Percentage Of COD Removal Research Articles

Remoción de cromo (VI) de agua residual de curtiembre empleando biomasa orgánica vegetal en un reactor biológico secuencial aerobio

[Introduction]: In the removal of chromium (VI) from tannery wastewater, physicochemical methods are the most used. However, these require high operating costs, and worse still, generate secondary pollutants that again require complementary treatments for their elimination. Given this, the applicability of plant organic biomass (VOB) emerges as an environmental alternative based on the adsorption of chromium (VI), the simplicity of obtaining it, the reduction as waste and, above all, it does not generate secondary pollutants. [Objective]: Use VOB waste in an aerobic sequential biological reactor (SBR) for the removal of chromium (VI) in the treatment of tannery wastewater. [Methodology]: 3 aerobic SBR systems were implemented; 2 controls (SBR1 and SBR2) and 1 study subject (SBR+VOB). Each system was fed with tannery wastewater (18 L) and connected to an aeration system (12.7 L/min). The bacterial inoculum, a fundamental part of an SBR system, was obtained from the selective culture of chromium (VI) reducing bacteria (RBCrVI) taken from the wastewater under study, and integrated into SBR2 and SBR+VOB at 0.6 g/L. The VOB was obtained from Stenotaphrum secundatum residues, fragmented, sieved, sterilized and integrated into the SBR+VOB at 1.5 g/L. [Results]: The SBR+VOB system achieved the highest percentage of chromium (VI) removal (93 %), followed by SBR2 (80.1 %), and finally SBR1 (2.8 %). With respect to COD and TSS, the statistical test (Tukey) showed that there was no significant difference between the system under study and the controls, recording COD removal percentages ranging from 87.8 % to 88.4 %, and TSS ranging from 63.8 % to 69.2 %. [Conclusions]: The viability of using VOB waste to remove chromium (VI) in the treatment of tannery wastewater has been evidenced. The results of this research create a promising panorama to mitigate the effects derived from inadequate management of tannery wastewater and organic solid waste.

Reduction of Chemical Oxygen Demand, Oil and Grease from Dairy Effluent using Unmodified Agricultural By-products as Adsorbents

An experimental investigation was carried out to treat Dairy Effluent using low-cost adsorbents. The peels of banana, sugarcane bagasse, and coconut husk were used as adsorbents in this study by carbonization and dehydration (biosorption) methods and the effect of adsorbent dosage, and adsorbent particle size in the removal of pollutants present in dairy effluent was evaluated. This study showed that Coconut Husk Powder is more effective than Banana peels and Sugarcane bagasse powder in the reducing COD of dairy effluent. The carbonization method is found to be more efficient than the de-hydration method in reducing both COD and Oil and Grease. The Coconut Husk Powder was found to be more efficient in reducing COD in both methods. Dehydrated Coconut Husk Powder of 90 μm 0.8 gm was found to be more efficient while reducing Oil and Grease in the dehydration method while in the carbonization method, 0.5 gm CBPP 90 μm was found to be more efficient. The highest percentage removal of COD was found when mixed with all powder is 63.1532%, obtained when using 0.2 gm CBPP + 0.2 gm CSBP + 0.2 gm CCHP 300 μm. The highest percentage removal of COD in the dehydration method was found when used 0.8 gm DCHP 150 μm which is 51.7735% and in the carbonization method was found when used 0.5 gm CCHP 90 μm which is 59.1724%.

