ASSESSING REUSE OF AGRICULTURAL AND FOOD RESIDUES FOR NITRATE ATTENUATION IN POROUS MEDIA

Abstract

Nitrate pollution in groundwater is related to surplus nitrate fertilizers and animal waste
disposal. As high nitrate concentration leads to health concern, mass reduction of nitrate in a contaminated
site is important. From the perspective of recent reuse streams, this paper assessed the potential of
agricultural and food residues such as rice husk, rice straw and used coffee as a nitrate attenuation material in
porous media. Under saturated flow conditions, column experiments were carried out in silica sand with a
mixture of residues. KNO3 or NaCl solutions were injected into columns and were analyzed using temporal
moment approaches to characterize the mobility of nitrate and chloride ions. The results showed that the
mixture of rice straw leads to the increase of the retardation factor. The results also revealed that the use of
rice husk and used coffee decreases the mass of both anions, whereas the rice straw has little effect on
attenuation of these anions.