Patent ID: 6083377
Filing Date: 2000-07-04
Classification: C02F

Abstract:
Procedure for in-situ treatment of groundwater contaminated by a nitrogenous contaminant, wherein:the water is groundwater in its native aquifer in the ground, and the treatment procedure is carried out in-situ, the contaminated water remaining in the aquifer during the procedure;the procedure includes the following steps:measuring the pH of the nitrogen-contaminated groundwater;determining, for that pH as measured, the voltages V-Ngas-upper and V-Ngas-lower, being the limiting Eh voltages between which the predominant nitrogen phase is nitrogen gas;providing a pair of electrodes in the nitrogen-contaminated-water, in the ground;so arranging the electrodes in the ground, that the electrodes are in electrolytic communication with each other through the nitrogen-contaminated-water, in the ground:thereby creating an electrochemical cell in the water, in the ground, being either an electrolytic or a galvanic cell, the nitrogen-contaminated-water comprising the electrolyte of the cell;measuring the Eh voltage V-Eh of the nitrogen-contaminated-groundwater;controlling the voltage V-cell, being the voltage as measured between the in-ground electrodes of the in-ground cell, to such a value as to maintain an Eh voltage in the water in the vicinity of one of the electrodes at a voltage V-Ngas, being an Eh voltage between V-Ngas-upper and V-Ngas-lower;whereby the nitrogenous contaminant in the groundwater is transformed, in-situ, in the ground, into nitrogen gas;providing means enabling the resulting nitrogen gas to bubble up out of the water and out of the ground;the Eh voltage of a solution being the redox voltage generated in the solution by comparison with a standard hydrogen electrode.