Search Results (178)

The accurate dosing of polyaluminum chloride (PAC) is essential for achieving effective coagulation in drinking water treatment, yet conventional methods such as jar tests are limited in their responsiveness and operational efficiency. This study proposes a hybrid modeling framework that integrates artificial neural networks (ANN) with genetic algorithms (GA) to optimize PAC dosage under variable raw water conditions. Operational data from 400 jar test experiments, collected between 2022 and 2024 at the Yanahurco water treatment plant (Ecuador), were used to train an ANN model capable of predicting six post-treatment water quality indicators, including turbidity, color, and pH. The ANN achieved excellent predictive accuracy (R² > 0.95 for turbidity and color), supporting its use as a surrogate model within a GA-based optimization scheme. The genetic algorithm evaluated dosage strategies by minimizing treatment costs while enforcing compliance with national water quality standards. The results revealed a bimodal dosing pattern, favoring low PAC dosages (~4 ppm) during routine conditions and higher dosages (~12 ppm) when influent quality declined. Optimization yielded a 49% reduction in median chemical costs and improved color compliance from 52% to 63%, while maintaining pH compliance above 97%. Turbidity remained a challenge under some conditions, indicating the potential benefit of complementary coagulants. The proposed ANN–GA approach offers a scalable and adaptive solution for enhancing chemical dosing efficiency in water treatment operations. Full article

Volcanic rock is a natural mineral material which has garnered interest for its potential application in water treatment due to its unique physicochemical properties. In this study, we prepared a polysilicate aluminum chloride (PSAC) coagulant using volcanic rock which exhibited good coagulation–flocculation performance. Further investigation into the influence of synthetic parameters, such as calcination temperature, reaction time, and alkali types, on the structure and performance of a volcanic rock-derived coagulant was conducted. Techniques including Scanning Electron Microscopy, Energy-Dispersive Spectroscopy, Fourier-Transform Infrared Spectroscopy, and X-Ray Diffraction were utilized to characterize it. Also, a ferron-complexation timed spectrophotometric method was used to study the distribution of aluminum species in the coagulant. Results indicated that the volcanic rock that was treated with acidic and alkaline solutions had the potential to form PSAC with Al-OH, Al-O-Si, Fe-OH, and Fe-O-Si bonds, which influenced the coagulation–flocculation efficiency. An acid leaching temperature of 90 °C, 8 mL of 2 mol/L NaOH, a reaction time of 0.5 h, and a reaction temperature of 60 °C were conducive to the preparation. A higher temperature could result in a higher proportion of Alb species, and, at 100 °C, the Ala, Alc, and Alb were 29%, 24%, and 47%, respectively, achieving a residual turbidity lower than 1 NTU at an appropriate dosage, as well as a reduction of over 0.1 to 0.018 in the level of UV₂₅₄. The findings of this study provide a feasible method to prepare a flocculant using volcanic rock. Further application is expected to yield good results in wastewater/water treatment. Full article

Currently, there is a demand for effective flocculant systems that can be used without adverse impact on the environment and health. However, the challenge is to find the minimum dose to achieve the same efficacy as conventional flocculants. One technique involves using a mixture of natural and synthetic flocculants, the synergistic effects of which can enhance treatment efficiency. Thus, this work provides an approach using a low-cost chitosan (CH56)–polyaluminum chloride (PAC) mixture as a flocculant system for river water. Therefore, water quality was monitored in the Tamazula and Humaya rivers, which are sources of water for potabilization plants. According to the results of flocculation tests, the use of the mixture required a lower dosage (0.75 mg L⁻¹ of CH56 with 1 mg L⁻¹ of PAC; 0.75 mg L⁻¹ of CH56 with 2 mg L⁻¹ of PAC) than that used with individual flocculants (3 mg L⁻¹ of CH56; 5 mg L⁻¹ of PAC). Conveniently, the mixture produced larger and more compact flocs, favoring sedimentation kinetics and thus flocculation. Fractal dimension (F_D) and lacunarity (Λ) from microscopy images were used as indicators of the quality of the flocs formed. In general, CH56 and the mixture performed better than PAC, and the mixture allowed the best removal of the model microplastic (polystyrene). Flocculant mixtures reduced the concentration of copper ions by 58%, of tetracycline by 22%, of microplastics by 80%, and of bacteria by >90%. Hence, the authors believe that this work offers valuable information that could be used for potabilization plants aiming to reduce the dose of PAC and introduce chitosan into their coagulation–flocculation process. Full article

