Search Results (1,682)

Microplastics have become a ubiquitous environmental pollutant, widely distributed across various media within natural ecosystems and human living environments. Currently, scholars have primarily focused on the characteristics of microplastics in natural environments, while research into microplastics within snow cover in agricultural areas remains scarce. This study focuses on the Songnen Plain in Northeast China, where 25 sampling points were selected in February 2023. Through laboratory analysis and modelling techniques, it examines the spatial distribution characteristics and potential sources of microplastics within snow cover on agricultural fields. Results indicate the following: (1) The average abundance of microplastics in snow cover on the Songnen Plain was 1451.07 N·L⁻¹. Fragment-type microplastics predominated, with over 86.38 ± 6.62% of particles concentrated within the 20–50 μm size range. A total of 27 types of microplastic polymers were detected, with polyamide (PA) being the predominant polymer type, while polyethylene (PE), polytetrafluoroethylene (PTFE), and polylactic acid (PLA) were the secondary predominant polymer types. Potential sources of microplastics in snow cover on the Songnen Plain encompass agricultural production activities, emissions from industrial buildings, domestic waste inputs, road traffic sources, and textiles and wastewater. (2) Microplastic abundance in agricultural areas is 1–4 orders of magnitude higher than in natural areas, and comparable to or 1 order of magnitude higher than in urban snow. The particle size of microplastics in farmland snow cover is comparable to that in natural areas, being slightly smaller than that in urban snow. The morphology of microplastics in snow cover farmland is essentially identical between natural and urban areas. The composition of microplastics in snow cover farmland differs from that in natural areas, with polyamide (PA) being the most prevalent component, whereas polyethylene terephthalate (PET) dominates in natural areas. Compared to urban areas, the proportion of polytetrafluoroethylene (PTFE) and polylactic acid (PLA) in snow microplastics is higher in agricultural regions. Full article

In this study, waste Moringa oleifera pod husk (MPH) was valorised as a low-cost biomass support for Cd_0.5Cu_0.5Fe₂O₄ mixed-metal spinel ferrite to develop an adsorption-assisted sustainable photocatalytic system for tetracycline (TC) removal. The prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and vibrating sample magnetometry (VSM). The effects of reaction time, initial TC concentration, catalyst dosage, solution pH, H₂O₂ concentration, and temperature were systematically investigated. Under the selected optimum conditions of 60 mg L⁻¹ catalyst, 400 mg L⁻¹ H₂O₂, pH 7.2, and 26 °C, the Cd_0.5Cu_0.5Fe₂O₄/MPH/UV/H₂O₂ system achieved approximately 96% TC removal and 87% COD removal within 60 min, demonstrating substantial degradation and mineralization at near-neutral pH and ambient temperature. Moreover, the kinetics of TC oxidation is studied and the results showed the reaction is following the pseudo-first-order kinetics. Radical-scavenging experiments identified •OH as the predominant oxidative species, while •O₂⁻ and h⁺ also contributed to the degradation pathway, supporting a synergistic mechanism involving MPH-assisted adsorption, photoinduced charge generation, and H₂O₂-assisted reactive oxygen species formation. Further, the composite retained approximately 79% TC removal after six successive reuse cycles, demonstrating substantial operational reusability under the investigated conditions. The composite also exhibited effective activity under natural solar irradiation, achieving approximately 93% TC removal within 120 min, demonstrating its potential for solar-driven wastewater treatment. Hence, the developed Cd_0.5Cu_0.5Fe₂O₄/MPH composite provides a promising route for coupling agricultural-waste valorisation with efficient adsorption–photocatalytic treatment of antibiotic-contaminated water. Full article

