ABSTRACT FROM AUTHOR]

Recovering phosphorus (P) from excess sludge of wastewater treatment plants (WWTPs) has attracted considerable attention. An efficient P release method is undoubtedly critical for a satisfactory recovery performance. In this study, the effectiveness of three sludge pretreatment methods, i.e. anaerobic digestion (AD), EDTA-anaerobic digestion (EA) and ultrasound combined with EA (U-EA), on P release and struvite recovery from excess sludge was investigated. The results showed that different pretreatment methods resulted in the different characteristics of P release and recovery. For P release, the highest P release rate (57.14% of sludge total phosphorus, TP) was achieved by U-EA pretreatment, followed by EA and AD. Furthermore, U-EA was beneficial for sludge disintegration and reduction, by which the mixed liquor suspended solids (MLVSS) reduction rate reached 42.00% at a specific energy of 110,000 kJ/kg TS. For the P recovery (in the form of struvite), there was only a little difference in the optimal conditions and P recovery rate (89.29–94.49% of TP in the supernatant). AD pretreatment was beneficial for the purity of products and achieved the highest struvite purity (85.14%), followed by EA (80.95%) and U-EA (77.56%). In summary, the highest recovery rate of TP from excess sludge (53.50% of sludge TP) and struvite yield (26.10 mg/gSS) was obtained by U-EA. [ABSTRACT FROM AUTHOR]

Atmospheric correction is one of the major challenges in ocean color remote sensing, thus threatening comprehensive evaluation of water quality within aquatic environments. In this study, five state-of-the-art atmospheric correction (AC) processors (i.e. Acolite, C2RCC, iCOR, L2gen, and Polymer) were applied to Operational Land Imager (OLI) Landsat-8 scenes and evaluated against in situ measurements across various types of waters worldwide. A total of 262 matchups between in situ measured and satellite-derived remote sensing reflectance (Rrs) at 20 sites were obtained between August 2013 and August 2021. Classification of optical water types (OWTs) was carried out using in situ measurements with matched satellite observations. OWT-specific analysis demonstrated that L2gen produced the most accurate Rrs with R2 ≥ 0.74 and root mean squared error (RMSE) ≤ 0.0018 sr–1 for the four visible bands of OLI, followed by Polymer, C2RCC, iCOR, and Acolite. In terms of Rrs spectral similarity, C2RCC yielded the lowest spectral angle (SA) of 8.55°, followed by L2gen (SA = 9.20°). The advantage and disadvantage of each AC scheme were discussed. Recommendations to improve the accuracy for atmospheric correction were made, such as polarization observations and concurrent aerosol and ocean color measurements. [ABSTRACT FROM AUTHOR]

Coastal waters have high ecological and economic relevance and are globally threatened by intense human activities leading to eutrophication. The decameter resolution of Sentinel-2 Multispectral Instrument (S2-MSI) provides an advantage to detect spatially heterogeneous phenomena that are limited in extent, such as harmful cyanobacterial blooms (cyanoHABs). Chlorophyll-a is typically used in remote sensing of blooms; however, it remains to be evaluated in several coastal regions of the world. The Río de la Plata estuary (South America) provides a key case study due to its highly variable concentrations of suspended sediments, and the increasing frequency of cyanoHABs. Here, we evaluate the potential and limitations of S2-MSI indices to retrieve chlorophyll-a in these optically complex waters, obtaining regional algorithms and comparing them to previously available ones. We propose an approach to follow the evolution of chlorophyll-a thresholds (10 and 24 μg/L) that can contribute to monitoring programs and early warning strategies of cyanoHABs. [ABSTRACT FROM AUTHOR]

Atmospheric correction (AC) is a crucial step in the quantitative analysis of inland and coastal waters. In this study, the performances of six water-based AC methods (SeaDAS, ACOLITE-DSF/EXP, C2RCC, iCOR) were evaluated by using multiple global datasets (N = 139). Four evaluation strategies were applied including spectral similarity and Chlorophyll-a retrieval. The results showed that SeaDAS and ACOLITE-DSF performed the best in terms of analytical match, band ratios, Chlorophyll-a retrieval, and spectral similarity. SeaDAS had the lowest RMSE in the blue-green bands and showed good consistency across the spectral with the lowest median spectral angle of 7°. It should be noted that ACOLITE-DSF outperforms SeaDAS in high turbidity waters. SeaDAS coupled with Chlorophyll-a retrieval algorithms of OC3 and Clark had the lowest RMSE, which showed the advantage of SeaDAS in Chlorophyll-a retrieval. This study provides scientific basis for choosing AC methods of Landsat-8 data for aquatic environment monitoring. [ABSTRACT FROM AUTHOR]