Evaluation of enhanced chemical coagulation method for a case study on colloidal liquid particle in wastewater treatment: Statistical optimization analysis and implementation of machine learning

Coal mines are one of the largest sources of energy supply and generate significant volumes of wastewater. Chemical coagulation is one of the most effective methods for wastewater treatment. In this research, ferric and aluminum-based coagulants, along with polyacrylamide flocculants with positive, negative, and neutral charges, were utilized in chemical coagulation. After applying the Plackett-Burman screening method, it was found that ferric chloride coagulant, neutral flocculant, and slow mixing duration had the greatest impact. The chemical coagulation process was modeled and optimized by examining these factors using the Box–Behnken statistical design as input parameters and sedimentation velocity as the output. Under optimal conditions, the values for ferric chloride coagulant, neutral flocculant, mixing time in slow mode, and sedimentation velocity were determined to be 106.3 mg/L, 3.98 mg/L, 29.6 min, and 1.10 cm/min, respectively. Under optimal conditions, the removal percentages of pollutants, including TSS, turbidity, TDS, COD, and BOD, were obtained at 100%, 100%, 87%, 93%, and 81%, respectively. The experimental data were fitted using the BBD and ANN methods. Both models demonstrated very high agreement, but the ANN method performed better with an AAD% of 0.66, an MSE of 0.0001, and an R2 value of 0.99. All results were calculated with a confidence level above 98%, indicating that both models had very high reliability in modeling and prediction.

Comparative evaluation between Taguchi method and response surface method for optimization of electrocoagulation process in the context of treatment of dairy industry wastewater.

The presence of a large amount of organic and inorganic pollutants in dairy effluent is a substantial environmental issue. This study investigated electrocoagulation (EC) as a potential treatment method for dairy wastewater under different operating conditions, such as applied voltage (5-25V), electrolysis time (30-90min), and inter-electrode distance (1-2cm) by using aluminum electrodes. This study focuses on achieving the maximum removal of BOD, COD, and nitrate in dairy effluents with the aforementioned operating conditions. The process was optimized using the response surface methodology (RSM) and Taguchi method. RSM method optimized the electrocoagulation operating conditions such as the voltage at 23.75V, time of 90min, and inter-electrode distance at 1.07cm. This optimization achieved the maximum removal percentage of BOD, COD, and nitrate at 79.06%, 84.35%, and 79.64%, respectively, in dairy effluent. Taguchi method optimized the electrocoagulation parameters such as the voltage at 25V, time duration of 90min, and inter-electrode distance of 1.00cm, showcasing improved removal percentages of BOD, COD, and nitrate as 90.54%, 89.28%, and 82.74% respectively. The current study attempts to understand the optimization efficiencies between Taguchi method and response surface method for diary wastewater treatment.

Hybrid Industrial Wastewater Treatment Using a Sono‐Alternating Current‐Electrocoagulation Technique with Power Usage Estimation

AbstractDistillery industrial wastewater (DIW) was tested for color and COD removal percentages using an electrochemical and advanced oxidation processes (AOPs). Specifically, the study compared direct/alternating–current–electrocoagulation (DC‐EC/AC‐EC), sono (US), and direct/alternating current–electrocoagulation coupled with sono (US) (DC‐EC/US and AC‐EC/US) processes. Also evaluated were the effects of these procedures on the power needed to treat DIW. Experimental results showed that compared to single processes such as DC‐EC, AC‐EC, US, hybrid DC‐EC/US, and the hybrid AC‐EC/US process achieved a total color elimination efficiency of 100 % and a COD elimination efficiency of 100 % while using a lower power consumption of 4.76 kWhrm−3. The effects of important operational factors such treatment duration, cycle of pulse duty, sonication power, current density, chemical oxygen demand, electrode spacing, electrode pairing, pH, concentration of electrolyte on the % removal of COD and power usage of DIW were investigated using hybrid AC‐EC/US process. When using a Fe/Fe electrode combination, the effectiveness of COD removal was shown to be enhanced by increasing the treatment duration, current, US power, and decreasing the COD concentration, electrode spacing. The study also provided the results of an investigation into the synergistic index between AC‐EC and US process and operational cost. Based on its ability to efficiently and effectively remove contaminants from wastewater and industrial effluent, the AC‐EC/US approach stands out among the other methods.