The persistence of extended-spectrum β-lactamase (ESBL)-producing E. coli in livestock and municipal wastewater systems represent a key environmental pathway for antimicrobial resistance (AMR) and virulence determinants with direct public-health implications. This study investigated the distribution of virulence genes and biofilm-forming capacity of ESBL-producing E. coli from two municipal WWTPs, a poultry farm, and a cattle farm. A total of 452 environmental samples were collected between May 2025 and May 2026. ESBL-producing E. coli were identified using culture-based and biochemical methods. Virulence genes were characterized by polymerase chain reaction (PCR) and whole-genome sequencing (WGS). Biofilm formation was assessed using the crystal violet microtiter plate assay. Of the 452 samples, 120 (26.5%) yielded ESBL-producing E. coli. PCR analysis showed that poultry farm isolates exhibited the highest prevalence of virulence genes, predominantly traT (64/66), ompA (61/66), fimH (54/66), and chuA (39/66), followed by isolates from WWTP-A, the cattle farm, and WWTP-B. Significant differences among sampling sources were observed for traT (p = 0.0398) and stx1 (p = 0.0224). WGS analysis identified significant source-dependent associations for several virulence genes, with the strongest associations observed for esp (FDR = 3.47 × 10⁻⁶) and fimH (FDR = 2.36 × 10⁻⁵). Most isolates were non-biofilm producers (52/120, 43.3%). Among biofilm-forming isolates, weak biofilm production predominated across all sampling locations, with the highest prevalence observed in poultry farm isolates (21/120, 17.5%), followed by isolates from the cattle farm and WWTP-A (10/120, 8.3% each) and WWTP-B (7/120, 5.8%). These findings identify poultry farms and wastewater environments as important reservoirs of virulence-associated ESBL-producing E. coli and support integrated One Health surveillance to limit the environmental spread of AMR. Full article

Nitrogen pollution and eutrophication are among the most significant environmental challenges affecting coastal ecosystems worldwide, stimulating interest in sustainable nutrient-removal strategies. Marine macroalgae have emerged as promising biological tools for nutrient biofiltration owing to their rapid growth, high nutrient uptake capacity, and ability to convert dissolved nitrogen into valuable biomass. This review examines the mechanisms underlying nitrogen utilization in marine macroalgae and their implications for photosynthetic regulation, biofiltration efficiency, and biomass valorization. Particular emphasis is given to the uptake and assimilation of nitrate, ammonium, urea, and dissolved organic nitrogen, as well as the physiological pathways governing nitrogen metabolism and photosynthetic performance. The interactions between nitrogen availability, chlorophyll synthesis, photochemical efficiency, and electron transport are discussed to highlight the central role of nitrogen in macroalgal productivity. The review further evaluates the application of marine macroalgae in wastewater treatment, integrated multitrophic aquaculture (IMTA), land-based aquaculture effluent remediation, and coastal nutrient management. Key environmental and operational factors influencing biofiltration efficiency, including light, temperature, salinity, water flow, seasonal variability, and species selection, are critically assessed. In addition, the potential for biomass valorization following nutrient recovery is explored, focusing on protein production, nutraceutical compounds, phycocolloids, agricultural biostimulants, and other high-value bioproducts that support circular bioeconomy approaches. Finally, future research directions are identified, with particular attention to climate change impacts, multifunctional cultivation systems, omics-based technologies, physiological modeling, and large-scale implementation challenges. Overall, marine macroalgae represent a sustainable and multifunctional solution for nutrient remediation, resource recovery, and biomass production, offering significant opportunities for advancing environmentally responsible aquaculture, wastewater management, and blue bioeconomy development. Full article

