Evaluating the performance of electrocoagulation system in the removal of polystyrene microplastics from water.

Emerging pollutants, particularly microplastics, present a significant threat to both the environment and human health. Traditional treatment methods lack targeted strategies for their removal. This study thoroughly investigated the efficacy of electrocoagulation as a method for efficiently extracting microplastics from water. Various critical operational parameters, including electrode combinations, pH levels, electrolyte concentrations, electrode geometries, configurations, current intensities, and reaction times, were systematically examined. The study systematically examined the impact of different combinations of aluminium (Al) and stainless steel (SS) electrodes, including Al-Al, SS-SS, Al-SS, and SS-Al. Among these combinations, it was found that the Al-Al pairing exhibited outstanding efficiency in microplastic removal, while simultaneously minimizing energy consumption. Initial pH emerged as a critical parameter, with a neutral pH of 7 demonstrating the highest removal efficiency. In the pursuit of optimizing parameters like electrolyte concentrations, electrode geometry, and configuration, it's noteworthy that consistently achieving removal efficiencies exceeding 90% has been a significant achievement. However, to ascertain economic efficiency, additional factors such as energy consumption, electrode usage, and post-treatment conductivity must be taken into account. To tackle the complexity posed by various parameters and criteria, using multi-criteria decision-making tools like TOPSIS is essential, as it has a track record of effectiveness in practical applications. The electrolyte concentration of 0.5 g L-1 is identified as optimal by TOPSIS analysis Additionally, the TOPSIS highlighted the superiority of cylindrical hollow wire mesh electrodes and established the monopolar parallel configuration as the most effective electrode connection method. The investigation carefully evaluated the effect of reaction time, determining that a 50-min window provides optimal microplastic removal efficiency. This refined system exhibited remarkable proficiency in eliminating microplastics of varying size ranges (0-75 µm, 75-150 µm, and 150-300 µm), achieving removal efficiencies of 90.67%, 93.6%, and 94.6%, respectively, at input concentration of 0.2 g L-1. The present study offers a comprehensive framework for optimizing electrocoagulation parameters, presenting a practical and highly effective strategy to address the critical issue of microplastic contamination in aquatic environments.

A hybrid electrocoagulation-biocomposite adsorption system for the decolourization of dye wastewater.

Among the various methods for the removal of azo dye, electrocoagulation is recognized to be highly efficient. However, the process is associated with high operation and maintenance cost, which demands the need for reducing the electrolysis time without compromising the performance efficiency. This can be achieved by adopting hybrid electrocoagulation process with a low-cost but effective process, such as adsorption. The study investigated the performance of a hybrid electrocoagulation-biocomposite system (H-EC-BC) for removing methyl orange dye. Firstly, the operating parameters of electrocoagulation process were optimized and a removal efficiency of 99% has been attained using Fe-SS electrodes at a pH of 6 for a reaction time of 30 min. The performance of EC process was found to be decreasing with increase in dye concentration. Secondly, biocomposite was synthesized from Psidium guajava leaves and characterized using SEM, FTIR, EDAX, and XRD analyses. The results suggested that it is having a porous nature and cellulose crystal structure and confirmed the presence of chemical elements such as carbon (65.2%), oxygen (29.1%) as primary with Fe, Cl, Na and Ca as secondary elements. The performance of the biocomposite was evaluated for the dye adsorption using spectrophotometric methods. Various operating parameters were optimized using experimental methods and a maximum removal efficiency of 65% was achieved at a pH of 6, dosage of 5 g/L and an adsorption contact time of 120 min. The maximum efficiency (92.78%) was obtained with Fe-SS electrodes and KCl as a sustaining electrolyte under acidic circumstances (pH 6). The biocomposite was observed to be more efficient for higher dye concentration. Langmuir and Freundlich adsorption isotherms were fitted with the experimental results with R2 values as 0.926 and 0.980 respectively. The adsorption kinetics were described using Pseudo-first and Pseudo-second order models, wherein Pseudo-second order model fits the experimental results with R2 value of 0.999. The energy consumption of electrocoagulation (EC) process in the hybrid H-EC-BC system was compared to that of a standard EC process. The results demonstrated that the hybrid system is approximately 7 times more energy efficient than the conventional process, thereby implicating its adaptability for field application.

Chemical methods to remove microplastics from wastewater: A review.

