Search Results (268)

This study focuses on the design and optimization of a monopolar electrode configuration for the hybrid electrochemical treatment of real washing machine wastewater. A combined electrocoagulation (EC) and electro-oxidation (EO) system was optimized to maximize pollutant removal efficiency while minimizing energy consumption. The monopolar setup employed mixed metal oxide (MMO) and aluminum anodes, along with a stainless steel cathode, operating under controlled conditions with sodium chloride as the supporting electrolyte. An applied current density of 15 mA cm⁻² achieved 90% chemical oxygen demand (COD) removal, 98% surfactant degradation, complete turbidity reduction within 120 min, and pH stabilization near 8. Additionally, electrochemical disinfection achieved <2 MPN/100 mL, with no detectable phenols and the presence of organic anions such as oxalate and acetate. These results demonstrate the effectiveness of an optimized monopolar EC–EO system as a cost-efficient and sustainable strategy for wastewater treatment and potential water reuse. Further studies should focus on refining energy consumption and monitoring reaction by-products to enhance large-scale applicability. Full article

Natural organic matter (NOM) in surface waters is a major challenge for drinking water treatment due to its role in the formation of disinfection byproducts (DBPs) during chlorination. This study evaluated the performance of chitosan, a biodegradable coagulant, dissolved in acetic, lactic, and L-ascorbic acids for NOM removal under three turbidity levels (403, 1220, and 5038 NTU). Jar tests were conducted using raw water from the Río Grande de Añasco (Puerto Rico), and TOC, DOC, and UV₂₅₄ were measured at multiple time points. TOC removal ranged from 39.8% to 74.3%, with the highest performance observed in high-turbidity water treated with chitosan–L-ascorbic acid. DOC and UV₂₅₄ reductions followed similar trends, with maximum removals of 76.4% and 76.2%, respectively. Estimated THM formation potential (THMFP) was reduced by up to 81.6%. Across all acids, flocculation efficiencies exceeded 95%. Compared to conventional aluminum-based coagulants, chitosan demonstrated comparable performance, while offering environmental benefits. These results confirm the potential of chitosan–acid systems for effective organic matter removal and DBP control, supporting their application as sustainable alternatives in drinking water treatment. Full article

Treated wastewater (TW) is a valuable source of water for plant irrigation, helping to protect water resources. However, to use it, a preliminary treatment is necessary, typically involving coagulation to reduce turbidity and then disinfection to ensure microbiological safety. The aim of this research was to determine changes in the concentrations of basic fertilizer components (N, P, and K) in TW after the coagulation process. The tests were carried out in three measurement series for volumetric and surface coagulation using three coagulants: Al₂(SO₄)₃, PAX-XL 19F, and PAX-XL 1911. Four doses of aluminum were used for each coagulation method (volumetric coagulation: 1, 2, 4, and 8 mg Al/L; surface coagulation: 0.25, 0.5, 1, and 2 mg Al/L). Studies have shown that despite the reduction in the concentration of nutrients during the coagulation process, the reclaimed water used for grass irrigation would cover the entire K requirement of this plant. In the case of N and P, the demand would be covered by 14.34% and 8.55%, depending on the coagulant used and its dose. It was also documented that the type of coagulant significantly influences the reduction of fertilizing properties during wastewater treatment. PAX-XL19F was found to cause the least reduction in P and K concentrations, while Al₂(SO₄)₃ had the least negative impact on N regardless of coagulation method or dose. Full article

