Nitrogen and Phosphorus Removal from Piggery Wastewater by Electrolysis Using Pair of Platinum Group Electrodes and Iron Plate

Abstract

This research showed that the addition of KCI to piggery wastewater and the application of electrolytic treatment enables the removal of nitrogen together with phosphorus from that wastewater, which is something that previous biological treatment methods were unable to accomplish. It also showed that the addition of an aerobic treatment method employing and activated sludge as a first step prior to electrolytic treatment results in a more efficient system for the removal of nitrogen and phosphorus from piggery wastewater than electrolytic treatment alone. This research showed clearly that (1) polarity switching removes scale that forms on the iron electrode, making nitrate reduction also possible with piggery wastewater, (2) it is difficult to generate hypochlorous acid with the platinum-wire electrode for nitrogen removal even when using polarity switching due to the formation of stubborn scale, (3) electrolysis of piggery wastewater using polarity switching can reduce the amount of nitrogen and phosphorus in the wastewater to virtually zero if the frequency of the switching is optimized, and (4) the amount of electric power used to remove nitrogen and phosphorus from piggery wastewater can be reduced significantly by conducting electrolysis after biological treatment rather than just electrolysis alone.