Sequential use of the electrocoagulationelectrooxidation processes for domestic wastewater treatment
Abstract
Nowadays, the decrease in useable water resources day by day necessitates studies on the protection of
resources by treating wastewater. It is also one of the best options for reusing the water to be treated, and
electrochemical technologies can be an alternative to existing technologies, because of the easy operation
and effectiveness of pollutants treatment. The study evaluated the treatment of domestic wastewater by
Electrocoagulation-Electrooxidation successive processes in continuous and batch modes. The effects of theoperational parameters on the Electrocoagulation and Electrooxidation processes were determined for removals of chemical oxygen demand, ammonium-nitrogen, nitrate-nitrogen, turbidity, phosphatephosphorus,nitrite-nitrogen, and Escherichia coli. The experiments revealed that the Electrocoagulationprocess effectively removed all pollutants but not ammonium-nitrogen. After the Electrocoagulation processwas completed, ammonium-nitrogen from domestic wastewater treatment was removed with the Electrooxidation
process for further treatment. The optimum operational conditions in the Electrocoagulation
process were electrode type iron anode-carbon felt cathode, current density 100 A m����� 2, initial pH original,
and operation time 20 min. Under these conditions, removal efficiencies of chemical oxygen demand,
turbidity, phosphate-phosphorus, nitrate-nitrogen, nitrite-nitrogen, and Escherichia coli were found to be
90.2%, 96%, 88.2%, 73.6%, and 97.9%, respectively. The removal efficiencies for the optimum operating
conditions of the Electrooxidation process using Ti/SbO2 anode and stainless steel cathode were obtained as
95.4% (chemical oxygen demand), 89.4% (ammonium-nitrogen), and 99.99% (Escherichia coli) at 100 A
m����� 2, 5 mm electrode distance, and 30 min operation time. Finally, the EC process is an effective process for
removing chemical oxygen demand, phosphate-phosphorus, turbidity, nitrite-nitrogen, and nitrate-nitrogen.
However, the Electrooxidation process is a successful process for the treatment of ammonium-nitrogen and