A novel continuous electroflotation cell design for industrial effluent treatment

The performance of a continuous flow electroflotation (EF) unit designed for industrial effluents treatment was investigated. The employment of synthetic wastewater composed of some heavy metal ions (Cr3+, Cu2+ and Pb2+), soluble dyes (Acid Red 1 and Basic Violet 3), and ultrafine particles (copper metal and copper oxide) was set for studying the cell parameters. The affecting parameters of the EF unit which are current density and type and ionic strength (conductivity) and feed flow rate were studied. The continuous flow EF unit was employed for the treatment of different industrial effluents which was supplied by Textile, Tannery and Wood factories. For synthetic wastewater, the removal efficiency of industrial effluents increased with increasing current density and ionic strength. DC current causes passivation of the anode, thus AC current was preferred. The lower feed flow rate increased the removal efficiency but consumed more power. The removal efficiency was achieved up to 95% at 25 °C, 5 V and an AC current intensity of 1 A with a feed flow rate of 50 ml/min (3 l/h). The energy consumption was 1.67 kWh/m3. For different industrial effluents, the removal efficiency approached up to 90%, at 25 °C, 5 V and an AC current intensity of about 1 A and a 30 ml/min feed flow rate. The energy consumption was about 3 kWh/m3. The removal efficiency could be increased up to about 99% by a further cleaning step with total energy consumption of about 6 kWh/m3.