Wastewater systems can serve as reservoirs and dissemination pathways for Listeria spp., yet comparative data from municipal and agricultural wastewater remain limited. The objective of this study was to isolate Listeria monocytogenes from municipal wastewater and dairy-farm runoff for use as enrichment hosts in a subsequent and separate study on the isolation of bacteriophage from the same wastewater streams. During this process, additional Listeria spp. were recovered and characterized along with L. monocytogenes. Identification of Listeria sp. was accommodated using multilocus sequencing, LIPI-1-targeted PCR, and phenotypic confirmation. Wastewater samples were filtered, enriched with Demi-Fraser broth, treated with anti-Listeria magnetic beads, and plated on MOX agar. Bead-captured Listeria were later plated on Listeria Brilliance Agar to differentiate phospholipase-positive L. monocytogenes. Putative isolates were characterized by sequencing of 16S rRNA, sigB, and iap genes, and by PCR detection of four Listeria Pathogenicity Island 1 (LIPI-1) markers (hlyA, inlA, actA, prfA). Using this combined approach, 27 Listeria isolates were recovered from 21 wastewater samples during a 6-week sampling period: 13 samples of municipal wastewater yielded 5 isolates of L. monocytogenes (38% prevalence rate) and 11 other Listeria sp. (85% overall prevalence rate; 1 L. innocua, and 5 Listeria sp.); 8 samples of dairy wastewater yielded 2 isolates of L. monocytogenes (25% prevalence) and 9 other Listeria sp. (100% overall prevalence rate; 8 L. innocua and 1 Listeria sp.). Seven isolates from municipal and dairy wastewater were confirmed as L. monocytogenes based on concordant sigB and iap gene sequence identities, LIPI-1 gene presence, and phospholipase-positive reactions on chromogenic agar. Six isolates yielded discordant results across the multilocus sequencing markers and could not be confidently assigned to a species and were designated Listeria sp. These findings highlight the value of integrating chromogenic media with multilocus genetic markers for accurate identification of L. monocytogenes in complex environmental matrices. Full article

In the present research, Zea mays stem (ZMS) agricultural waste and its corresponding activated carbon (AC-ZMS) were successfully utilized as alternative low-cost adsorbents for the removal of Acid Green 25 (AG25), a highly resilient and toxic contaminant textile dye. The evaluation was systematically conducted using synthetic wastewater precisely prepared in the laboratory by dissolving the commercial analytical-grade dye in distilled water to eliminate external chemical interference. The ZMS powder exhibited a fibrillar morphology characteristic of lignocellulosic materials, and AC-ZMS a porous morphology. The removal experiments showed that at an initial concentration of 50 mg/L, pH = 2, an adsorbent dose of 20 g/L, and 20 °C, both materials reached equilibrium in 30 min, achieving removal efficiencies of 87.57% (ZMS) and 91.43% (AC-ZMS). The equilibrium data were fitted to the Langmuir isotherm model, resulting in maximum adsorption capacities (q_mL) that increased with temperature, reaching maximum values of 12.61 mg/g for ZMS and 13.56 mg/g for AC-ZMS at 40 °C. Thermodynamic and mechanism analyses justified the process of preparing AC-ZMS from ZMS for the removal of AG25, since ZMS powder would exhibit predominantly weak and reversible physical adsorption (ΔH⁰ = 15.94 kJ/mol), driven by pH-sensitive electrostatic attraction; in contrast, the adsorption of AG25 onto AC-ZMS is consistent with a chemisorption regime (ΔH⁰ = 86.64 kJ/mol). This change would prevent the degradation of active sites, allowing AC-ZMS to retain a remarkable 80.66% of its initial capacity after 5 consecutive regeneration cycles, whereas untreated ZMS suffers a severe drop in performance to 49.25%. The theoretical study demonstrated that the defect and oxygenated sites present in AC-ZMS attract and immobilize AG25, which causes it to be efficiently removed from synthetic solutions. In conclusion, AC-ZMS is a promising adsorbent in synthetic solutions; further work needed for real wastewater and reuse. Full article

