Electrokinetic remediation (EKR) has shown great potential for the remediation of in situ contaminated soils. For heavy metal-contaminated soft clay with high moisture content and low permeability, an electrokinetic remediation method with electrolytes placed above the ground surface is used to avoid issues such as electrolyte leakage and secondary contamination that may arise from directly injecting electrolytes into the soil. In this context, using this novel experimental device, a set of citric acid (CA)-enhanced EKR tests were conducted to investigate the optimal design parameters for Cu- and Zn-contaminated soft clay. The average removal rates of heavy metals Cu and Zn in these tests were in the range of 27.9-85.5% and 63.9-83.5%, respectively. The results indicate that the Zn removal was efficient. This was determined by the migration intensity of the electro-osmotic flow, particularly the volume reduction of the anolyte. The main factors affecting the Cu removal efficiency in sequence were the effective electric potential of the contaminated soft clay and the electrolyte concentration. Designing experimental parameters based on these parameters will help remove Cu and Zn. Moreover, the shear strength of the contaminated soil was improved; however, the degree of improvement was limited. Low-concentration CA can effectively control the contact resistance between the anode and soil, the contact resistance between the cathode and soil, and the soil resistance by increasing the amount of electrolyte and the contact area between the electrolyte and soil.

Rapid industrialization has significantly boosted economic growth but has also introduced severe environmental challenges, particularly in water pollution. This study evaluates the effectiveness of a nanocomposite composed of Rumex Abyssinicus Activated Carbon/Acid Activated Bentonite Clay/Graphene Oxide, and Iron Oxide (RAAC/AABC/GO/Fe3O4) for chromium removal from aqueous solutions. The preparation of the nanocomposite involved precise methods, and its characterization was performed using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area analysis, and the point of zero charge (pHpzc). Batch adsorption experiments were designed using Design Expert software with a central composite design under response surface methodology. The factors investigated included pH (3, 6, and 9), initial Cr (VI) concentration (40, 70, and 100 mg/L), adsorbent dose (0.5, 0.75, 1 g/200 mL), and contact time (60, 90, and 120 min). Adsorption isotherms were analyzed using nonlinearized Langmuir, Freundlich, and Temkin models, while pseudo-first-order and pseudo-second-order models were applied to adsorption kinetics. Characterization revealed a pHpzc of 8.25, a porous and heterogeneous surface (SEM), diverse functional groups (FTIR), an amorphous structure (XRD), and a significant surface area of 1201.23 m2/g (BET). The highest removal efficiency of 99.91% was achieved at pH 6, with an initial Cr (VI) concentration of 70 mg/L, a 90 min contact time, and an adsorbent dose of 1 g/200 mL. Optimization of the adsorption process identified optimal parameters as pH 5.84, initial Cr (VI) concentration of 88.94 mg/L, contact time of 60 min, and adsorbent dose of 0.52 g/200 mL. The Langmuir isotherm model, with an R2 value of 0.92836, best described the adsorption process, indicating a monolayer adsorption mechanism. The pseudo-second-order kinetics model provided the best fit with an R2 value of 0.988. Overall, the nanocomposite demonstrates significant potential as a cost-effective and environmentally friendly solution for chromium removal from wastewater.

Per- and polyfluoroalkyl substances (PFAS) in water requires sufficient removal due to their extreme chemical stability and potential health risk. Membrane separation can be a promising strategy, while membranes with conventional structures used for PFAS removal often face challenges such as limited efficiency and stability. In this study, a novel metal-organic framework (MOF) membrane with local modification of polyamide (PA) was developed by introducing interfacial polymerization process during the construction of lamellar membranes with MOF nanosheets. Benefiting from the dense structure and strong negative surface charge, the PA-modified MOF membrane could effectively remove 11 types of PFAS (five short-chain and six long-chain ones with molecular weights ranging from 214.0 to 514.1 Da), especially displaying high rejections for short-chain PFAS (over 84%), along with a remarkable water permeance of 21.4 L·m⁻²·h⁻¹·bar⁻1. The membrane removal characteristics for PFAS were deeply analyzed by elucidating various rejection mechanisms, with particularly distinguishing the rejection and adsorption capacity. Moreover, the membrane stability was significantly enhanced, demonstrated by the structural integrity after 10 min of ultrasonic treatment and stable separation efficiency over 120 h of continuous filtration. With enhanced surface hydrophilicity and negative charge as well as dense membrane pores, the novel membrane also exhibited more superior anti-fouling performance compared to conventional lamellar and PA membranes, further manifesting advantages for practical applications. This work provides a promising solution for developing high-performance membranes tailored specifically for efficient PFAS removal, addressing a critical need in water treatment.

