Mechanical integrity of a flexor hallucis longus tendon transfer using an all-inside endoscopic approach.

Earthen canals in seismically active regions face combined hydraulic and earthquake loading that can compromise slope stability. This study evaluates the effectiveness of vetiver grass as a bioengineering reinforcement through Pseudostatic slope stability analysis of a critical section (IT3) of the Khush Tepa Canal using the Morgenstern-Price limit equilibrium method. Steady-state, rapid drawdown, and seismic scenarios were systematically assessed to quantify their influence on slope performance and reinforcement benefits. Results show that the canal is stable under steady-state conditions (FoS = 2.11), while seismic loading reduces stability (FoS = 1.25, a 40.8% reduction), and rapid drawdown represents the most critical scenario (FoS = 1.10). Vetiver grass reinforcement substantially improves levee stability, increasing the FoS from 1.93 to 2.37 (a 22.8% gain) under static conditions. This improvement is attributed to increased apparent cohesion from the dense root network, which constrains failure surfaces to shallower depths and prevents deep rotational sliding. These quantitative improvements demonstrate that vetiver grass provides measurable structural reinforcement. The findings support integrating nature-based solutions into earthen canal design to enhance both hydraulic and seismic resilience in earthquake-prone regions.

Continuous backwash media filtration for advanced primary treatment and resource recovery from wastewater.

Wastewater plants (WWPs) are widely recognised as nature-based solutions for wastewater management in West Africa, yet empirical data from their commissioning phase remain limited. This study investigates the rehabilitated Arzêké WWP in Parakou, Bénin, which treats wastewater from a large urban market through a three-stage anaerobic, facultative, and maturation pond system. A two-phase monitoring protocol compliant with ISO 5667-10 was applied, yielding 293 flow observations and 70 concurrent flow -quality pairs. Eleven physicochemical parameters were analysed: pH, electrical conductivity, total suspended solids (TSS), chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD5), total nitrogen, total phosphorus, iron, copper, lead, and zinc. Phase 1 yielded a mean daily flow of 6.14 m³/d (27.4% of design); Phase 2 confirmed underloading at 5.47 m³/d (24.4%). This resulted in a nominal hydraulic retention time of 549 days, 4.1 × the design value, with implications for sludge accumulation and greenhouse gas emissions. The influent was concentrated but biodegradable (median BOD5 983 mg/L; COD/BOD5 1.85). Trace metals were strongly associated with TSS (rs = 0.68-0.81), with inter-week increases exceeding 100% for Pb and Zn. This study provides the first commissioning-phase reference dataset for a market-fed WWP in West Africa.

Machine learning and explainable AI for predicting antibiotics removal in constructed Wetlands: Key factors and management implications

Novel hybrid biochar-based constructed wetlands for contaminant of emerging concern removal in water reuse.

During extreme storm events, waves that run-up and overtop levees cause a significant hydraulic load on the landside slopes. In order to determine the effects of these loads on the flood risk, it is necessary to determine the sensitivity of the landside slope to erosion. Models exist for determining the erosion resistance of grass covers to wave overtopping. The challenge has been to qualitatively describe the erosion process due to wave overtopping and to quantify the erosion rate of clay exposed to wave overtopping loads. To address this challenge, prototype scale wave overtopping experiments have been performed. To facilitate the transfer of the results to other locations and clay types, the Erosion Function Apparatus has been used to predict the erosion characteristics from small samples collected from the test sites. Here we present a dataset containing measurements from four experimental campaigns designed to evaluate the erosion resistance of existing and newly constructed clay covers under controlled overtopping loads. It includes soil properties, hydraulic loading programs, overtopping characteristics, wavefront velocities, and erosion progression data. The dataset enables comparative analyses across levee types and provides a reproducible foundation for model calibration, erosion assessment, and flood defence design.

