Fluoxetine removal by anodic oxidation using different anode materials and graphite cathode.

Fluoxetine (FLX) is a selective serotonin reuptake inhibitor (SSRI) medication commonly used to treat mental health disorders, but it can be harmful to the environment if not properly disposed of due to incomplete metabolism. In this study, electrochemical anodic oxidation with mixed metal oxide anodes was studied as a method to remove FLX from water and wastewater. Iridium dioxide-coated titanium (Ti/IrO2) and ruthenium dioxide-coated Ti (Ti/RuO2) electrodes were found to be more effective than platinum-coated Ti (Ti/Pt) electrodes, with removal efficiencies of 91.5% and 93.9%, respectively. Optimal conditions for FLX removal were determined to be an applied current of 150 mA, initial pH of 5, and oxidation time of 120 min. The rate of FLX degradation (kFLX) for the Ti/Pt, Ti/IrO2, and Ti/RuO2 electrodes were determined to be 0.0081 min-1 (R2:0,8161), 0.0163 min-1 (R2:0,9823), and 0.0168 (R2:0,9901) min-1 for 25 mg/L initial FLX concentration, respectively. The kFLX values varied based on the initial FLX concentration and decreased as the initial FLX concentration increased. The specific energy consumption (SEC) after 120 min of operation was 51.0 kWh/m3 for the Ti/Pt electrode, 39.6 kWh/m3 for the Ti/IrO2 electrode, and 48.6 kWh/m3 for the Ti/RuO2 electrode under optimised conditions. Overall, electrochemical anodic oxidation is an effective method for removing FLX from water and wastewater, with Ti/IrO2 and Ti/RuO2 electrodes providing superior performance compared to Ti/Pt electrodes.

Spatio-temporal distribution of microplastic pollution in surface sediments along the coastal areas of Istanbul, Turkey.

Microplastics (MPs) have become prevalent in various environmental compartments, including air, water, and soil, attracting attention as significant pollutant parameters. This study investigated the prevalence of MP pollution in surface sediments along Istanbul's Marmara Sea, encompassing the megacity and the Bosphorus. A comprehensive sampling approach was employed, covering 43 stations across four seasons and depths ranging from 5 to 70 m. The objective was to assess the impact of terrestrial, social, and industrial activities on MPs. The average concentrations varied per season, with fall, winter, spring, and summer values recorded as 2000 ± 4100, 1600 ± 3900, 4300 ± 12,000, and 9500 ± 20,300 particles/kg-DW. The study identified river stations in the Golden Horn and sea discharge locations as hotspots for high concentrations. Notably, the dominant shape shifted from fibers in fall, winter, and spring to fragments during summer, coinciding with mucilage occurrences. The study identified 11 different polymers, with polyethylene (44 %) and polypropylene (31 %) being the most common.

Chemical oxygen demand and tannin/lignin removal from paper mill wastewater by electrocoagulation combined with peroxide and hypochlorite treatments.

The present investigation sought to assess the practicality of utilizing a combined pre-treatment approach comprising electrocoagulation, peroxide, and hypochlorite treatments for the removal of chemical oxygen demand (COD) and tannin/lignin from paper mill wastewater. The study aimed to optimize the operating parameters with a view to maximizing the removal efficiencies while minimizing energy consumption. A pair of iron electrodes were used as anode and cathode in the study, and the main operating parameters were determined as initial pH, applied current, treatment time and oxidant dosage/COD ratio. Response surface methodology (RSM) was used to evaluate the effect of these parameters on COD and tannin/lignin removals. The primary findings of the investigation indicated that the integration of electrocoagulation with peroxide and hypochlorite treatments exhibited efficacy in removing COD, tannin/lignin, colour, phenol, and turbidity from paper mill wastewater. The optimized conditions resulted in COD removal efficiencies of 48.13 ± 2.2% and 29.53 ± 1.4% for EC with H2O2 and Ca(OCl)2, respectively. Tannin/lignin removal efficiencies were 92.59 ± 3.6% and 94.09 ± 1.8% for EC-H2O2 and EC-Ca(OCl)2, respectively. The specific energy consumption (SEC) values showed that EC-Ca(OCl)2 required 7 times more energy than EC-H2O2 for removing 1 kg COD. The principal deduction drawn from the study was that EC-H2O2 pre-treatment demonstrated superior COD removal efficiency and lower energy consumption, while EC-Ca(OCl)2 pre-treatment exhibited greater efficiency in removing toxic and recalcitrant pollutants. In future studies, it would be useful to conduct research to increase COD removal efficiency in addition to tannin/lignin removal in EC-Ca(OCl)2 process.

