Water Research最新文献

To reduce the harm of water contamination incidents in drinking water source areas (DWSAs) and explore feasible approaches, the research developed a hydrodynamic water quality model for DWSAs based on two dimensional water quality and quantity equations, Geographic Information System (GIS), and Digital Elevation Model (DEM). The Heshangshan Drinking Water Source Area (HDWSA) in the Three Gorges Reservoir Area (TGRA) was selected as the research area, with total phosphorus (TP) as the representative pollutant in the water. The research investigated the changes in TP content during various hydrological phase under pollution incident, compared the duration and trends of TP concentration exceeding standard value before and after joint reservoir group dispatch. The results showed that the migration speed of TP pollutants varied from slowest to fastest in the following order: dry phase, recession phase, storage phase, and flood phase. Under pollution incident condition, the time demanded for TP content to meet standard value in each water phase was 36 min (dry phase), 33 min (recession phase), 30 min (storage phase), and 27 min (flood phase). The joint dispatch group 1–3 shortened the time required to meet standard value by 6–13 min (dry phase), 5–11 min (recession phase), 4–9 min (storage phase), and 3–7 min (flood phase). The trend of TP concentration before and after joint dispatch showed four stages: significant increase, sharp decrease, rapid decrease, and slow decrease. Joint dispatch of reservoir group can effectively reduced the TP concentration in DWSA under pollution incident.

Ultrafiltration technology (UF) is efficient in surface water treatment, but its development and widespread application are limited by membrane fouling. Herein, an efficient and stable polymerized ferric titanium coagulant (PFTC) was synthesized and used as a UF pretreatment agent in actual lake water treatment. The control mechanism of PFTC on membrane fouling was investigated from the perspective of organic removal efficiency and in-situ membrane surface regulation. PFTC demonstrated a remarkable affinity for soluble metabolic intermediates and hydrophilic proteins through complexation and hydrogen bonding force, achieving removal efficiencies of 66.4 % for UV₂₅₄ and 81.3 % for DOC, respectively. The hydrophilic pollutants with high molecular weight and non-saturated structure could be preferentially removed by PFTC due to its diverse hydrolysates including positively charged Fe-based hydrolysates, amorphous Ti-based hydrolysates, and highly polymerized Fe-Ti copolymers. The flocs generated by PFTC exhibited strong hydrophilicity, allowing for the formation of a loose porous cake layer on the ultrafiltration membrane, which acted as a hydrophilic layer to enhance the anti-fouling performance of ultrafiltration membrane. With its dual function of contaminant removal and in-situ membrane surface regulation, PFTC alleviated 98.9 % of membrane fouling. This study provides new insights into membrane fouling control by coagulation pretreatment and efficient treatment of surface water.

Ultraviolet light-emitting diodes (UV-LEDs) have demonstrated the ability to inactivate microorganisms in water, offering an environmentally safer alternative to the conventional mercury lamp, in UV applications. While several studies have explored the microbiological effect of UVC-LEDs (200nm-280nm), limited information exists regarding their effects on waters with critical qualities. These critical qualities encompass bacteria, viruses, and protozoa – drinking water quality indicators defined by the World Health Organization for small water systems. For the first time, this work reports on the Escherichia coli, PhiX-174, MS2, and Cryptosporidium oocysts inactivation using a bench-scale UVC-LED (280 nm) water disinfection system. UV doses at a wavelength of 280 nm (UV₂₈₀) of up to 143.4 mJ/cm² were delivered under two quality-critical water conditions: filtered water (UV transmittance at 280 nm – UVT₂₈₀ 90.2 %) and WHO challenge water (UVT 15.7 %). Results revealed microbiological reductions dependent on exposure time and UVT. For UV₂₈₀ dose of 16.1 mJ/cm², 2.93-3.70 log E. coli reductions were observed in UVT 90.2 % and 15.7 %, 3.49-4.21 log for PhiX-174, 0.63-0.78 log for MS2, and 0.02-0.04 log for Cryptosporidium oocysts. Significantly higher UV₂₈₀ doses of 143.4 mJ/cm² led to reductions of 3.94-5.35 log for MS2 and 0.42-0.46 log for Cryptosporidium oocysts. Statistical analysis revealed that the sensitivity among the organisms to UV₂₈₀ exposure was E. coli = PhiX-174 > MS2 >> Cryptosporidium oocysts. Although experiments with WHO challenge water posed greater challenges for achieving 1 log reduction compared to filtered water, this difference only proved statistically significant for PhiX-174 and MS2 reductions. Overall, UVC-LED technology demonstrated notable efficacy in microbiological inactivation, achieving significant reductions based on WHO scheme of evaluation for POU technologies in both bacteria and viruses even in critical-quality waters. The findings emphasize the potential for extending the application of UVC-LED as a viable solution for household water treatment.