Constructed wetlands are nature-based technologies widely used for the treatment of wastewater and contaminated surface water. This study evaluated the efficiency of free water surface (FWS) and horizontal subsurface flow (HSSF) constructed wetlands in reducing the turbidity of mine spoil rainwater using the w-C* model. Different hydraulic retention times (2, 4, and 6 days) were tested, and the influence of macrophyte type and substrate on the w parameter was investigated. Model calibration was performed based on correlation coefficients (R), coefficient of determination (R²), Nash–Sutcliffe efficiency (NSE), and root mean square error (RMSE). The results indicated a 99% reduction in turbidity, with average values of R = 0.87 ± 0.05 (FWS) and 0.87 ± 0.03 (HSSF), and NSE of 0.76 ± 0.04 (FWS) and 0.74 ± 0.07 (HSSF), demonstrating good agreement between observed and predicted data. The settling rate (w) ranged from 0.16 to 0.40 m·d⁻¹ in FWS and from 0.20 to 0.70 m·d⁻¹ in HSSF, with the lowest value recorded in the control (0.09 m·d⁻¹). The best performances were observed in FWS-P with Pistia stratiotes (0.40 m·d⁻¹) and HSSF with Typha domingensis (0.70 m·d⁻¹), demonstrating that vegetation, combined with the use of medium-grain substrate (9.5–19.0 mm), enhances turbidity removal. The w-C* model proved to be a robust tool for describing the kinetics of suspended colloidal particle removal in constructed wetlands, providing valuable insights for optimizing hydraulic parameters and design criteria for full-scale application. 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 investigated the use of ultrafiltration for sustainable protein recovery and the treatment of shrimp washing wastewater (SWW). Three ultrafiltration membranes with molecular weight cut-offs of 5, 10, and 50 kDa were tested using a combined ultrafiltration–diafiltration process (UF-DF). The performance of each membrane was assessed based on protein recovery efficiency, chemical oxygen demand (COD) reduction, turbidity, fouling behavior, and cleaning efficiency. The 5 kDa membrane showed superior performance, achieving over 90% protein and COD rejection and producing the highest protein-enriched retentate. It also exhibited the lowest fouling index and best cleaning recovery, confirming its suitability for protein concentration and wastewater treatment. This research highlights UF-DF as a promising, eco-efficient technology for valorizing seafood processing effluents by recovering high-value proteins and reducing environmental discharge loads. 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

This study investigates the effectiveness of electrocoagulation (EC) with locally sourced iron electrodes for treating olive mill wastewater (OMW) prior to adsorption with olive stone (OS). Using Response Surface Methodology (RSM), 60 experiments were conducted to evaluate various operational parameters, including current density (CD), reaction time (T), distance between electrodes (D), and the number of electrodes (N). The optimal conditions identified were a reaction time of 53.49 min, a current density of 15.1104 mA/cm², 1 cm electrode spacing, and six electrodes. Under these conditions, the removal efficiencies achieved were 54.46% for total phenols (TPh), 73.25% for total Kjeldahl nitrogen (TKN), 92% for turbidity, 58.91% for soluble chemical oxygen demand (COD_soluble), and 58.55% for total COD (COD_total), with an energy consumption of 14.3146 kWh/m³ and a projected cost of USD 3.92/m³. Following the EC process, the treated OMW underwent further adsorption using OS, enhancing pollutant removal. The combined EC and adsorption (ECA) method demonstrated superior performance, achieving TPh removal at 62.63%, TKN removal at 77.52%, and turbidity reduction at 83.73%. Additionally, COD_total removal increased to 72.88% with COD_soluble removal at 70.04%. This integrated approach significantly improves pollutant removal, presenting a promising solution for effective OMW treatment. Full article

The environmental impacts of industrial processes have increased the demand for sustainable alternatives in wastewater treatment. Conventional chemical coagulants, though widely used, can generate toxic residues and pose environmental and health risks. Biocoagulants, derived from natural and renewable sources, offer a biodegradable and eco-friendly alternative. This review explores their potential to replace synthetic coagulants by analyzing their origins, mechanisms of action, and applications. A total of 15 studies published between 2020 and 2025 were analyzed, all focused on industrial wastewater. These studies demonstrated that biocoagulants can achieve similar, or the superior, removal of turbidity (>67%), solids (>83%), and heavy metals in effluents from food, textile, metallurgical, and paper industries. While raw materials are often inexpensive, processing costs may increase production expenses. However, life cycle assessments suggest long-term advantages due to reduced sludge and environmental impact. A textile industry case study showed a 25% sludge reduction and improved biodegradability using a plant-based biocoagulant compared to aluminum sulfate. Transforming this waste into inputs for wastewater treatment not only reduces negative impacts from disposal but also promotes integrated environmental management aligned with circular economy and cleaner production principles. The review concludes that biocoagulants constitute a viable and sustainable alternative for industrial wastewater treatment. Full article