This study evaluated the performance of a hybrid constructed wetland (CW) system consisting of horizontal subsurface flow (HF), vertical subsurface flow (VF), and free water surface (FWS) units for domestic wastewater treatment under rural conditions. The system was operated at two hydraulic loading rates (HLR) of 5 and 10 cm/day to assess treatment efficiency under different operational scenarios. Results showed high removal efficiencies for organic matter and nitrogen, with average BOD₅ and NH₄⁺-N removal reaching approximately 82.6–84.8% and 85.7–88.2%, respectively. Total suspended solids (TSS) removal ranged from 67.1% to 83.8%, while total coliform removal exceeded 98%. However, phosphorus removal remained low and unstable (14.2–17.2%), indicating the need for improved substrate materials. The performance of HF units varied depending on plant species, with Caladium bicolor demonstrating superior BOD₅ removal efficiency. The integration of HF and VF units, combined with intermittent feeding, enhanced nitrification–denitrification processes and improved nitrogen removal. Overall, the study demonstrated that the hybrid CW system was an effective, low-cost, and sustainable solution for domestic wastewater treatment in rural areas without requiring recirculation.

Physical and biological fate of protozoan (oo)cysts in slow sand filtration: A review.

Abstract Urbanization exacerbates water scarcity by increasing demand while reducing the availability of natural water reserves. Food waste is another critical issue that affects urban sustainability. Recycling treated greywater presents a sustainable alternative, particularly for irrigation purposes. This study evaluated the effectiveness of a media blend of spent coffee grounds and date seeds (1:2 ratio) for cultivating five ornamental plants irrigated with treated greywater at two hydraulic loading rates: 200 mL/day and 400 mL/day. Plants irrigated with 200 mL/day of greywater showed significant improvements compared to those supplied with freshwater. Increases were observed in plant height (27.3 ± 11.7 cm), pinnula count (6.3 ± 2.1), leaf number (55.3 ± 6.7, excluding Portulaca grandifolia ), dry shoot weight (13.06 ± 8.83 g), and root length (115.1 ± 10.9 cm). Plant moisture content also increased from 70 ± 4% to 74 ± 3%. In terms of treatment performance, Cyperus alternifolius achieved the highest pollutant removal: 70% TOC, 98% NH 4 + -N, 44% PO 4 3− -P, and 84% isobutyric acid. Portulaca grandifolia showed the best TN removal at 93%. The two loading rates showed no significant difference in pollutant removal (p = 0.19), suggesting rate flexibility in design. Among the tested species, Alternanthera amoena had the highest growth rate, while Cyperus alternifolius showed the greatest biomass yield. These species demonstrate strong potential for use in greenwall systems, offering both effective greywater treatment and robust plant performance. This study supports greywater irrigation as a practical approach to sustainable horticulture and urban water conservation. Graphical Abstract

Geomembranes are extensively used for seepage control in the reservoir of pumped-storage power stations due to their superior deformability, ease of construction, and low cost. The deformation behavior of geomembranes under high hydraulic pressure is of great importance for seepage-control design and operational safety evaluation. Nevertheless, existing hydrostatic pressure resistance tests cannot effectively measure the hydraulic bulging deformation of geomembranes subjected to water pressure. This study proposes a non-contact binocular vision method to quantify the hydraulic bulging deformation of geomembranes. The method combines underwater camera calibration, image enhancement, stereo matching, triangulation, and three-dimensional reconstruction to achieve both visualization and accurate measurement of geomembrane deformation. After experimental validation and accuracy calibration, the proposed method was preliminary applied to four geomembrane materials, including HDPE, LLDPE, PVC, and TPO, under hydraulic loading. The results show that the measurement error is less than 5% in the large-deformation range under medium and high water pressures. The method can effectively capture the hydraulic bulging behavior of geomembranes and accurately characterize the deformation features of different materials under high hydraulic pressure. This study provides a practical technical approach for underwater deformation measurement of geomembranes and supports seepage-control design and operational safety monitoring.

Contrasting effects of biofilm on arsenic removal between activated carbon and reverse osmosis point-of-use water filtration systems.