The enhancement of electron or proton transfer between syntrophic microbes has been widely recognised as a means for improving methane generation. However, the uncoupled supplementation of electrons and protons in multiphase anaerobic environment hinders the balanced uptake of electrons and protons in the cytoplasm of methanogens, limiting methanogenesis efficiency. Herein, the cooperative effect of a proton-conductive material (PM) and an electron-conductive material (EM) in enhancing proton-coupled electron transfer (PCET) and driving efficient methanogenesis in anaerobic digestion was investigated. The cooperation of the PM and EM significantly increased methane production and the maximum methane generation rate by 78.9 % and 103.5 %, respectively, indicating enhanced methanogenesis efficiency. Analysis of the physicochemical properties, biochemical components, and microbial dynamics revealed that the cooperation of the PM and EM improved the metabolism of syntrophic microbes, which was critically dependent on electron and proton transfer. This enhancement was primarily due to the improvement in PCET, as mainly supported by hydrogen/deuterium kinetic isotope effect measurements, multi-omics integration analyses and reaction thermodynamics and kinetics analyses. Our findings suggest that the PCET enhancement stimulated efficient membrane-bound enzymatic reactions related to electron-driven proton translocation and facilitated electron and proton supply for CO₂ reduction to realise highly efficient methane generation. These findings are expected to provide a new insight into effective electron and proton coupling transfer for methanogenic metabolism in multiphase anaerobic environments.

Urban stormwater management systems, particularly storm sewers, are critical for managing runoff in urban areas. These systems are designed to function during wet weather events; however, field-based observations of these systems suggest that they may also be active flow pathways in dry weather conditions, ultimately contributing to streamflow. Unlike dry weather flow in wastewater systems, storm sewer dry weather flow has not been thoroughly explored. This research used stable isotopes of oxygen and hydrogen in water to examine the sources of dry weather flow from storm sewers in a highly urban catchment. A stable isotope mixing model was applied at the outfalls of two stormwater catchments and the receiving Black Creek, located in Toronto, Canada. Findings suggest that during dry periods, storm sewers receive non-stormwater inputs from tap water, wastewater, and groundwater, along with some precipitation, and that these sources may constitute up to 19 % of Black Creek's flow at the watershed scale. Seasonal patterns in flow and water sources were observed for the Black Creek and outfalls. At one outfall, dry weather flow was predominantly from the water distribution system (i.e., tap water and/or wastewater) throughout spring, summer, and fall. In contrast, at the second outfall, groundwater dominated in spring and summer, and groundwater and water distribution were equally proportioned in fall. Black Creek baseflow comprises a dynamic mix of water sources that at times are similar to the sources observed at the stormwater outfalls. Considering these findings, future work should incorporate strategic sampling of additional outfalls, and multiple years of data collection to explore inter-annual variability in these processes and focus on replicating a similar study in other urban watersheds with different climates and/or water infrastructure design. The study findings highlight that our understanding of dry weather flow from storm sewers is relatively limited, emphasizing the need for further exploration of this phenomenon to inform urban hydrological modelling, water quality studies, and urban water management.

CrAssphage has been recognized as the most abundant and human-specific bacteriophage in the human gut. Consequently, crAssphage has been used as a microbial source tracking (MST) marker to monitor human fecal contamination. Many crAss-like phages (CLPs) have been recently discovered, expanding the classification into the new order Crassvirales. This study aims to assess CLP prevalence in South Korea and develop a detection system for MST applications. Thirteen CLPs were identified in six human fecal samples and categorized into seven genera via metagenomic analysis. The major head protein (MHP) displayed increased sequence similarity within each genus. Eight PCR primer candidates, designed from MHP sequences, were evaluated in animal and human feces. CLPs were absent in animal feces except for those from raccoons, which hosted genera VI, VIIa, and VIIb. CLPs were detected in 91.52% (54/59) of humans, with genus VI (38 out of 59) showing the highest prevalence, nearly double that of p-crAssphage in genus I (22 out of 59). This study highlights genus VI as a potent MST marker, broadening the detection range for CLPs. Human-specific and selectively targeted MST markers can significantly impact hygiene regulations, lowering public health costs through their application in screening liver, sewage, wastewater, and various environmental samples.

