Study on ammonia stripping process of leachate from the packed towers.

Abstract

About 245 thousand tones of municipal solid waste are collected daily in Brazil. Nearly 32 thousand tones of the collected amount are treated in sanitary landfill, which generates biogas and leachate as byproduct. The leachate resulting from sanitary landfill contains high concentration of carbonaceous and nitrogenized material. The crucial question is that the biodegradation of the carbonaceous material is difficult as long as the nitrogenized material is present in the form of ammoniacal nitrogen (NH4+), which compromises performance of biological treatment process. Therefore, a physical and chemical treatment of the leachate should be done before its biological treatment, especially for reduction of ammoniacal nitrogen concentration and for propitiating the realization of application of biological treatment. The treatment of leachate requires specific consideration, which is not needed for other types of waste. In the specific case in this study, where ammoniacal nitrogen concentration was about 2,200 mgN L-1 and the BOD5/COD ratio was 0.3, the study of ammonia stripping process was performed. Ammonia stripping process was studied in packed towers of 35 L capacity each and the parameters investigated were pH, ratio of contact area/leach volume and the aeration time. One of the parameters that influenced most in efficiency of ammonia stripping process was pH of the leachate since it contributes in conversion of ammoniacal nitrogen from NH4+ to NH3.