Microplastics (Mps) have emerged as a pervasive environmental concern, with their presence detected not only in freshwater ecosystems but also in drinking and bottled water sources. While extensive research has centered on understanding the origins, migration patterns, detection techniques, and ecotoxicological impacts of these contaminants, there remains a notable research gap about the strategies for Mps removal. This study reviews existing literature on chemical approaches for mitigating microplastic contamination within wastewater systems, focusing on coagulation precipitation, electrocoagulation, and advanced oxidation methods. Each approach is systematically explored, encompassing their respective mechanisms and operational dynamics. Furthermore, the comparative analysis of these three techniques elucidates their strengths and limitations in the context of MPs removal. By shedding light on the intricate mechanisms underlying these removal methods, this review contributes to the theoretical foundation of microplastic elimination from wastewater and identifies future research trajectories and potential challenges.

Nomogram for predicting electrocoagulation syndrome after endoscopic submucosal dissection of esophageal tumors.

BACKGROUND: Endoscopic submucosal dissection (ESD) was widely used for the removal of esophageal tumors, and post-endoscopic submucosal dissection electrocoagulation syndrome (PEECS) was one of the postoperative adverse events. The aim of this research was to develop and validate a model to predict electrocoagulation syndrome after endoscopic submucosal dissection of esophageal tumors. MATERIALS AND METHODS: Patients who underwent esophageal ESD in our hospital were retrospectively included. A predictive nomogram was established based on the results of multivariate logistic regression analysis, and bootstrapping resampling was used for internal validation. Besides, the clinical usefulness of the nomogram was evaluated using decision curve analysis (DCA) and clinical impact curve. RESULTS: A total of 552 patients who underwent esophageal ESD were included in the study, and the incidence of PPECS was 12.5% (69/552). Risk factors associated with PEECS (p < 0.1) were analyzed by multivariate logistic regression analysis, and the final model included four variables, namely gender, diabetes, tumor size and operation time. The predictive nomogram was constructed based on the above four variables, and the area under the ROC curve (AUC) was 0.811 (95% CI 0.767-0.855). The calibration curve of the nomogram presented good agreement between the predicted and actual probabilities. DCA showed that the model improved patient outcomes by helping to assess the risk of PEECS in patients compared to an all-or-no treatment strategy. In addition, the clinical impact curve of the model also indicates that the nomogram has a high clinical net benefit. CONCLUSION: In conclusion, we have developed a predictive nomogram for PEECS after ESD for esophageal tumors with good predictive accuracy and discrimination. This predictive nomogram can be effectively used to identify high-risk patients with PEECS, which will help clinicians in clinical decision-making and early intervention.

Association of local steroid injection as a risk factor for electrocoagulation syndrome after esophageal endoscopic submucosal dissection.

BACKGROUND: Postendoscopic submucosal dissection electrocoagulation syndrome (PEECS) is commonly observed after performing endoscopic submucosal dissection (ESD) for esophageal neoplasia. However, data on the incidence and risk factors for PEECS in the esophagus are lacking due to an unclear definition of PEECS and varied clinical settings. Therefore, we aimed to determine the risk factors for PEECS in patients undergoing ESD for esophageal neoplasia. METHODS: We retrospectively reviewed data of relevant clinical and endoscopy-specific parameters from 202 consecutive patients with esophageal neoplasias (139 carcinomas and 63 dysplasias) who underwent ESD under general anesthesia. Esophageal PEECS was defined by satisfying at least two of the following criteria: fever ≥ 37.8 °C, leukocytosis ≥ 10,800/mm3, and localized chest pain ≥ 5/10 points as assessed on a numeric rating scale within 24 h after ESD. Significant factors associated with PEECS were determined by regression analysis. RESULTS: PEECS was recorded in 98 of 202 (48.5%) patients. Patients with PEECS exhibited a larger tumor size (25.0 vs. 17.0 mm, P = 0.002), longer procedure (40.0 vs. 29.5 min, P = 0.021) and hemostasis times (5.0 vs. 3.5 min, P = 0.004), required greater submucosal injection volume (60.0 mL vs. 50.0 mL, P = 0.030), and had a lower rate of local steroid injection (4.1% vs. 12.5%, P = 0.029) than those without PEECS. Multivariate regression analysis revealed tumor size ≥ 17 mm (P = 0.047), procedure time ≥ 33 min (P = 0.027), and hemostasis time ≥ 5 min (P = 0.007) as risk factors for PEECS. In addition, local steroid injection was a significant negatively associated factor (P = 0.001). CONCLUSIONS: Patients with a large tumor, prolonged procedure and hemostasis times are at a high risk of PEECS occurrence. Further, local steroid injection is a negatively associated factor.

