Water Science and Technology最新文献

A curtained stormwater storage and treatment facility was constructed in Lake Storsjön (Sweden) to treat urban stormwater runoff discharges. Over two and a half years, sediments were sampled four times across four facility zones (from inlet to outlet) in two depths to inform facility operation and polluted sediment management. Sediments were analysed for particle size distribution, metals, polycyclic aromatic hydrocarbons, and organic matter content to assess the spatial distribution of deposited sediment characteristics. Finer sediments (<0.016 mm) prevailed near the outlet, with a higher presence of fine particles in the deeper layer (10-20 cm). Substantial variations in chemical concentrations were observed, differing by up to three orders of magnitude. Higher concentrations were consistently found in the inlet zone and deeper layers (10-20 cm depth) throughout the sampling program. Combined horizontal and vertical distributions of sediment characteristics indicated a predominance of historical deposits in the sediments collected. Frequent exceedances of Predicted No-Effect Concentrations of chemicals, particularly in the inlet zone, highlighted potential risks to the aquatic environment that would result from dredging activities. This underscores the importance of considering broad mitigation strategies, including the capping of contaminated sediment, to control the environmental impacts of contaminated sediments on the lake ecosystem.

Thermal hydrolysis (THP) combined with thermophilic anaerobic digestion (TAD) offers promising pathways for enhancing sewage sludge treatment. This study is among the first to directly compare THP as both pre- and post-treatment options for TAD. Pre-treatment of waste activated sludge (THP-WAS) and post-treatment of digested sludge (THP-DS) were evaluated on their impacts on process stability, biogas production, and sludge dewaterability. Pilot-scale trials at a wastewater treatment plant (WWTP) in Prague revealed that THP-WAS increased sludge solubilization but faced challenges such as volatile fatty acid accumulation, adversely affecting reactor stability and specific biogas yield. In contrast, THP-DS enhanced biogas production by 10%, improved sludge dewaterability, and achieved superior methane content (73.2%). Further research is needed to optimize THP parameters for reactor stability and to better understand interactions between hydrolyzed WAS and primary sludge.

Industrial activities generate significant volumes of wastewater with various heavy metals, suspended solids, oils, tannins, toxic chemicals, organic and inorganic compounds, often with elevated biochemical oxygen demand (BOD) and chemical oxygen demand (COD) levels. This study mainly focuses on providing an in-depth review of the characteristics of effluents, available treatment processes, and regulatory frameworks for managing five common commodity manufacturing industry effluents (textile, pulp and paper, dye, leather, and rice mill). All these manufacturing industries consume large amounts of water and subsequently produce tons of effluents. Direct disposal of these effluents in the open environment poses potential hazards to the environment and human health and requires mitigation before discharge. Different conventional technologies are available to treat these effluents, which are associated with certain merits and demerits and highlighted here. The review also emphasized the most frequently applied process technologies to reduce BOD and COD load from the effluents of particular industries, with their limitations. Therefore, assessing economically viable and sustainable wastewater treatment approaches is crucial. It is concluded that conducting cost-benefit analysis in terms of BOD and COD removal efficiency and life cycle assessment is a must to select the most economical and sustainable solutions for the existence of any technology.

Thermal hydrolysis process (THP) can break down sludge structures and enhance organic solubilization into the liquid fraction. Separately treating liquid and solid fractions could benefit energy and material balances. In this study, five primary sludges (PSs) and seven waste activated sludges (WASs) were treated with thermal alkaline process (TAP) (160 °C, 30 min, pH 9-12), followed by centrifugation for liquid and solid separation. The liquid fractions of PSs after TAP yielded 348 ± 66 L/kg COD_added of biogas. They produced up to 29 ± 7% of the biogas from hydrolysates. In contrast, the liquid fraction of WASs after TAP yielded 395 ± 34 L/kg COD_added of biogas and produced up to 77 ± 4% of the biogas from hydrolysates. Additionally, the dewaterability of WAS increased by about 54%, while the dewaterability of PS decreased by roughly 48% after thermal treatment. With digestion of the liquid fraction and disposal of the solid fraction in WAS treatment with TAP at pH 11, biogas production increased by 4%, and the discharged sludge volume decreased by 10%. Although net electricity generation decreased by 22%, the digester volume could be reduced by 90%, allowing for more capacity for co-substrate digestion in WWTPs.

With the development of human civilization and the rapid progress of urbanization, the water environment and aquatic ecology need more systematic treatment to support the construction of ecological civilization and sustainable development. Based on a large number of research results and from the four dimensions including governance concept, governance technology, management and control platform and engineering strategy suggestions, this study systematically analysed the cutting-edge concepts such as reverse-driven governance, explored the application of key technologies such as remote sensing in the water environment and water ecological governance, put forward strategic suggestions on building an intelligent analysis and decision-making platform and avoiding great leap forward-style vanity projects in the water environment and aquatic ecology governance. Finally, six cutting-edge governance concepts, four key technologies, two types of governance and control platforms and two engineering strategies were sorted out and formed a governance system covering concept guidance, technical support, platform integration and application, and engineering strategy guarantee. The research enriches the theory of the water environment and aquatic ecology governance, and has important reference value for policy-making and engineering practice of watershed water environment and aquatic ecology governance.