Synthesis and utilization of titanium dioxide nano particle (TiO2NPs) for photocatalytic degradation of organics

A green technique that emerged as a promise in the degradation of numerous organic contaminants is photocatalysis. The aim of this study concerns photocatalytic degradation of organic using titanium dioxide nano particles (TiO2 NPs) which syntheses from ilmenite by different leaching methods using different ingredients such as HCl, HNO3 and Aqua Regia. The affecting factors such as rate of addition, reaction time, ilmenite grain size, acid to ilmenite ratio and reaction temperature were conducted. Comprehensive physicochemical characterization of Ilmenite and TiO2 NPs were conducted using different analytical techniques such as XRD, XRF, SEM, TEM and FTIR. Photocatalytic degradation of organics is confirmed by studies of affecting factors on the effectiveness of TiO2 NPs such as dose, agitation forces, light intensity, initial concentration, pH, time, and temperature. The removal percentages of TSS, COD, BOD and TN of organics were explored. From the results the maximum removal percentage of TSS were 97.3 and 96.9% before and after secondary treatment conducted using ferric chloride (FC). The maximum removal percentage of TKN, BOD, and COD before secondary treatment were conducted using mixture of TiO2 NPs, FC, and chitosan, which reached 44.2, 44 and 46.3%, respectively. The maximum removal percentage of TKN, BOD, and COD after secondary treatment were conducted using mixture of TiO2 NPs, FC, and chitosan, which reached 94.9, 99.7 and 99.6%, respectively. Overall, the results derived from this investigation suggest that the TiO2 NPs/UV holds significant advanced treatment of sewage water, making it a viable choice for water reuse applications.

Study on COD and color removal efficiency in textile dyeing wastewater by iron electro-coagulation technology combined with persulfate

Electrocoagulation (EC) is an attractive method for treating many types of wastewater due to its advantages. The purpose of this study is to investigate the effect of persulfate addition on the efficiency of textile wastewater treatment through the removal percentage of COD and color parameters. Persulfate is proven to significantly enhance the rate and efficiency of pollutant removal in textile wastewater. The removal percentage of COD could reach 91.33 ± 1.23% and 97.99% ± 0.52% was the highest removal percentage of the color parameter at the optimal reaction parameters. The effluent concentration meets the standards according to Vietnam national technical regulation on textile industry wastewater. By using persulfate, the COD and color removal efficiency increased by 17.53 ± 2.69% and 8.81 ± 0.91%, respectively, compared to the single electrocoagulation process. The amount of sludge generated in the system is 0.542 ± 0.0357 kg/m3, significantly reduced compared to the flocculation process of 0.875 ± 0.0295 kg/m3.

Palm oil mill secondary effluent treatment using ZNO-clay liquid photocatalyst in membrane photocatalytic reactor

In recent years, photocatalytic treatment of palm oil mill secondary mill effluent (POMSE) incorporating ZnO nanoparticles with various types of capping agents via membrane photocatalytic reactor (MPR) has gained great interest among researchers. Nevertheless, most of previous studies have employed a rather time-consuming oven drying and calcination method to synthesise ZnO in powder form. Therefore, a simpler synthesis method is considered necessary. In this study, ZnO-clay was synthesised in liquid form using the precipitation method, without undergoing oven drying and calcination. The effect of different ZnO-clay ratios on the degradation performance of POMSE via MPR was also examined. Results indicated that ZnO-clay 1:3 was efficient in BOD removal percentage, while the removal percentages of COD, colour and turbidity were higher for ZnO-clay 1:5 compared to other ratios.

Innovative electrocoagulation strategies for landfill leachate treatment: Comparative analysis of aluminum and iron electrodes

ABSTRACT This study investigates landfill leachate treatment using aluminum (Al-Al) and iron (Fe-Fe) electrodes in electrocoagulation (EC). Aluminum experiments revealed COD removal percentages of 22% (pH 7.4) and 20% (pH 6.0), while iron demonstrated higher efficiency at 32% (pH 7.4) and 30% (pH 6.0). Both processes excelled at neutral pH, with Fe-Fe EC displaying superior removal efficiency. To address electrode passivation, external aeration improved COD removal (31% to 61%) under specific conditions (3 V, pH 7.4, 60 min). The EC process established a neutralization mechanism, eliminating the need for further treatment before discharge. External aeration and polarity changes at intervals mitigated passivation, enhancing COD removal (61% to 69%). Voltage testing (1 V, 3 V, 5 V, 7 V) revealed a direct correlation, peaking at 91% efficiency with 5 V. Specific energy consumption was 2.34 kWh g−1, and sludge generation varied with voltage. The combined use of external aeration and polarity shifts resulted in 270 ml of sludge, demonstrating improved efficiency in the EC process.