The release of synthetic dyes like Basic Red 46 (BR46) from industrial wastewater has raised growing concerns due to their toxicity, long-term persistence, and resistance to standard biological treatment methods. In this work, we developed and tested a pilot-scale electrocoagulation–ozonation (EC–O) hybrid system aimed at removing BR46 from aqueous solutions. The system integrates electrocoagulation, using iron electrodes, with ozone-based advanced oxidation processes, facilitating a combination of coagulation, adsorption, and oxidative breakdown of dye molecules. The response surface methodology (RSM) with a central composite design (CCD) was applied to optimize the treatment process, focusing on five variables: current density, flow rate, ozone dosage, ozonation time, and initial dye concentration. The quadratic model exhibited strong predictive power, with an adjusted R² of 0.9897 and a predicted R² of 0.9812. The optimal conditions identified included a current density of 70 A/m², flow rate of 1.6 L/min, ozone dose of 2.0 g/h, and an ozonation time of 20 min, achieving a predicted removal efficiency of 91.67% for a solution with BR46 at an initial concentration of 300 mg/L. Experiments conducted under these conditions confirmed the model’s reliability, with observed removal rates exceeding 90% and deviations under 2%. The EC–O system had a treatment capability of 26.19 L/h and an energy consumption of 3.04 kWh/m³. These findings suggest that the EC–O system is an effective and scalable option for treating dye-contaminated wastewater, offering faster and more efficient results than conventional techniques. Full article

High turbidity in raw water poses a major challenge to drinking water quality and requires effective, sustainable treatment solutions. This work investigates the reduction in turbidity in raw water and the enhancement of overall drinking water quality through the coagulation–flocculation process. The performance of Pine cone extract as a bio-coagulant was evaluated using four different solvent-based extractions (PC-H₂O, PC-HCl, PC-NaCl, and PC-NaOH). The effects of key operational parameters were analyzed, and jar tests were carried out to enhance the coagulation–flocculation process by identifying the optimal conditions. Experimental design was further refined using RSM based on a BBD, incorporating three factors: initial pH, coagulant dosage, and settling time, with turbidity removal efficiency as the response variable. Statistical analysis confirmed that initial pH, coagulant dosage, and settling time significantly influenced turbidity reduction at a confidence level of p-value < 0.05 for all four solvents. Among the extracts tested, PC-HCl demonstrated the highest turbidity removal efficiency. The optimal conditions achieving 78.57% turbidity reduction were a pH of 8.5, a coagulant dosage of 100 mL/L, and a settling time of 120 min. These findings highlight the significant potential of Pine cone extract as an effective, sustainable, and eco-friendly organic coagulant for raw water treatment. Full article

This study evaluated the combined effect of a cationic coagulant (Magnafloc 1727^®) and a high molecular weight anionic flocculant (SNF 604^®) on the settling properties, aggregate structure, and rheological behavior of synthetic tailings suspensions composed of kaolinite and quartz in industrial water at pH 11. Settling tests, focused beam reflectance measurement (FBRM), zeta potential measurement, and rheological characterization were used to analyze the system’s performance under different coagulant dosages (0–150 g/t), while keeping the flocculant dosage constant (20 g/t). The results indicated that the coagulant favored surface charge neutralization, shifting the zeta potential from −13.2 mV to +4.0 mV. This resulted in larger, more efficient flocs capturing fines, with a 46% turbidity reduction. FBRM analysis revealed a significant increase in aggregate size and a slight decrease in fractal dimension (from 2.35 to 2.20), consistent with larger volume structures and lower bulk density. Rheologically, a substantial increase in yield stress was observed, especially in 50 wt% suspensions, suggesting the development of a continuous flocculated network with greater mechanical strength. These findings highlight the importance of sequential chemical conditioning in clayey tailings and its impact on clarification efficiency and water recovery under alkaline conditions representative of industrial mining processes. Full article

