Field Experiment on Remediation of Municipal Solid Waste Dumping Site by Combining Air Injection and Leachate Recirculation

Municipal solid waste (MSW) dumping sites have attracted much attention recently due to the increasing demand for land brought on by urban construction in China. In this study, a three-month field experiment on the effects of combining air injection and leachate recirculation was analyzed based on the indicators examined, such as solid waste moisture content (MC), volatile solid (VS), and dissolved total organic carbon (DTOC) of the leaching solution, as well as chemical oxygen demand (COD), biochemical oxygen demand (BOD), and NH₄-N of the leachate. Results show that 58.9% of VS and 97.5% of DTOC were reduced during the experimental period. The pH level of the leachate was always basic (pH > 7.4), indicating that volatile fat acids (VFAs) did not accumulate. COD content of the leachate remained at a low concentration range of 1200–1500 mg/L. The BOD/COD ratio of the leachate was low and the biodegradability of leachate worsened. The VS/FS ranged from 0.16–0.21. The quick decrease in release intensity of pollutants in the leachate illustrated the acceleration of stabilization of the dumped MSW through the combination of forced aeration and leachate recirculation.