Risk factors and a nomogram for prediction of post-endoscopic submucosal dissection electrocoagulation syndrome for superficial colorectal lesions.

BACKGROUND: Post-endoscopic submucosal dissection electrocoagulation syndrome (PEECS) is an uncommon complication after colorectal endoscopic submucosal dissection (ESD). This study aimed to explore the risk factors of PEECS for superficial colorectal lesions based on the latest and consistent diagnostic criteria and to establish a predictive nomogram model. METHODS: This retrospective analysis included patients with superficial colorectal lesions who underwent endoscopic submucosal dissection (ESD) between June 2008 and December 2021 in our center. The independent risk factors of PEECS for superficial colorectal lesions were identified using least absolute shrinkage and selection operator (LASSO) logistic regression analysis, as well as univariate analysis and multivariate logistic regression, and derived predictive nomogram model was constructed. RESULTS: Among the 555 patients with superficial colorectal lesions enrolled, PEECS occurred in 45 (8.1%) patients. Multivariate logistic regression revealed that female sex (OR 3.94, P < 0.001), age > 50 years (OR 4.28, P = 0.02), injury to muscle layer (OR 10.38, P < 0.001), non-lifting sign (OR 2.20, P = 0.04) and inadequate bowel preparation (OR 5.61, P < 0.001) were independent risk factors of PEECS for superficial colorectal lesions. A predictive nomogram model was constructed based on the above five predictors. For this model, the area under the receiver operating characteristic (ROC) curve was 0.855, the calibration curve exhibited good consistency between the prediction and the actual observation, and the C-index was confirmed as 0.843 by bootstrap method. CONCLUSION: Female sex, age > 50 years, injury to muscle layer, non-lifting sign and inadequate bowel preparation were independent risk factors of PEECS for superficial colorectal lesions. The proposed nomogram could accurately predict the risk of PEECS for superficial colorectal lesions.

Hemangioma of the Urinary Bladder: A Brief Narrative Review of Their Diagnosis, Histology, and Treatment Options.

BACKGROUND: Hemangioma of the urinary bladder is a rare benign tumor. Although benign, their presenting symptoms are alarming for both patients and doctors, and their rarity makes them challenging to correctly diagnosis and treat. This review paper summarizes current knowledge about hemangioma of the urinary bladder, treatment options, and follow-up modalities. SUMMARY: After the kidney, the bladder is the second most common location of hemangiomas in the urinary tract. There is painless gross hematuria on clinical presentation once the lesion has eroded the urothelium. Magnetic resonance imaging (MRI) has been reported to be valuable in diagnosing soft-tissue hemangiomas. Cystoscopic findings of a sessile, blue, multilocular mass suggest hemangioma. Most tumors are solitary, smaller than 3 cm, and have smooth or irregular surfaces. Histologically, lesions comprise numerous proliferative capillaries with thin-walled, dilated, blood-filled vessels lined with flattened endothelium. The treatment of patients with hemangioma has been controversial. It depends on the tumor size and the degree of penetration. The prognosis of these tumors is excellent. KEY MESSAGES: Despite the widespread use of MRI, CT, and endoscopy in evaluating hematuria, hemangioma remains one of the rarest bladder tumors. Moreover, only a histological examination can confirm the diagnosis. Transurethral resection, fulguration, and YAG laser ablation are standard treatments for small tumors. In terms of follow-up, cystoscopy after 6 months of treatment helps assess recurrence. In addition, MRI is a practical, noninvasive technique for follow-up of small hemangiomas.

Potential damage to ovarian reserve from laparoscopic electrocoagulation in endometriomas and benign ovarian cysts: a systematic review and meta-analysis.

