Removal of COD from Industrial Biodiesel Wastewater Using an Integrated Process: Electrochemical-Oxidation with IrO2-Ta2O5/Ti Anodes and Chitosan Powder as an Adsorbent
- 2 Downloads
The production of biodiesel is an energy and water-intensive process that produces wastewater with high concentrations of COD, BOD, and FOG. Conventional treatment processes are not capable of treating contaminants and pollutants in biodiesel wastewater to satisfactory concentrations, and hence, advanced treatment processes are necessary. Untreated discharge of biodiesel wastewater results in additional costs during the production of biodiesel when penalties and fines are applied. In this research, a lab-scale integrated treatment process was used to investigate the successful abatement of contaminants, COD, BOD and FOG, present in industrial biodiesel wastewater. The integrated treatment process consisted of three consecutive steps: acidification, electrochemical oxidation, and adsorption. Acidification as a pre-treatment occurred at a pH of 2. Electrochemical oxidation using IrO2-Ta2O5/Ti anodes at a current density of 1 mA/cm2 and NaCl concentration of 0.08 M was followed by three consecutive adsorption stages using Chitosan powder at a concentration of 4.5 g/L. The experimental results show that the integrated treatment process could reduce COD, BOD and FOG levels by 94%, 86% and 95%, respectively. The treated effluent complies with local industrial effluent discharge standards, which could be disposed of safely without further treatment.
KeywordsBiodiesel wastewater Electrochemical oxidation Adsorption Chitosan MMO anode COD removal
The National Research Foundation (NRF) of South Africa for the student scholarship. NMT Electrodes (PTY) Ltd., Durban, South Africa, for supplying the IrO2–Ta2O5 anodes used in the electrochemical cell. The biodiesel producing company in Cape Town, South Africa, that supplied the industrial biodiesel wastewater effluent, used in this project.
- Coledam DAC, Aquino JM, Rocha-Filho RC, Bocchi N, Biaggio SR (2014) Influence of chloride-mediated oxidation on the electrochemical degradation of the direct black 22 dye using boron-doped diamond and β-PbO2 anodes. Quim Nova 37:1312–1317. https://doi.org/10.5935/0100-4042.20140219 CrossRefGoogle Scholar
- Costa NM, Silva VM, Damaceno G, Sousa RMF, Richter EM, Machado AEH, Trovó AG (2017) Integrating coagulation-flocculation and UV-C or H2O2/UV-C as alternatives for pre- or complete treatment of biodiesel effluents. J Environ Manag 203:229–236. https://doi.org/10.1016/j.jenvman.2017.07.069 CrossRefGoogle Scholar
- Daud Z, Awang H, Abdul Latif AA, Nasir N, Ridzuana MH, Ahmad Z (2015) Suspended solid, colour, COD and oil and grease removal from biodiesel wastewater by coagulation and flocculation processes. Procedia - Soc Behav Sci 195:2407–2411. https://doi.org/10.1016/j.sbspro.2015.06.234 CrossRefGoogle Scholar
- Foley T, Thornton K, Dixon RK (2015) REN21. 2015. Renewables 2015 Global Status ReportGoogle Scholar
- Ltaïef AH, D’Angelo A, Ammar S, Gadri A, Galia A, Scialdone O (2017) Electrochemical treatment of aqueous solutions of catechol by various electrochemical advanced oxidation processes: effect of the process and of operating parameters. J Electroanal Chem 796:1–8. https://doi.org/10.1016/j.jelechem.2017.04.033 CrossRefGoogle Scholar