Energy expenditure is a limiting factor for the production of cellulose micro/nanofibrils in mechanical processing. This study evaluated the effect of novel alkaline pretreatments on unbleached Eucalyptus sp. pulps (hardwood) and Pinus sp. cellulose (softwood) to facilitate the production of cellulose nanofibrils by mechanical fibrillation and reduce the energy consumed by the mill. Pretreatments with NaOH in concentrations of 5% for 2 h and 10% for 1 h and 2 h and a hybrid pretreatment with 5%/16% NaOH/H2O2 for 2 h were evaluated. The 10% pre-treatment was done at 1 h and 2 h to evaluate the effect of the less aggressive treatment (1 h). The morphology, chemical composition, turbidity of the fibers/suspensions, mechanical properties, fibrillation quality index and energy expended during the fibrillation were evaluated for each pretreatment. The less aggressive pretreatments produced micro/nanofibrils with fewer passes of the pulp through the fibrillator, which effectively facilitated extraction with lower energy consumption. The hybrid pretreatment did not show satisfactory results in reducing energy consumption, and the quality of the nanofibrils produced by this pretreatment was inferior to the others. This study showed innovation in performing novel and efficient NaOH and hybrid (NaOH/H202) pretreatments on commercial unbleached pulps to obtain pulp micro/nanofibrils. [ABSTRACT FROM AUTHOR]

In addition to the large volume, the generated wastewater in paper and cardboard recycling industry contains various organic compounds and dyes. Treatment of these wastewaters is difficult due to the diversity of contaminants and the complexity of their chemical structure. This study aimed to investigate the efficiency of the coagulation and flocculation process by the new mixture of coagulants for wastewater treatment in one of the paper and cardboard recycling industries. To determine the efficiency of the coagulation and flocculation process in removing the parameters, including turbidity, colour, TSS, and COD, the Jar Test was used in laboratory conditions. By changing the variables, such as pH, coagulant type (PAC/MgCl2, PAC/Polymer, MgCl2/Polymer, MgCl2/PAC, PAC/MgCl2/Polymer), coagulant dose, and polymer dose, the optimal conditions were determined. Based on the results, the highest turbidity removal efficiency was achieved for the combination of coagulant and coagulant aid (PAC/MgCl2/Polymer) at pH 11. According to the experiments, the highest removal efficiency of turbidity, colour, COD and TSS were95.43%, 25.16%, 16.16%, and 83.33%, respectively. According to the obtained results, the coagulation and flocculation is a suitable method to remove turbidity and suspended solids in the paper and cardboard recycling industry wastewater. However, in order to remove more colour and COD, additional treatment is required. [ABSTRACT FROM AUTHOR]

Opuntia ficus-indica: (OFI) cladode mucilage was extracted using conventional extraction (CE) and ultrasound-assisted extraction (UAE), to test its effect on the efficiency of electrocoagulation-electroflotation (EC-EF) water treatment process. The mucilage was identified by biochemical assays, by scanning electron microscope analysis (SEM), and by Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The results showed that the UAE enhanced mucilage extraction yield. At 10 min of extraction time, the extraction yield attained 60.77 ± 1.07% at 60% of the amplitude sonication, while CE allows only 36.71 ± 1.07% after 60 min at 80 ⁰C. EC-EF mucilage-assisted process enhanced turbidity removal efficiency by 30% at 15 min of treatment time. Mucilage identification showed a bio-material, of a polysaccharide nature, with several functional groups through SEM, biochemical essays and ATR-FTIR, respectively. The addition of 5 mg/L OFI mucilage to EC-EF allowed 89.47% of EC-EF efficiency at 25 min. [ABSTRACT FROM AUTHOR]

