Search Results (232)

Aquaponic systems couple fish and plant production in recirculating loops, yet quantitatively assessed dynamic models for engineering analysis, scale-up, and operation under realistic conditions remain limited. Here, a modular process-based MATLAB R2026a framework is developed for the recirculating aquaponic system operated at the ASTREDHOR facility (France). The model links hydraulic transport with fish metabolism, nitrification, solids removal, and plant nitrate uptake, using monitoring-derived boundary conditions for temperature, dissolved oxygen, pH, and electrical conductivity. The fish-growth component was calibrated and evaluated against archived, temporally reconstructed biomass trajectories derived from campaign-based biometrics in three production cycles with different fish compositions and environmental regimes. Tank-wise $R^2$ values were 0.865–0.952 in the calibration windows and 0.700–0.921 in the fixed-parameter prediction windows, with prediction-period NRMSE values of 0.64–3.91%. These descriptive metrics quantify agreement on the reconstructed evaluation grid rather than performance over independently retained biometric sampling occasions. Complete corresponding time series were unavailable for TAN, ${\mathrm{NO}}_2^{-}$, ${\mathrm{NO}}_3^{-}$, total suspended solids, and plant uptake; these simulated outputs were therefore used only for mechanistic consistency assessment and exploratory scenario analysis, rather than independent validation. Local sensitivity analysis showed limited effects of temperature sensitivity (${\alpha }_T$), optimal temperature ($T_{opt}$), and minimum dissolved oxygen ($D{O}_{min}$) under observed conditions, whereas the feeding ratio ($TR$) and metabolic scaling exponent (n) strongly influenced simulated fish growth and nitrogen loading. Parametric sweeps provided preliminary, model-derived indications of feeding and biofilter-sizing limits under intensified loading; these thresholds require confirmation against independent water-quality measurements. The resulting framework is positioned as an off-line digital shadow with a fish-growth component assessed against reconstructed biomass trajectories and exploratory water-quality simulations. Full article

A synergistic system integrating iron corrosion, chemical phosphorus removal, and biological nitrogen removal was established for advanced piggery tailwater treatment. Increasing NO₃⁻–N concentration from 15 to 60 mg/L enhanced Fe²⁺ dissolution in iron–carbon biofilter (ICBF) by 61.7%. The in situ released iron ions improved the phosphate removal efficiency to 96.08% via chemical precipitation. Iron corrosion provided additional electron donors, enriching an integrated autotrophic–heterotrophic denitrifying community (Dechloromonas, Thermomonas, and Limnobacter). This elevated the total nitrogen removal efficiency to 79.07%, representing an 81.62% improvement over conventional biofilter BF-C. After sodium humate addition, microbial activity influenced secondary mineral formation, which may be associated with partial mitigation of iron passivation in the ICBF. This study clarified the nitrate-driven in situ iron corrosion and its associated chemical-biological cascade responses, providing a novel strategy and theoretical basis for achieving simultaneous nitrogen and phosphorus removal in low C/N wastewater. Full article

Optimizing oxygen supply and nitrogen removal in recirculating aquaculture systems (RAS) requires species-specific metabolic benchmarks. This study quantified the effects of body size and stocking density on oxygen consumption and total ammonia nitrogen (TAN) excretion in the silverside Odontesthes bonariensis under controlled RAS conditions. A 2 × 2 factorial design was used to compare small (48–140 g) and large (>140–250 g) fish stocked at low (3.2 kg m⁻³) and high (6.2 kg m⁻³) densities. Oxygen consumption was significantly influenced by both factors, with mean routine rates ranging from 146.12 ± 35.07 mg O₂ kg⁻¹ h⁻¹ in high-density large fish to 226.31 ± 50.71 mg O₂ kg⁻¹ h⁻¹ in low-density small fish. Smaller fish exhibited higher mass-specific rates, and individuals held at lower densities consumed more oxygen, consistent with allometric scaling and density-dependent metabolic suppression. In contrast, TAN excretion was unaffected by size or density, with mean values ranging from 4.59 ± 0.77 to 10.81 ± 3.76 mg TAN kg⁻¹ h⁻¹ across treatments, indicating stable protein catabolism under a uniform feeding regime. Both parameters displayed pronounced diurnal fluctuations, with postprandial peaks associated with specific dynamic action: oxygen consumption fluctuated between 61.75 and 333.03 mg O₂ kg⁻¹ h⁻¹, while TAN excretion ranged from 0 to 78.63 mg TAN kg⁻¹ h⁻¹ over 24 h cycles. These findings demonstrate that oxygen demand in O. bonariensis is strongly modulated by bioenergetic scaling and stocking density (ranging from 146 to 226 mg O₂ kg⁻¹ h⁻¹), whereas ammonia excretion (4.6–10.8 mg TAN kg⁻¹ h⁻¹) is primarily driven by dietary input. These results provide species-specific baseline benchmarks for aeration sizing and biofilter design, thereby supporting the sustainable intensification of silverside aquaculture in RAS. Full article