In this study, the treatment of pharmaceutical tail water (PTW) by coagulation, Fenton combined with membrane bioreactor (MBR), was studied. Optimal parameters were obtained according to batch experiment and central composite design (CCD). Results showed that Polymeric Ferric Sulfate (PFS) was the best coagulant for original pharmaceutical tailwater due to less dosage and higher removal efficiency to TOC, COD, NH₄⁺-N and UV_254m, with the optimized pH = 7.25 and 0.53 g/L PFS dosage. The best coagulation performance was achieved when the mixer was stirred at 250 rpm for 3 min, 60 rpm for 10 min, and then left to stand for 60 min. Coagulation mainly removed organics with molecular weight above 10 kDa. After treated by coagulation, 43.1% TOC removal efficiency of PTW was obtained by Fenton reaction with 11.6 mmol/L H₂O₂, 3.0 mmol/L FeSO₄, pH = 3.3 and T = 50 min. A type of common macromolecule aromatic amino acid compounds which located Ex = 250 nm and Em = 500 nm was the main reason that caused the high TOC concentration in the effluent. Stable COD and NH₄⁺-N removal efficiencies in the MBR reactor within 10 d were observed when the mixture of pre-treated PTW (20%, v) and domestic sewage (80%, v) was fed into the MBR reactor, and over 95% COD and 50% NH₄⁺-N were removed. One kind of amino acid similar to tryptophan was the prime reason that caused PTW resistance to be degraded. Analysis of the microorganism community in the MBR suggested that norank_f__Saprospiraceae was the key microorganism in degrading of PTW. Full article

This study proposes a circulating pelletized fluidized bed (CPFB) with micro-sand loading for treating high-algae surface water. Key operational parameters (coagulant dosage, flow rate) were optimized to simultaneously remove algae, turbidity, and disinfection byproduct precursors. Results revealed that 20 mg/L polyaluminum chloride (PACl) and 0.8 mg/L PAM achieved optimal removal of algae (density removal > 80%) and organic matter. The fluidized bed exhibited robust performance across algal species, with the highest dichloroacetonitrile (DCAN) precursor removal of 66.20%, demonstrating superior efficiency for trihalomethane precursors over haloacetic acids. These findings provide critical operational guidance for high-algae water treatment using fluidized beds. Full article

The wastewater treatment involves various techniques at different technological levels. Treatment takes place in several stages, of which coagulation and flocculation are the most important. Most suspended solids are indeed eliminated during this stage by the addition of a coagulant. In this research, bio-coagulant was extracted from pumpkin seed (PS) waste after extraction of the essential oils, and used with ferric chloride to treat wastewater from the plant of Chalghoum El Aid-Oued El Athmania Mila. In this study, the Box–Behnken design (BBD) with three factors was used to investigate the effect of pH, organic coagulant dosage Pumpkin seed extract (PSE), and chemical coagulant dosage (FeCl₃) on coagulation–flocculation performance in relation to turbidity, chemical oxygen demand (COD), aromatic organic matter (UV 254), and phosphate. The main characteristics of the raw water were turbidity (250 NTU), COD (640 mg/L), UV 254 (0.893 cm⁻¹), and phosphate (0.115 mg/L). The results obtained were very significant. All the statistical estimators (R² ≥ 97% and p ≤ 0.05) reveal that the models developed are statistically validated for simulating the coagulation–flocculation process. It should be noted that the residual values of turbidity, COD, UV 254, and phosphate after treatment by this process were 0.754 NTU; 190.88 mg/L; 0.0028 cm⁻¹; and 0.0149 mg/L, respectively. In this case, the pH, bio-coagulant dosage, and chemical coagulant dosage values were 4; 17.81 mL/L; and 10 mL/L, respectively. In this study, Fourier-transform infrared spectrometer (FTIR) and scanning electron microscope (SEM) characterization of the bio-coagulant proved the presence of the active functional groups responsible for coagulation, namely carboxyl group. Full article