This study evaluated Al-based coagulants for turbidity removal optimization in drinking water facility using Jar test and CCD/RSM analysis. The wide use of aluminum salts requires researching improved Al-based coagulants to reduce the treatment dosage. Eight polyaluminum chloride coagulants (PACl), i.e., Hyperlon 4064-PACl 2, Hyperlon 4393, 1757 X1, 1757 XL8- PACl 1, Ultrafloc 1406, Ultrafloc 3759, AlcoPAC 6, and AlcoPAC 1010 were first compared using a series of jar tests to determine the best candidate in removing the settled and filtered turbidity in water. The results showed that all PACls performed better than alum in removing water turbidity, but Hyperlon 4064 was the best. Then, the central composite design/response surface methodology (CCD/RSM) analysis was applied to Hyperlon 4064 to optimize dosage and pH to achieve the lowest final settled and filtered turbidity in the treated water, which were 21.7 mg/L, 7.53 and 27.95 mg/L, 7.91, respectively. Two quadratic models were generated by the CCD/RSM analysis with high correlations between the actual and predicted responses (R2 = 0.9881 and 0.9809 for final settled turbidity and final filtered turbidity). The results from this study can provide useful information to the operating water treatment plants that use Al-based coagulants to remove turbidity in water. [ABSTRACT FROM AUTHOR]

It is difficult to predict and manage the ecological consequences of multiple water quality stressors on our freshwater systems. This is due to the dynamism of the source-stressor-response relationships and multiple factors including lack of data, complex impact pathways and risks, and uncertainties that are difficult to parameterise. We present a risk-based probability modelling approach using a Bayesian network (BN), to manage multiple water quality stressors at multiple spatial scales. We illustrate the use of this approach, by evaluating the probable ecological effects of altered water quality associated with multiple sources in three case study rivers in South Africa. Water quality and land use activity were used to describe conceptual risk pathways, parameterise the BNs and model the probable consequences of multiple water quality stressors. The BN model demonstrated that the endpoints that were selected for the study reflected the risks associated with the levels of the input water quality variables. The model further demonstrated that the electrical conductivity BN was just as sensitive as the more complex salt model. The BN model was further able to accurately represent risks to all systems irrespective the water quality data base size. This approach can contribute towards more sustainable water resource management. [ABSTRACT FROM AUTHOR]

Photo-aging is caused mainly by sun radiations, which consist mainly of the ultraviolet radiation (UVA and UVB). Ascorbic acid (AA) has been widely used in the cosmetic field as an anti-wrinkle, anti-pigmentary, and antioxidant agents, however, its cosmetic application is limited due to its poor penetration across the skin, rapid oxidation, and instability of the formulation. The objective of the present study was to utilize a nanoemulsion as a nanocarrier strategy to deliver AA dermally and stabilize it. A concentration of 80 mg/mL AA was loaded into oil-in-water (O/W) nanoemulsion and characterized in terms of droplet size, zeta potential, thermodynamic stability, and morphology. Patches were then prepared using hydroxypropyl methylcellulose (HPMC) and sodium carboxymethyl cellulose (NaCMC), AA nanoemulsion, and plasticizers (PEG 400 in Formulation 1, F1, and isopropanol in Formulation 2, F2) and evaluated in terms of stability, in vitro release, and ex vivo permeation study. The mean droplet size of the AA nanoemulsion was 14.4 ± 1.9 nm, zeta potential was close to zero. The AA nanoemulsion was physically stable showing no phase separation or turbidity after centrifugation and heating/cooling tests. The cumulative amount per area of AA permeated across Strat-M® membrane was 602.2 ± 57.9 µg/cm2. The ex vivo permeation profile showed a controlled-release profile of AA within 24 h, achieving a maximum amount of 414 µg permeated across the stratum corneum. The release fitted the Higuchi model with a correlation coefficient of 0.995. Nanoemulsion-based patches could serve a potential system for the dermal delivery of unstable hydrophilic compound [ABSTRACT FROM AUTHOR]

The Cenomanian/Turonian strata of the Kasserine area: Tunisia exhibit a unique sedimentological and palaeontological pattern. Five lithological units have been identified: 1) lower unfossilferous black shale; 2) well-bedded marly unit with thin limestone interbeds; 3) marl unit, 4) same as 2, and 5) unfossilferous dolomitic thick-bedded limestone. The middle three units contain low diversity macrofaunal communities dominated mainly by oyster bivalves with few gastropods and echinoids. Fortunately, three marker ammonite species were identified and are used to subdivide the studied interval into three biozones, including 1) Calycoceras cenomanense, 2) Pseudaspidoceras pseudonodosoides and 3) Neoptychites Cephalotus. Based on constrained clustering and ordination techniques, three distinct macrofaunal associations were identified: 1) Ceratostreon flabellatum, 2) Ilymatogyra africana and 3) Tylostoma (Tylostoma) globosum. In general, the macrofaunal diversity decreases at the Cenomanian-Turonian boundary, which is interpreted to be a consequence of a global sea-level rise and the destruction of shallower habitats. Based on the life habits of the macrofaunal communities, a change from a high-energy (Ceratostreon and Ilymatogyra) to a low-energy (Tylostoma) shallow marine environment was indicated. The dominance of oysters in these nutrient-rich sediments was attributed to their ability to tolerate high turbidity water and to colonise soft-substrate sea bottoms. [ABSTRACT FROM AUTHOR]

