Search Results (223)

A treatment process was developed for effluents from direct physical lithium-ion battery (LIB) recycling with a focus on the removal of organic contaminants. The high chemical oxygen demand to biological oxygen demand ratio (COD/BOD₅) of 3.9–4.6 indicates that biological treatment is not feasible. Therefore, three advanced oxidation processes were evaluated: UV/H₂O₂ oxidation, the Fenton process and electrochemical oxidation. Two target scenarios were considered, namely compliance with the limit for discharge into the sewer system (COD = 800 mg/L) and compliance with the stricter limit for direct discharge into surface waters (COD = 200 mg/L). Under the investigated conditions, UV/H₂O₂ oxidation and the Fenton process did not meet the required discharge limits and exhibited high chemical consumption. In contrast, electrochemical oxidation achieved both discharge criteria with a lower energy demand, requiring 32.8 kWh/kgCOD_removed for sewer discharge and 95.3 kWh/kgCOD_removed for direct discharge. An economic assessment further identified electrochemical oxidation as the most cost-effective option, with treatment costs of EUR 6.63/m³, compared to EUR 17.31/m³ for UV/H₂O₂ oxidation and EUR 28.66/m³ for the Fenton process. Overall, electrochemical oxidation proved to be the most efficient and environmentally favorable technology for treating wastewater from LIB recycling, enabling compliance with strict discharge regulations while minimizing the chemical and energy demand. Full article

The Electro-Fenton (EF) process is a promising technology for the sustainable remediation of organic contaminants in complex wastewater. In this study, a weak magnetic field (~150 G) was applied to enhance the performance of an EF system using magnetite (Fe₃O₄) synthesized by a controlled co-precipitation route as a recyclable solid iron source. The magnetite was characterized by FTIR, SEM/EDS, and XPS, confirming the coexistence of Fe²⁺/Fe³⁺ species essential for in situ Fenton-like reactions. Under the selected operating conditions (90 min reaction time), magnetic-field assistance improved methylene blue decolorization from 14.2% to 46.0% at pH 3. FeSO₄ was used only as a homogeneous benchmark, whereas the magnetite-based system operated without soluble iron addition, minimizing sludge formation and secondary contamination. These results demonstrate the potential of magnetite-assisted and magnetically enhanced EF systems as a low-cost, sustainable alternative for the treatment of dye-containing industrial wastewater and other complex effluents. Full article

Efficient water recycling in the hydrometallurgical industry requires the dewatering of hypersaline Na₂SO₄ or similar brines via non-evaporative methods. Unfortunately, many non-evaporative methods require the use of specific solutes and are not compatible with complex hydrometallurgical effluents. Forward Osmosis (FO) uses a draw solution to link known non-evaporative water recycling methods with feed solutions that are otherwise incompatible. There is minimal experimental data on the dewatering performance of today’s available commercial FO membranes, especially with hypersaline concentrations (>70,000 mg/L total dissolved solids). This study tests the commercially available Aquaporin HFFO2 hollow fibre FO membrane module with hypersaline Na₂SO₄ or NaCl feed solutions versus a MgCl₂ draw solution. It identifies a key requirement to maintain water flux above a certain threshold to prevent a decrease in Na Rejection or an increase in Mg reverse flux. It also defines a minimum osmotic differential that can be used to parameterize water flux, similar to the temperature of approach in heat exchangers, but to determine the extent of water removal in FO. We demonstrate that even under mildly acidic conditions, existing FO membranes can concentrate Na₂SO₄ to saturation, paving the way for their use in the hydrometallurgical industry. Full article

The effectiveness of manmade wetlands with four different macrophyte species (Arundo donax, Typha latifolia, Pistia stratiotes, and Eichhornia crassipes) in treating wastewater from the paper recycling industry, located in the Hattar Industrial Estate in Haripur, is reported. The findings show that each plant species has distinct pollutant removal capacities, which contribute to the overall treatment effectiveness of the system. Notably, Arundo donax performed exceptionally well in lowering chemical oxygen demand (COD) from 1013 mg/L to 119.66 mg/L and nitrate levels from 79.66 mg/L to 10.66 mg/L. In contrast, T. latifolia was successful in reducing biochemical oxygen demand (BOD) from 436 mg/L to 55 mg/L and total solids from 837.66 mg/L to 242.66 mg/L. The P. stratiotes species have high phosphate removal capacity, lowering values from 134.66 mg/L to 25.66 mg/L. RSM revealed that time, Arundo donax, and wetlands significantly enhance pollutant removal, while specific plant–treatment combinations yield variable efficiencies, highlighting synergistic effects crucial for optimal performance. Furthermore, all plant species have shown competency in removing heavy metals from effluent. This study’s findings highlight the potential of artificial wetlands as a natural and eco-friendly alternative for treating complex industrial wastewater, promoting the development of sustainable wastewater treatment methods in industrial settings. Full article