BACKGROUND: The majority of existing industries in Ethiopia discharge untreated effluents into nearby water bodies, streams and open land. The wastewater generated by Gondar malt factory (GMF) was disposed freely and join a natural wetland implemented for the treatment of the wastewater. The objective of the study was to analyze and characterize wastewater from GMF and to evaluate the effectiveness of the wetland for the treatment purpose.
METHODS: Different Physicochemical quality indicators (color, turbidity pH, temperature, Total Dissolved solids, Total Suspended solids, total solid, conductivity, alkalinity, hardness, nitrate, phosphate, sulfate, free chlorides, heavy metals-(Cd, Cr, Fe, Mn, and Pb)and Biological Oxygen Demand were measured according to the standard procedures. Data was analyzed using Statistical Package for Social Sciences (SPSS-25). Analysis of Variance (ANOVA) was used to find whether significant differences existed in the different sampling stations for the parameters studied. P value less than 0.05 was considered to show significant difference.
RESULTS: The results of this study revealed that most of the quality indicators were improved in value after the water passed through the wetland except for alkalinity M, sulfite, Mn, temperature and pH. From ANOVA result, it was noted that there was a significant mean difference between the stations except for chromium, manganese and lead. The result showed that the wetland plays a great role in the removal of pollutants where the best performance was obtained at removal efficiency of 96.188% PO4HR,75.63% Nitrate,>99% Cl2, ammonia and nitrite 99.99%, 92.77% sulfate,84.36% Total hardness,87.43% color, and for others it is ranged between 30 and 60%.
CONCLUSIONS: the study concluded that GMF wetland was almost effective and had potential in treatment of the wastewater from the discharging facilities (especially for nutrients, alkalinity P, hardness, color and chloride). It is recommended that wetlands should be conserved and used as wastewater treatment facility.

Water resources play a crucial role in sustaining life on earth yet chemicals of emerging concern (CECs) arising from extensive human applications are an increasing threat towards their existence. In this study, we examined the occurrence, removal and potential risk of CECs found in rivers and wastewater treatment plants (WWTPs) in western Kenya. Samples were prepared by solid-phase extraction and analysed using high performance liquid chromatography-mass spectrometry with a target list of 785 compounds. Out of these, 333 and 352 (influent 322, effluent 265) compounds were quantified in rivers and wastewater respectively, with pharmaceuticals, industrial compounds, and pesticides being frequently detected in both rivers and WWTPs. Compounds with highest concentrations included saccharin (9.9 μg/L), metformin (7.5 μg/L), and oxypurinol (6.5 μg/L) in rivers whereas caffeine (280 μg/L), deoxycholic acid (179 μg/L), 2-oxindole (10.9 μg/L) and ibuprofen (8.1 μg/L) were found at high concentrations in WWTPs. Based on the types of crops grown, samples from maize growing regions recorded the highest number of pesticides (75) which coincided with the spraying season. The WWTP showed the capacity to eliminate some compounds although the removal efficiencies varied greatly with 204 compounds exhibiting an average removal efficiency exceeding 50 %. Based on the risk assessment, crustaceans had the highest potential risk for toxicity with toxic unit (TU) values up to 5.4 driven primarily by diazinon and dichlorvos followed by algae (TU up to 0.07) and fish (TU up to 0.01) in rivers. A similar trend was observed in WWTP with diazinon (TU up to 5.5), diuron (TU up to 0.07) and carbendazim (TU up to 0.006) driving the risk for crustaceans, algae and fish respectively. These findings highlight the significance of surface water and WWTPs as sources and sinks of CECs in the environment translating to potential risks on aquatic organisms and humans.

The presence of emerging organic micropollutants (OMPs) in drinking and potable waters is a matter of great concern due to the health hazards associated with these. In this work, we present the preparation and application of a thin-film nanocomposite (TFN) membrane containing functionalized graphene oxide to effectively remove low-molecular-weight OMPs from water. Graphene oxide was functionalized with amino silane to enhance its cross-linking capability during the formation of the polyamide active layer via interfacial polymerization of diethylene triamine and trimesoyl chloride. The TEM analysis showed that amino silane functionalized GO had 2-3 layered sheets, while non-functionalized graphene oxide appeared multilayered or stacked. XPS analysis confirmed the successful functionalization of GO. Characterization of the membranes with advanced techniques confirmed the successful incorporation of the GO and its functionalization: spectra from Fourier Transform Infra Red spectroscopy had the characteristic peaks of GO and NH groups; scanning Electron Microscopy (SEM) images showed a continuous presence of GO nanosheets. Contact angle measurements showed the TFN membranes to be more hydrophilic than their thin film composite (TFC) counterparts. Incorporating functionalized oxide nanosheets in the active polyamide layer produced additional water permeation channels, resulting in an improvement of ∼25 % in permeate flux compared to the pristine TFC and the TFN membrane with non-functionalized GO. The removal efficiencies of four OMPs commonly found in natural waters: Amitriptylene HCl (ATT HCl) and Bisphenol-A (BPA), Acetaminophen (ACT), and Caffeine (CFN) were determined for the synthesized membranes. The TFN membrane with functionalized GO outperformed its TFC counterpart with ∼100 % removal for BPA, ∼ 90 % for CFN and ATT HCl, and ∼80 % removal for the low molecular weight ACT. The high-efficiency rejection of OMPs was attributed to the synergistic effects of size exclusion as well as the reduced specific interactions between the functional groups.