Hydraulic infrastructures, such as embankments, dams, and levees, are highly vulnerable to suffusion under complex mechanical and hydraulic loading conditions, posing serious threats to their structural integrity. To better understand the underlying micromechanics of suffusion in gap-graded soils, this study investigates fine particle migration and microstructural evolution, with a focus on the effects of coarse particle shape and fines content. A coupled multibody dynamics and discrete element method framework is employed to generate soil specimens with varying fines contents and particle morphologies, while the suffusion process is simulated using the coupled computational fluid dynamics and discrete element method, enabling the thorough examination of the interactions between fluid flow, particle migration, and force chain evolution during seepage infiltration. The results reveal that the particle shape plays a crucial role in determining the stability of force chains and fine particle migration patterns. A novel motion-based classification of fine particle migration during suffusion is introduced, encompassing four distinct mechanisms: clogging, voiding, detour, and punching. Following a rapid fines loss period during early seepage infiltration, the remaining fine particles primarily stabilize in a clogging state. The concept of tortuosity is proposed to characterize migration complexity, with results showing a nonmonotonic relationship with particle aspect ratio. Additionally, a clogging ratio is developed to quantify the accumulation of fine particles in clogging states. This study provides insights into the complex behaviors of fine particle migration in gap-graded soils, establishing a foundational framework for a better understanding of suffusion dynamics in hydraulic infrastructures.

Combined sewer overflows (CSO) are a significant source of urban water pollution, with sediments originating from sewers contributing substantial loads of organic matter, nutrients, and particulate-associated contaminants to receiving waters. In Germany, constructed wetlands for CSO treatment (CSOCWs) are well-established, yet their large surface area limits their implementation in urban areas. The present study investigates the potential of compact CSOCWs, operated at doubled flow rate, with tailored filter substrates and the addition of biopolymers to enhance treatment performance. A series of flocculation experiments was first conducted to identify a suitable biopolymer for CSO treatment. Subsequently, small-scale pilot column tests were performed to evaluate compact CSOCW configurations. Here, different filter substrates were investigated, including sand, sand-gravel, gravel, shells, sand-activated carbon, and sand-zeolite, with and without the selected biopolymer introduced into the inflow to assess its effect on treatment performance. Results show that compact CSOCWs with suitable substrates and increased flow rates achieved removal efficiencies comparable to the reference CSOCW in standard operation, exhibiting only minor deviations. Sorptive and fine-grained substrates (activated carbon, zeolite) demonstrated high performance for particulates, COD, DOC, and NH4N, respectively. Biopolymer dosing significantly enhanced particle and COD retention in coarse filter substrates (gravel, shells), thereby reducing performance differences across configurations. In contrast, phosphorus removal remained limited across all configurations, independent of biopolymer dosing. These findings demonstrate that compact CSOCWs can provide a robust treatment option for CSOs and urban runoff under increased hydraulic loading, particularly in densely populated areas.

Understanding how spatially distributed electroactive units contribute to the collective performance of multi-anode-constructed wetland-microbial fuel cells (CW-MFCs) is essential for advancing system design and optimization. In this study, we systematically dissect the individual anodic electrochemical and biological contributions of pyrite- and graphite-based multi-anode CW-MFCs (Py-MACW-MFC and GG-MACW-MFC) under varying organic and hydraulic load conditions to elucidate anode-specific mechanisms driving wastewater treatment and power generation. The Py-MACW-MFC exhibited superior treatment performance, achieving optimal removal efficiencies of 96.33 ± 0.72% (COD), 82.60 ± 3.12% (NH4⁺-N), and 47.09 ± 0.58% (TP) at an influent COD of 400mg L-1, representing 1.03-, 1.2-, and 1.1-fold improvements over the GG-MACW-MFC, respectively. The optimal hydraulic retention time was determined to be 1.5days, beyond which performance declined, yielding maximum removal efficiencies of 95.92 ± 0.37% (COD), 72.98 ± 0.70% (NH4⁺-N), and 48.26 ± 5.43% (TP) in the Py-MACW-MFC. Spatially resolved electrochemical analysis revealed distinct anodic behaviors, with the power density of individual anodes following the order A2 (25.54 mW m-3) > A1 (24.14 mW m-3) > A3 (23.81 mW m-3), which were 1.47-, 1.28-, and 1.22-fold higher than those of the GG-MACW-MFC, respectively. The results demonstrate that electrode composition critically shapes localized bio-electrochemical performance. Microbial community analysis further revealed that pyrite promoted a higher abundance of Proteobacteria and Bacteroidetes, alongside enhanced denitrification-related functional genes, underpinning its superior pollutant removal and energy recovery capacity. These findings established pyrite as a promising electrode material and revealed how anode-specific bio-electrochemical interactions shape system-wide functionality, offering a mechanistic foundation for the rational design of next-generation, spatially optimized CW-MFCs.