Background/Objectives: Environmental sustainability is increasingly recognized as a key component of healthcare governance, and dentistry represents a high-impact subsector due to its intensive use of materials, resources, and biosafety-driven disposables. Despite rising scientific interest, available evidence remains fragmented and methodologically heterogeneous. This study aims to systematically map the existing review-based evidence on sustainability in oral healthcare services. Methods: The protocol was prospectively registered on OSF. Narrative, scoping, and systematic reviews evaluating sustainability within oral healthcare services were eligible. Comprehensive searches were conducted in Embase, PubMed/MEDLINE, Scopus, Web of Science, LILACS, Cochrane Library, and regional databases (WPRIM, WHOLIS, BBO, BDENF, IBECS, PIE, ColecionaSUS), without language or date restrictions. Two reviewers independently screened studies via Rayyan, resolved discrepancies by consensus, and extracted descriptive and thematic data using a structured Population-Concept–Context eligibility framework. A qualitative inductive synthesis identified recurring domains, and methodological rigor was appraised with a modified 12-item AMSTAR-2 tool. Results: Of 5793 records retrieved, 17 reviews met inclusion criteria (8 narrative, 5 scoping, 4 systematic). Most publications (82.4%) were from the past five years. Three thematic axes were identified: (1) the 4Rs (rethink, reduce, recycle, reuse); (2) waste and effluent management; and (3) barriers, practices, and sustainability policies. Evidence was strongly concentrated in high-income countries, and methodological quality varied widely, with ten reviews scoring below 60% on AMSTAR-2. Conclusions: Review-based evidence on sustainable dentistry is expanding yet remains limited and operational in focus. The literature remains disproportionately centered on operational issues—primarily waste management and material consumption—while broader systemic determinants such as governance, equity, financing, and professional education receive comparatively little attention. Strengthening methodological rigor, harmonizing sustainability indicators, and advancing empirical evaluations are essential for guiding equitable and environmentally responsible oral healthcare systems. Full article

Textile dyeing effluents are characterized by recalcitrant organics and high salinity, requiring robust pretreatments prior to biological polishing. The heterogeneous Fenton-type (HFT) oxidation over Prussian Blue nanoparticles supported on γ-alumina (PBNP/γ-Al₂O₃) was investigated in a liquid batch-recycle packed-bed reactor treating a synthetic textile wastewater (STW) reproducing an industrial dye bath with the Reactive Black 5 (RB5) dye, together with simplified RB5 and RB5 + NaCl matrices. Hydrogen peroxide decay followed pseudo-first-order kinetics. Using fixed initial doses (11, 20, 35 mmol L⁻¹), the catalyst exhibited an early adaptation phase and then reproducible operation: from the fourth reuse onward, both the H₂O₂ decomposition rate constant and DOC removal varied by <10% under identical conditions. Among matrices, STW exhibited the highest oxidant efficiency. With an initial H₂O₂ dose of 11 mmol L⁻¹, the treatment enabled complete discoloration and produced effluents with negligible toxicity. Increasing the initial dose to 20 or 35 mmol L⁻¹ did not improve treatment and led to a decrease in the hydrogen peroxide decomposition rate with reuses and loss of PB ν(C≡N) Raman bands, indicating surface transformation. Overall, PBNP/γ-Al₂O₃ demonstrated reproducible activity and structural resilience in saline, dyeing-relevant matrices at H₂O₂ doses that preserve catalytic integrity, confirming its feasibility as a stable and reusable pretreatment catalyst for saline dyeing effluents, and supporting its integration into hybrid AOP–biological treatment schemes for dyeing wastewater. Full article

