Removal of organics from bilge water by batch electrocoagulation process

• Published in: Separation and purification technology Vol. 159; pp. 108 - 115
• Main Authors: Aswathy, P., Gandhimathi, R., Ramesh, S.T., Nidheesh, P.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 08.02.2016
• Subjects: Aluminium; Aluminum; Bilge water; Coagulation; Electrocoagulation; Electrodes; Optimization; Rate constants; Sludge; Sludge characterization; Soluble COD; Sludge characterization; Bilge water; Electrocoagulation; Soluble COD
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2016.01.001

•Treatment of bilge water using electrocoagulation.•Better performance of electrocoagulation over chemical coagulation.•Characterization of sludge generated.•Comparison of various electrode combinations.•Adsorption isotherm and kinetic studies. A batch electrocoagulation study was conducted using aluminium electrodes to check the treatability of synthetic bilge water. The studies were conducted to investigate the effect of various operational parameters on the treatment efficiency. At a pH of 7, applied voltage of 10V, spacing of 1cm and effective electrode area of 45cm2, a maximum soluble COD (CODS) removal efficiency of 85% was obtained after an electrolysis time of 120min. The second order rate constant was derived and a maximum rate constant of 3×10−6L/mg-min was observed at optimum experimental conditions. CODS experimental measurements give an acceptable fit for both Langmuir model and Freundlich isotherm models. A comparative study between electrocoagulation and chemical coagulation was performed and chemical coagulation showed only 59.3% removal efficiency. The sludge formed after the electrocoagulation process was characterized for mineral composition and functional groups. XRD and FTIR results represent the formation of aluminium hydroxide during electro coagulation process and the presence of hydrocarbons and heavy metals in the sludge indicates the removal of these pollutants from bilge water by electrocoagulation process. Among different electrode combinations of aluminium and iron, AlAl combination showed maximum removal efficiency. A case study on real bilge water was conducted and a maximum removal of 89.84% was obtained at optimum conditions using aluminium electrodes.