Landfill Leachate treatment by sono-evaporation

Sanitary landfill releases two pollutants into the environment, leachate and gases. Leachate may be treated by evaporation to attain acceptable discharge limits for various types of contaminants. One of the most important operational problems with evaporation is scaling. As ultrasound can affect many leachate compounds, this study was done to test its influence on scale treatment using evaporation. In order to determine the effect of sonication on leachate evaporation, some leachate samples were sonicated at a frequency of 25 kHz and 500 W. Sonication periods were tested in the range of 10-40 min on leachate samples. Evaporation and distillation were performed on leachate samples. The tests demonstrated that 90% of the leachate was distilled. When evaporation-distillation processes were carried out, chemical oxygen demand (COD) reduction was 83.56%. However, when sonication was used, COD reduction was 86.56-88.36% for 10-40 mi sonication, respectively. During evaporation, a part of total Kjeldahl nitrogen (TKN) remained in the concentrate and the rest entered into the distillate. In case where sonication was applied, TKN reduction was 83.70% and 89.71% for 10 and 40 min, respectively. Sonication had no considerable effect on EC and heavy metals reduction. When using sono-evaporation, efficiency of scale removal (ESR) reached 95.97%.