The aim of this study was to investigate the ability of sewage sludge-derived biochar to remove PO4-P from real biologically treated wastewater. Biochar was produced via the pyrolysis of anaerobically digested sewage sludge pretreated with nanoscale zero-valent iron (nZVI) at concentrations of 3%, 1.5%, and 0.5% (w/w, based on total solids). A sample without nZVI addition was used as a control. The properties of biochar samples were analyzed, including elemental composition, specific surface area, and pore size. PO4-P removal was evaluated using both batch adsorption and column experiments. The highest adsorption capacity determined in the batch experiment was 2.5 mg/g. When wastewater was passed through columns packed with 0.3–0.6 mm biochar particles at a hydraulic loading rate of 1 m/h, a 3-fold-higher phosphorus retention capacity was obtained in the range of 7.26–7.82 mg/g. The column containing biochar derived from sewage sludge with 3% nZVI accumulated 7% more PO4-P than the biochar without nZVI. All columns effectively removed phosphates from wastewater (efficiency > 80%) due to the chemical composition of biochar, which mainly contained Fe and Ca elements. In contrast to the batch experiment, the columns were subject to the biological sorption of phosphates via microorganisms, physical retention between particles, and the formation of precipitates on the surface of a column.

This paper developed a probabilistic framework for system level reliability and risk assessment that coupled hydraulic loading with structural response and explicitly modelled cascading interactions and statistical dependence between components. The contribution is a system-level reliability and risk modelling methodology that integrates dynamic cascading interactions, non-stationary design-life reliability accumulation, and system-level optimisation within a unified Monte Carlo architecture. Dynamic Monte Carlo simulation was used to evaluate individual, joint, conditional, and system-scale probabilities of failure across varying flood magnitudes and design lives. Model verification confirmed that discretisation and sampling errors were small relative to parameter-driven variability. Results showed that long-term system reliability arose from the combined influence of flood frequency, exposure duration, and the strength of interaction between interdependent structures. Frequent loading accelerates the accumulation of failure probability through repeated events, whereas rare events contribute more slowly but dominate extreme outcomes, indicating that cumulative reliability cannot be inferred by the linear extrapolation of annual probabilities. In an examined diversion–levee–basin configuration, strong structural coupling amplified vulnerability by contracting joint stability margins and increasing conditional failure probabilities. The system-level optimisation of structural parameters over the examined design life reduced cumulative system failure probability from 0.305 to 0.153, whereas single-component optimisation redistributed risk within the system without reducing total system risk. The framework advances beyond static risk analysis by integrating time-dependent reliability, cascading dependencies, and design-life optimisation for system-scale mitigation.

