AN IN-SITU DENITRIFICATION AND OXIDATION PROCESS WITH INJECTION OF ELECTROLYTIC HYDROGEN AND OXYGEN

Abstract

 Continuous treatments of synthetic groundwater were conducted by using an in-situ denitrification and oxidation process, and measurements of water quality parameters such as nitrate, nitrite, DO, etc. were made over one year. In the in-situ process, hydrogen gas and oxygen gas were produced by using an electrolytic cell and were injected separately into a laboratory scale aquifer filled with glass beads. Experimental results demonstrated that stable denitrification and oxygenation of groundwater were achieved. During the initial phase of experiment, nitrite was accumulated in a hydrogen-injected zone; however, it was oxidized to nitrate in subsequent oxygen-injected zone. In addition, water quality parameters such as TOC, SS, turbidity and chromaticity were smaller in the effluent than influent, and no clogging problem was observed. From these results, we concluded that the present process has several superior performances in terms of stability, effluent water quality and simplicity in long-term operation.