PURPOSE: Laparoscopic cystectomy for ovarian endometriomas and benign ovarian cysts is often conducted through hemostatic methods, with bipolar electrocoagulation as a common approach. This study evaluated the impact of electrocoagulation, primarily through bipolar energy, versus nonthermal hemostatic methods on ovarian reserve in patients undergoing laparoscopic cystectomy for ovarian endometriomas and benign ovarian cysts. METHODS: A systematic review with meta-analysis was conducted by searching the Cochrane Library, PubMed, EMBASE, and Web of Science databases. Randomized controlled trials (RCTs) comparing the impact of nonthermal hemostatic methods and electrocoagulation on the ovarian reserve during laparoscopic cystectomy were included. The Cochrane Risk of Bias Tool for Randomized Controlled Trials (ROB 2.0) was utilized to assess the quality of the included studies. The meta-analysis included 13 RCTs involving 1043 patients. Postoperative serum anti-Müllerian hormone (AMH) levels and antral follicle counts (AFCs) were analyzed using Review Manager ver. 5.4. RESULTS: Compared with the bipolar group, patients with endometriomas in the nonthermal hemostatic group exhibited significantly higher postoperative AMH levels at 1, 3, 6, and 12 months. Conversely, no significant differences in AMH levels were observed in patients with benign ovarian cysts. Similarly, AFCs showed no significant differences, except for lower postoperative AFCs in patients with endometrioma in the electrocoagulation group. CONCLUSION: Nonthermal hemostatic methods are associated with more effective preservation of the ovarian reserve compared with bipolar electrocoagulation in laparoscopic cystectomy for ovarian endometriomas. However, no significant impact of bipolar electrocoagulation on the ovarian reserve was observed in patients with benign ovarian cysts. TRIAL REGISTRATION: Registered in PROSPERO on April 10, 2023; ID # CRD42023413158.

A pilot-scale electrocoagulation-treatment wetland system for the treatment of landfill leachate.

In the present study, the technical feasibility of an electrocoagulation-treatment wetland continuous flow system, for the removal of organic matter from landfill leachate (LL), was evaluated. The response surface methodology (MSR) was used to assess the individual and combined effects of the applied potential and distance between electrodes, on the removal efficiency and optimization of the electrocoagulation process. The hybrid treatment wetland system consisted of a vertical flow system coupled to a horizontal subsurface flow system, both planted with Canna indica. For a chemical oxygen demand (COD) concentration - without pretreatment of 5142.8 ± 2.5 mg L-1, the removal percentage for the electrocoagulation system was 79.4 ± 0.16%, under the optimal working conditions (Potential: 20 V; Distance: 2.0 cm). The COD removal efficiency in the treatment wetland with Canna indica showed a dependence with the hydraulic retention time, reaching 59.2 ± 0.2 % over 15 days. The overall efficiency of the system was about 91.5 ± 0.02 % removal of COD. In addition, a decrease in the biochemical oxygen demand (94.8 ± 0.14%) and total suspended solids (88.2 ± 0.22%), also related to the contamination levels of the LL, were obtained. This study, for the first time, shows that the coupling of electrocoagulation together with a treatment wetland system is a good alternative for the removal of organic contaminants present in LL.

Intelligent algorithms-aided modeling and optimization of the deturbidization of abattoir wastewater by electrocoagulation using aluminium electrodes.

The removal of turbidity from abattoir wastewater (AWW) by electrocoagulation (EC) was modeled and optimized using Artificial Intelligence (AI) algorithms. Artificial neural networks (ANN), adaptive neuro-fuzzy inference systems (ANFIS), particle swarm optimization (PSO), and genetic algorithms (GA) were the AI tools employed. Five input variables were considered: pH, current intensity, electrolysis time, settling time, and temperature. The ANN model was evaluated using the Levenberg-Marquardt (trainlm) algorithm, while the ANFIS modeling was accomplished using the Sugeno-type FIS. The ANN and ANFIS models demonstrated linear adequacy with the experimental data, with an R2 value of 0.9993 in both cases. The corresponding statistical error indices were RMSE (ANN = 5.65685E-05; ANFIS = 2.82843E-05), SSE (ANN = 1.60E-07; ANFIS = 3.4E-08), and MSE (ANN = 3.2E-09; ANFIS = 8E-10). The error indices revealed that the ANFIS model had the least performance error and is considered the most reliable of the two. The process optimization performed with GA and PSO considered turbidity removal efficiency, energy requirement, and electrode material loss. An optimal turbidity removal efficiency of 99.39 % was predicted at pH (3.1), current intensity (2 A), electrolysis time (20 min), settling time (50 min), and operating temperature (50 °C). This represents a potential for the delivery of cleaner water without the use of chemicals. The estimated power consumption and the theoretical mass of the aluminium electrode dissolved at the optimum condition were 293.33 kW h/m3 and 0.2237 g, respectively. The work successfully affirmed the effectiveness of the EC process in the removal of finely divided suspended particles from AWW and demonstrated the suitability of the AI algorithms in the modeling and optimization of the process.