Pesticide contamination in urban runoff, stormwater, and peri-urban drainage networks is an increasing concern because of the persistence, mobility, and ecological toxicity of many pesticide residues and their transformation products. Nature-based solutions (NBSs), including constructed wetlands, bioretention systems, biofilters, and permeable reactive bio-barriers, provide low-energy and ecologically compatible platforms for urban water treatment; however, their performance is often constrained by limited sorption capacity, substrate saturation, variable hydraulic loading, and incomplete degradation of persistent pesticides. Biochar offers a multifunctional amendment for strengthening these systems because its tunable porosity, surface functionality, mineral composition, redox activity, and microbial habitat-forming capacity can support pesticide adsorption, catalytic transformation, and biodegradation. This review critically evaluates biochar-integrated NBSs for pesticide-contaminated urban water systems by linking biochar production and modification strategies with pesticide removal mechanisms, biochar–microbe interactions, engineered treatment configurations, and field-scale applicability. A comparative synthesis is provided across material-level mechanisms, system-level performance, machine learning-assisted prediction, techno-economic feasibility, life-cycle impacts, and environmental risk considerations. By integrating material properties, removal mechanisms, NBS configurations, predictive modeling, sustainability assessment, and risk considerations, this review provides a broader comparative basis than previous studies focused mainly on individual aspects of biochar-based pesticide remediation. Future priorities include standardized biochar production, long-term field validation, spent-biochar management, ecotoxicological assessment, and data-driven optimization of biochar-assisted NBSs. Full article

Ornamental aquarium keeping collectively involves millions of freshwater, marine, and reef systems in which fish, corals, invertebrates, biofilters, microbial communities, and human husbandry practices are closely interconnected. In these domestic aquatic animal systems, preventive and curative treatments may include antimicrobials, antiparasitics, antiseptics, oxidizing agents, copper-based products, dips, and commercial formulations targeting microbial proliferations or visible system deterioration. Many interventions occur without veterinary diagnosis, microbiological confirmation, standardized dosing, active-ingredient transparency, or post-treatment monitoring. This raises concerns for aquatic animal health and welfare, as whole-system treatments may affect not only the intended pathogen or pest but also non-target organisms, biofilter communities, animal-associated microbiota, and water quality stability. Digital communities and online platforms can rapidly circulate empirical treatment protocols, although they may also provide opportunities for stewardship education and improved husbandry guidance. Current evidence does not support interpreting ornamental aquaria as major independent drivers of antimicrobial resistance. The more defensible concern is stewardship: biologically active compounds may be used repeatedly and empirically in animal systems without diagnosis, professional guidance, or systematic monitoring. This Perspective argues that ornamental aquaria should be recognized as an overlooked interface between aquatic animal health, welfare, antimicrobial stewardship, and One Health. It proposes a research and communication agenda focused on treatment transparency, diagnosis, prevention, biofilter protection, and responsible care practices. Full article