The global demand for sustainable food systems requires innovative strategies that reconcile productivity with environmental stewardship, particularly in biodiversity-rich regions such as the Amazon. This study evaluated the cultivation of Acmella oleracea (jambu) using effluent from Colossoma macropomum (tambaqui) aquaculture as a partial substitute for chemical fertilizer. Five treatments were tested under greenhouse conditions: 100% fertilizer, 75% fertilizer, 50% fertilizer, 25% chemical, and 0% fertilizer. Significant treatment effects were observed for leaf number, plant height, stem diameter, and shoot biomass, while root biomass showed no differences. Treatments with 100%, 75%, and 50% fertilizer exhibited statistically similar performance across several growth parameters, indicating that up to 50% of the chemical fertilizer can be replaced by aquaculture effluent without significant yield reduction. Treatments with 50% fertilizer and 0% fertilizer showed reduced growth and higher tissue accumulation of nitrate and ammonium, reflecting nutritional imbalances. In parallel, tambaqui showed 100% survival and satisfactory growth, confirming the stability of the integrated system. These results highlight that, although exclusive use of effluent is insufficient to match chemical fertilizer, partial substitution represents a viable strategy to reduce input costs and recycle nutrients, reinforcing the bioeconomic potential of aqua-culture–agriculture integration in the Amazon. Full article

The increasing demand for industrial resource optimization has driven the creation of integrated methodologies for the technical assessment of complex operations such as gas oil hydrocracking. This study examines the technical performance of a mass and energy-integrated gas oil hydrocracking process using the Extended Water–Energy–Product (E-WEP) methodology, which enables the quantification of 12 key indicators related to water, energy, and raw material usage. The research addresses the challenge of high demineralized water consumption in conventional hydrocracking processes. The findings show a production yield of 95.77% and a recycled hydrogen reuse rate of 67.99%, expressed as the Index of Reused Unconverted Material (IRUM). In terms of water use, fresh water demand decreased to 26.99 m³/h and wastewater discharge to 21 m³/h, although 77.79% of the total water processed is released as effluent, corresponding to the Wastewater Production Ratio (WPR). From the energy standpoint, total energy consumption increased to 2966.57 MMBTU/h, primarily due to the use of additional electrical equipment for mass integration. The Total Cost of Energy (TCE) reached 3,563,840.10 USD/day, with electricity (1630.82 kWh/t) as the dominant source, negatively influencing the process’s economic efficiency. Despite this energy drawback, the evaluated configuration achieves the most sustainable water use compared to conventional and integrated PVC production schemes, underscoring the importance of adopting holistic evaluations that jointly address technical efficiency, environmental impact, and economic feasibility. Full article

Following on from a circular economy in water, membrane technologies can play a role in resource recovery and high-quality water production but should also consider membrane industry circularity. Anaerobic membrane bioreactors (AnMBRs) are being used for advanced wastewater treatment, and their applications are growing due to advantages like lower sludge volume, better permeate quality, and the generation of biogas. High-Rejection (HR) AnMBRs retain a higher fraction of dissolved and particulate components to further promote resource recovery and obtain improved effluent quality. With the development of membrane technologies, end-of-life (EOL) membrane recycling is emerging for various applications. The feasibility of transforming EOL Reverse Osmosis (RO) membranes into ultrafiltration (UF)- and nanofiltration (NF)-like membranes and applying these membranes to submerged HR-AnMBR applications was evaluated. A small pilot AnMBR with granular biomass was operated with EOL RO membranes converted to submerged UF- and NF-like membranes and compared to commercial microfiltration (MF) membranes. UF- and NF-like plates were constructed, characterized, and introduced step-by-step into the AnMBR by the substitution of MF plates. A chemical oxygen demand (COD) removal study showed that while 77% removal of COD was possible with MF membranes, improved COD removal (i.e., 81.40% and 88.39%) was achieved using UF-like and NF-like membranes, respectively. Because of the higher retention of salts of the NF-like membrane, the salinity in the membrane bioreactor increased from 1300 to 1680 µS·cm⁻¹ but stabilized quickly and without a negative impact on system performance. Even without cleaning, minimal fouling and flux decline were observed for all tested configurations thanks to the use of granular biomass and low permeation flux. Permeate flux in the case of the NF-like membrane was slightly lower due to the required higher pressure. The present study demonstrated that the EOL-RO membranes may find applications in HR-AnMBRs to achieve superior permeate quality and move toward circular membrane processes. Full article