The effect of physicochemical properties on paracetamol photodegradation in cuboid bubble column

Paracetamol is one of the most anthropogenic micropollutants, and their removal from the environment often requires a specialized method of remediation. In this study, a photocatalyst technique aided with air bubbles was used to degrade the pharmaceutical pollutant paracetamol (PCT) from the water via the COD test and HPLC analysis under different operating conditions. The experiments were carried out in a semi-batch rectangular bubble column with dimensions of 1500 mm height, 30 mm depth, and 200 mm width under UV light. Titanium oxide (TiO2) was used as a source of catalyst. The effect of operating conditions of pH (3-10), air flow rate (0-2) L/min, salinity of solution represented by NaCl concentration (0-1000) mg/L, and 240 min irradiation time on the paracetamol removal were studied. The Box–Behnken design was adopted to study the individual effects of pH (A), air flow rate (B), and salinity (C) and their interactive effects. From the experimental and regression data, a second-order polynomial regression model is predicted, and the variance analysis of the regressions shows that the linear terms (A and B), and all quadratic terms (A, B, and C) have significant effects on the removal percentage of COD. According to numerical optimization, the greatest %COD removal is 76.7 in the process conditions of 5.3 pH, 1L/min, and 269 mg/L of NaCl. The experimental results show that the maximum %COD removal was 78% at pH=7, 1L/min, and 0mg/L of NaCl. HPLC analysis shows 91.2% of paracetamol degradation.

Evaluation of Scenedesmus dimorphus under Different Photoperiods with Eutrophicated Lagoon Water

Given the need to improve bioenergy production processes, it is necessary to focus on low-cost culture media and environmental conditions of radiation and temperature. The Scenedesmus dimorphus species was cultured in eutrophicated lagoon water and Bayfolan 0.3% as culture media under four photoperiods with the objective of evaluating the biomass productivity, bioremediation capacity and influence of illumination on the composition and lipid content. It is concluded that the increase of light hours in the culture with eutrophicated lagoon water produces a decrease in the biomass productivity and COD removal percentage. The highest biomass productivity was obtained in photoperiod F1 (10.5:13.5) hours L:O, 0.053 ± 0.0015 g/L day and a removal of 95.6%. Bayfolan 0.3% with F2 (11.5:12.5) and F3 (12.5:11.5) did not show significant differences in the biomass productivity and COD removal. The increase in light hours in the photoperiod induced an increase of 1.01% and 2.84% of saturated fatty acids and 0.8% and 2.14% of monounsaturated fatty acids, as well as a decrease of 3.85% and 2.88% of polyunsaturated fatty acids in eutrophicated lagoon water and Bayfolan 0.3%, respectively.

