ASSESSMENT OF LEACHATES FROM SANITARY LANDFILLS: IMPACT OF AGE, RAINFALL, AND TREATMENT

摘要

The purpose of this study is to search for effects of landfill age and rainfall on landfill leachate in Taiwan, as well as to carry out a site-treatment study of a typical leachate treatment plant (Tatun). According to the results of analysis, the critical time, so-called leachate-mature-time, is much shorter than the record, 10 to 20 y, in the literature. In addition, it is clearly shown that the leachate flow increases linearly with increasing rainfall, i.e., the leaching coefficient C value decreases. The total organic carbon and the conductivity exhibit different dilution slopes on continuous and continual raining days; the higher slope is observed at continual days. Finally, the typical treatment of leachate in Taiwan includes two parts, biological treatment and a chemical-aided precipitation system. The biological treatment processes are dominating in the removal efficiency of biochemical oxygen demand, chemical oxygen demand, ammonia nitrogen (NH_4~+ -N), and total Kjeldahl nitrogen. However, the best removal of suspended solids, volatile suspended solids, and total phosphorus is obtained with the chemical precipitation system.