Treatment of wastewater from the washing process of a municipal solid waste collection container by electrochemical treatment using different anode materials: a statistical optimization.

An underground municipal solid waste (MSW) container should be washed periodically to prevent/reduce odor and leachate production. In this study, the treatment process of wastewater derived from the washing process of an MSW container was investigated using the electrochemical (EC) treatment process with different anode materials (Fe, TiO2, and graphite). Response surface methodology (RSM) was used to evaluate the effect of process parameters such as initial pH, applied current, and reaction time on chemical oxygen demand (COD), Tannin/Lignin, and color removals. According to the results obtained from the RSM models, all process parameters were significant. The optimum process parameters in terms of COD removal were derived from the models for each anode material. Under the optimized conditions, the COD removals were determined to be 93.25%, 75.95%, and 98.46% for Fe-Fe, TiO2-Fe, and graphite-Fe electrode pairs, respectively. The color and Tannin/Lignin removals were determined as 98.12% and 77.78% for the Fe-Fe, 92.76% and 98.45% for the TiO2-Fe and 94.50% and 79.56% for the graphite-Fe electrode pair, respectively. The specific energy consumption (SEC) values were found as 46.95, 300.02, and 32.95 kWh/m3 for each electrode combination given above, respectively. In terms of both removal efficiencies and SEC, the most effective anode material was determined as graphite, followed by iron.

Effects of hydrogen peroxide and calcium hypochlorite on chemical oxygen demand solubilization and disintegration of waste activated sludge by electro-chemical pretreatment.

ABSTRACTThe combination of electrochemical (EC) pretreatment with hydrogen peroxide (HP) and calcium hypochlorite (CHC) was investigated in this study for their effect on soluble chemical oxygen demand (CODs) and disintegration degree (DD) of waste activated sludge (WAS). For this aim, response surface methodology (RSM) and Box-Behnken design (BBD) were applied the determination of the optimum operational conditions. Operational conditions were varied between 0.2 and 2.0 mmol/g SS for HP and CHC dosages, 1-5 A for the applied current, 2-10 for the initial pH, and 15-45 min for the treatment time. Obtained results for each treatment were accurate and significant with correlation coefficients (R2) of 0.8639% and 0.9189% for EC combined with HP pretreatment and EC combined with CHC pretreatment, respectively. According to the obtained results, CODs increased in comparison to the raw sludge (168 mg/L) noting that CODs for EC - CHC (1155 ± 21 mg/L) was higher than EC - HP (811.5 ± 15 mg/L) at optimized conditions (for EC-HP pretreatment: HP dosage: 0.34 mmol/g TSS, Applied current:5 A, Initial pH:10, Time: 45 min, For EC-CHC pretreatment: CHC dosage: 0.23 mmol/g TSS, Applied current:4.83 A, Initial pH:10, Time: 40 min). Besides, the DD in terms of COD, total nitrogen (TN) and total organic carbon (TOC) (DDCOD, DDTN and DDTOC) registered increased values after the application of the EC treatment with both oxidants. The highest DDCOD, DDTN and DDTOC values were obtained with EC-CHC pretreatment for 11.34%, 20.34% and 9.18% respectively compared to EC-HP pretreatment (DDCOD: 7.37%, DDTN: 15.18% and DDTOC: 6.94%).

Highlighting the cathodic contribution of an electrooxidation post-treatment study on decolorization of textile wastewater effluent pre-treated with a lab-scale moving bed-membrane bioreactor.