Removal of Remazol Black B dye using recirculation batch electrocoagulation

Textile industry wastewater mainly contains high concentration of organic matter including the active dye of Remazol Black B. This wastewater effluent needs to be properly treated before discharge into water bodies. Electrocoagulation is one of physico-chemical methods that can be used as an alternative of wastewater treatment in the textile industries because it has a good efficiency in removing colour. A wide range of pH measured in the textile industry wastewater (i.e., 3.9-14) may affect the effectiveness of electrocoagulation process. Other factors that affect electrocoagulation process were current intensity and wastewater flow. This study aims to determine the optimum of electrocoagulation process in the recirculation batch method using recirculation batch reactor. The applied current tested were 10 A, 15 A and 20 A, with flow rate of 2 L/min, 3 L/min, and 4 L/min. A synthetic textile wastewater was prepared with a Remazol Black B dye colour concentration of 10 ppm, 3 g/L of NaCl, and pH of 11. The parameters tested periodically in this study were pH, TDS and removal of colour and COD. Result of this study showed that by increasing the electric current strength and decreasing the flowrate, efficiency of pollutants removal was increased. Highest removal percentage of COD and colour were 100% and 88,78%% with current strength of 20 A, and flow rate of 2 L/min, the final pH was 11,4, whereas total dissolved solid fluctuated (i.e., 1785 mg/L– 1902 mg/L).

Investigation of spent caustic effluent treatment by electro-peroxone process; cost evaluation and kinetic studies

Spent caustic is an extremely polluted industrial wastewater with quite complex chemistry and various environmental negative impacts. Conventional wastewater treatment methods are not adequately efficient for the remediation of spent caustic. In the present work, for the first time, the treatment of spent caustic effluent was investigated by the Electro-Peroxone (EP) method as a subdivision of Advanced Oxidation Processes (AOPs). The Central Composite Design (CCD) was employed to optimize the operational parameters, including initial COD, applied current, pH, and ozone flow rate in the removal of COD. The statistical investigations showed an acceptable determination coefficient and a suitable second-order model. The predicted optimal circumstances were as the following: initial COD = 1076 mg. L-1, applied current = 0.79 A, pH = 7.9 and O3 flow rate = 1.68 L.min−1. At optimum points, the predicted and actual COD removal percentages were 96.3 and 95.0 %, respectively. The kinetic investigations showed that the removal of COD followed the first-order kinetic with the half-life and constant reaction rate at 18 min and 0.038 min−1, respectively. The specific energy consumption (SEC) value in the EP process was calculated at 33.96 kWh/Kg COD removal, showing that the combined EP process could be a cost-effective technique for the treatment of spent caustic effluent on an industrial scale.

High-throughput screening to evaluate optimum coagulation conditions via colloidal stability analysis

Current methods of optimizing the coagulant dosage in wastewater treatment processes typically rely on the use of labor- and material-intensive jar testers, which are inadequate when coagulation processes require frequent adjustments due to variations in properties of the incoming feed. Analytical centrifuges (ACs) employ an integrated optics system that simultaneously monitors the position of the boundary between two separating phases in multiple samples of fairly low volumes (∼2 mL) – thus it was expected that ACs would be ideally suited to study the stability and settling kinetics of coagulation treatment processes. In this study, wastewater samples from a biogas generation facility (known as centrate) were collected in February 2022 (Batch A) and July 2022 (Batch B). A comprehensive screening of the treatment performance for Batch B was conducted at three pHs (5, 6, and 7) and nine concentrations of ferric chloride (0–500 mg-Fe3+/L) – it was found that the front-tracking profiles measured by the integrated optics system could be used to identify the minimal coagulation conditions needed to transition from slow to rapid settling. While the settling velocity was found to be well correlated with the instability index, a dimensionless number between 0 and 1 (where values closer to 1 indicate better separation), it was determined that the percentage of COD removal from the centrate samples increased up to an instability index of approximately 0.5 and then plateaued. Finally, it was found that the front-tracking profiles could be used to estimate the volume of sludge produced at various coagulation conditions. Thus, the results from this study establish ACs as an important screening tool for rapid evaluation of treatment performance while consuming minimal material and time – in this study, a total of 132 screening experiments were conducted using approximately ∼11 L of centrate and ∼6 hours of operator time.

