Present COD removals were much higher than those previously reported for real BW in UASB-septic tanks at 10–18 1C (Bogte et al., 1993; Luostarinen et al., manuscript; Table 6) and also considerably higher than those expected from UASB-septic tanks treating real BW at 5–20 1C (52–54% CODt removal and 71–86% CODss removal; Zeeman and Lettinga, 1999). Moreover, the removals were comparable with those reported at 420 1C for a UASB-septic tank treating real BW (Lettinga et al., 1993) and at 13 1C for a two-phased