Abstract
Anaerobic digestion of acidified citrus peel press liquors by completely mixed and upflow anaerobic sludge blanket (UASB) processes are compared. Completely mixed digestion was overloaded at a hydraulic retention time of 10.7 days (organic load 7.41 g COD[chemical O2 demand]/l .cntdot. day); UASB digestion at a retention time of 7 days (11.15 g COD/l .cntdot. day) was stable and achieved 95% removal of COD.