Alternative sequential combinations of electrocoagulation with electrooxidation and peroxi-coagulation for effective treatment of adhesive production industry wastewater.

Adhesive production industry wastewater can be characterized by high chemical oxygen demand (COD) sourced from high refractory organic contaminants and high total suspended solids (TSS) concentration. Biodegradability of the wastewater is low and wastewater quality is unstable. Various treatment processes have limited applicability in such characterized wastewater. In this study, the treatment performance of electrochemical processes was investigated. Because it is not possible to meet the discharge standards by application of only one process for high refractory organic content, sequential electrochemical processes were studied in this work. In the first step of the sequential process, electrocoagulation (EC) using Al electrodes by which better performance was achieved was applied. In the second step, electrooxidation (EO) and peroxi-coagulation (PC) processes were applied to the EC effluent. In EO, Ti/MMO was selected as the most effective anode whereas in PC, Fe was used as the anode, and graphite was used as the cathode. Box-Behnken Design was applied to optimize the operating conditions of EO and PC processes and to obtain mathematical model equations. In the EC process, 77% COD, 78.5% TSS, and 85% UV254 removal efficiency were obtained under the optimum conditions (pH 7.2, reaction time 35 min, and current density 0.5 mA/cm2). With the EO and PC processes applied to the effluent of EC, 68.5% COD, 77% TSS, and 83% UV254 removal and 77.5% COD, 87% TSS, and 86.5% UV254 removal were obtained, respectively. The specific energy consumption of EC-EO and EC-PC processes was 16.08 kWh/kg COD and 15.06 kWh/kg COD, respectively. Considering the treatment targets and process operating costs, it was concluded that both sequential electrochemical systems could be promising alternative systems for the treatment of adhesive production industry wastewater.

Optimizing microplastic treatment in the effluent of biological nutrient removal processes using electrocoagulation: Taguchi experimental design.

Microplastics (MPs) have become one of the most critical environmental pollution problems in recent years. Due to the growing abundance of MPs in aquatic environments, extensive research has been conducted and continues to be ongoing to develop effective treatment methods. In this study, the removal of MPs in the effluent of biological wastewater treatment plant (WWTP) was investigated by electrocoagulation (EC) process with aluminum electrodes. Using Taguchi design, the importance of process variables such as pH, current density, and reaction time were evaluated by Analysis of Variance (ANOVA). Statistically, according to F and p values, the most effective parameter for microplastic (MP) removal was current density, followed by pH and reaction time. The R2 value of the created model was found to be above 98%. According to Taguchi results, the optimum process conditions were determined as pH 9, current density 1.905 mA/cm2, and reaction time 15 min and 99% MP removal efficiency was obtained. Under these optimum conditions, the process cost was calculated as 0.049 $/m3 wastewater, considering energy and electrode consumption. As a result of visual analyses, fiber, film, pellet, amorphous, and undefined forms were dominant in WWTP effluent, while only fiber structures were observed after treatment with EC. In this study, it was concluded that the EC process is an alternative treatment method that can be integrated into wastewater treatment plant effluent to achieve MP removal at very low cost and high efficiency. In addition, as a result of this study, it was observed that the EC process can also be used in MP removal by applying it to real wastewater.

Comparative evaluation of drying methods for struvite produced from electrocoagulated source-separated urine: Implications for quality, energy and cost-effectiveness.