Water scarcity is an increasingly urgent global challenge, prompting the development of new water purification technologies that surpass conventional solutions. Decentralized greywater treatment is emerging as a viable option for enhancing water reuse in multifunctional systems that contribute to microclimate regulation, cooling, and urban climate adaptation. In this context, water-storage mats have been identified as a form of decentralized, roof-based biofilter for greywater treatment. The aim of this study was to assess the performance of newly developed, innovative, bio-based textile mats and assess their effectiveness in treating pre-treated greywater from a canteen (CGW) with a high organic content, in both laboratory- and pilot-scale experiments. The findings from the lab-scale testing revealed that the mats made from polyethylene terephthalate (PET) nonwoven fabric materials had the highest water storage capacity and dried out more slowly in outdoor conditions than mats made from polylactide (PLA) spunbonded fabric and polyhydroxyalkanoate (PHA) spunbonded nonwoven fabric. The PET hydroentangled nonwoven fabric mat (PET-WS) performed better than the other sample mats in the lab-scale experiment, and also outperformed the PHA mat consistently in the pilot-scale experiment when treating CGW. Apparent reductions in the concentration of the macro-pollutant parameters were observed at the outflow of the PET-WS mat compared to the inflow (p < 0.05) at the pilot-scale. Mean concentration reductions were comparatively higher for the five-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), total nitrogen (TN), and total suspended solids (TSS), with mean reductions of 64%, 54%, 39% and 60%, respectively. This indicated the superior treatment performance of the PET-WS mat compared to the PHA mat, with mean reductions of only 36%, 25%, 6%, and 32%, respectively. However, the lower E. coli counts of 1.1 and 0.5 log reduction for the PET-WS and PHA mats, respectively, indicated that an additional disinfection unit was necessary. The findings of this study may help to determine the performance, stability and reliability of using lightweight, nonwoven fabric mats to treat high-strength GW, which is currently considered as an intermediate treatment step. The study also provides recommendations for process optimization. Additional post-treatment steps are required to produce high-quality treated effluent for non-potable reuse, particularly in urban areas facing high water scarcity, provided that the relevant reuse regulations or discharge criteria are met. Full article

In this study, total ammonia nitrogen (TAN) excretion rates were quantified in juvenile (mean weight: 1.79 ± 0.17 g) and adult (mean weight: 15.91 ± 0.63 g) prawns (Macrobrachium caementarius) reared under recirculating aquaculture system (RAS) conditions representative of small-scale farming operations. Prawns were fed a commercial dry pelleted diet (48.5% crude protein) at a daily ration equivalent to 5% of total biomass. Water quality parameters were maintained within species-specific tolerance ranges to ensure normal physiological and metabolic function. TAN excretion rates were estimated using a mass balance approach under closed-flow batch conditions. A significant difference in TAN excretion was observed between life stages (p = 0.008): juveniles excreted 0.009 ± 0.006 mg TAN g⁻¹ h⁻¹ (0.22 ± 0.18 mg TAN g⁻¹ day⁻¹), whereas adults excreted 0.03 ± 0.01 mg TAN g⁻¹ h⁻¹ (0.73 ± 0.06 mg TAN g⁻¹ day⁻¹). Distinct diel postprandial patterns were evident in both life stages, with peak TAN release occurring 1–2 h after each feeding event, followed by a gradual decline. These life-stage differences have direct implications for RAS design and biofilter management and should be interpreted in the context of the dietary conditions used. The quantified excretion rates provide baseline bioengineering parameters for sizing biofilters, estimating nitrogen loading, and optimizing water quality management for this emerging aquaculture species. Full article

Limited access to clean water and reliable electricity infrastructure remains a major challenge in many remote regions of Indonesia, particularly for building-scale domestic use. Conventional water treatment systems are often constrained by high operational costs and dependence on grid power, highlighting the need for sustainable and autonomous infrastructure solutions. This study presents the design, development, and performance evaluation of an integrated solar-powered clean water treatment system for smart building applications in remote areas using a Research and Development (R&D) approach. The proposed system combines off-grid polycrystalline photovoltaic panels with a multi-stage water treatment process consisting of a floss (mud) filter, activated carbon filter, water hyacinth cellulose bio-filter, ultraviolet (UV) sterilization unit, storage tank, and an IoT-based real-time water quality monitoring system. System performance was evaluated through microbiological, physical, and chemical water quality testing, with monitoring conducted via Wi-Fi-enabled sensors connected to the Blynk platform. The results demonstrate substantial improvements in treated water quality. Escherichia coli and total coliform bacteria were eliminated (100% reduction). Total dissolved solids (TDSs) decreased from 450 mg/L to 218 mg/L (51.6%), and dissolved manganese was reduced from 30 mg/L to 0.01 mg/L (99.97%), while nitrate levels decreased by 50%. Water pH and temperature remained stable and within regulatory limits. All treated water parameters complied with national clean water standards for hygiene and sanitation. The system operated independently using solar energy and achieved a clean water production capacity of 1000–1500 L/day. These findings indicate that the proposed system is a feasible, cost-effective, and sustainable civil engineering solution for clean water infrastructure in remote building environments. Full article