Estuaries are hotspots of primary productivity and nutrient transformation that contribute to food webs and ecosystem functioning locally and in adjacent ecosystems. The depth-dependence of nutrient transformation and primary productivity rates in the water column and the seafloor were investigated, and the lateral transport of solutes and materials across the estuary mouth were quantified. Using an estuary dominated by shallow soft-sediment habitats as a case study, the effects of sea level rise (SLR) on productivity and nutrient transformation processes were projected. The estuary was a net importer of dissolved nutrients from the coast, and a net exporter of suspended sediments and chlorophyll a, supporting the notion that estuaries are important nutrient transformation reactors. A significant depth (and light) effect on productivity indicates that increasing stressors associated with climate change that reduce light at the seafloor (SLR and increased turbidity) will negatively impact estuarine productivity. Intertidal and shallow subtidal benthic habitats were responsible for most of the productivity of the estuary and this is likely to be consistent for other shallow estuaries globally. SLR and anthropogenic intervention that prevents landward migration (i.e. seawalls and armouring), will result in the loss of these habitats and their significant contributions to adjacent coastal ecosystems. [ABSTRACT FROM AUTHOR]

The taxonomic composition of the diatom flora of the Taleghan River and reservoir in Iran is described. The Taleghan River is one of the main tributaries of the Sepid Roud River, which is the second-longest river in Iran (∼ 670 km). Its headwaters are located in the Alborz Mountains in northwestern Iran and discharge into the Caspian Sea (North Iran). The current study was conducted from November 2017 to October 2018. A total of 167 taxa belonging to 49 genera and 27 families were identified. Nitzschia (28 spp.) Navicula (20 spp.), Cymbella (12 spp.), and Gomphonema (10 spp.) were the most abundant genera. The identified taxa can be classified as oligosaprobic to eutrophic and Canonical Correspondence Analysis (CCA) showed that temperature, NO32−, salinity, turbidity, EC, Si, and DO were the most significant environmental variables influencing diatom assemblages across seasons and sites in the river. [ABSTRACT FROM AUTHOR]

Chlorine and chloramine are widely used to maintain the microbial safety after drinking water treatment plants. Particles existing in the treated water may react with these chemical disinfectants, and impact the efficacy of disinfection. However, the protective effects of particles without-disinfectant demand on bacteria in the chlorination/chloramination are not well known. In this study, two laboratory-derived bacteria (Staphylococcus aureus and Escherichia coli) and two no-disinfectant demand particles (Fe2O3 and kaolin) in drinking water were selected to build particle-associated bacteria (PAB) systems, and their resistance to chlorine/chloramine was further assessed. Flow cytometry (FCM) was employed to image PAB systems and assess the removal rate of bacteria. The results were that particles showed protective effects on bacteria in half of chlorine experiments and 90% of chloramination. The protection was related to the combination form of particles and bacteria tied to neither particle species nor size, and there was no positive relationship between the protection effect and water turbidity. S. aureus attached to Fe2O3 had stronger resistance than kaolin, and kaolin protected E. coli better than Fe2O3. The same trend was observed in both chemical disinfectants, and more significant resistance had been shown in chloramination than chlorination. FCM images which gave a qualitative description on the combination states of different PAB systems may be a clue to explain the strength of the resistance. Environmental bacterial strains and particles are recommended in the future to explore practical applications. [ABSTRACT FROM AUTHOR]