Struvite precipitation from source-separated urine is crucial for waste utilization and sustainability. However, after precipitation, the high moisture content of struvite necessitates an additional drying process that can be costly and inefficient. In the present study, the performance of different drying methods-open sun drying, air drying, conventional drying (20-100 °C), and microwave drying (180-720 W) on the quality of struvite obtained from source-separated urine through electrocoagulation using Mg-Mg electrodes were evaluated. It was found that higher temperatures and power in the convective oven and microwave resulted in higher diffusivity (10-9-10-7 m2s-1), leading to reduced drying times. Different models were employed to comprehend the drying mechanism, and the one with the highest correlation coefficient (R2 = 0.99) and the lowest statistical values was selected. The key findings indicated that higher power and temperature levels were more cost-effective. However, characterization of the dried struvite using X-ray diffraction and Fourier-transformed infrared spectroscopy, disintegration of struvite crystals at temperatures above 60 °C in the conventional oven and 180 W in the microwave oven was observed. Based on the results, we conclude that sun drying is a cost-effective and environmentally friendly alternative for drying struvite without compromising its quality.

Concurrent arsenic, fluoride, and hydrated silica removal from deep well water by electrocoagulation: Comparison of sacrificial anodes (Al, Fe, and Al-Fe).

Some studies have reported the removal of As (As) and fluoride (F-) using different sacrificial anodes; however, they have been tested with a synthetic solution in a batch system without hydrated silica (SiO2) interaction. Due to the above, concurrent removal of As, F-, and SiO2 from natural deep well water was evaluated (initial concentration: 35.5 µg L-1 As, 1.1 mg L-1F-, 147 mg L-1 SiO2, pH 8.6, and conductivity 1024 µS cm-1), by electrocoagulation (EC) process in continuous mode comparing three different configurations of sacrificial anodes (Al, Fe, and Al-Fe). EC was performed in a new reactor equipped with a small flow distributor and turbulence promoter at the entrance of the first channel to homogenize the flow. The best removal was found at j = 5 mA cm-2 and u = 1.3 cm s-1, obtaining arsenic residual concentrations (CAs) of 1.33, 0.45, and 0.77 µg L-1, fluoride residual concentration ( [Formula: see text] ) of 0.221, 0.495, and 0.622 mg L-1, and hydrated silica residual concentration ( [Formula: see text] ) of 21, 34, and 56 mg L-1, with costs of approximately 0.304, 0.198, and 0.228 USD m-3 for the Al, Fe and Al-Fe anodes, respectively. Al anode outperforms Fe and Al-Fe anodes in concurrently removing As, F- and SiO2. The residual concentrations of As and F- complied with the recommendations of the World Health Organization (WHO) (As < 10 µg L-1 and F- < 1 mg L-1). The spectroscopic analyses of the Al, Fe, and Al-Fe aggregates showed the formation of aluminosilicates, iron oxyhydroxides and oxides, and calcium and sodium silicates involved in removing As, F-, and SiO2. It is concluded that Al would serve as the most suitable sacrificial anode.

Treatment of azo dye-containing wastewater in a combined UASB-EMBR system: Performance evaluation and membrane fouling study.

This work investigated the treatment of azo dye-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor combined with an electro-membrane bioreactor (EMBR). Current densities of 20 A m-2 and electric current exposure mode of 6'ON/30'OFF were applied to compare the performance of the EMBR to a conventional membrane bioreactor (MBR). The results showed that dye (Drimaren Red CL-7B) removal occurred predominantly in the UASB reactor, which accounted for 57% of the total dye removal achieved by the combined system. When the MBR was assisted by electrocoagulation, the overall azo dye removal efficiency increased from 60.5 to 67.1%. Electrocoagulation batch tests revealed that higher decolorization rates could be obtained with a current density of 50 A m-2. Over the entire experimental period, the combined UASB-EMBR system exhibited excellent performance in terms of chemical oxygen demand (COD) and NH4+-N removal, with average efficiencies above 97%, while PO43--P was only consistently removed when the electrocoagulation was used. Likewise, a consistent reduction in the absorption spectrum of aromatic amines was observed when the MBR was electrochemically assisted. In addition to improving the pollutants removal, the use of electrocoagulation reduced the membrane fouling rate by 68% (0.25-0.08 kPa d-1), while requiring additional energy consumption and operational costs of 1.12 kWh m-3 and 0.32 USD m-3, respectively. Based on the results, it can be concluded that the combined UASB-EMBR system emerges as a promising technological approach for textile wastewater treatment.

Optimization and kinetic analysis of electrocoagulation-assisted adsorption for treatment of young landfill leachate.