Hand hygiene (HH)-related illnesses, such as diarrhea, are one of the leading causes of death in children under five, whereas handwashing with soap can reduce infection rates in this age group. This study monitored whether a simple intervention in the form of a handwashing exercise could reduce the pathogens on preschool children’s hands, potentially reducing HH-related diseases. Hand bag-wash samples were collected from preschool children (N = 160) participating in an intervention study. The samples were collected pre- and post-intervention from the intervention group (IG) and control group (CG). The samples were analyzed using flow cytometry, where the microbiological counts and turbidity were compared between the left and right hands, genders, and pre- and post-intervention groups. The results indicated no significant difference in the microbiological counts of the left and right hands or between the genders of participants, with a significant reduction in intact live cells on the IG children’s hands post-intervention (p = 0.000). There was a significant positive correlation (p = 0.000) between the turbidity pre- and post-handwashing, with a decreased mean in terms of the turbidity recorded for both groups. Handwashing either with or without soap reduced the microbiological counts on preschoolers’ hands. Reinforcing handwashing at critical times and promoting correct handwashing procedures can assist in reducing hand-hygiene-related diseases in preschool children. Full article

The tequila industry faces several environmental challenges due to its high yields of contaminants, especially tequila distillation stillage or tequila vinasses, with ten to twelve liters produced per liter of tequila. All treatments aim to shorten retention times to avoid the need for large equipment or new facilities and the saturation of residues within tequila distilleries. The complexity of tequila vinasses has led to treatments with several stages, whereby most of the organic matter content is reduced, but the treatment range results are insufficient. This study aimed to evaluate a fourth-stage tequila vinasse treatment using an electrocoagulation system that uses inexpensive electrodes (SS cathodes and iron anodes), has a low electrical consumption, and applies low voltages in order to meet safety, economic, and environmental criteria so as to comply with Mexican norm NOM-001-SEMARNAT-2021. Three sets of voltage–amperage controllable power source, a 4 mm cylindrical 304 stainless-steel cathode, and a 9 mm iron anode with 200 mL samples in 250 mL beakers were used; three replicas (R1, R2, and R3) underwent 2 h treatment at 1–6 volts to evaluate the voltage effect and 1–6 h of 5-volt treatment to assess the time effect. All samples were filtered with 8 μm and 0.25 μm meshes. Chemical oxygen demand, pH, electrical conductivity, turbidity, and color measurements (SAC for λ 436, 525, and 620 nm) were taken. The experiments determined the optimal voltage and time, considering a hydraulic retention time below 6 h. The results show that electrocoagulation of pretreated tequila vinasses effectively helps in the final removal of organic matter measured as COD, reaching values below 150 COD mg/L at 5–6 h with 5 V treatments and color reduction with 5 V, 1 h treatment. This leads to final polishing that complies with the Mexican wastewater discharge norm criteria. Full article

The increasing prevalence of polystyrene nanoplastics (PSNPs) in aquatic environments poses significant risks due to their persistence and potential toxicity. Conventional water treatment methods have proven ineffective in removing these emerging pollutants, highlighting the urgent need for sustainable and efficient treatment. This study investigates the application of catalytic ozonation using natural pyrolusite (n-MnO₂) and oxalic acid (OA) as a co-catalyst for the environmentally friendly degradation of PSNPs. Key operational parameters, including pH, applied ozone dose, pyrolusite dosage, and OA concentration, were systematically evaluated. Results demonstrate that the MnO₂ + OA + O₃ system enhances the generation of reactive oxygen species (ROS), leading to improved PSNP removal while maintaining the applied ozone dose compared to the single ozonation reaction. The highest TOC removal of 75% was achieved within 30 min of treatment under optimal conditions (pH = 4, [MnO₂] = 0.5 g L⁻¹, [OA] = 10 mg L⁻¹, and ozone dose of 37.5 mg min⁻¹), with significant turbidity reduction, indicating both chemical and physical degradation of PSNPs. Catalyst reusability after three consecutive cycles confirmed minimal loss in activity, reinforcing its potential as a sustainable catalytic system. These findings highlight natural MnO₂-driven catalytic ozonation as a green and effective strategy for nanoplastic removal in water treatment applications. Full article