Our goal is to compare the performance of Classification and Regression Tree, Naive Bayes and Random Forest algorithms, from supervised image classification, and approaches on Pixel-Based Image analysis (PBIA) and Geographic Object-Based Image Analysis (GEOBIA), to classify turbidity in reservoirs. Tod do so, we use Landsat 8 image and bands and spectral indices, as predictive parameters, as well as the classification algorithms based on PBIA and GEOBIA. The Brazilian Itaipu reservoir was adopted, as a case study. Our results show that the RF classifier obtained the highest accuracy in both classification approaches, followed by CART and NB. The KA and OA indices of the GEOBIA classifications were superior to the PBIA classifications in both algorithms. This study contributes with an approach to quickly and accurately delineating turbidity spectral limits in reservoirs. [ABSTRACT FROM AUTHOR]

The Lake Saint-Pierre (LSP) is a wide (≈300 km2) and shallow (≈3 m) lake created through a widening of the St. Lawrence River. Each spring, freshet makes it the largest floodplain in the province of Quebec. Agricultural practices in the littoral increase the water turbidity, which deteriorate the habitat's quality of many fish species. However, measuring spatio-temporal turbidity patterns in the LSP floodplain remain difficult because turbidity is highly variable in space and time. This study aims to evaluate the potential to use an Unmanned Aerial Vehicle (UAV) to measure the water turbidity in the LSP's floodplain. The results show that the UAV can efficiently measure the variation of turbidity in the LSP with a RMSE of 28.22 FNU. We also compared the turbidity retrieved from UAV with those retrieved from Sentinel-2 observations. The results show that the two models are comparable, even if Sentinel-2 yields better results. However, challenges remain when using UAV for turbidity monitoring, such as software limitations for mosaics creation over large water bodies. Nevertheless, the high spatial and temporal information can provide insights into the complex water turbidity patterns which characterize floodplains. The method could help land use management to improve the water quality of these ecosystems. [ABSTRACT FROM AUTHOR]

Optical imaging usually shows significant differences in underwater environments with different characteristics. The general underwater imaging model ignores the influences of turbidity on the attenuation of light. For turbid water with different particle types and concentrations, we introduced background light correction and turbidity factors to express the influences. A parametric turbid underwater image generation model based on dark channel prior theory was proposed, in which, the transmission map changes with the turbidity while the image tone changes with the background light correction. Based on experiments, the high similarity between generated images and real images confirmed that our model can fit the imaging in different bodies of water. Thus, the model can be used to generate a greater diversity of samples of turbid underwater images. We also applied the model to turbid underwater image enhancement. The image quality evaluation results indicated that the model can enhance turbid underwater images well. [ABSTRACT FROM AUTHOR]

This work combines in situ measurements with a time series of satellite turbidity derived from Landsat 8-OLI images to provide a first synoptic overview of the main hydrometeorological drivers of turbidity in the Bahía Blanca Estuary (Argentina). An empirical relationship between turbidity and SPM concentrations was established for the study area (R2 = 0.92; RMSE = 0.098 mg m−3; NMAE = 6.2%). Several atmospheric correction schemes and turbidity retrieval algorithms were tested and the combination of the SWIR-v and the retrieval algorithm by Dogliotti et al. (2015) were applied to 121 Landsat 8-OLI scenes (2013–2021). The effects of tides, winds, and rainfall on satellite turbidity were evaluated through Generalized Linear Models (GLM) built for three different sectors along Canal Principal, from the inner zone to its mouth. Regardless of the zone, cumulative rainfall had negligible effects on turbidity. Tides had a significant effect in the inner and middle zones. In the inner zone, higher turbidity values significantly associated with ebb tide conditions, which produce erosion. In the middle section tidal current speeds positively correlated with turbidity, suggesting sediment resuspension over shallow banks. Close to the mouth of the estuary, turbidity responded entirely to winds. Winds blowing from de NW, aligned with the azimuth of Canal Principal, would aid to the export of estuarine sediments to the shelf. [ABSTRACT FROM AUTHOR]

