Abstract
This study examined characteristics of leachate from the Go Cat landfill in Ho Chi Minh City, Vietnam and the performance of a lab-scale bioreactor equipped with a microfiltration unit (membrane bioreactor; MBR) for leachate treatment. The COD concentrations of leachate were 39.6–59.8 g l–1 and 1.1–4.0 g l–1 in the dry season (Nov. 2003 – Apr. 2004) and the rainy season (May – Aug. 2004), respectively, indicating that intensive precipitation of the monsoon climate in summer promotes leachate generation and changes in its quality because of the enhanced degradation and increased dilution. The BOD/COD ratio over 0.68 through the year suggested that biological wastewater treatment processes are promising for leachate treatment. The MBR was operated for 90 days at volumetric loading rates of 1.9–4.2 g－COD l–1 d–1. The microfiltration membrane kept the sludge concentration high in the MBR. The specific loading rate remained at 0.097–0.616 g－COD g－VSS–1 d–1 because of the high MLVSS concentration. The MBR showed high COD removal of 84–97% throughout the experimental period. Those results suggest that the effluent COD standard of 100 mg l–1 is probably achieved in the rainy season, but some post-treatment processes are needed, especially for the dry season.
