The effect of y-irradiation on the nitrogen compounds in landfill leachate

Abstract

When a landfill leachate was irradiated with 60Co y-rays under aeration for the purpose of the treatment of its microbially reactory organic components, the fate of the organic nitrogen and ammonia which were also the main components in the leachate was examined. The organic nitrogen (about 200 mg− N 1 ) decreased with dose, and the decreasing rate was approximately equal to that of total organic carbon. The ammonia (about 2000 mg− M 1 ) decreased rapidly with increasing dose, but this is mainly due to the elimination of ammonia by aeration. In the irradiated sample, hydroxylamine and nitrite and nitrate ions were observed. The amount of hydroxylamine increased to 50 mg− N 1 by a dose of 120 kGy and then decreased with dose. The amounts of nitrite and nitrate ions, on the other hand, increased with dose; the concentrations reached to 17 and 12 mg− N 1 , respectively, by irradiation of 500 kGy. Considering that 90% of the total nitrogen in the leachate is ammonia and it is a source of nitrite and nitrate ions which accumulate with dose, the ammonia should be eliminated before the radiation treatment of the leachate.