Treatment of Oily Wastewater with Iron-Carbon Internal Electrolysis Process Enhanced by Ultrasonic

Ultrasonic (US), iron-carbon internal electrolysis and the both combination were investigated on treating oily wastewater. Orthogonal and single factor experiments were used to analyze the effect factors of treating oily wastewater by oil and CODcr removal efficiency. The results showed that the optimum condition parameters of treating wastewater with iron-carbon internal electrolysis process enhanced by ultrasonic included iron to carbon mass ratio (4:1), pH(9), irradiation temperature (45 °C), irradiation time (40 min) and particle size of scrap iron (80 mesh). Compared with US and internal electrolysis, oil removal rate of iron-carbon internal electrolysis process enhanced by ultrasonic was increased from 73.0% and 96.6% to about 98.4%, which was improved by 25.4% and 1.4% respectively. Meanwhile, CODcr removal rate was boosted from 58.8% and 88.2% to about 91.0%. Although the augment ratio was not much, the concentration of oil in wastewater was significantly reduced with iron-carbon internal electrolysis process enhanced by ultrasonic compared to US and internal electrolysis, and could satisfy the A1 national standard. The effects of internal electrolysis process contained electric field, redox of H₂, coagulation of iron ion and reduction of iron, and ultrasonic relied on cavitation, oscillation-crushing, stirring, pretreatment, regeneration and synergistic effect. But the iron-carbon internal electrolysis process enhanced by ultrasonic consolidated with both two of the above, so it's a more effective and convenient wastewater treatment method.