Electron transfer rates and energy releases during denitrification of municipal wastewater

Abstract

This paper presents the results of studies on denitrification of municipal wastewater in the bulk water phase under condition of excess electron acceptor and excess electron donor. Experiments conducted on 13 wastewater samples have shown that the denitrification process in the bulk water phase could be simplified by a two-stage process. In the first stage, nitrate was utilised with significant accumulation of nitrite. In the second stage nitrite was utilised when nitrate depleted. Denitrification rates during the two stages were expressed in terms of electron equivalents (e-eq.) in order to compare the process when differennt electron acceptors namlely, nitrate and nitrite were utilised. The energy release rates during the two stages were calculated and compared.