Application of Central Composite Design approach for dairy wastewater treatment by electrocoagulation using iron and aluminum electrodes: modeling and optimization

Abstract

In this study, response surface methodology approach using Central Composite Design was applied to develop a mathematical model and to optimize process parameters for the COD, color, orthophosphate, TSS, and turbidity removal from dairy wastewater by electrocoagulation process using iron and aluminum electrodes. The second-order regression model was developed to predict the removal efficiencies using Statgraphics Centurion XVI.I software program. The optimum conditions for the COD removal were found to be 5.06 min for reaction time, 5.0 for pH, and 50.5 A/m 2 for current density with Al electrodes, whereas 5.21 min for reaction time, 5 for pH, and 65 A/m 2 for current density with Fe electrodes. High removal efficiencies (98.91% COD and 99.78% orthophosphate removal with Al electrodes, and 98.84% COD and 98.24% orthophosphate removal with Fe electrodes) were achieved under optimum conditions. The operating costs for the COD removal from dairy wastewater by electrocoagulation process using Fe and Al electrodes at optimized conditions were calculated to be 0.54 and 0.42 €/m 3 , respectively. The sludge formed under optimized conditions in EC process was characterized by Fourier Transform Infrared Spectroscopy (FT-IR) analysis. The FT-IR results showed that pollutants in dairy wastewater were linked with aluminum hydroxide and iron hydroxide complexes, precipitated at the bottom of the reactor containing milk components.

Paper mill wastewater treatment by Fe2+ and heat‐activated persulfate oxidation: Process modeling and optimization

“…To evaluate the significance of the linear, quadratic, or interactive parameters in ANOVA, the sum of square value indicating the significance of a particular variable should be taken into account in addition to the F ‐value and the related Prob > F ‐value. To indicate that a parameter has a significant effect on the response, a high SS (sum of square) value, a high F ‐value, and a low Prob > F ‐value should be obtained by analysis of variance 48,52 . Moreover, it may also be concluded that among the significant parameters, the parameter with the higher F ‐value can be identified as more significant.…”

Electroflotation Treatment of Dairy Wastewater: Chemical-Technological Aspects

“…Електрохімічні установки компактні та прості у використанні. Серед електрохімічних методів, що в теперішній час ефективно застосовуються для очищення стічних вод від жирів та білків, необхідно відмітити електрофлотацію та електрокоагуляцію [6][7][8][9][10][11][12].…”

Treatment of cheese whey wastewater by combined electrochemical processes

“…The EC treatment was carried out at natural pH using an optimum stirred Fe/AISI 304 cell at j = 30 mA cm −2 for 60 min. After conditioning the filtered wastewater at pH 3.0, the PEF treatment using a 6-W UVA lamp was made with a stirred cell equipped with a (circle) boron-doped diamond (BDD), (triangle) Pt, (inverted triangle) IrO 2 -based, or (diagonal cross) RuO 2 -based anode and an air-diffusion cathode, all of 3 cm 2 area, at j = 100 mA cm −2 and 35 °C for 420 min can be related to the parallel quicker attack of the powerful BDD( • OH) originated from reaction (5) [17,18] on organics, enhancing the mineralization process.…”

“…Greater effectiveness has been achieved by means of electrochemical technologies. However, little information is still available on their use, being limited to either single electrocoagulation (EC) with Fe or Al anodes [14][15][16][17][18][19], EC coupled with chemical Fenton and ozonation [20] and electro-oxidation (EO) with Pt [21] or dimensionally stables anodes (DSA ® ) [3,22]. More research is then needed to clarify the feasibility of sequential electrochemical processes for treating cheese whey wastewater.…”