One of the expected outcomes of global warming is increased algal and cyanobacterial blooms. Based on its ability to separate algal particles, dissolved air flotation (DAF) is considered as a climate change adaptation technology for water treatment. The feasibility of DAF treatment is often assessed using DAF jar tests; however, they are not particularly good at predicting a full-scale DAF system's turbidity removals. Therefore, our group has developed a more reliable larger-diameter/larger-volume batch apparatus (LB-DAF), which was optimized by comparison with a full-scale DAF plant treating a low turbidity, highly coloured river water (SUVA ∼ 4.3). The objective of this study was to verify that the LB-DAF was capable of simulating full-scale DAF systems treating two significantly different waters. One was water from a large eutrophic bay in Lake Ontario (SUVA ∼2.6) and the second was a river water (SUVA ∼3.5). The turbidity removals achieved by the full-scale DAF systems treating these waters were compared with those for the LB-DAF tests conducted using different flocculation velocity gradients, saturated water pressures, recycle ratios and water depth to diameter ratios. The LB-DAF tests are good predictors of the full-scale DAF turbidity removals, the average difference for the two waters tested were 2% and 6%. The LB-DAF natural organic matter (NOM) removals for both waters differed by less than 1% from that measured at the corresponding treatment plants. In addition, as in our previous LB-DAF study, varying the different LB-DAF operational variables did not have a significant impact on turbidity and NOM removals. [ABSTRACT FROM AUTHOR]

In this study, cellulose was extracted from waste paper using alkaline and bleaching treatments. The flocculation performance of six quaternized cellulose (QC) samples (QC-1, QC-5, QC-10, QC-15, QC-20, and QC-30) was evaluated through kaolin suspension using the standard jar test method at varying flocculant dosages, kaolin concentrations, pH values, and settling times. The cellulose content of the waste paper and extracted celluloses were 68.6% and 78.1%, respectively. Fourier-transform infrared spectroscopy, x-ray diffraction, thermogravimetric analysis, and scanning electron microscopy showed that the waste paper properties changed after chemical treatment, confirming that the extracted product was cellulose. The QC derivatives were homogeneously synthesized by reacting the extracted cellulose with 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) in the aqueous medium of sodium hydroxide/urea. QC-15 exhibited a highly effective flocculation capability (99.67%) compared to alum (83.91%), with good performance in a wide pH range. The flocculation kinetics (kNo: 5.9 × 10−1 s-1) supported this finding. QC-15 removed 99.67% of turbidity compared to alum (83.9%). Besides, filtration of the conditioned sludge with QC-15 was relatively easy, with low specific resistance compared to the commercial alum. Overall, Q-15 was an effective and environmentally friendly flocculant with potential application for treating drinking water. [ABSTRACT FROM AUTHOR]

Turbidity is one of the key water quality parameters in environmental monitoring, water treatment or industrial process operation. Turbidity is however very challenging to measure reliably due to the many factors affecting the reading and functionality of the measurement device. In this paper, the results of the experiments to study the effects of changes in water quality and environmental condition to the readings of turbidity measurement devices are presented. The experiments were carried out in stable laboratory conditions where controlled changes were made to water pH, the temperature, salinity, colour, environment brightness and the mixing speed of the water. The study showed that even though the actual turbidity of the water remained constant the changes in other variables caused in the worst-case significant disturbances to the turbidity measurements. This knowledge is vital, for instance in monitoring or developing a robust model for forecasting regional turbidity in natural waters. [ABSTRACT FROM AUTHOR]

The Upper Blue Nile Basin (UBNB) is the main flow contributor to the downstream river. Given the competing demands, we characterize the water balance by statistical analysis of past observations and data assimilation models. UBNB runoff shows minimal trend (1% of variance) and a large annual cycle (69%) governed by the equatorial trough and Hadley circulation. The diurnal cycle linked to local heat fluxes contrasts with modulation by the slower Pacific El Niño Southern Oscillation and faster Indian Dipole. Using daily measurements over ~25 years, we found that the inflow to Lake Tana (average 48 m3/s) obtains a linear regression fit of r2 = 76% with the discharge at Khartoum (average 1380 m3/s) at a lag of +6 days, implying that the small catchment conveys the hydro-climate signal to the entire Nile Basin. The inflow-induced turbidity in Lake Tana was studied using changes in colour detected by satellite. Land-use changes in the UBNB were quantified by satellite infra-red temperature and aerosol density. Trends in vegetation temperatures showed a + 0.2°C/year rise in agricultural zones. Ensemble model-projected trends in runoff are upward and may keep pace with the growing demand for Nile water. [ABSTRACT FROM AUTHOR]

In the present investigation, the settling performance of coal fine tailings was optimized with central composite rotatable design and response surface methodology. Pulp density, pH, and flocculant dosage were considered as theoperating parameters in the study. The maximum settling rate was observed as 230 mm/min while minimum turbidity was observed as 26.7 NTU. Coefficient of correlation (R2) between the experimental and the predicted values of the settling rate and the turbidity wereobserved to be 0.99 and 0.99, respectively. The optimum conditions of pH 7.6, flocculant dosage 16.43 gpt, and pulp density 5.4% solid, w/w, were obtained from the desirability function at the desirability of 89%. [ABSTRACT FROM AUTHOR]

