Treating Mariculture Wastewater Using Electrocoagulation-Microscreen Drum Filter Technology: Electrode Passivation and Influencing Factors

Abstract

This study aimed to improve the performance of the continuous flow electrocoagulation (EC)-microscreen drum filter (MDF) system in treating mariculture wastewater by investigating the passivation behavior of electrodes under different factors. Using response surface methodology, the effects of salinity (10–30‰), current density (15–75 A/m²), inlet flow (100–300 L/h), and electrode's continuous working time (without polarity change) (8–40 min) on current efficiency, total suspended solids (TSS) removal, cathode, and energy consumption of the EC-MDF system were investigated. Results showed that higher salinity improved current efficiency, alleviated anode passivation, enhanced TSS removal, reduced energy consumption, but aggravated cathode passivation. The current and TSS removal efficiencies increased with the current density, whereas the energy consumption and cathode passivation were intensified. By increasing the inlet flow, the current efficiency was improved, the anode passivation and energy consumption were alleviated, but the removal of TSS depreciated. Initially, the cathode gained significant weight before decreasing slightly as the inlet flow was upped, and the inflection point was about 250 L/h. By increasing the continuous working time of the electrode without polarity change, the passivation of the anode and cathode was aggravated, resulting in lower current and TSS removal efficiencies but higher energy consumption.