Facilitating the electrochemical characterization and biofilm enrichment through anode modification in microbial fuel cells

Poor anodic performance is a significant obstacle for scalable applications of air-cathode microbial fuel cells (MFCs), and it can be significantly improved with graphite anodic surface modifications. Morphological and electrochemical performance of modified anode with reduced graphene oxide rGO), polyaniline (PANI), carbon nanotubes (CNTs), each mixed with plant powder, showed improvement in electron transfer rate and anodic biocapacitance over unmodified anode in MFC. PANI-modified anode showed maximum power generation (149.7 mW/cm2) over other variations in MFCs. The highest COD percentage removal was obtained by the PAIN-modified anode (91.9%) followed by the CNTs-modified anode (86.7%) and the rGO-modified anode (82.4%). Electrochemical analyses revealed the enhancement in redox current generation with low charge transfer resistance with enrichment in electrogens in anodic biofilm using such anode modifiers, especially PANI, than unmodified anode in MFC. Biological and physiological analyses also support favoring electrogenic microbial activities and community structure towards the electroactive response and secretion of extracellular polymeric substances (EPS) for mediating electrons with modified anode conditions. Thus, the PANI-modified anode can be a promising and a sustainable anode candidate for MFC's long-term stability and scalable applications. Likewise, it could potentially be utilized as an innovative approach for developing a high-performance anode with extended operation for COD reduction in wastewater.

Development of electrocoagulation-based continuous-flow reactor for leachate treatment: Performance evaluation, energy consumption, modeling, and optimization

This study investigated the performance of continuous-flow electrocoagulation (CFR-EC) reactor for aged landfill leachate treatment with a novel configuration of iron and aluminum electrodes to enhance the applicability of the process. The effects of the applied current density (ACD), initial pH, and hydraulic retention time (HRT) on the percentage removal of COD, TOC, BOD5, color, turbidity, and heavy metals (HMs) were modeled with Box-Behnken design (BBD). The results demonstrated that the models are significant (R2 0.97—p-value < 0.0029 and R2 0.92—p-value < 0.0001 for Fe and Al electrodes). COD, TOC, BOD5, and NH3-N removal were maximized at HRT 50 min (40.0 mL min−1) and pH 11 reaching 59, 64, 55, and 27%, respectively, by applying the ACD of 1.1 mA cm−2 in the CFR-ECFe reactor. The CFR-ECFe reactor presented a higher color (59%) and turbidity reduction (86%) than the CFR-ECAl reactor. At optimum condition, the removal percentages of HMs: Cr6+, Pb2+, As3+, Mg2+, B3+, Mn3+, Ni2+, and Ba2+ were 50, 70, 80, 99, 81, 99, 20, and 65%, respectively. The total process cost for landfill leachate treatment was 0.21 $/m3. The CFR-ECFe was an effective and affordable reactor for pollutant removal from landfill leachate.

Development and application of random forest regression soft sensor model for treating domestic wastewater in a sequencing batch reactor

Small-scale distributed water treatment equipment such as sequencing batch reactor (SBR) is widely used in the field of rural domestic sewage treatment because of its advantages of rapid installation and construction, low operation cost and strong adaptability. However, due to the characteristics of non-linearity and hysteresis in SBR process, it is difficult to construct the simulation model of wastewater treatment. In this study, a methodology was developed using artificial intelligence and automatic control system that can save energy corresponding to reduce carbon emissions. The methodology leverages random forest model to determine a suitable soft sensor for the prediction of COD trends. This study uses pH and temperature sensors as premises for COD sensors. In the proposed method, data were pre-processed into 12 input variables and top 7 variables were selected as the variables of the optimized model. Cycle ended by the artificial intelligence and automatic control system instead of by fixed time control that was an uncontrolled scenario. In 12 test cases, percentage of COD removal is about 91. 075% while 24. 25% time or energy was saved from an average perspective. This proposed soft sensor selection methodology can be applied in field of rural domestic sewage treatment with advantages of time and energy saving. Time-saving results in increasing treatment capacity and energy-saving represents low carbon technology. The proposed methodology provides a framework for investigating ways to reduce costs associated with data collection by replacing costly and unreliable sensors with affordable and reliable alternatives. By adopting this approach, energy conservation can be maintained while meeting emission standards.

