Two cube-type media and two curtain-type media were provided to explore better sponge media for the DHS (Table 1). Two of the four compartments of the DHS used cube-type media, and the other two used curtain-type media. The cube-type media were stacked into four cubic baskets (side length, 1 m) and vertically suspended in line in the compartments. For the curtain-type media, the compartments were horizontally divided into two stages, and the media were directly suspended in each stage. The influent
(i.e. the UASB effluent) was trickled in parallel to each compartment. The effluent quality, biological preservation and operational execution for each type of medium were compared.