Hungary faces increasing water challenges, including frequent droughts and a growing dependence on irrigation, which necessitate alternative water sources for agriculture. This study evaluated the use of saline aquaculture effluent—characterized by elevated sodium (Na⁺) and chloride (Cl⁻) concentrations—as an irrigation resource for forage sorghum (Sorghum bicolor L.) over four consecutive growing seasons. Three hybrids (‘GK Áron’, ‘GK Balázs’, and ‘GK Erik’) were tested under five irrigation regimes, including freshwater and aquaculture effluent applied via drip irrigation at weekly doses of 30 mm and 45 mm, alongside a non-irrigated control. Effluent irrigation at 30 mm weekly increased biomass yield by up to 61% and enhanced nitrogen uptake by 22% compared to the control. Soil electrical conductivity (EC) values remained below 475 µS/cm, with effluent treatments showing lower EC than non-irrigated plots. The effluent water also supported the recycling of nutrients, especially nitrogen and phosphorus. Unlike conventional saline water, aquaculture effluent contains organic compounds and microbial activity that may improve nutrient mobilization and uptake. Our results highlight how we can reuse aquaculture wastewater in irrigated crop production. The results demonstrate that moderate effluent irrigation (30 mm/week) can optimize crop water use while maintaining soil health, offering a viable strategy for forage sorghum production in water-limited environments. Full article

This research determines the techno-economic feasibility of valorizing as biofertilizer the nitrogen (N) and the phosphorus (P) from a municipal wastewater effluent using the microalgae Scenedesmus sp., contributing to phosphorus recycling, resource optimization, and diminishing eutrophication by capturing 74% of N, 97% of P, and 41% of chemical oxygen demand in effluents. The inoculum was conditioned in 20 L photobioreactors by weekly harvesting and refilling at room temperature (25 °C day, 12 °C night) with a 12:12 photoperiod and 4 L/min atmospheric air bubbling. The improved operational conditions were obtained using a Box–Behnken experimental design, establishing that 70% wastewater concentration (vol./vol.), 4.5% nutrient addition, and 3 days’ harvesting time were the best conditions. The estimated biomass production was 176 tons/year, and this represents a maximum net present value of 1.5 MUSD for a 6.8 Ha plant, capturing 10% of municipal wastewater effluent, which serves 64000 inhabitants. The representative operational costs (OPEX) were 32% for utilities, 30% labor costs, and 25% for raw materials, and the required capital expenditures (CAPEX) were 11 MUSD and are related to photobioreactors (64%) and land (21%). The findings demonstrate the potential of microalgae-based systems as a feasible and profitable approach to wastewater valorization, while also highlighting the need for scale-up validation and integration with existing treatment infrastructures, where land requirements and photobioreactor installation will be relevant for financial feasibility. Full article

Population growth drives increasing energy demands, agricultural production, and organic waste generation. The organic waste contributes to greenhouse gas emissions and increasing landfill burdens, highlighting the need for novel closed-loop technologies that integrate water, energy, and food resources. Within the context of the Water–energy–food Nexus (WEF), wastewater can be recycled for food production and food waste can be converted into clean energy, both contributing to environmental impact reduction and resource sustainability. A novel household-scale, closed-loop WEF system was designed, installed and operated to manage organic waste while retrieving water for irrigation, nutrients for plant growth, and biogas for energy generation. The system included a biodigester for energy production, a sand filter system to regulate nutrient levels in the effluent, and a hydroponic setup for growing food crops using the nutrient-rich effluent. These components are operated with a daily batch feeder coupled with automated sensors to monitor effluent flow from the biodigester, sand filter system, and the feeder to the hydroponic system. This novel system was operated continuously for two months using typical household waste composition. Controlled experimental tests were conducted weekly to measure the nutrient content of the effluent at four locations and to analyze the composition of biogas. Gas chromatography was used to analyze biogas composition, while test strips and In-Situ Aqua Troll Multi-Parameter Water Quality Sonde were employed for water quality measurements during the experimental study. Experimental results showed that the system consistently produced biogas with 76.7% (±5.2%) methane, while effluent analysis confirmed its potential as a nutrient source with average concentrations of phosphate (20 mg/L), nitrate (26 mg/L), and nitrite (5 mg/L). These nutrient values indicate suitability for hydroponic crop growth and reduced reliance on synthetic fertilizers. This novel system represents a significant step toward integrating waste management, energy production, and food cultivation at the source, in this case, the household. Full article