This study is carried out to investigate the effect of the cathodic contribution in the performance of electro-oxidation process for decolorization of the textile wastewater effluent pre-treated with a lab-scale moving bed-membrane bioreactor. For this purpose, titanium dioxide (TiO2) was used as anode electrode and four different cathodic electrode materials: Graphite, TiO2, TiO2-coated Platine, and TiO2-coated ruthenium dioxide (RuO2) (namely RuO2) were tested and compared for their color removal efficiencies. Besides, the optimization parameters that affect color removal in correspondence to the electrode materials, such as applied current, electrolysis time, and pH were studied. In this context, the optimum parameters for each electrode material were selected, and the color removal percentages were found as 92.95%, 91.58%, 91.40%, and 89.17% for TiO2/Graphite, TiO2/Platine, TiO2/TiO2, and TiO2/RuO2, respectively. Finally, the operational cost for each of the tested cathodic electrode materials was calculated in each of the studied optimization parameters making it easier and practical for the selection and evaluation of the electrode materials by the readers. The correlation coefficients (R2) were 81.2%, 87.1%, 86.7%, and 88.6% respectively as a result of the optimization study using the nonlinear regression modeling.

Decolorization of textile wastewater by electrooxidation process using different anode materials: Statistical optimization.

The presence of reactive dyes in textile wastewater is a serious environmental concern due to their associated mutagenic and carcinogenic effects. The present study aims to analyze the effect of different anodic materials on the decolorization of a real textile wastewater effluent. For this purpose, four different anodic materials-TiO2 -coated platine, TiO2 -coated ruthenium dioxide (RuO2 ) (viz., RuO2 ), titanium dioxide (TiO2 ), and graphite-were connected, respectively, to titanium dioxide (TiO2 ) used as a cathode electrode. Color and cost optimization studies were performed using the response surface methodology and the Box-Behnken experimental design (BBD). According to ANOVA results, the R2 values for Pt/TiO2 , RuO2 /TiO2 , TiO2 /TiO2 , and graphite/TiO2 electrode pairs were found to be 97.4%, 93.8%, 92.44%, and 92.2%, respectively, indicating a good compatibility as it is close to one. The results show that color removal efficiencies at the optimal conditions were 86.3%, 90.8%, 91.5%, and 93.6% for Pt/TiO2 , graphite/TiO2 , TiO2 /TiO2 , and RuO2 /TiO2 , respectively. Furthermore, energy consumption cost at the optimum conditions was also evaluated, and the results were as follows: Pt/TiO2 (0.95 €/m3 ), graphite/TiO2 (0.74 €/m3 ), TiO2 /TiO2 (0.31 €/m3 ), and RuO2 /TiO2 (0.26 €/m3 ). Consequently, this research paper shows that all of the tested anodic materials give satisfactory color removal efficiencies higher than 86%. When energy consumption and color removal are considered together, the use of TiO2 /TiO2 and RuO2 /TiO2 pairs would be preferred. PRACTITIONER POINTS: Anodic contribution was investigated for decolorization of textile wastewater by electrooxidation process. Graphite, TiO2 -coated Pt, TiO2 -coated RuO2 , and TiO2 were used as anode materials. Highest color removal with lowest energy consumption was achieved with TiO2 -coated RuO2 anode material (93.6%).

Preliminary study testing the effects of tea and coffee on sludge characteristics and N-butyryl-l-homoserine lactone in an MBR system.

Membrane bioreactors (MBRs) are rapidly developing systems widely used for the treatment of municipal and industrial wastewater prior to their discharge into the environment. Membrane fouling is the most important challenge in MBRs, because it negatively affects membrane performance, resulting in low permeate flux, higher transmembrane pressure and frequent membrane cleaning/replacement. In this study, the effect of tea and coffee on sludge characteristics, membrane fouling and the bacterial signalling molecule N-butyryl-l-homoserine lactone (C4-HSL) in a membrane bioreactor system were investigated. For this purpose, four different continuously operated membrane bioreactors, treating synthetic domestic wastewater and dairy wastewater were operated in parallel under the same conditions. The results indicated that the soluble microbial products (SMP) and the extracellular polymeric substances (EPS) in the reactors showed similar trends for both synthetic domestic and dairy wastewater, where protein levels were higher than carbohydrate levels. Other parameters such as floc size, zeta potential, hydrophobicity, sludge volume index and capillary suction time were also analysed prior to and after the addition of coffee and tea. Analysis of the wastewater samples by GC-MS revealed that coffee and tea significantly enhance the extraction efficiency of C4-HSL. The results obtained in this study can serve as a good basis for further research.

Performance evaluation of conventional membrane bioreactor and moving bed membrane bioreactor for synthetic textile wastewater treatment.