The treatment of high-salinity, low-carbon marine aquaculture wastewater poses significant challenges for biological denitrification. This study systematically evaluated the performance of a polycaprolactone (PCL)-based aerobic denitrification biofilter under varying temperatures (15 °C and 25 °C) and PCL addition levels (282, 564, 846, 1128, and 1410 g). Optimal nitrogen removal, total nitrogen (TN) removal efficiency exceeding 92%, was achieved with 1128 g PCL at 15 °C (HRT 10 h) and 1410 g PCL at 25 °C (HRT 8 h), significantly outperforming the low-PCL baseline treatment. Microbial community analysis revealed that increased PCL dosage promoted the dominance of the hydrolytic genus Flavobacterium over Simplicispira, enhancing polymer degradation capacity and system stability. Metagenomic sequencing further elucidated the complete PCL degradation pathway, wherein hydrolysis products were oxidized to generate NADH and FADH₂, serving as electron donors for denitrification. Key functional genes (narG, nirK, nosZ) and enzymes associated with both PCL decomposition and nitrate reduction were significantly enriched in high-performance reactors (e.g., AT15H6, AT25H6, ET15H10, ET25H10), correlating strongly with observed nitrogen removal rates. By integrating reactor performance with microbial ecology and functional genetics, this work provides a comprehensive “material–microorganism–gene–performance” framework, offering both practical strategies and mechanistic insights for enhancing denitrification in saline aquaculture systems. Full article

Groundwater serves as a vital source of domestic and agricultural water in rural areas of the Songnen Plain. Its chemical composition and water quality directly impact public health and regional sustainable development, making them subjects of significant concern. This study employed a comprehensive analytical framework, integrating Piper trilinear diagrams, ionic ratio analysis, the Water Quality Index (WQI), and the Human Health Risk Assessment (HHRA) model, to preliminarily evaluate groundwater conditions in a rural township of the Songnen Plain. The multi-method approach was designed to provide scientific insights for groundwater pollution prevention and remediation strategies in the region. Results indicate that the predominant groundwater chemical type in the study area is HCO₃-Ca. The hydrochemical process is primarily controlled by weathering and dissolution of silicate and carbonate minerals, accompanied by cation exchange. The WQI ranged from 84.78 to 192.82, with an average of 132.68, indicating overall moderate water quality. Fe and Mn are significant factors affecting water quality. The potential non-carcinogenic risks posed by groundwater to children, females, and males (0.988, 0.701, 0.534) and carcinogenic risks (1.77 × 10⁻⁵, 6.27 × 10⁻⁵, 4.81 × 10⁻⁵) are both below the USEPA recommended threshold (1.0, 1 × 10⁻⁴), indicating that the health risks were generally acceptable, though the HI for children approached the threshold. The results underscore the need for targeted mitigation of elevated Fe/Mn concentration (e.g., via aeration biofilters) while highlighting the region’s low health risks under current conditions. This work provides a template for integrating geochemical and health risk paradigms in groundwater management. Full article

