Water Science and Technology最新文献

Precise streamflow prediction is fundamental for effective water resources management, flood risk mitigation, and sustainable agricultural planning, particularly in regions dependent on rainfed agriculture. This study evaluates the prediction capability of four hydrological models of parameter-efficient distribution (PED), Hydrologiska Byråns Vattenbalansavdelning (HBV), Hydrological Engineering Center-Hydrological Modeling System (HEC-HMS), and Soil and Water Assessment Tool (SWAT) in the Koga Watershed, Ethiopia. The models were calibrated from 1997 to 2006 and validated from 2007 to 2011 using observed daily streamflow. During calibration, the PED model showed the best performance with coefficient of determination (R²) (0.79), Nash-Sutcliffe efficiency (NSE) (0.782), root mean square error (RMSE) (0.42), and percentage of bias (PBIAS) (7.56%), while SWAT simulated the highest flows, and HEC-HMS slightly overestimated flows. During validation, PED had an excellent performance (R² = 0.70, NSE = 0.72, RMSE = 0.65, and PBIAS = 16%), whereas HBV had minimum flows, and SWAT forecasted minimal flows. Inclusively, the PED model is found to be the most suitable model for flow prediction in the watershed established due to its consistency for sustainable water resource management. The findings provide valuable insights for selecting suitable hydrological models to improve water resource planning and execution.

Groundwater contamination, particularly nitrate pollution, poses serious health and environmental risks in hyper-arid regions, where water scarcity compounds these challenges. Despite its critical importance, comprehensive frameworks for assessing groundwater quality, focusing on nitrate contamination, remain limited. This study aims to evaluate nitrate contamination and overall suitability of groundwater for drinking and farming purposes in the hyper-arid Adrar region of southwestern Algeria, where salinity and nitrate pollution pose significant risks. One hundred and thirty groundwater specimens were gathered and analyzed for 12 physicochemical features. To assess contamination sources and water quality, an integrated approach combining the groundwater quality index (GWQI), principal component analysis (PCA), and geochemical tools (Gibbs and Piper diagrams) was applied. Results indicate that 80% of the samples were deemed to be in 'extremely poor' condition (GWQI > 150), with a mean total dissolved solids (TDS) concentration of 1,484.70 mg/L and nitrate concentrations averaging 43.05 mg/L, both of which exceed World Health Organization standards. PCA identified salinity (47.33% variance) and nitrate contamination (9.95% variance) as the primary contributors, which are linked to mineral dissolution and agricultural inputs. The findings underscore the urgent need for sustainable water management and provide a replicable model for assessing groundwater quality in similarly challenged regions.

In this study, an air-bubbling humidifier, a dehumidifier (also referred to as an open-air HD system) and a closed-air HD system for desalting high-salt wastewater were designed and constructed. Experimental tests and analyses of these desalination systems were conducted under different operating parameters. The results showed that for the closed-air HD system, the recommended evaporation temperature and the condensate solution temperature are 50-80 and 20-40 °C, respectively. The system achieved a maximum energy recovery rate of 24.55% and a minimum specific vapor consumption ratio (SVCR) of 0.756. In addition, the air-bubbling closed-air HD system was proven effective in treating high-salt wastewater, with the electrical conductivity of the condensate solution reaching a maximum of 670.22 μS/cm. This study demonstrates that the air-bubbling HD system has great potential for high-salt wastewater treatment without requiring an indirect contact heat exchanger.

Pyrrhotite (Fe_1-xS) was prepared by the pyrolysis of pyrite and the sulfidation of hematite, and subsequently used to activate H₂O₂ for the degradation of tetracycline (TC). The pyrite-derived Fe_1-xS samples (P600 and P700) and the hematite-derived Fe_1-xS samples (S600, S700), prepared at 600 and 700 °C, respectively, were characterized using X-ray diffraction (XRD), X-ray photoelectronic spectroscopy (XRS), scanning electron microscopy (SEM) and magnetism analysis. The effects of annealing temperature, preparation method, and initial solution pH on TC degradation were systematically investigated. The results showed that the degradation of TC increased with the decrease in annealing temperature and initial solution pH. Quenching experiments and electron spin resonance (ESR) demonstrated that ^•OH and ¹O₂ were reactive oxygen species (ROSs) in acidic and alkaline media, respectively. Moreover, the sulfidation-derived pyrrhotite, featuring a monoclinic Fe_1-xS shell, exhibited superior catalytic performance than pyrolysis-derived pyrrhotite with a hexagonal Fe_1-xS shell. Notably, ¹O₂ was easier to produce in the P600/H₂O₂ system. Both P600 and S600 maintained a high catalytic activity after five runs. These findings offer a novel approach for pyrrhotite preparation and promote the comprehensive utilization of pyrite and hematite.

We quantified the ecological risks posed by cadmium (Cd) in Baiyangdian Lake (BYDL) sediments, and established region-specific sediment quality criteria (SQC) and risk thresholds, using an approach that combined benthic bioassays with an improved version of the equilibrium partitioning (EqPA) method that incorporated acid volatile sulfide (AVS)-bound and residual fraction correction terms. The resulting SQC for Cd in BYDL sediments was 9.01 mg/kg, which was substantially higher than other threshold effects level (2.58 mg/kg) and is attributable to the suppression of Cd bioavailability by AVS in the sediments (average logKp = 3.86). Furthermore, we conducted a 21-day exposure experiment using the native bivalve Anodonta woodiana at Cd concentrations between 1 and 20 mg/kg. Significant impacts were observed at concentrations ≥15 mg/kg, including reduced survival (70%), increased tissue accumulation (4.93 mg/kg), and the inhibition of the superoxide dismutase and carboxylesterase enzymes (>40%). By integrating the data from the benthic bioassays, enzyme activity analysis, and the EqPA method, we determined an ecological risk threshold of 10-15 mg/kg for Cd in BYDL sediments. This region-specific threshold can support targeted sediment management in BYDL, and the combined EqPA-bioassay approach provides a method for developing sediment quality benchmarks elsewhere.