An investigation was conducted on the electrocoagulation treatment of high-strength young landfill leachate using an electrode made of aluminium in a batch electrochemical cell reactor. An iron sheet of 1 m⨯1 m⨯1.1 m (L: B: H) was used to construct the two landfill simulating reactors, both the reactors were operated at different conditions, i.e., one without rainfall (S1) and the other with rainfall (S2). Both reactors have 51% wet and 49% dry waste, which is the typical waste composition of India, and the quantity of waste taken was 450 kg; hence, the generated leachate was treated. This work focuses on the utilization of electrocoagulation as the sole treatment method where coagulation and adsorption occur simultaneously for young landfill leachate. The study employed a central composite design (CCD) to systematically vary the initial pH, current density (CD), and reaction time to examine their impact on the removal efficiency of COD (Chemical oxygen demand), TOC (Total organic carbon), and TSS (Total Suspended Solids). The optimum conditions obtained were a pH of 7.35, a CD of 15.29 mA/cm2, and a reaction duration of 57 min. When the conditions were optimized, the COD, TSS, and TOC removal efficiencies were 83.56%, 73.12%, and 85.58%, respectively. Also, the electrodes depleted 2.78 g of Al/L. In addition, pseudo-first-order and pseudo-second-order kinetics were employed to examine the elimination of contaminants by adsorption on aluminium hydroxide, thereby confirming the adsorption process. After investigation through energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD), with the produced sludge confirmed that electrocoagulation removed a significant amount of metals from landfill leachate.

Electrocoagulation enhanced gravity driven membrane bioreactor for advanced treatment of rural sewage.

The daily discharge of rural sewage in China occupies 30 % of the national wastewater discharge, and developing an energy-efficient, easy to operate, and decentralized rural sewage treatment technology becomes an important task. In this work, a novel rural sewage treatment technology, Electrocoagulation enhanced Gravity-Driven Membrane Bioreactor (EC-GDMBR) was exploited for the rural sewage treatment under long-term operation (160 days). Two EC-GDMBRs with various module structures of ceramic membrane (horizontal module and side module) not only displayed the desirable effluent quality, but also sustained the stable flux (8-13 LMH). The electrocoagulation, electrooxidation, biodegradation, and separation in EC-GDMBRs were able to synergistically remove the particle matter, organic (CODCr effluent <11.6 ± 1.2 mg/L) and nutrients (NH3-N effluent <0.1 mg/L, TN effluent <8.5 mg/L, TP effluent <0.05 mg/L). Besides, the high permeability of ceramic membrane and large porosity of biofilm on its surface improved the sustainability of stable flux during the long-term operation. Moreover, by analyzing bacterial abundance, Extracellular Polymeric Substances, Adenosine Tri-Phosphate and Confocal Laser Scanning Microscopy, a large number of microorganisms grew and accumulated on the carrier, as well as formed the biofilm (23.46-659.9 µm), while Nitrobacteria (1.6-4.1 %) and Nitrate (0.01-0.06 %) exited in the carrier biofilms, promoting the nitrogen removal. Compared with EC-GDMBR with side module of ceramic membrane, EC-GDMBR with horizontal module of ceramic membrane has advantages in flux behavior, organic/nutrient removal, microbial abundance/activity, abundance of nitrogen removal functional bacteria and water permeability of biofilm, because the ceramic membrane of horizontal module can promote the uniform growth of biofilm and improve the uniformity of flow penetration distribution. In general, the findings of this work verify the reliability of EC-GDMBR for the sustainable operation of wastewater treatment and improve its application value of rural sewage treatment.

Biofilm growth characteristic and footprint identification in gravity-driven ceramic membrane bioreactor with electro-coagulation under extreme conditions for roofing rainwater purification.

The identification of biofilm growth footprints influencing on the biofilm detachment and breakup can advance research into how biofilms form. Thus, a gravity-driven ceramic membrane bioreactor (GDCMBR) was used to investigate the growth, detachment and breakup of biofilm using rainwater pretreated by electrocoagulation under 70-days continuous operation. The in-situ ultrasonic time-domain reflectometry (UTDR) technique was applied to non-invasively determine the biofilm thickness. Initially, the biofilm was slowly thickening, but it would collapse and became thinner after accumulating to a certain level, and then it thickened again in a later period, following a cyclic pattern of 'thickening - collapsing - thickening'. This is because the biofilm growth is related with the accumulation of flocs, however, excessive floc formation results in the biofilm being overweight till reaching the thickness limit and thus collapsing. Subsequently, the biofilm gradually thickens again due to the floc production and continuous deposition. Although the biofilm was dynamically changing, the water quality of treatment of the biofilm always remained stable. Ammonia nitrogen and total phosphorus have been almost completely removed, while CODMn removal efficiency was around 25%. And total bacteria amount in the membrane concentrate was obviously higher than that in the influent with the greater microbial activity, demonstrating the remarkable enrichment effect on bacteria. The understanding of biofilm growth characteristic and footprint identification enables us to develop rational approaches to control biofilm structure for efficient GDCMBR performance and operation lifespan.