The effluent from the tannery industry contains high concentrations of organic pollutants, particularly chromium (Cr), which is a priority pollutant that harms human health, plants, animals, and affects compliance with environmental standards. This study significantly reduced tannery wastewater pollution and its toxic effects through the innovative use of an integrated treatment system with a coagulation/flocculation/settling process followed by a membrane bioreactor (MBR). Experiments were conducted to maximize the removal of pollutants by evaluating the effects of pH values, coagulant doses in the chemical treatment, and the biological treatment coupled with membrane separation within the MBR. The results indicated that optimizing the parameters achieved the highest reductions during the chemical treatment step: 97% for Cr, 63% for chemical oxygen demand (COD), and 90% for turbidity. The wastewater was then treated using the MBR system, which further improved removal efficiency to 99% for Cr, 96% for COD, and 99.8% for turbidity. These outcomes demonstrate the effectiveness of the hybrid treatment process in significantly lowering pollutant concentrations in tannery wastewater, ensuring compliance with Environmental Protection Agency (EPA) standards and the regulatory obligations under European Regulation (EU) 2020/741. This hybrid approach offers promising potential for broader industrial applications. Full article

Wastewater from soap production often contains high levels of organic pollutants, exceeding regulatory discharge limits and posing significant environmental concerns. This study investigates a two-stage treatment approach integrating ferric chloride (FeCl₃)-based coagulation–flocculation with membrane filtration to enhance wastewater purification efficiency. This method is one of the appropriate treatment techniques to reduce water pollution. Thus, numerous Jar test trials have been carried out in order to determine the optimal conditions and parameters that make it possible to reduce suspended solids. Key water quality parameters, including chemical oxygen demand (COD), pH, and turbidity, were monitored to assess process performance. Optimization experiments identified optimal coagulation–flocculation conditions, achieving a substantial COD reduction from 9200 mg/L to 351 mg/L significantly improving water quality. However, the treated effluent still failed to meet reuse standards, necessitating further purification. A subsequent membrane filtration stage was implemented, achieving a significant decrease in turbidity to 0.85 Ntu and a turbidity removal efficiency of 99.97%, indicating high treatment efficiency. The final COD of the collected water was 58 mg/L, well below regulatory limits. This hybrid treatment approach offers a highly effective and sustainable solution for soap wastewater management, supporting environmental protection and resource recovery. Full article

The growing global freshwater scarcity urgently requires innovative wastewater treatment technologies. This study hypothesized that biomimicry-inspired automated machine learning (AML) could effectively manage wastewater variability through adaptive processing techniques. Utilizing decentralized swarm intelligence, specifically the Respected Parametric Insecta Swarm (RPIS), the system demonstrated robust adaptability to fluctuating influent conditions, maintaining stable effluent quality without centralized control. Bio-inspired oscillatory control algorithms maintained stability under dynamic influent scenarios, while adaptive sensor feedback enhanced real-time responsiveness. Machine learning (ML) methods inspired by biological morphological evolution accurately classified influent characteristics (F1 score of 0.91), optimizing resource allocation dynamically. Significant reductions were observed, with chemical consumption decreasing by approximately 11% and additional energy usage declining by 14%. Furthermore, bio-inspired membranes with selective permeability substantially reduced fouling, maintaining minimal fouling for up to 30 days. Polynomial chaos expansions efficiently approximated complex nonlinear interactions, reducing computational overhead by approximately 35% through parallel processing. Decentralized swarm algorithms allowed the rapid recalibration of system parameters, achieving stable pathogen removal and maintaining effluent turbidity near 3.2 NTU (Nephelometric Turbidity Units), with total suspended solids consistently below 8 mg/L. Integrating biomimicry with AML thus significantly advances sustainable wastewater reclamation practices, offering quantifiable improvements critical for resource-efficient water management. Full article