Landsat-8 (L8) and Sentinel-2 (S2) terrestrial satellite missions have shown to contain useful information for aquatic applications. However, quantitative retrieval of water quality parameters, such as turbidity, strongly depend on the performance of atmospheric correction algorithms. Among available processors, ACOLITE () is simple to incorporate in imagery processing routines and has shown to have better performance than other processors for sediment-rich waters. Recently (in 2018), it incorporated a new default atmospheric correction approach, the dark spectrum fit (DSF), which remains to be tested in most of the Southern hemisphere coastal areas. In this work, we present new in-situ radiometric measurements collected in the northern coast of the Río de la Plata estuary, South America, during field campaigns along a 2-year period. The data set was used to evaluate the performance of ACOLITE's DSF and exponential extrapolation (EXP) methods with L8 and S2 imagery, and to recalibrate a turbidity algorithm. The DSF did not perform very well, giving particularly poor results in the near infrared (NIR) bands. However, its performance was greatly improved with an optional sun glint correction (DSF+GC), although some positive bias was still present in the NIR bands. A GC seemed to be most important in dates with higher sun elevation (austral spring and summer), and should be strongly considered for other water bodies in the region and in similar or lower latitudes (35°S). Additionally, the EXP method gave good results in the green-NIR spectral region when a low (5th) percentile aerosol type was selected. Finally, the effect of the atmospheric correction on turbidity retrieval from satellite imagery was assessed: if the red and a NIR band were combined, the effect of the bias in the NIR region was negligible for the DSF+GC method; however, some impact was noticed for the lowest turbidity levels if a single NIR band was used. [ABSTRACT FROM AUTHOR]

Environmental changes for the past ca. 50 years were studied in a short sediment core from inner Krossfjorden, Svalbard, investigating benthic foraminifera and stable isotopes ƹ18O, ƹ13C). A depth-age model based on anthropogenic 137Cs time markers indicates that record covers the period from 1955 to 2007 and has sediment accumulation rates of ca. 0.3 to 1 cm/year. The benthic foraminifera are arctic and/or common in glaciomarine environments. Six fauna assemblages were identified using stratigraphically constrained cluster analysis. Benthic foraminiferal fauna assemblages are mainly dominated by Cassidulina reniforme. Elphidium clavatum is dominant from 1973 to 1986 and 2002 to 2007, likely due to greater turbidity in the water column. We interpret the increased percentages of Spiroplectammina biformis over the same intervals to reflect a slightly lower salinity probably caused by meltwater. During a short time period, 1970 to 1973, Stainforthia concava dominates the benthic foraminiferal fauna interpreted to reflect increased productivity within a marginal ice zone. Other species as Islandiella norcrossi, Nonionellina labradorica, Islandiella helenae, and Melonis barleanus also indicate more nutrient-rich waters are present but not very abundant throughout the record probably due to the glacier proximal position of the study site. The stable isotope record (ƹ18O) shows lighter values from 2001 to 2007, which seem to correlate well with oceanographic monitoring data showing increasing core temperatures of West Spitsbergen Current. [ABSTRACT FROM AUTHOR]

The nature of undesirable and unfilterable haze particles observed by craft breweries remains nebulous and presents a challenge when the aim is the production of bright beer. A commercial beer was studied in which the brewery had sporadically encountered unfilterable haze. In this study, it was hypothesized that unfilterable haze particles were formed due to increased concentrations of proteins, polyphenols, and/or beta-glucans. Samples of a high haze and low haze India Pale Ale were degassed and digested with enzymes amyloglucosidase, pepsin, and UltraFlo Max (NovozymesTM). Additionally, the protein, polyphenol, and beta-glucan content of each sample was measured. When comparing protein, polyphenol, and beta-glucan concentrations substantial differences between high haze and low haze protein concentrations were observed. Due to the unfilterable nature of these hazes, combined with experimental findings, it was hypothesized that yeast cell-wall proteins were responsible for this haze. Understanding of the source of these hazes offers brewers the opportunity to mitigate against their formation by adjusting brewing practices. [ABSTRACT FROM AUTHOR]