The performance of a sequencing batch biofilter granular reactor (SBBGR), followed by a dual media granular activated carbon (GAC) column, was evaluated in terms of its ability to remove selected per- and polyfluoroalkyl substances (PFAS) from landfill leachate. The results show that the SBBGR achieved an overall reduction of 51%, with the preferential removal of long-chain PFAS, while short-chain PFAS were only partially removed. Subsequent GAC treatment exhibited compound-specific breakthrough behavior, which was governed by chain length. Short-chain PFAS (e.g., perfluorobutanoic acid) exhibited rapid bed volumes at 50% breakthrough (BV₅₀ ≈ 88), whereas long-chain PFAS (e.g., perfluorooctanoic acid and perfluorooctanesulfonic acid) were substantially more retained (BV₅₀ ≈ 446 and 361, respectively), with perfluorohexanesulfonic acid and perfluorodecanoic acid failing to reach BV₅₀ within the monitored period. Mass balance analysis showed that the hybrid GAC column captured ~73% of the influent PFAS mass. This resulted in >80–95% retention of long-chain PFAS and <40% retention of short-chain PFAS. Although long-chain PFAS were preferentially adsorbed, mobile short-chain species dominated residual effluent loads. These findings highlight the need for optimized contact times or dual-media strategies to control the breakthrough of short-chain PFAS. Full article

Bioaerosol emissions from biological treatment processes like composting, livestock operations, and wastewater plants pose notable occupational and environmental health risks. Biofiltration is a common mitigation measure for gaseous pollutants, but its effectiveness in controlling bioaerosols is less studied. This review synthesizes current evidence on biofiltration for the removal of bioaerosols. Findings indicate that biofiltration can significantly reduce emissions from waste-related biological processes, although results vary widely and depend heavily on design and operational factors. In composting, agricultural, and wastewater treatment contexts, fungal bioaerosols are consistently removed with high efficiency, often over 90%. Conversely, bacterial removal shows greater variability, from negligible to above 90%, influenced primarily by airflow rate, bed depth, and media stability. Systems with residence times of tens of seconds and bed depths of at least 1 m tend to reliably reduce bacterial counts, whereas undersized, high-flow systems experience marked efficiency losses. The choice of packing material is also crucial; mature, stable media maintain performance, whereas nutrient-rich or unstable substrates can lead to fungal emissions, turning the biofilter into a secondary source. Data on endotoxin removal are limited and remain insufficient for firm design recommendations. Overall, biofiltration’s effectiveness depends on complex interactions among physical retention, biological stability, and design. These insights emphasize the need for future research to focus on standardized, performance-based design criteria supported by consistent reporting and full-scale validation. Full article

Rapid urbanisation and climate-induced extreme weather events have intensified urban stormwater runoff challenges. Biofiltration systems have emerged as effective, sustainable urban drainage solutions for mitigating these impacts. A total of 78 peer-reviewed studies were assessed to synthesise findings on how design parameters influence pollutant removal performance in biofiltration systems treating urban stormwater runoff. Peer-reviewed articles published from 1 January 1995 to 3 June 2025 were retrieved from Scopus and Web of Science (WoS). Non-peer-reviewed, non-empirical, incomplete, or non-relevant studies were excluded. Rigorous application of a standardised review protocol and predefined criteria was employed to mitigate bias. The findings reveal high removal efficiencies for certain trace metals, ammonium, Escherichia coli (E. coli), hydrocarbons, and microplastics, with inconsistent removal for total nitrogen, nitrates, and phosphorus. The primary pollutant removal mechanisms were adsorption, ion exchange with select media, and denitrification in saturated zones. Only 22% of the reviewed studies incorporated a saturated zone, while 18% included a protective surface layer, despite both design elements being associated with improved pollutant removal performance. Variations in media composition and stormwater quality limit comparability across studies. This review highlights the need for context-specific design guidance and further exploration of multi-functional media to enhance multi-pollutant removal. Full article

