Removal of Nitrogen and Phosphorus by Electrolysis using a Iron Cathode and a Platinum Group Anode

Abstract

Nitrogen and phosphorus in wastewater impose a burden on the environment and cause damages such as eutrophication in closed water bodies. In the former paper, we showed that a pair of iron cathodes is able to reduce nitrate to ammonia via nitrite and discussed the reduction mechanism by comparing with nitrate reduction by ferrous ions dissolved anodically. Here we showed that, in addition to nitrite reduction, nitrite re-oxidation can be caused by hypochlorous acid in the solution generated at anode and by electrically on anode. We also showed that the nitrite oxidation can be suppressed by reducing the size of anode by minimizing the cross section of the nitrite oxidation reaction on anode.