Comparative Studies on Application of Various Adsorbents in Textile Waste Water

This thesis aims to explore the potential of employing natural adsorbents, such as cashew nut shells, date seeds, orange peels, and coir pith, to mitigate COD levels in textile wastewater. The wastewater used for the study was sourced from a textile industry located in Salem. The investigation involved batch studies, wherein the effectiveness of each selected absorbent in reducing COD was assessed to determine the most efficient among the four sorbents. The initial concentration from the batch research served as a basis for identifying the optimal adsorbent, with the COD of the textile wastewater maintained consistently along with the initial dye concentration. To conduct the study, the adsorbent was incrementally introduced in 10 g portions into conical flasks. Over a10-minute period following a 20-minute contact time, the supernatant liquid from each conical flask was collected using syringes. The COD concentration in the obtained samples was determined using a standard methodology. Results revealed that date seeds exhibited the highest percentage of COD removal at 67%, followed by cashew nut shells at 45%, coir pith at 33%, and orange peels at 23%. The data obtained indicated that cashew nut shells and date seeds achieved the highest percentages of COD reduction, respectively. On the other hand, the Orange Peel Adsorbent displayed the least reduction in COD. Based on the collected findings, date seeds emerge as a promising adsorbent for effectively lowering COD in the treatment of textile wastewater.

Assessment Efficiency Evaluation of Al-Diwaniya Sewage Treatment Plant in Iraq

This study aims to evaluate the performance of the sewage treatment plant in Al-Diwaniya, one of cities in the southern part in Iraq. This evaluation could be used to facilitate effluent quality assessment or optimal process control of the plant. The influent reaching the plant is considered a medium to strong in strength with BOD5/COD ratio in the range 0.23 and 0.69 which can be considered an easily degradable sewage by the biological processes performed by the activated sludge unit. The quality of the effluent was found to be higher than the Iraqi standards for disposal to water bodies. The BOD5/COD ratios of the treated sewage varied over a wide range as low of 0.13 to 1.48 indicating operational problems in the plant. Regression analysis was performed to estimate the removal percentages of BOD5, COD, TSS and NO3 that the plant should perform by to reach the disposal limitations.

Landfill leachate treatment by activated carbon (AC) from banana pseudo-stem, iron oxide nanocomposite (IOAC), and iron oxide nanoparticles (IONPs)

This study investigated the efficiency of activated carbons (ACs) produced from banana pseudo-stem, iron oxide nanocomposite (IOAC), and iron oxide nanoparticles (IONPs) for chemical oxygen demand (COD, mg/L), dissolved organic carbon (DOC, mg/g), and color (mg/g) removal from landfill leachate. A continuous-flow bed column study was conducted to ascertain behavioral pattern of the adsorbents during adsorption experiments (variables: bed column height, flow rate, and influent concentration). Kinetics (pseudo-first (PFO) and pseudo-second (PSO) orders) and isotherms (Langmuir, Freundlich, and Temkin) models were used to describe adsorption trends of pollutants. An artificial neural network (ANN) was used to model the adsorption process. Risk assessment analysis on the treated effluent was determined based on risk quotients (RQ) from COD standards for sewage and effluents. The bed column study showed that percentage removal of COD, DOC, and color increased with increasing the bed height while empty bed contact time (EBCT) increased from 1.6 to 4.7 min as the column bed height increased from 7.5 to 12.5 cm respectively. The adsorption kinetics for all treatments were well-fitted with the PSO kinetic model suggesting that the removal rate of COD, DOC, and color is dependent on the availability of the sorption sites. The adsorption process was observed to have good linearity in the three isotherm models with an overall R2 > 0.90. The values from tqt for each dataset of AC, IOAC, and IONPs fit the Levenberg–Marquardt (LM) training algorithm with best validation performance, lowest mean square error (MSE) of 0.19789 at epoch 8 and highest coefficient of determination (R2) of 0.9922. The IONPs treatment showed the lowest RQ (0.5732–0.4723) from all dosages of adsorbents indicating medium risk to aquatic organisms.