Assessment of the Use of Hand Warmer for Nitrate Retardation in Porous Media

概要

論文の詳細を見る
This paper assessed the possible reuse of used hand warmer contents (HWCs) as a nitrate retardation material in porous media. Under saturated and unsaturated flow conditions, column experiments with a pulse source of potassium nitrate solution were conducted in silica sand and Andisols with a mixture of HWCs. Mixture of HWCs and flow velocities in a flow field were varied in order to investigate the relation between the degree of retardation and the amount of HWCs under the approximately one order range of Reynolds number. Experimental breakthrough curves measured by capillary electrophoresis were analyzed using temporal moments to estimate the dispersion coefficient, retardation factor and distribution coefficient. The results of column experiments showed that the increase in the amount of HWCs added resulted in the increase of the first two temporal moments and retardation factor in both soils, particularly in silica sand. Reuse of HWCs would be useful to alleviate an immediate leaching of nitrate with high concentration to groundwater in a sandy medium rather than in an aggregated medium.