Phosphorus is essential for plant growth and freshwater ecosystems. However, excessive concentrations in aquatic environments accelerate eutrophication and threaten aquatic life and biodiversity. In this study, walnut shell-derived activated carbon (WAL-AC) was modified with magnesium (WAL-AC@Mg), calcium (WAL-AC@Ca), and tin (WAL-AC@Sn) in different mass ratios, as well as with chitosan/magnesium (WAL-AC@CS/Mg), and evaluated for the removal of PO₄³⁻ from aqueous solutions and real wastewater. Among all modifications, magnesium-activated WAL-AC (WAL-AC@Mg_4:1) performed best, achieving consistently high phosphate removal efficiency (approximately 95%; 95.3% at pH 7.0) across the tested pH range (3–9). The adsorption of WAL-AC@Mg_4:1 followed pseudo-second-order kinetics and the Langmuir isotherm (Q_m = 41.80–46.13 mg/g, 303–323 K), with thermodynamics confirming spontaneous, endothermic uptake. FTIR, and SEM-EDS analyses revealed surface Mg-O sites, a P-O band at 996 cm⁻¹, and phosphorus accumulation (up to 8.61 at.%) after adsorption, consistent with ligand exchange and possible Mg-phosphate precipitation. WAL-AC@Mg_4:1 remained effective in real secondary wastewater (73% removal) and maintained approximately 34% removal after five regeneration cycles. A preliminary agronomic test showed that WAL-AC@Mg_4:1 potentially recovered from wastewater supported the growth of tomato seedlings, providing a preliminary proof-of-concept for phosphorus recovery and reuse rather than a demonstrated fertilizer benefit. These findings identify magnesium-functionalized WAL-AC as the most promising adsorbent among those tested, derived from a low-cost agricultural waste precursor, combining phosphate removal from secondary wastewater with resource recovery. Full article

The transition towards a circular economy in the wastewater sector necessitates the sustainable management and valorisation of sewage sludge. This study provides a comprehensive longitudinal analysis of sewage sludge land application in Romania (2006–2024), contextualized within the broader Central and Eastern European (CEE) region (Poland, Czechia, Hungary, Bulgaria, and Slovakia; 2000–2024). Utilizing harmonized datasets from the Romanian National Institute of Statistics (INSSE TEMPO) and Eurostat, this research applies non-parametric Mann–Kendall trend tests, Sen’s slope estimator, Modified Trend-Free Pre-Whitening Mann–Kendall (TFPW-MK) tests to address serial autocorrelation, ordinary least squares regression with comprehensive residual diagnostics, exploratory detrended correlation matrices, and subperiod sensitivity analysis. Results indicate that Romanian municipal sludge applied to agricultural land increased from 0.38 thousand tonnes (kt) of dry matter (DM) in 2006 to a peak of 63.08 kt in 2022 and 53.97 kt in 2024 (+53.59 kt DM absolute increase; ~142-fold relative expansion), with the agricultural valorisation rate rising from 0.17% to a record 31.29% in 2024 (TFPW-MK Z = +5.000, p < 0.001). Municipal sludge production followed a non-linear trajectory, contracting to a historical minimum of 65.80 kt DM in 2012 before expanding to 283.34 kt in 2017 and reaching an infrastructural plateau around 172.49 kt in 2024 (2013–2024 subperiod τ = +0.030, p = 0.945). Conversely, reported industrial wastewater volumes experienced a substantial decline (TFPW-MK Z = −4.545, p < 0.001), reflecting industrial restructuring and a 2012/2013 reporting reclassification. Comparative CEE analysis reveals marked heterogeneity: Czechia (6.50 kg DM/capita) and Poland (4.07 kg DM/capita) lead in per capita agricultural recycling, while Romania reached 2.83 kg DM/capita (4.00 kg DM/ha Utilized Agricultural Area). An agronomic mass-balance assessment indicates that applying 53.97 kt DM under statutory limits requires a theoretical national land footprint of 10,794–17,990 ha (<0.133% of Romania’s agricultural area and <0.220% of conventional arable land), demonstrating that macro-scale physical land competition with certified organic farming does not exist. Furthermore, exploratory detrended and first-difference correlation analyses demonstrate that raw correlations between sludge and mineral fertilizers reflect parallel multi-decadal growth rather than guaranteed farm-level substitution. These empirical findings provide robust benchmarks for national circular sludge strategies under the recast EU Urban Waste Water Treatment Directive (Directive (EU) 2024/3019). Full article

