Optimization of Coagulation Process for Disperse Navy Blue Dye Wastewater Treatment Using Response Surface Methodology

2014 ◽  
Vol 977 ◽  
pp. 270-273
Author(s):  
Ming Li ◽  
Yan Zhen Yu ◽  
Guang Yong Yan

A response surface methodology (RSM) was used for the determination of optimum coagulation process conditions for disperse navy blue dye wastewater treatment. The experimental design was Box-Behnken design (BBD) with three operational variables: coagulant dosage, pH value and settling time. The influence of these three independent variables on the chroma removal was evaluated using a second-order polynomial multiple regression model. Quadratic model was predicted for the response variable and the maximum model-predicted chroma removal efficiency was 95%. Based on surface and contour plots, the optimum conditions were obtained to be coagulant dosage of 70.98 mg/L, pH value of 7.46, and settling time of 15.80 min with the actual chroma removal efficiency as 93%.

2018 ◽  
Vol 77 (6) ◽  
pp. 1765-1776 ◽  
Author(s):  
Gagik Badalians Gholikandi ◽  
Khashayar Kazemirad

Abstract In this study, the performance of the electrochemical peroxidation (ECP) process for removing the volatile suspended solids (VSS) content of waste-activated sludge was evaluated. The Fe2+ ions required by the process were obtained directly from iron electrodes in the system. The performance of the ECP process was investigated in various operational conditions employing a laboratory-scale pilot setup and optimized by response surface methodology (RSM). According to the results, the ECP process showed its best performance when the pH value, current density, H2O2 concentration and the retention time were 3, 3.2 mA/cm2, 1,535 mg/L and 240 min, respectively. In these conditions, the introduced Fe2+ concentration was approximately 500 (mg/L) and the VSS removal efficiency about 74%. Moreover, the results of the microbial characteristics of the raw and the stabilized sludge demonstrated that the ECP process is able to remove close to 99.9% of the coliforms in the raw sludge during the stabilization process. The energy consumption evaluation showed that the required energy of the ECP reactor (about 1.8–2.5 kWh (kg VSS removed)−1) is considerably lower than for aerobic digestion, the conventional waste-activated sludge stabilization method (about 2–3 kWh (kg VSS removed)−1). The RSM optimization process showed that the best operational conditions of the ECP process comply with the experimental results, and the actual and the predicted results are in good conformity with each other. This feature makes it possible to predict the introduced Fe2+ concentrations into the system and the VSS removal efficiency of the process precisely.


2020 ◽  
Vol 81 (6) ◽  
pp. 1308-1318
Author(s):  
Yue Sun ◽  
Xinlei Feng ◽  
Shun Fu

Abstract Inspired by metalloporphyrin-based enzymes, a biomimetic catalyst, R-N-Fe, was prepared by grafting iron phthalocyanine (FePc) covalently onto a macroporous chloromethylated polystyrene-divinylbenzene resin (R), which was pre-functionalized using 4-aminopyridine (4-ampy) as an axial ligand. The novel catalyst was used for the degradation of oxytetracycline hydrochloride (OTCH). The response surface methodology was employed to optimize the independent operating parameters, including temperature, catalyst amount, H2O2 dosage, and initial pH value. The results displayed that the initial pH and temperature had the most significant effect on the removal efficiency. Under optimum conditions, the OTCH removal efficiency was 93.98%. Additionally, the classical quenching experiment and electron paramagnetic resonance (EPR) test indicated that R-N-Fe could generate hydroxyl radicals by decomposing H2O2, which was the main active species for eliminating OTCH. Furthermore, R-N-Fe can be easily recycled and can maintain high stability in the reusability test, rendering it a good potential for practical application.


Author(s):  
Bukola M. ADESANMI Yung-Tse HUNG and Howard H. PAUL

The interference of synthetic dye in the water bodies and environment poses a risk to both human and environmental health. Due to the recalcitrant nature of dye and presence of many other pollutants in industrial wastewater, efficient method of treatment of industrial effluent is required to address the lingering problem over the years. To address this major concern, experimental was carried out on synthetic dye and flour wastewater treatment by coagulation-flocculation while varying operating parameters (dosage, concentration, coagulant type etc.). The effectiveness of coagulation-flocculation process for the removal of Naphthol Green B in a mixture of dye wastewater and flour wastewater at different concentrations (50 ppm, 100 ppm, 150 ppm, 200 ppm) was investigated. Using 3 coagulant (FeCl3, FeSO4 and Al2(SO4)3), color removal efficiency was also investigated. The effectiveness of the coagulation process was measured for transmittance and absorbance as indices using UV-Vis Spectrophotometer. Also, the total organic carbon (TOC) was measured. Transmittance and absorbance values of 99.6% and 0.001 respectively were achieved post treatment. Ferric Chloride and Aluminum Sulfate gave better results than Ferrous Sulfate which gave the poorest transmittance and absorbance values indicating reduced color removal efficiency. The results of this study revealed that coagulation process is an efficient preliminary treatment for appreciable suspended particles and color removal from dye wastewater. It also showed the impact of coagulant dosage, dye strength and combined wastewater samples on the removal efficiency and resulting effluent quality.


2017 ◽  
Vol 76 (4) ◽  
pp. 776-784 ◽  
Author(s):  
Mijia Zhu ◽  
Jun Yao ◽  
Zhonghai Qin ◽  
Luning Lian ◽  
Chi Zhang

Wastewater produced from polymer flooding in oil production features high viscosity and chemical oxygen demand because of the residue of high-concentration polymer hydrolysed polyacrylamide (HPAM). In this study, steel slag, a waste from steel manufacturing, was studied as a low-cost adsorbent for HPAM in wastewater. Optimisation of HPAM adsorption by steel slag was performed with a central composite design under response surface methodology (RSM). Results showed that the maximum removal efficiency of 89.31% was obtained at an adsorbent dosage of 105.2 g/L, contact time of 95.4 min and pH of 5.6. These data were strongly correlated with the experimental values of the RSM model. Single and interactive effect analysis showed that HPAM removal efficiency increased with increasing adsorbent dosage and contact time. Efficiency increased when pH was increased from 2.6 to 5.6 and subsequently decreased from 5.6 to 9.3. It was observed that removal efficiency significantly increased (from 0% to 86.1%) at the initial stage (from 0 min to 60 min) and increased gradually after 60 min with an adsorbent dosage of 105.2 g/L, pH of 5.6. The adsorption kinetics was well correlated with the pseudo-second-order equation. Removal of HPAM from the studied water samples indicated that steel slag can be utilised for the pre-treatment of polymer-flooding wastewater.


2016 ◽  
Vol 74 (3) ◽  
pp. 564-579 ◽  
Author(s):  
Ceyhun Akarsu ◽  
Yasin Ozay ◽  
Nadir Dizge ◽  
H. Elif Gulsen ◽  
Hasan Ates ◽  
...  

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box–Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5–15 V), initial pH (4.5–8.0) and time (30–90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P > 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R2 and Radj2 values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R2 values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage–time and pH–time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.


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