Inlet modifications applied to culverts can increase the culvert discharge capacity, which will help stormwater drainage systems adapt to larger flood events. Wingwalls and headwalls are already widely used as retaining structures. It is therefore feasible to optimise these inlet structures to increase culvert capacity. Building upon previous physical modelling research, this study evaluated a wider range of headwall and wingwall angle combinations to refine the findings. Headwalls and wingwalls were compared with rounded-edge box culvert inlets with the aim of improving capacity under inlet control. Numerical modelling was used to optimise wingwalls and headwalls and rounded-edge inlets, quantify their improvement, and verify the alignment of results with established references and guidelines. A 15° headwall with a 15° wingwall added to a box culvert improved the flow by up to 34% at a headwater depth of twice the culvert height (2D), or up to 26% at 1.2D. This solution provides the best balance between hydraulic performance and practical implementation. The largest improvement obtained by rounding the edges of a square box culvert is 30% at 2D. Inlet modifications provide a sustainable solution to increase culvert drainage capacity, which can mitigate flood risks.

Predicting wastewater influent is essential for reliable, energy-efficient operation in climate-sensitive, data-limited utilities. This study benchmarks monthly influent forecasts for major treatment plants in Kuwait using stepwise linear regression (SLR), ensemble trees (ET), support vector machines (SVM), kernel approximation, and penalized linear baseline (LASSO), with air temperature, relative humidity, municipal water consumption, and population as predictors. A five-fold cross-validation with a chronologically held-out test block is adopted. Performance is reported using RMSE, MAE, MSE, R², and MAPE. LASSO achieved the lowest test errors while selecting a sparse specification; SLR/ET were close, and kernel methods underperformed. Model behavior was examined using SHAP summary and feature importance plots. Results indicate that low-complexity, transparent models, particularly penalized linear models, provide strong skill at low tuning cost, supporting operator trust and auditability. The framework offers actionable month-ahead guidance for load management, storage/reuse planning, and alternative water-supply decisions in hyper-arid utilities.

The widespread detection of sulfamethoxazole (SMX) in aquatic environments necessitates understanding its impact on the anaerobic/oxic/anoxic (AOA) process. This study systematically elucidated the multidimensional mechanisms by which SMX affects AOA system performance, sludge characteristics, and microbial metabolism, integrating analyses of oxidative stress and sludge parameters. Results demonstrated concentration- and time-dependent effects. Long-term exposure to medium-high SMX concentrations (≥5 mg/L) significantly inhibited microbial metabolic activity (13.5% decrease in specific oxygen utilization rate, suppression of polyphosphate synthetase), induced oxidative damage (46.3% increase in lactate dehydrogenase leakage), and reduced removal efficiencies for ammonium nitrogen (9.1%), total nitrogen (15.9%), and phosphate phosphorus (12.5%). Concurrently, it decreased sludge biomass (13.8% lower volatile suspended solids/total suspended solids ratio), worsened settleability (12.2% increase in sludge volume index), and disrupted extracellular polymeric substance (EPS) composition (PN/PS ratio decreased to 1.6). While low-concentration SMX (0.5 mg/L) elicited a transient stress response (10% compensatory EPS increase), microbial community adaptation ensured system stability. These findings reveal novel interference mechanisms of SMX in biological nutrient removal. Proposed strategies for microbial community optimization and process regulation offer crucial theoretical support and technical pathways for efficiently treating SMX-containing wastewater, advancing practical engineering applications for antibiotic pollution control.

Excessive inflow and infiltration (I&I) can compromise sanitary sewer safety and resilience. I&I assessments support the design and operation of resilient sanitary sewers, but data scarcity in low- and middle-income countries hinders many traditional I&I assessment methods. This paper introduces a two-stage approach, leveraging multiple I&I assessment methods. First, I&I assessment methods are compared to reveal network and data concerns. Second, I&I methods are combined in inverse proportion to their sensitivity to variable (mis)estimation to improve accuracy. When combining water balance and pollutant mass flux methods, higher I&I assessments receive larger weights since they are less sensitive to variable misestimation. Our proposed combination of these methods (the hybrid method) had negligible bias (<0.2%) and improved accuracy (reduced mean average percentage error by >10 percentage points). We applied this hybrid method to assess quarterly I&I over two decades in 46 sanitary sewer networks in Brazil, combining water balance and pollutant mass flux methods (using biological oxygen demand). I&I consumed 24% of total sewer capacity and >50% of capacity in four networks. Unlike previous I&I research, we propose and demonstrate how to learn from and combine multiple I&I assessment methods; our approach proved well-suited for data-sparse environments, increasing accuracy and insights.

The increasing amount of plastics in aquatic systems poses risks to water quality and biodiversity by transporting pathogens and antibiotic resistance genes. This article reviews how plastics spread and persist as vectors for these contaminants. In addition, their attachment, transport, and release mechanisms on plastic surfaces are discussed, underscoring the need for advanced detection and monitoring methods. Future research should focus on developing practical mitigation strategies and policy interventions to address plastic-mediated microbial pollution. Ultimately, this article emphasizes the value of interdisciplinary work to protect aquatic ecosystems and public health from the adverse effects of plastic pollution and proposes potential solutions to address this global challenge.