Water Science and Technology最新文献

Fruit waste is one of the main components of municipal waste. To study its potential and characteristics in anaerobic digestion, this study took fruit waste and its waste liquid as raw materials, investigate the influence of thermal pretreatment on the anaerobic digestion characteristics under 35 ± 17 °C. The anaerobic digestion materials were fruit waste liquid (group A1), fruit waste liquid after thermal pretreatment (group A2), fruit slurry (group A3), and the material of A2 and A3 mixed with municipal sludge (groups A4 and A5) has also been involved. The results showed that the thermal pretreatment is in favor of increasing the total gas production rate, which the waste liquid after thermal pretreatment (A2) was the highest one with 767.09 mL/gVS which 6.51% higher than A1; while it has not obviously influence on the total hydrogen production rate of waste liquid; the addition of municipal sludge increased the total methane production rate of fruit waste or its liquid. After thermal pretreatment, the pH of fruit waste was 0.37 lower than initial pH; VFAs and SCOD content were both increased, which are benefit for anaerobic digestion. In addition, the experimental data were verified by the modified Gompertz model.

Urban flooding is a pervasive global risk, posing a great challenge to urban planners, policymakers, and particularly communities. This paper reviews the literature to analyze how urban flooding is defined across scientific disciplines. Our objectives are to uncover the elements used to define urban flooding and evaluate how these elements can impact future research and practice. A key difficulty is the lack of a consistent, comprehensive definition that captures both physical and social dimensions of urban flooding. Current definitions often focus solely on physical aspects (e.g., rainfall, infrastructure) or social impacts, rarely integrating both. This fragmentation hinders effective flood risk management and interdisciplinary collaboration. Our contribution is a multifaceted definition incorporating spatial and social concerns, including water origins, built environment characteristics, and local community aspects. We introduce the 'Urban Water Transect' concept to illustrate the continuum of flood risk across urban zones, addressing a gap in the literature. The analysis reveals that many papers discuss flooding causes without providing an explicit definition. Urban flooding is predominantly defined based on water source, imperviousness, and drainage infrastructure. Future research should adopt an interdisciplinary perspective considering both physical and social aspects, potentially transforming urban flood risk management.

A series of dewaterability tests were conducted on various types of sludges to establish a wholistic relationship between sludge water fractions. Sludge samples were obtained from batch and continuous sludge digesters, which were operated anaerobically and aerobically under mesophilic and thermophilic conditions. Dewaterability of the sludge samples and the distribution of water fractions were studied using centrifugation and thermal drying. Thickened waste activated sludge (T-WAS) contained 10-11 g bound water (BW)/g of total solids (TS), and it was more hydrophilic than primary and digested sludges. During anaerobic digestion, BW content fluctuated between 3.2 and 4.2 g BW/g TS. However, aerobic digestion at 55°C reduced the BW content of the mixed T-WAS + primary sludges from 3.7 to 2.1 g BW/g TS. A linear function was developed to correlate supernatant and BW mass fractions (R² = 0.995). An equation was derived from the linear function to estimate the mass of dewatered sludge based on the TS concentration of the initial wet sludge. The developed expression is applicable to different kinds of wastewater sludges. Such an expression would be helpful for the designers and operators of sludge thickening and dewatering systems that use centrifugal separation.

Bioretention systems effectively capture rubber particles and other microplastics in stormwater runoff. However, it is uncertain whether long-term particle accumulation affects pollutant removal efficacy. This study investigated the impact of various concentrations of ethylene-propylene-diene-monomer (EPDM) particles (0, 50, 100, and 400 mg/L) on bioretention system nitrogen removal performance. The input of EPDM during short-duration (2 h) rainfall favored the removal of nitrogen, and the total nitrogen effluent concentration of the bioretention system with EPDM was reduced by 0.59-1.52 mg/L compared with that of the system without EPDM. In addition, the input of EPDM reduced the negative effects of drought. During long-duration (24 h) rainfall, higher concentrations of EPDM led to lower nitrate-nitrogen concentrations in the effluent. The bioretention system with EPDM required less time for nitrate-nitrogen removal to reach 50% than that without EPDM input. Microbial community analysis showed that EPDM increased the relative total abundance of denitrifying bacteria (such as Dechloromonas, Zoogloea, Ramlibacter, and Aeromonas) by 7.25-10.26%, which improved the denitrification capacity of the system.

Chemical kinetics can be a useful tool for determining the optimal operating time of electrochemical processes. The main objective of the study was to determine the mineral oil removal rate by sono-electrochemical treatment. In this study, zero-, first-, and second-order kinetic models were used to determine the reaction rate of mineral oil removal with the sono-electrochemical process. The reaction rate experiments were conducted under the following optimal conditions: 8 min of treatment time, a current density of 53.1 A/m², and a flow rate of 0.23 L/s. It was found that the changes in mineral oil concentrations follow second-order kinetics with a coefficient of determination of 0.9732. The mineral oil removal efficiency was 94.4%. This study concludes that sono-electrochemical process could be a promising technology for the removal of mineral oil from wastewater, and that the mineral oil removal rate can be determined by chemical kinetics. The results obtained may be useful for the optimization of the sono-EC process and reactor design.

