Mathematical Modelling and Response Surface Methodology Approach of Electrocoagulation Hybrid Activated Sludge Process for an Efficient Removal of Selenium from Mining Wastewater
N. P. Kavitha, N. Balasubramanian, R. Jothiramalingam, M. Karnan
{"title":"Mathematical Modelling and Response Surface Methodology Approach of Electrocoagulation Hybrid Activated Sludge Process for an Efficient Removal of Selenium from Mining Wastewater","authors":"N. P. Kavitha, N. Balasubramanian, R. Jothiramalingam, M. Karnan","doi":"10.3103/S1063455X24030056","DOIUrl":null,"url":null,"abstract":"<p>Selenium (Se) is an important nutritional element which exists at very low concentrations, easily accumulates via the food chain and creates adverse effects such as a deprived reproduction rate and diminutive growth in human and aquatic organisms. So, it has become a severe concern around the world. We explore electrocoagulation using Al and Fe electrodes and activated sludge process (ASP) in batch process and also in an integrated process to remove Se. The optimized parameters of the current density in the batch process were: 6.7 and 5.7 mA/cm<sup>2</sup> for Al and Fe, respectively. The mass transfer coefficient has been estimated through numerical modelling for batch and integrated processes using the equations <i>K</i> = <span>\\({\\text{0}}{\\text{.0146}}C_{{{\\text{Se}}}}^{{{\\text{0}}{\\text{.3651}}}}{{I}^{{{\\text{0}}{\\text{.8916}}}}}\\)</span> and <i>K</i> = <span>\\({\\text{295}}{\\text{.387}}C_{{{\\text{Se}}}}^{{{\\text{6}}{\\text{.607}}}}{{I}^{{{\\text{3}}{\\text{.587}}}}}\\)</span>; the energy consumption and metal dissolution were 138240 and 384 MWh/m<sup>3</sup>, 60 and 3.58 g, respectively. The response surface methodology (RSM) was implemented in Box−Benken design to assess the parametric optimization, and the validation of experimental data was done using ANOVA and regression analysis. The obtained <i>p</i>-values and model <i>F</i>-values were 0.000 and 63.09 for Al and 0.000 and 79.98 for Fe, which indicated the significance of the model. The chemical oxygen demand (COD) reduction values estimated along with Se reduction in real effluent treatment were above 90 and 60% in electrolytic and 80% in an integrated ASP with very high-cost efficiency. The results assure that this proposed hybrid work will provide a higher reduction, improved energy and cost efficiency for the effluent with indeterminate influent Se and COD concentration. The proposed model also helps to make predictions of removal efficiency without requiring an extensive time and cost burden.</p>","PeriodicalId":680,"journal":{"name":"Journal of Water Chemistry and Technology","volume":"46 3","pages":"279 - 291"},"PeriodicalIF":0.5000,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Water Chemistry and Technology","FirstCategoryId":"92","ListUrlMain":"https://link.springer.com/article/10.3103/S1063455X24030056","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, ANALYTICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Selenium (Se) is an important nutritional element which exists at very low concentrations, easily accumulates via the food chain and creates adverse effects such as a deprived reproduction rate and diminutive growth in human and aquatic organisms. So, it has become a severe concern around the world. We explore electrocoagulation using Al and Fe electrodes and activated sludge process (ASP) in batch process and also in an integrated process to remove Se. The optimized parameters of the current density in the batch process were: 6.7 and 5.7 mA/cm2 for Al and Fe, respectively. The mass transfer coefficient has been estimated through numerical modelling for batch and integrated processes using the equations K = \({\text{0}}{\text{.0146}}C_{{{\text{Se}}}}^{{{\text{0}}{\text{.3651}}}}{{I}^{{{\text{0}}{\text{.8916}}}}}\) and K = \({\text{295}}{\text{.387}}C_{{{\text{Se}}}}^{{{\text{6}}{\text{.607}}}}{{I}^{{{\text{3}}{\text{.587}}}}}\); the energy consumption and metal dissolution were 138240 and 384 MWh/m3, 60 and 3.58 g, respectively. The response surface methodology (RSM) was implemented in Box−Benken design to assess the parametric optimization, and the validation of experimental data was done using ANOVA and regression analysis. The obtained p-values and model F-values were 0.000 and 63.09 for Al and 0.000 and 79.98 for Fe, which indicated the significance of the model. The chemical oxygen demand (COD) reduction values estimated along with Se reduction in real effluent treatment were above 90 and 60% in electrolytic and 80% in an integrated ASP with very high-cost efficiency. The results assure that this proposed hybrid work will provide a higher reduction, improved energy and cost efficiency for the effluent with indeterminate influent Se and COD concentration. The proposed model also helps to make predictions of removal efficiency without requiring an extensive time and cost burden.
期刊介绍:
Journal of Water Chemistry and Technology focuses on water and wastewater treatment, water pollution monitoring, water purification, and similar topics. The journal publishes original scientific theoretical and experimental articles in the following sections: new developments in the science of water; theoretical principles of water treatment and technology; physical chemistry of water treatment processes; analytical water chemistry; analysis of natural and waste waters; water treatment technology and demineralization of water; biological methods of water treatment; and also solicited critical reviews summarizing the latest findings. The journal welcomes manuscripts from all countries in the English or Ukrainian language. All manuscripts are peer-reviewed.