In this study, conventional membrane bioreactor (MBR) and moving bed-membrane bioreactor (MB-MBR) processes were compared in synthetic textile wastewater treatment. For this purpose, the bioreactors were operated as a conventional MBR, an MB-MBR with a biocarrier filling ratio of 20 % and an MB-MBR with a biocarrier filling ratio of 10 %, respectively. In the conventional MBR operation, 93.1 % chemical oxygen demand (COD) and 87.1 % color (Reactive Red 390) removal efficiencies were obtained. In both MB-MBR operations, almost equal COD and color removal efficiencies were found as 98.5 % and 89.5 %, respectively. Moreover, offline physical and chemical membrane cleaning processes were applied every other day and every 15 days throughout the conventional MBR operation, respectively, while no physical or chemical membrane cleaning was required during both MB-MBR operations. Furthermore, lower polysaccharide concentrations of extracellular polymeric substances (EPS) and floc sizes of sludge and higher zeta potential of sludge were determined in MB-MBR. Considering the obtained results, it may be stated that the MB-MBR process is an attractive treatment technology for reducing membrane fouling propensity for treatment of textile wastewater.

Binary Dispersive Liquid-Liquid Microextraction Strategy for Accurate and Precise Determination of Micropollutants in Lake, Well and Wastewater Matrices.

In this study, a binary mixture in dispersive liquid-liquid microextraction was used for the preconcentration and determination of selected pesticides, pharmaceutical and hormone by GC-MS. A Box-Behnken experimental design was used to optimize the amounts of binary mixture, dispersive solvent and salt. The optimum parameters obtained were dichloromethane/1,2-dichloroethane binary mixture (200 µL), ethanol (2.0 mL) and potassium nitrate (1.0 g). Analytical performance of each analyte was determined under the optimum conditions and the lowest and highest detection limits calculated were 0.43 and 5.9 ng/mL. Low relative standard deviations were obtained even in the lowest concentrations in linear calibration plots, signifying high precision for the sample preparation procedure and instrumental measurement. Accuracy of the developed method and applicability to real samples was tested on well, lake, hospital and municipal wastewater. The percent recoveries acquired at different spiked concentrations were satisfactory (89%-108%), validating the accuracy of the method for the quantification of the analytes in the selected matrices.

Wastewater treatment from the biodiesel production using waste cooking oil by electrocoagulation: a multivariate approach.

This study mainly focuses on the process of electrocoagulation (EC) for the wastewater treatment from biodiesel production using waste cooking oil. The effects of current density, initial pH and electrolysis time on the EC process using aluminum (Al) and iron (Fe) electrodes were investigated for removal of chemical oxygen demand (COD). The COD removal efficiencies were found to be 62.7% and 63.4% at optimum conditions for Al (current density: 43 mA/cm2, pH: 5, time: 21 min) and Fe (current density: 47 mA/cm2, pH: 7.7, time: 30 min) electrodes, respectively. At these optimum conditions, the removal efficiencies of oil & grease, total phosphorus (TP), orthophosphate (PO4-P) and total suspended solids (TSS) were determined respectively to be above 89.9%, 98.9%, 99.5%, 86.7% for Al electrodes and 90.8%, 98.5%, 97.6%, 89.6% for Fe electrodes. Total operating costs were also found to be 6.43 €/m3 and 7.01 €/m3 for Al and Fe electrodes, respectively. The results indicate that the EC process using both types of electrodes seems to ensure an efficient treatment of biodiesel wastewater in terms of oil & grease and TP.

Performance and activated sludge characteristics at short solid retention time in a submerged MBR: effects of C/N ratio of wastewater.

This study investigated the effect of carbon to nitrogen (C/N) ratio of influent wastewater on performance and activated sludge properties at a sludge retention time of 5 d in a submerged membrane bioreactor. The chemical oxygen demand and ammonia-Nitrogen (NH3-N) removal efficiencies were found to be over 96.3% and 86.9% in the sMBRs having different C/N ratios. It was found that total extracellular polymeric substances and total soluble microbial products increased with an increase in C/N ratio. It was also observed that critical flux, relative hydrophobicity and zeta potential values decreased, and capillary suction time, particle size and viscosity of sludge increased as the C/N ratio increased.