The sustainable valorization of non-recyclable synthetic polymers alongside agricultural residues into high-value carbonaceous materials represents an imperative pathway for environmental remediation and waste management. In this study, a nanostructured ${\mathrm{Ru}/\mathrm{CeO}}_2$ catalyst was successfully synthesized via a hydrothermal route followed by chemical reduction, and its catalytic influence on the co-pyrolysis of waste polystyrene (PS) and corn stalks (CS) was systematically investigated. Powder X-ray diffraction (XRD) confirmed the formation of pure cubic fluorite ${\mathrm{CeO}}_2$ (JCPDS No. 34-0394) with highly dispersed Ru nanoparticles. Incorporating ${\mathrm{Ru}/\mathrm{CeO}}_2$ into the PS/CS blend (mass ratio 1:2) during co-pyrolysis at ${500 }^{\circ }\mathrm{C}$ for 1.5 h significantly enhanced the structure and porous architecture of the resulting biochar. Nitrogen physisorption analysis revealed a substantial increase in the Brunauer–Emmett–Teller specific surface area ($S_{\mathrm{BET}}$) from $58.74{ \mathrm{m}}^2/\mathrm{g}$ (non-catalytic) to $115.94{ \mathrm{m}}^2/\mathrm{g}$ (catalytic), alongside concurrent improvements in micropore volume ($V_{\mathrm{micro}}$ from $0.027{ \mathrm{cm}}^3/\mathrm{g}$ to $0.049{ \mathrm{cm}}^3/\mathrm{g}$) and total pore volume ($V_{\mathrm{total}}$ from $0.058{ \mathrm{cm}}^3/\mathrm{g}$ to $0.117{ \mathrm{cm}}^3/\mathrm{g}$). Mechanistically, the active Ru species are proposed to facilitate structural transformation and volatile cracking, while the redox couple is hypothesized to regulate the local oxygen micro-atmosphere, thereby favoring the formation of microporous polycyclic aromatic structures is strongly supported by ex situ characterizations such as BET, SEM, XRD, and FTIR observations in this work and previous literature. More importantly, the evaluation of tetracycline (TC) removal efficiency from wastewater was conducted to compare the performance of activated carbons synthesized with and without the addition of the ${\mathrm{Ru}/\mathrm{CeO}}_2$ catalyst during the co-pyrolysis stage. At the treatment tests ($C_0=50 \mathrm{mg}/\mathrm{L}$, $0.5 \mathrm{g}/\mathrm{L}$ dosage, $100 \min$), ${\mathrm{Ru}/\mathrm{CeO}}_2\text{-}\mathrm{AC}$ demonstrated outstanding performance, achieving $95.9\%$ Tetracycline removal versus $89.6\%$ for the non-catalyzed counterpart (${\mathrm{AC}}_0$). These findings demonstrate that ${\mathrm{Ru}/\mathrm{CeO}}_2$-assisted co-pyrolysis provides an effective strategy for engineering high-performance microporous carbon materials from mixed organic waste. Full article

Phosphogypsum (PG) is a bulk industrial solid waste generated during wet-process phosphoric acid production. Its agricultural use may improve specific soil properties but may also increase the risk of agricultural non-point-source pollution. Differences in phosphate-rock source, production process, degree of washing, stockpiling history, and treatment method result in substantial variation among PG materials in mineral composition and in the concentrations, modes of occurrence, and release potential of P, F, soluble salts, potentially toxic elements, and naturally occurring radionuclides. This review combines a structured literature search with a qualitative synthesis of risk evidence and uses agricultural soils, the root zone, and field boundaries as the principal assessment domains. It examines the release, transformation, immobilization, crop uptake, leaching below the root zone, and export through runoff, erosion, and drainage of PG-associated constituents. It also evaluates the mechanisms, pollutant partitioning, agronomic effects, and non-target risks of hazard-reduction and functionalization technologies. Available evidence indicates that the agronomic effects and environmental risks of PG cannot be assessed solely on the basis of total constituent concentrations, Ca and S supply, the results of a single leaching test, or short-term crop responses. They also depend on the releasable pollutant load, cumulative application rate, soil chemical and hydrological conditions, crop exposure, and long-term stability. Washing, leaching, separation, stabilization, thermal treatment, and biological treatment can reduce the concentrations or releasability of some pollutants in the treated solid but may also transfer pollutants to wastewater, sludge, residues, or gaseous streams. Following source traceability, risk screening, and treatment where necessary, PG may be used to ameliorate sodic soils, regulate nutrient availability, or stabilize some pollutants through ion exchange, adsorption, precipitation, surface complexation, and organic–mineral binding. Its effectiveness and associated risks depend on material properties, soil conditions, target pollutants, and application methods. Accordingly, this review proposes a conceptual framework for the safe utilization of PG that integrates source traceability, material classification, selective hazard-reduction treatment, functionalization design, soil–crop matching, tiered verification, and long-term monitoring. The framework identifies assessment priorities and management considerations for specific materials and application scenarios. Full article

