Abstract
The iron electrolysis process was applied to an existing domestic wastewater treatment plant that used the contact aeration process. The wastewater in the second contact aeration tank was pumped up into the iron electrolysis tank that contained iron electrodes and flowed back to the first sedimentation/ separation tank. The removal efficiencies for phosphorus and nitrogen were improved by introducing the iron electrolysis process and were 75% and 50%, respectively, when it was operated at an Fe:P ratio or 1.5, a polarity reversal of 24 hours, and a recycle ratio of 1.0 Iron electrolysis did not inhibit biochemical oxygen demand removal. The voltage between the electrodes were stable during 90 days operation and then increased. The amount of eluted iron that was controlled by electric current was almost equal to the theoretical amount. The cost of electrolysis was estimated and was shown to be less expensive than the poly aluminium chloride coagulation process.