Bioretention cells (BRCs) are among the most popular low-impact development techniques in the United States. They effectively mitigate the runoff hydrograph and excessive pollutant loadings affected by widespread urbanization. Overwhelmingly, the literature focuses on the effectiveness of newly constructed BRCs and does not account for the variety of designs found in BRCs installed less recently. The objective of this study was to evaluate the efficacy of a BRC in mitigating runoff quantity, reducing peak flow rate, and improving water quality parameters (i.e., sediment, nutrients, heavy metals, and indicator bacteria) 8 years post-construction. Total runoff volume reduction was substantial (83%), accredited to mature vegetation promoting evapotranspiration, canopy interception, and hydraulic properties of the mature BRC soil. Additionally, the BRC provided similar peak flow mitigation (median 93%) to newly constructed BRCs in the literature. Significant reductions in event mean concentrations and loads of sediments (>88%), particulate-bound nutrients (>60%), and heavy metals (>70%) were observed. In many cases, the BRC had better - or at least similar - pollutant removal efficiencies than younger BRCs. The excellent function of this BRC provides evidence that these systems may improve over time, given proper long-term maintenance.

Weather parameters that influence evapotranspiration are air temperature, solar radiation, relative humidity and wind speed. Daily weather data during the wheat-growing period were collected from 1970 to 2018 for the Amritsar district of Punjab state in India. To improve evapotranspiration estimation, a well-defined area of artificial intelligence called machine learning is used. To improve the accuracy of evapotranspiration estimation during the wheat-growing period, a model was developed by random forest (RF), support vector machine (SVM) and artificial neural network (ANN) using different weather input combinations. Based on the evaluation done using various standard statistical criteria during calibration and validation performance of RF was found to be best, followed by SVM and ANN. The model developed by (T_max, T_min, RHM, RHE and R_s) weather input combination was ranked first. Two weather input combinations (R_s, T_max) and (R_s, T_min) performed excellently by RF and SVM, while the weather input combination (T_max, T_min) performed excellently by the ANN. Hence, these input combinations can be used in the estimation of evapotranspiration when the availability of data is limited. From this study, it can be concluded that instead of a large amount of weather data, ET₀ estimation can be done with a few data points by the machine learning technique.

Gross solid materials carried in stormwater runoff can obstruct stormwater systems and transport nutrients and other pollutants to waterways. To characterize key drivers of the mass of gross solid delivered to stormwater systems and the amount of total phosphorus (TP) contributed by these solids, we collected these materials from the inlets of 13 stormwater control measures (SCMs) located in the Minneapolis - St. Paul metropolitan region in Minnesota, USA. Samples were collected from sampler devices during the years 2021-2022. Dry mass and mass organic matter (OM) were measured for all 420 samples collected, and 35% of all samples were analyzed for TP. A regression equation was developed to estimate TP mass for all samples based on measured OM. Additional analysis was performed to determine statistically significant factors that predicted the mass of gross solid material collected at each SCM. Annual dry mass, mass OM, and mass TP of the gross solid materials ranged from 6.1 to 76.9, 1.9 to 45.4, and 0.004 to 0.119 kg yr^-1, respectively. The tree canopy area over the street was the best predictor of the annual dry mass, OM mass, and TP mass delivered at the SCMs, with R² values of 0.44, 0.47, and 0.5, respectively.

Anaerobic co-digestion (AnCoD) presents a promising route for valorizing sludge generated from recycled paper processing. This study explored the co-digestion of primary sludge (PS) and secondary sludge (SS) at various mixing ratios to enhance methane generation and system stability. Batch biochemical methane potential (BMP) assays revealed that the 1:3 PS:SS ratio produced the highest methane yield (918.66 mL CH₄/g VS_fed) with a notably short lag phase of 1.59 days. Kinetic assessment using both modified Gompertz and logistic models indicated that the former offered superior fitting accuracy (R² > 0.986), effectively describing methane production dynamics. A two-stage continuous stirred-tank reactor (CSTR) system operated under this optimal ratio showed distinct functional separation: the acidogenic stage facilitated hydrolysis and volatile fatty acid (VFA) degradation, while the methanogenic stage supported biogas generation with stable pH and low VFA/alkalinity ratios. Microbial analysis confirmed a clear differentiation between fermentative and methanogenic communities, with evidence suggesting enhanced electron transfer pathways. These findings underscore the potential of AnCoD for efficient sludge stabilization and bioenergy recovery in the pulp and paper sector.

The recovery and utilization of phosphorus elements from biogas slurry can effectively prevent secondary pollution caused by biogas slurry application in farmland and eutrophication of water bodies. This study systematically evaluated the adsorption efficiency of soluble P from biogas slurry using biochars (corn straw biochar (CSB), cherry wood biochar (CWB), and cattle manure biochar (CMB)) and biomass power plant residues ash (BPP-ash) and slag (BPP-slag). Physicochemical characterization revealed that BPP-slag exhibited the highest soluble P removal efficiency (92.17%) at 30 g L^-1 dosage, attributed to its high metal oxide content (e.g., Ca²⁺, Mg²⁺). Kinetic and isotherm analyses indicated that adsorption followed pseudo-second-order kinetics (R² > 0.96) and Freundlich models (R² > 0.98), suggesting chemisorption-dominated multilayer adsorption. Mineral precipitation (contributing >70% to total adsorption) was identified as the primary mechanism via XRD and quantitative analysis. This work highlights the potential of biomass power plant residues as cost-effective adsorbents for P capturing, offering a sustainable strategy for waste valorization.