Groundwater quality is jointly regulated by natural geological processes and anthropogenic activities. However, in regions subject to intense human disturbance, the quantitative identification of pollution sources remains poorly constrained. Taking the groundwater of the Shandong section of the lower Yellow River as the study object, this research systematically revealed regional groundwater quality characteristics and pollution sources by integrating hydrochemical analysis with the positive matrix factorization (PMF) model. Results indicate that groundwater in the study area has been significantly impacted by human activities, with the proportions of samples exceeding standards for Mn, TH, Fe, TDS, SO₄²⁻, Cl⁻, and NO₃⁻ reaching 66.0%, 63.8%, 42.6%, 38.3%, 29.8%, 25.5%, and 12.8%, respectively. The dominant hydrochemical type is HCO₃·SO₄·Cl-Na·Ca·Mg, signifying the superimposed effects of evaporation–concentration, water–rock interaction, and anthropogenic inputs. The PMF model identified three pollution sources: a composite source of agricultural runoff and industrial wastewater (44.7%), a mixed source of domestic sewage and carbonate dissolution (32.1%), and a source dominated by evaporite and fluorite dissolution (23.3%). Quantitative source contribution analysis shows that the industrial–agricultural composite source contributes 81.4%, 56.1%, 67.7%, 42.7%, and 42.3% of Mn, COD, K⁺, NO₃⁻, and TH, respectively. The evaporite and fluorite dissolution source accounts for 84.5% of SO₄²⁻ and 53.1% of F⁻. The domestic sewage and carbonate dissolution source contributes 40.4%, 44.3%, and 43.1% of Na⁺, Cl⁻, and NO₃⁻, respectively. This study identifies the sources of groundwater quality deterioration and quantifies the relative contributions of natural processes and human activities, thereby providing a scientific basis for groundwater resource protection and pollution control in the Yellow River Basin and regions with similar geological settings. Full article

The application of organic wastes as fertilisers is important for sustainable agriculture, provided that resulting changes in microbial communities do not disrupt nutrient cycling or soil fertility. To the authors’ knowledge, this study was the first to use PacBio 16S rRNA sequencing to characterise soil microbiota changes following waste application to land. This technology provides high taxonomic resolution, improving the characterisation of complex soil microbial communities. To assess the microbiota of five organic wastes and describe soil microbiota following field application, 18 plots received each waste in triplicate at nitrogen-equivalent rates simulating band spreading. Soil cores were collected at 0, 1, 3, 6, and 10 weeks post-application. The primary genera in pre-application soil were Niallia (7.6%) and Unclassified_type_III (7.3%). Following waste application, the dominant genera included UCG-001 (13.3%) and DMER64 (8.8%) in bovine-treated soil, Candidatus_Udaeobacter (8.5%) and unclassified_Xanthobacteraceae (7.9%) in ovine, Niallia (6.1%) and Candidatus_Udaeobacter (5.8%) in pig, Staphylococcus (27.3%) and Brachybacterium (26.7%) in poultry, and unclassified_Anaerolineaceae (25.8%) and Thiopseudomonas (14.2%) in anaerobically digestated wastewater treatment sludge (DWWTS). The time required for soil to return to its pre-application microbiota ranged from 0 to 6 weeks. Organic waste type strongly influenced disturbance magnitude and duration, with prolonged shifts potentially affecting microbial diversity, nutrient cycling and soil fertility. Full article