Removal of micropollutants from wastewater is currently drawing a lot of attention in the field of municipal wastewater treatment plants. Firstly, this is because of their unpredictable and potentially damaging fate in the environment, and secondly, due to newly established requirements in the relevant European Union Directive (EU) 2024/3019. This article assesses coagulation, oxidation with chlorine dioxide, sand biofilter, and their combinations as potentially cheaper and sustainable alternatives to well-established, but more expensive methods. For the experiments, citalopram, carbamazepine, and diclofenac were chosen as representatives of micropollutants. Removal efficiencies were evaluated using HPLC, COD, and absorbance UV/VIS at different wavelengths. The demand for chlorine dioxide was assessed using the chlorophenol red method. Owing to analytical limitations, the concentrations examined were in mg/L, which significantly exceeds actual concentrations found in wastewater. The application of stand-alone chlorine dioxide oxidation exhibited the best performance as it sufficiently removed citalopram and diclofenac. On the contrary, biodegradation was found to be the least efficient method, as none of the compounds tested were sufficiently removed in a short period of time. However, the results may be partially biased owing to high concentrations of the micropollutants assessed. In the following stage of the research, the evaluation of transformation products is desired to prevent such potentially harmful chemicals from entering the environment. Full article

(1) Research Highlights: This study provides the first integrated assessment of Scots pine (Pinus sylvestris L.) growing in the urban forests of Karaganda, Kazakhstan, a city consistently ranked among the most air-polluted cities globally. We examined the adaptive phyto-chemical response of needles to extreme technogenic stress and evaluated their dual potential as biological filters and renewable sources of bioactive compounds. (2) Background and Objectives: Urban forests are critical for mitigating air pollution; however, the biochemical responses of trees in heavily industrialized environments remain poorly understood. Karaganda faces severe atmospheric pollution from mining, metallurgy, and energy sectors, with particulate matter (PM) levels exceeding permissible limits by up to 20-fold. This study aimed to evaluate the state of Pinus sylvestris, a key component of local protective plantations, by studying heavy metal accumulation, anatomical localization of secondary metabolites, and the phytochemical profile and biological activity of needle extracts obtained using different extraction techniques. (3) Materials and Methods: Needles were collected from 15 trees across three sites in Karaganda’s industrial green zones. Heavy metal content (Pb, Cd, As, and Hg) was determined using atomic absorption spectroscopy and voltammetry. Anatomical–histochemical analysis localizes major metabolite classes. Liquid extracts were prepared using four methods, percolation (PER), vortex-assisted (VAE), microwave-assisted (MAE), and ultrasound-assisted (UAE) extraction, and analyzed by GC-MS. Antimicrobial activity was tested against S. aureus, B. subtilis, E. coli, and C. albicans using the disk diffusion method. The antioxidant capacity (water- and fat-soluble) was measured amperometrically. Statistical analysis was performed using one-way ANOVA with Tukey’s HSD test (p < 0.05). Results: Despite extreme ambient pollution, heavy metal concentrations remained below pharmacopoeial limits (Pb < 0.1, Cd < 0.05, As < 0.01, Hg < 0.001 mg/kg), indicating effective biofiltration without toxic accumulation. Histochemistry confirmed the active synthesis of protective phenolics, flavonoids, and essential oils in the mesophyll, epidermis, and schizogenic cavities. GC-MS identified 72 compounds in the PER extract, 70 (the VAE), 72 in (MAE), and 46 in (UAE). The PER extract exhibited the highest relative abundance of bioactive terpenoids: α-cadinol (5.24%), α-muurolene (4.32%), and caryo-phyllene (2.20%). UAE extracts exhibited elevated 5-hydroxymethylfurfural (6.90%), indicating degradation. Antimicrobial testing revealed that PER produced the largest inhibition zone against S. aureus (15.0 ± 1.0 mm), significantly exceeding that of the other methods (p < 0.001). PER extract also demonstrated the highest water-soluble antioxidant capacity (3600 ± 0.40 mg quercetin equiv./dm³) and substantial fat-soluble activity (1633 ± 0.23 mg gallic acid equiv./dm³). (4) Conclusions: Pinus sylvestris in Karaganda exhibits remarkable adaptive resilience, maintaining safe heavy metal levels while accumulating a rich repertoire of stress-induced secondary metabolites. Classical percolation optimally preserves this native phytocomplex, yielding extracts with superior antimicrobial and antioxidant properties. These findings support a dual-use model wherein urban pine plantations simultaneously serve as living biofilters and renewable sources of standardized bioactive extracts, a concept with direct implications for circular bioeconomy strategies in industrial regions worldwide. This supports the strategic importance of coniferous plantations for bioremediation and sustainable resource use in industrial regions. Full article