In this study, a microbial fuel cell was constructed using Raoultella sp. XY-1 to efficiently degrade tetracycline (TC) and assess the effectiveness of the electrochemical system. The degradation rate reached 83.2 ± 1.8 % during the 7-day period, in which the system contained 30 mg/L TC, and the degradation pathway and intermediates were identified. Low concentrations of TC enhanced anodic biofilm power production, while high concentrations of TC decreased the electrochemical activity of the biofilm, extracellular polymeric substances, and enzymatic activities associated with electron transfer. Introducing electrogenic bacteria improved power generation efficiency. A three-strain hybrid system was fabricated using Castellaniella sp. A3, Castellaniella sp. A5 and Raoultella sp. XY-1, leading to the enhanced TC degradation rate of 90.4 % and the increased maximum output voltage from 200 to 265 mV. This study presents a strategy utilizing tetracycline-degrading bacteria as bioanodes for TC removal, while incorporating electrogenic bacteria to enhance electricity generation.

Increasing consumption of pharmaceuticals and the respective consequences for the aquatic environment have been the focus of many studies over the last thirty years. Various aspects in this field were investigated, considering diverse pharmaceutical groups and employing a wide range of research methodologies. Various questions from the perspectives of different research areas were devised and answered, resulting in a large mix of individual findings and conclusions. Collectively, the results of the studies offer a comprehensive overview. The large variety of methods and strategies, however, demands close attention when comparing and combining information from heterogeneous projects. This review critically examines the application of diverse sampling techniques as well as analytical methods in investigations concerning the behavior of pharmaceutically active compounds (PhACs) and contrast agents (CAs) in wastewater treatment plants (WWTPs). The combination of sampling and analysis is discussed with regard to its suitability for specific scientific problems. Different research focuses need different methods and answer different questions. An overview of studies dealing with the fate and degradation of PhACs and CAs in WWTPs is presented, discussing their strategic approaches and findings. This review includes surveys of anticancer drugs, antibiotics, analgesics and anti-inflammatory drugs, antidiabetics, beta blockers, hormonal contraceptives, lipid lowering agents, antidepressants as well as contrast agents for X-ray and magnetic resonance imaging.

Solar Fenton is an important and extensively used advanced oxidation process (AOP) to degrade pharmaceutical pollutants. The objective of this study was to evaluate the performance of simultaneous degradation of the mixed pollutants (amoxicillin, acetaminophen, and ciprofloxacin) for an aqueous solution using the solar Fenton process. Operating parameters such as pH, iron doses, H2O2 doses, pollutant concentrations, and time were studied. From the experimental results, the ideal conditions were obtained for the removal of mixed pollutants such as pH 3, Fe2+ 0.04 mM, H2O2 4 mM, the concentration of the mixed pollutants 5 mg/L, solar radiation 400 W/m2, and time 10 min, respectively. The pseudo-first-order kinetics were utilized to investigate the degradation efficacy of the mixed pollutants. The result of the study indicates that the degradation efficiency was > 99% for the mixed pollutants. A maximum of 63% mineralization was observed, and hydroxyl radical scavenger effects were studied. The best optimal conditions were applied to assess the spiked wastewater (municipal wastewater (MWW) and hospital wastewater (HWW)). The highest elimination rates for AMX, ACET, and CIP were observed as 65%, 89%, and 85% for MWW and 76%, 92%, and 80% for HWW, respectively. The degraded by-products were detected by LC-ESI-MS in the water matrix (aqueous solution and spiked wastewater), and ECOSAR analysis was performed for the transformed products. The study concluded that the solar Fenton technique is promising and effective for the removal of mixed pollutants from the water matrix.

This study investigates the effectiveness of vertical flow constructed wetlands (VFCWs) planted with a climbing ornamental plant for on-site treatment of real laundry wastewater. Specifically, the presence or absence of Trachelospermum jasminoides was evaluated for the removal performance of conventional pollutants (turbidity, TSS, COD, TP) and benzotriazoles (BTRs): 1H-benzotriazole (BTR), 5-methyl-1H-benzotriazole (5-TTR), 5-chlorobenzotriazole (CBTR), and xylytriazole (XTR). Results revealed that high removal efficiencies ranging from 92 to 98% were presented in both planted and unplanted systems for turbidity, TSS, and COD. Moreover, high removal rates were observed for CBTR and XTR, which were the only compounds found in real laundry wastewater, in both VFCW systems (planted: 100%; 94%; unplanted: 87%; 92%, respectively). The contribution of plants to the pollutant\'s removal was not statistically significant for all examined parameters. However, T. jasminoides demonstrated the ability to survive and grow without any visible symptoms under the harsh conditions of laundry wastewater, enabling the development of green facade. According to the findings, the application of VFCWs for on-site laundry wastewater treatment in buildings seems to be a highly promising solution, not only for primarily removing conventional pollutants but also for addressing emerging contaminants, specifically BTRs.