Phosphorus (P) is essential for crop production, yet its use still follows a largely linear pathway: phosphate rock is mined, applied to agricultural land, transferred through food and waste systems, and often lost to rivers, lakes, and coastal waters. This review examines how P supply vulnerability, agricultural surpluses and deficits, legacy soil P, eutrophication, climate-sensitive transport, and recovery technologies are connected across food and water systems. A structured narrative review was conducted using Web of Science, Scopus, Google Scholar, and relevant institutional sources. The searches focused on phosphorus fertilizer, legacy P, eutrophication, runoff, wastewater recovery, circular economy, and governance. English-language peer-reviewed studies and high-authority reports, mainly published between 1995 and 2026, were screened for relevance, methodological clarity, and quantitative evidence. A total of 191 records were identified, 115 full texts were assessed, and 101 sources were included. Evidence was grouped into four areas: mineral supply and trade, soil and aquatic P accumulation, recovery from waste streams, and policy. The review shows that concentrated reserves can increase supply risk, but do not alone indicate imminent scarcity. Costs, ore quality, trade, demand, recycling, and technological change also influence P security. Legacy P may support crop uptake while continuing to impair water quality. Recovery technologies such as struvite production and sludge-ash processing offer useful pathways, but their adoption depends on economics, contaminants, regulation, and logistics. Effective P stewardship therefore requires region-specific strategies that reduce losses, improve access and efficiency, manage legacy P, and support practical recovery. Full article

The growing pressure on water resources and the demand for sustainable wastewater treatment have driven interest in low-cost, renewable coagulants for industrial effluent remediation. In this context, chestnut shells (Castanea sativa) were explored as a potential source of natural coagulants through tannin extraction, followed by cationic modification using the Mannich reaction. A Box–Behnken Design was employed to assess the effects of chestnut shell mass, extraction pH, and extraction time on methylene blue decolorization in synthetic wastewater. The quadratic response surface model was not statistically significant, indicating that the tested variables did not collectively explain the observed variation within the investigated range. Consequently, the results were interpreted as exploratory observations within the investigated experimental domain rather than as evidence of optimized or predictive operating conditions. Under the tested conditions, methylene blue removal efficiencies ranged from 20 to 26%, and increasing the coagulant dosage improved decolorization, likely through polymeric bridging. Furthermore, this study demonstrated practical regional industrial integration in Northern Portugal by upcycling agricultural waste to mitigate the impact of textile effluents. This engineering approach aligns with the United Nations Sustainable Development Goals (SDG 6, 9, and 12), suggesting a promising pathway for sustainable industrial scale-up. Full article

Water quality management is a growing global priority due to increasing pressures from climate change, population growth, urbanisation, industrialisation, agricultural intensification, and emerging contaminants. These challenges threaten freshwater ecosystems, public health, economic development, and progress towards Sustainable Development Goal 6 (SDG 6). This critical review employed a PRISMA-guided systematic literature review to evaluate future directions in water quality management from sustainability, resilience, and social equity perspectives. A total of 11,485 records were identified, with 3632 duplicates removed. Following the screening of 7853 records and assessment of 1441 full-text articles, 117 studies met the inclusion criteria for qualitative synthesis. Geographical analysis showed that 88 studies (75.2%) adopted a global perspective encompassing both developed and developing countries, while 24 studies (20.5%) focused on developing countries and 5 studies (4.3%) on developed countries. The review identified notable progress in water quality monitoring, wastewater treatment, pollution control, and integrated water resources management. Emerging technologies such as smart monitoring systems, artificial intelligence, advanced treatment processes, and resource recovery approaches were consistently highlighted as promising tools for improving water quality and enhancing adaptive capacity. Despite these advances, significant barriers remain, including fragmented governance systems, climate-related risks, emerging contaminants, and persistent inequalities in access to safe water resources. The findings underscore the importance of integrating sustainability, resilience, and social equity within water governance frameworks. Achieving long-term water security will require coordinated and transformative approaches that strengthen links between science, policy, and practice while promoting inclusive, resilient, and sustainable water management. Full article