Recently, researchers have been focused on the recycling as well as transforming of bio-waste streams into a valuable resource. Banana peels are promising for such application, due to their wide availability. In this context, the integration of banana peel-derived biochar with environmentally benign magnetite has significantly broadened its potential applications as a solar photocatalyst compared to the conventional photocatalysts. The materials are mixed in varied proportions of Ban-Char500-Mag@-(0:1), Ban-Char500@Mag-(1:1) and Ban-Char500@Mag-(2:1) and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) augmented with dispersive X-ray spectroscopy (EDX). Such modification is leading to an improvement in its application as a solar photocatalyst using the photochemical solar collector facility. The study discusses the factors controlling acetaminophen removal from aqueous effluent within 30 min of solar illumination time. Furthermore, the highlighted optimum parameters are pH 3.0, using 10 mg/L of the Ban-Char500@Mag-(1:1) catalyst and 100 mg/L of the hydrogen peroxide as a Fenton combination system for removing a complete acetaminophen from wastewater (100% oxidation). Also, the temperature influence in the oxidation system is studied and the high temperature is unfavorable, which verifies that the reaction is exothermic in nature. The catalyst is signified as a sustainable (recoverable, recyclable and reusable) substance, and showed a 72% removal even though it was in the six cyclic uses. Further, the kinetic study is assessed, and the experimental results revealed the oxidation process is following the first-order kinetic reaction. Also, the kinetic–thermodynamic parameters of activation are investigated and it is confirmed that the oxidation is exothermic and non-spontaneous in nature. Full article

Water pollution continues to pose a critical global challenge, largely due to the unregulated discharge of industrial, agricultural, and municipal effluents. Among emerging solutions, enzymatic bioremediation stands out as a sustainable and environmentally friendly approach, offering high specificity and efficiency under mild conditions. Nonetheless, the practical application of free enzymes is hindered by their inherent instability, poor reusability, and susceptibility to denaturation. To address these limitations, the immobilization of enzymes onto solid supports, particularly clay minerals, has garnered increasing attention. This review presents a detailed analysis of clay minerals as promising carriers for enzyme immobilization in wastewater treatment. It explores their classification, structural characteristics, and physicochemical properties, highlighting key advantages such as a large surface area, cation exchange capacity, and thermal stability. Functionalization techniques, including acid/base activation, intercalation, grafting, and pillaring, are discussed in terms of improving enzyme compatibility and catalytic performance. Various immobilization methods such as physical adsorption, covalent bonding, entrapment, crosslinking, and intercalation are critically evaluated with regard to enhancing enzyme activity, stability, and recyclability. Recent case studies demonstrate the effective removal of pollutants such as dyes, pharmaceuticals, and heavy metals using enzyme–clay composites. Despite these advances, challenges such as enzyme leaching, mass transfer resistance, and variability in clay composition persist. This review concludes by outlining future prospects, including the development of hybrid and magnetic clay-based systems and their integration into advanced water treatment technologies. Overall, enzyme immobilization on clay minerals represents a promising and scalable approach for the next generation of wastewater bioremediation strategies. Full article

The suspension polymerization process of polyvinyl chloride (PVC) production involves significant freshwater consumption alongside substantial wastewater emissions. Mass integration strategies have been used to address this problem, but only through direct recycling approaches. Therefore, in this study, a regeneration approach was applied to integrate a PVC suspension process to improve water management. The reuse network was evaluated through a water–energy–product (WEP) technical analysis after being simulated in AspenPlus software v.14. The mass integration allowed for a 61% reduction in freshwater consumption and an 83% reduction in wastewater. However, 258.6 t/day of residual wastewater still remained after regeneration. The WEP analysis found that the process was efficient in handling raw materials and process products due to the high yield and recovery of unreacted materials. Similarly, the integration significantly benefitted the process performance as water usage indicators improved substantially, with freshwater consumption of 83%, a wastewater production rate of 63%, and freshwater water costs of $267,322 per year (from $694,080 before integration). In terms of energy performance, the results were regular. The processes showed high energy consumption (below 50%), with indicators related to the use of natural gas, electricity, and energy costs being affected by the regeneration. However, the limited heat integration provided minor energy savings (11 MJ/h). Finally, this work gives an interesting insight into water conservation and the circular economy, since the study used the latest systems in regeneration of effluents for plastic plants (emerging technologies), showcasing important benefits and trade-offs of these strategies. Full article