Water reuse is increasingly adopted to address global water scarcity, particularly for nonpotable applications. This study evaluated a pilot-scale treatment train consisting of a vertical flow constructed wetland (VFCW) followed by sequential double filtration (DF) consisting of a sand filter followed by activated carbon and clinoptilolite media as posttreatment of domestic wastewater previously treated in an upflow anaerobic sludge blanket (UASB) reactor. The system was operated under three hydraulic loading rates (200, 400, and 600 mm/day), corresponding to organic loading rates of 26.8 to 94.9 g COD/m2·day. The VFCW provided effective polishing of organic matter, achieving COD and BOD removals of up to 78% and 87%, respectively, relative to the UASB effluent, while additional total suspended solids removal ranged from approximately 25% at low and intermediate loadings to about 11% at the highest loading rate. Total nitrogen removal remained moderate and variable (~30%-65%), reflecting the predominance of aerobic conditions and limited denitrification potential within the wetland. Phosphorus removal in the VFCW was variable, with low efficiencies under low and high loadings (~14%-18%) and evidence of phosphorus remobilization under intermediate loading conditions. Microbial attenuation in the VFCW resulted in Escherichia coli removals of 90%-96% at low to intermediate hydraulic loads, with reduced performance at the highest loading rate. In contrast, the downstream DF consistently provided additional E. coli removal exceeding 99%, yielding final effluent concentrations on the order of 102 CFU/100 mL and complying with international reuse guidelines. Overall, the integrated VFCW-DF configuration functioned as a robust multibarrier system, enhancing operational reliability and demonstrating the potential of combined nature-based and low-cost filtration processes for decentralized wastewater reuse. Importantly, the results demonstrate that coagulant-free double filtration acts as a stabilizing barrier, transforming variable wetland performance into consistent and reuse-compliant effluent quality.

To address poor hydraulic shock load resistance, excessive energy consumption, and low mixing efficiency in existing mixers, a novel power-free tubular dynamic mixer was designed. In this design, orifice size adjusts dynamically based on water flow rate by spring expansion and contraction. Springs connect to the orifice plate and maintain a nearly constant flow velocity. A one-year comparative experiment was conducted at two water treatment plants to compare the novel dynamic mixer with mechanical agitation and tubular static mixers. The results showed that the dynamic mixer achieved an annual average sedimentation outlet turbidity of 0.70 NTU, a coagulant dosage of 68.94 mg/L, a chemical oxygen demand (COD Mn ) of 2.18 mg/L, and a residual aluminum content of 0.078 mg/L; these values were lower than those of the static (1.71 NTU, 85.16 mg/L, 2.73 mg/L, and 0.133 mg/L, respectively) and mechanical agitation (1.32 NTU, 80.03 mg/L, 2.39 mg/L, and 0.091 mg/L, respectively) mixers. This power-free mixer combines the effective mixing of mechanical agitation mixers with the energy efficiency of tubular static mixers, thereby yielding the lowest operating cost. Overall, this novel mixer exhibits strong potential for widespread application in water treatment, seawater desalination, and advanced pretreatment. • Designed a novel power-free tubular dynamic mixer. • Adjust the size of orifices according to changes in water inflow rate, Strong shock load resistance. • Stable output water quality, lower effluent turbidity and residual aluminum content. • It can save coagulant dosage by 10-30%. • Solved the back-mixing problem present in other types of mixers.

Expanded granular sludge bed (EGSB) reactors have emerged as promising high-rate anaerobic treatment systems for industrial wastewater (WW) with increasing organic loads and complex compositions. This review provides a systematic overview of the main operational parameters, including organic loading rate (OLR), volatile fatty acids (VFA), pH, temperature, influent solids, upflow velocity (Vup), extracellular polymeric substances (EPS) production and solids retention time (SRT), focusing on their effects on granule formation and process performance. EGSB stability is governed by defined operational limits, with optimal performance at OLRs of 10-30kg COD m-3 d-1, VFAs below 500-1000mg L-1, and moderate Vup (3-6m h-1). Exceeding critical thresholds in VFA, Vup, or influent solids (>5000mg L-1) induces washout and granulation failure, while protein-rich EPS enhance the cohesion and shear resistance of granular biomass under high hydraulic and organic loads. Special attention is paid to microbial community dynamics, emphasizing how substrate characteristics, operational conditions, height-to-diameter ratio, and microbial kinetics jointly shape community shifts, syntrophic interactions, and overall process stability in EGSB reactors. Furthermore, the insights derived from these analyses are used to provide a more robust explanation of anaerobic granulation mechanisms, integrating conceptual models, key physicochemical drivers, and the role of quorum sensing (QS). Based on this integrated framework, this review identifies existing knowledge gaps and proposes future directions to support the development of robust and efficient EGSB systems for the sustainable treatment of complex industrial WW.