In this study, the impact of exogenous N-acyl-homoserine lactones (AHLs) on greenhouse gas (GHG) emissions in anaerobic/anoxic/oxic (A/A/O) systems was analyzed by manipulating the type and dosage of AHLs. The mechanism behind AHLs' effects on GHG emissions was explored through changes in microbial community structure. Findings revealed that N-octanoyl-homoserine lactone (C8-HSL) and high-dose N-dodecanoyl-homoserine lactone (C12-HSL) increased GHG emissions, while low-dose C12-HSL decreased them. Moreover, C8-HSL and high-dose C12-HSL promoted methane (CH₄) and nitrous oxide (N₂O) production by affecting sludge particle size. Bacterial community analysis highlighted Acinetobacter and Flavobacterium's roles in N₂O emissions and acetate methanogens in methane synthesis. Metabolic pathway analysis showed that the acetic acid (CH₃COOH) methanogenic pathway was the main methanogenic pathway; C8-HSL and C12-HSL influenced methane emission by affecting the methanogenic pathway and N₂O emission by changing nitrous oxide reductase (Nos) abundance. This research underscores AHL-based quorum sensing's potential in mitigating GHG emissions during activated sludge wastewater treatment, offering insights into their application and impact on key microbial activities. Limitations include the absence of methane emission reduction by signaling molecules and the need for further investigation into their effects on sludge accumulation.

Introducing microplastics (MPs) into the marine environment is a global problem. Tire-derived microplastics (TMPs) are estimated to account for 60% of all secondary MPs dispersed in aquatic environments. To effectively detect TMPs in environmental samples using micro-Fourier transform infrared (μFTIR) spectroscopy, a high-quality reference library is essential. However, the use of conventional diamond crystals in FTIR presents challenges for the detection of materials containing carbon black, such as rubber and tires. In addition, there is a discrepancy between spectra from standard libraries and spectra from environmental samples, which makes detection difficult. In order to overcome these problems in the detection of TMPs by μFTIR, we developed four reference libraries to improve the detection, and 'The 26 tire wear library' was found to be the best among these four. Furthermore, a comparison of these new libraries revealed the following requirements to improve TMP detection: (i) the reference spectra must be acquired under the same setup used for material observation including prism material, (ii) tires, not rubber, must be used as reference materials, and (iii) tire wear samples must be prepared to replicate the actual generation conditions on roads.

Petroleum hydrocarbons (PHCs) are organic substances that occur naturally on earth. PHCs have emerged as one of the most prevalent and detrimental contaminants in regions comprising soil and water resources. The limitations of conventional physicochemical and biological remediation solutions could be solved by combining remediation techniques. An effective, affordable, and environmentally benign method of reducing petroleum toxins is provided by the advanced idea of bioremediation, which has evolved into nanobioremediation. Environments contaminated with PHCs have been restored through microbe-plant-nanoparticle (NP)-mediated remediation, this review emphasizes how various metallic NPs interact with microbes and plants changing both their activity and that of enzymes, therefore accelerating the remediation process. This work further examines the challenges and possible uses of nanobioremediation, as well as the application of novel technologies in the interactions between bacteria, plants, and NPs for the bioremediation of PHCs. Furthermore, it has been shown that the use of plant-based, microbe-based, microbe-plant-based, and microbe-plant-NP-based techniques to remediate contaminated soils or water bodies is economical and environmentally beneficial. Microbial consortia have been reported as the treasure houses for the cleaning and recovery of hydrocarbon-contaminated environments, and the development of technologies for bioremediation requires an understanding of hydrocarbon degradation mechanisms.

In the present study, bio-citric acid/tungsten oxide (WO₃) (BCAWO) nanoparticles (NPs) were prepared by using Solanum lycopersicum fruit extract as a reducing as well as a capping agent. The photocatalysts were characterized by UV-vis diffuse reflectance spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy, and photoluminescence spectroscopy techniques. Diffraction peaks in the XRD spectrum were identified as the crystal planes of crystalline tungsten oxide. The BCAWO had an average size of 23.14 nm. For W-O bonds, the Fourier transform infrared spectrum displays the vibrational peak at 671.23 cm^-1. A prominent absorption band was observed at 268 nm, indicating the 1.2 eV bandgap. Under xenon (Xe) lamp irradiation, the synthesized BCAWO nanoparticles showed notable photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP), with a degradation rate of 96%. With BCAWO concentrations of 2.5 g/L, pH of 4, reaction period of 180 min, and 2,4 DCP concentration of 10 mg/L, the degradation of 2,4-DCP had the highest efficacy, 96%. The degradation of phenols in wastewater may be facilitated by using the green WO₃ nanoparticles as a photocatalyst, according to the results.

Wastewater treatment plants (WWTPs) comprise energy-intensive processes, serving as primary contributors to overall WWTP costs. This research study proposes a novel approach that integrates support vector regression (SVR) with the firefly algorithm (FFA) for the prediction of energy consumption in a WWTP in Chlef City, Algeria. The database comprises a comprehensive set of 1,653 samples, capturing diverse information categories. It includes chemical and physical characteristics, encompassing chemical oxygen demand, 5-day biochemical oxygen demand, potential of hydrogen, water temperature, total suspended sediment in water and basin, influent N-NH₃ concentration, number of aerators, and operating time. Additionally, the hydraulic and energy-related parameters are represented by the flow entered at the station and the energy consumed by aerators, respectively. Finally, meteorological data, comprising rainfall, temperature, relative humidity, and the aridity index, are part of the dataset required for analysis. In this regard, 15 different models that correspond to 15 different combinations of input parameters are assessed in this study. The results show that the SVR-FFA-15 can render an improvement in the prediction accuracy of energy consumption in WWTPs. This study provides a useful tool for managing the energy consumption of wastewater treatment and makes insightful recommendations for future energy savings.