Removal of organics from bilge water by batch electrocoagulation process

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 10 V, spacing of 1 cm and effective electrode area of 45 cm2, a maximum soluble COD (CODS) removal efficiency of 85% was obtained after an electrolysis time of 120 min. The second order rate constant was derived and a maximum rate constant of 3 × 10−6 L/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.