Coupling Electro-Fenton and Electrocoagulation of Aluminum-Air Batteries for Enhanced Tetracycline Degradation: Improving Hydrogen Peroxide and Power Generation.

Electro-Fenton (EF) technology has shown great potential in environmental remediation. However, developing efficient heterogeneous EF catalysts and understanding the relevant reaction mechanisms for pollutant degradation remain challenging. We propose a new system that combines aluminum-air battery electrocoagulation (EC) with EF. The system utilizes dual electron reduction of O2 to generate H2O2 in situ on the air cathodes of aluminum-air batteries and the formation of primary cells to produce electricity. Tetracycline (TC) is degraded by ·OH produced by the Fenton reaction. Under optimal conditions, the system exhibits excellent TC degradation efficiency and higher H2O2 production. The TC removal rate by the reaction system using a graphite cathode reached nearly 100% within 4 h, whereas the H2O2 yield reached 127.07 mg/L within 24 h. The experimental results show that the novel EF and EC composite system of aluminum-air batteries, through the electroflocculation mechanism and ·OH and EF reactions, with EC as the main factor, generates multiple •OH radicals that interact to efficiently remove TC. This work provides novel and important insights into EF technology, as well as new strategies for TC removal.

Impact of haemostasis methods during ovarian cystectomy on ovarian reserve: a pairwise and network meta-analysis.

BACKGROUND: Haemostasis during ovarian cystectomy is reported to damage the ovarian reserve, but the comparative impacts of three haemostasis methods (bipolar energy, suture and haemostatic sealant) on ovarian reserve in patients with ovarian cysts are not well known. METHODS: The Cochrane Library, PubMed and Web of Science databases were searched from the date of inception of the database to June 2022 for literature exploring the impact of haemostasis methods during ovarian cystectomy on ovarian reserve. A traditional meta-analysis was performed using Review Manager software. A network meta-analysis (NMA) was performed using Stata and GemTC software. RESULTS: The direct meta-analysis comparison indicated that the mean postoperative reduction of anti-Müllerian hormone (AMH) level was significantly higher in the electrocoagulation (bipolar) group than suture and haemostatic sealant group, both in the overall group and subgroup of women with ovarian endometrioma. In NMA, the reduction of postoperative AMH levels in the electrocoagulation (bipolar) group was higher than the suture group at 6 months with a statistical significance, and at 1, 3 and 12 months without a significant difference. The difference in the postoperative decrease of AMH level did not reach statistical significance between suture and sealant, coagulation and haemostatic sealant. The comprehensive ranking results revealed that suture treatment was, with the highest probability, beneficial to the protection of the ovarian reserve. CONCLUSIONS: There was insufficient research to detect the optimal haemostasis method for ovarian reserve preservation in ovarian cystectomy. Nevertheless, haemostasis by electrocoagulation (bipolar) should be avoided when possible, and the suture might be considered as the best choice.

Haemostasis during ovarian cystectomy is reported to damage the ovarian reserve, but the comparative impacts of three haemostasis methods (bipolar energy, suture and haemostatic sealant) on ovarian reserve in patients with ovarian cysts are not well known. The level of AMH is the most widely used surrogate for ovarian reserve. Our research compared the impact of three haemostasis methods (electrocoagulation, suture and haemostatic sealant) on changes in the levels of anti-Müllerian hormone at 1, 3, 6 and 12 month(s) after the operation. The outcomes revealed that there was insufficient research to detect the optimal haemostasis method for ovarian preservation in ovarian cystectomy. Nevertheless, haemostasis by electrocoagulation (bipolar) should be avoided when possible, and the suture might be considered as the best choice.