Accurately predicting the concentration of organochlorine pesticides (OCPs) presents a challenge due to their complex sources and environmental behaviors. In this study, we introduced a novel and advanced model that combined the power of three distinct techniques: Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN), Variational Mode Decomposition (VMD), and a deep learning network of Long Short-Term Memory (LSTM). The objective is to characterize the variation in OCPs concentrations with high precision. Results show that the hybrid two-stage decomposition coupled models achieved an average symmetric mean absolute percentage error (SMAPE) of 23.24 % in the empirical analysis of typical surface water. It exhibited higher predictive power than the given individual benchmark models, which yielded an average SMAPE of 40.88 %, and single decomposition coupled models with an average SMAPE of 29.80 %. The proposed CEEMDAN-VMD-LSTM model, with an average SMAPE of 13.55 %, consistently outperformed the other models, yielding an average SMAPE of 33.53 %. A comparative analysis with shallow neural network methods demonstrated the advantages of the LSTM algorithm when coupled with secondary decomposition techniques for processing time series datasets. Furthermore, the interpretable analysis derived by the SHAP approach revealed that precipitation followed by the total phosphorus had strong effects on the predicted concentration of OCPs in the given water. The data presented herein shows the effectiveness of decomposition technique-based deep learning algorithms in capturing the dynamic characteristics of pollutants in surface water.

The efficient capture of uranium from wastewater is crucial for environmental remediation and the sustainable development of nuclear energy, yet it poses considerable challenges. In this study, amphiphilic ionic covalent organic framework intercalated into graphene oxide (GO) nanosheets functionalized with polyethyleneimine (PEI) were used to construct hybrid membranes with ultrafast uranium adsorption. These hybrid membranes achieved equilibrium in just 10 min and the adsorption capacity was as high as 358.8 mg g⁻¹ at pH = 6. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses revealed that the strong interaction between sulfonic acid groups and uranyl ions was the primary reason for the high adsorption capacity and selectivity. The extended transition state and natural orbitals for chemical valence (ETS–NOCV) analysis revealed that the interaction between the 7 s and 5f orbitals of uranyl and the 2p orbitals of S and O in the sulfonate was the primary reason for the strong interaction between the sulfonate and the uranyl ion. This research presents an effective method for the rapid extraction of uranium from wastewater.

Dual electron donor bioretention systems have emerged as a popular strategy to enhance dissolved nitrogen removal from stormwater runoff. Pyrite-woodchip mixotrophic bioretention systems showed a promoted and stabilized removal of dissolved nutrients under complex rainfall conditions, but the sulfate reduction process that can induce iron sulfide generation and reuse was overlooked. In this study, experiments and models were applied to investigate the effects of filler configuration and dissolved organic carbon (DOC) dissolution rate on treatment performance and iron sulfide generation in pyrite-woodchip bioretention systems. Key parameters govern that DOC dissolution and microbe-mediated processes were obtained by experiments. The water quality models that integrate one-dimensional constant flow, sorption and microbial transformation kinetics were used to predict the performance of bioretention systems. Results showed that the mixotrophic bioretention system with woodchip mixed in the vadose zone and pyrite in the saturated zone achieves a better performance in both nitrogen removal efficiency and by-product control. Comparably, woodchip and pyrite mixed in the saturated zone could encounter a high secondary pollution risk. The sensitivity coefficients of oxic/anoxic DOC dissolution rates to total nitrogen removal are 0.36 and -2.43 respectively. Iron sulfide generation was affected by DOC distribution and the competition between heterotrophic denitrifiers, autotrophic denitrifiers, and sulfate-reducing bacteria (SRB). DOC accumulation has an antagonistic effect on iron production and sulfate reduction. Extra DOC accumulation favors sulfate reduction while high DOC concentration inhibits pyrite-based denitrification and reduces Fe(III) production. The recycling of iron sulfide can improve the robustness and sustainability of bioretention systems.

N-nitrosodimethylamine (NDMA) is a carcinogenic disinfection byproduct formed from reactions between dichloramine and organic nitrogen-containing precursors. It is unclear if NDMA precursors in surface water intakes originate in anthropogenic (i.e., wastewater) or natural sources. The Truckee River has a single point source release of treated wastewater effluent, making it an ideal system to study the relative importance of precursor sources. Three Lagrangian sampling events were conducted. NDMA formation potential (FP, a measurement of precursors) above the wastewater outfall indicated that the natural background of NDMA precursors was 2-28 ng/L. NDMA FP increased to 18-31 ng/L immediately downstream of the wastewater outfall, but decreased rapidly in a first order manner, and were not statistically different from the upstream samples in only ∼6 km. This suggests that the dominant source of NDMA precursors may be wastewater derived only near wastewater outfalls and deviates from the previous belief that wastewater-derived precursors are responsible for NDMA formation in drinking water sources located further downstream. Additionally, given the rapid loss of the wastewater precursors in this study, precursors which are slow to biodegrade/photolyze/adsorb to sediment are likely to be poor surrogates for the overall wastewater NDMA precursor pool. To understand temporal changes in the wastewater impact on environmental NDMA precursor loading, two 24-hour sampling events were conducted near (<3 km) the wastewater outfall and demonstrated that temporal changes in the NDMA precursors directly downstream of the wastewater outfall are directly linked to the wastewater flow contribution.