Fluoride contamination in water sources presents critical public health challenges, particularly in regions where groundwater exhibits elevated fluoride levels. Chronic exposure can result in dental and skeletal fluorosis, necessitating efficient and sustainable remediation strategies. This study investigates the spherical agglomeration technique (SAT) as an alternative fluoride removal method, assessing the performance of sunflower oil versus n-heptane as humectants and evaluating the synergistic effects of Agave durangensis leaf extract. A factorial experimental design optimized dosage parameters in aqueous models and well water samples, ensuring reliable fluoride removal. Sunflower oil significantly outperformed n-heptane, achieving fluoride removal efficiencies of up to 95.19% under optimal conditions (5 mL _Hum/g _TMCs at pH 6.5). Incorporating A. durangensis extract sustained high fluoride removal while reducing the required extract dosage to 0.5 g _Extr/g _TMCs. When applied to well water samples, the SAT consistently maintained an 88.9% fluoride removal efficiency. Compared to conventional methods such as coagulation–flocculation and adsorption, the SAT demonstrated enhanced effectiveness with a lower environmental footprint. These findings reinforce the viability of sunflower oil and A. durangensis extract as eco-friendly alternatives to n-heptane, positioning the SAT as a scalable, cost-effective solution for large-scale fluoride remediation. Full article

The persistent challenge of achieving cost-effective total phosphorus (TP) removal in wastewater treatment necessitates innovative coagulant development. While polyaluminum chloride (PAC) demonstrates efficacy in eliminating total nitrogen (TN), ammonia nitrogen (NH₄⁺-N), suspended solids (SSs), and pH stabilization, its limitations in attaining economical TP removal remain unresolved. This study introduces a novel FeSO₄-Al₂(SO₄)₃ composite coagulant to address PAC’s shortcomings through systematic formulation optimization. Utilizing single-variable experiments and response surface methodology (RSM), we determined the optimal reagent combinations under simulated high-efficiency sedimentation tank conditions. The results revealed that the FeSO₄-Al₂(SO₄)₃ composite achieved a TP removal efficiency approximately 40% greater than the PAC at equivalent dosages. A cost–benefit analysis indicated an approximate 50% reduction in the chemical expenditure relative to conventional PAC-based systems. The optimized formulation demonstrated synergistic effects between the Fe²⁺ and Al³⁺ ions, enhancing the charge neutralization and sweep flocculation mechanisms. These findings establish FeSO₄-Al₂(SO₄)₃ as a technically and economically viable alternative for TP-centric wastewater treatment, with implications for process sustainability. Further investigations should validate the long-term operational stability across diverse water matrices and assess the environmental impacts of residual metal ions. Full article

Excessive nutrient levels, particularly phosphorus, in wastewater have led to severe environmental issues such as eutrophication, necessitating effective treatment methods for nutrient removal. Traditional coagulants like alum (Al₂(SO₄)₃) are commonly used but often require high dosages and are sensitive to pH, limiting their effectiveness in varying wastewater conditions. Cerium, a rare-earth element, has emerged as a promising alternative coagulant due to its ability to remove nutrients efficiently across a wide pH range. This study investigates the performance of cerium in comparison to alum for phosphorus and organic matter removal. Cerium demonstrates superior performance, achieving up to 98.9% phosphorus removal at a lower dose (1.5 mg-Ce/mg-P) compared to alum (5.0 mg-Al/mg-P) while maintaining stable removal efficiency across both acidic and alkaline conditions. Furthermore, cerium also facilitates moderate organic matter (COD) removal, achieving up to 27.9% COD removal, enhancing overall water treatment performance. The main precipitate formed during the coagulation process is cerium phosphate (CePO₄, 94% pure), which provides a stable, crystalline structure for nutrient capture. In conclusion, cerium offers a more efficient and cost-effective solution for wastewater treatment, reducing the need for pH adjustment and additional chemical inputs, while achieving higher phosphorus and organic matter removal compared to traditional coagulants. Full article

