A Fundamental Study on In-situ Method for Removal of Nitrate-Nitrogen Contaminated Groundwater

摘要

One of worsening environmental problems is contamination of groundwater by nitrate-nitrogen supplied by excessive amounts of agricultural fertilizer. In order to remove such nitrate-nitrogen at a site, installation of a permeable reactor barrier (PRB) is thought to be a solution. A sulfur/limestone autotrophic denitrification (SLAD) system is known to be closer to a natural system of removing nitrate from groundwater. In this research, application of this SLAD system to the PRB was examined. Feasibility of the SLAD system was evaluated from a series of experiments using three column reactors. Consequently, nitrate- and nitrite-nitrogen first-order reaction rate constants were obtained from the column experiments and the nitrate- and nitrite-nitrogen profiles were clarified based on the first-order reaction rate. By calculating the designed thickness of the PRB, the application of the SLAD system to the PRB was confirmed to be feasible.