Abstract
A combined system of DHS (Down-flow Hanging Sponge) reactor and following USB (Up-flow Sludge Blanket) reactor, was applied for biological nitrogen removal from landfill leachate. The DHS and the USB reactors were employed, respectively, as a nitrification process and as a denitrification process. The system performance with respect of nitrogen removal was evaluated by feeding an actual landfill leachate containing 158 mg NH4+-N/L and high salinity (approx. 22200 mg Cl-/L) for an experimental duration of 400 days.
The system exhibited a satisfactory nitrogen removal of 90% at an ammonium-nitrogen loading rate of 0.30 kg N/m3-spomge/d and HRT of 15 h (12 h for DHS reactor and 3 h for USB reactor, respect ively). The DHS seems reasonably promising as an energy-saving and high-rate nitrification process, since it requires neither external aeration input nor tedious operation -and -maintenance.