The sedimentation process of coal slurry water is influenced by numerous factors and has complex mechanisms. Its nonlinear and large hysteresis characteristics pose great challenges to process optimization control, making it a current research hotspot. This paper takes the typical slime water treatment process of a coal preparation plant as the object, and, on the basis of selecting raw coal quantity, flocculation dosage, coagulation dosage, overflow turbidity, raw coal ash content, underflow concentration, and slime quantity as the key variables, establishes a quality control method for process detection data consisting of data acquisition → data anomaly detection → data filling and noise reduction; subsequently, different machine-learning algorithms are used to predict the performance of coal-slurry-settling agents. It was found that Long Short-Term Memory shows the highest prediction accuracy for coagulants, with corresponding root mean square errors of 2.72% and 6.23%. Finally, using iFix software (version 5.5), an intelligent control system for the settling process of coal slurry water was constructed, which reduced the usage of coagulants by 31.56% and 37.21%. Full article

An understanding of snake venom pharmacokinetics is essential for determining clinical outcomes of envenoming and developing therapeutic approaches to the treatment of envenoming, especially regarding the timing and optimal dosage of antivenom administration. Daboia siamensis (Eastern Russell’s viper) envenoming causes systemic coagulopathy and severe hemorrhage including acute kidney injury. These toxic outcomes can be diminished by the administration of high quantities of Russell’s viper antivenom. This study aimed to determine the correlation between the clinical profiles of D. siamensis envenomed patients and experimental data by measuring plasma venom concentration and conducting histopathological analyses of heart, kidney, and liver tissues in rats 6 h after experimental D. siamensis envenomation. Intramuscular (i.m.) administration of D. siamensis venom to anesthetized rats (200 µg/kg) resulted in a rapid absorption of venom which reached a peak concentration at 60 min before declining and then plateauing. Urine samples detected 209.3 ± 21.6 ng/mL of D. siamensis venom following i.m. administration at 6 h. Histopathological studies showed morphological changes in heart, kidney, and liver tissues following 3 h experimental envenoming and exhibited a higher degree of severity at 6 h. A retrospective study of the clinical profile and laboratory examination of Russell’s viper envenomed patients in Central Thailand was also evaluated, showing that systemic coagulopathy and local effects were commonly observed in the early stage of D. siamensis envenoming. An abnormal increase in creatinine levels was found in 13.6% of the population. Early administration of specific antivenom within 1–2 h following envenoming is highly recommended to prevent life-threatening outcomes such as severe coagulation and acute kidney injury. Full article

Pre-mixed fluidized solidified soil (PFSS) has the advantages of pumpability, convenient construction, and a short setting time. This paper took the excavated loess in Fuzhou as the research object and used cement–fly–ash–ground granulated blast furnace slag–carbide slag as a composite geopolymer system (CFGC) to synthesize PFSS. This study investigated the fluidity and mechanical strength of PFSS under different water–solid ratios and curing agent dosages; finally, the microstructure of the composite geopolymer system–pre-mixed fluidized solidified soil (CFGC-PFSS) was characterized. The results showed that when the water–solid ratio of PFSS increased from 0.46 to 0.54, the fluidity increased by 77 mm, and the flexural strength and compressive strength at 28 d decreased to 450.8 kPa and 1236.5 kPa. When the curing agent dosage increased from 15% to 25%, the fluidity increased by 18.0 mm, and the flexural strength and compressive strength at 28 d increased by 1.7 times and 1.6 times. A large number of needle-like AFt, C-S-H gel, and C-(A)-S-H gel coagulate with soil particles to form a three-dimensional reticular structure, which is the mechanism of the strength formation of PFSS under the action of CFGC. Full article