Performance of an upflow anaerobic reactor combining a sludge blanket and a filter treating sugar waste

A new hybrid reactor, the upflow blanket filter (UBF), which combines an open volume in the bottom two-thirds of the reactor for a sludge blanket and submerged plastic rings (Flexiring, Koch Inc., 235 squared m/cubic m) in the upper one-third of the reactor volume, was studied. This UBF reactor was operated at 27 degrees C at loading rates varying from 5 to 51 g chemical oxygen demand (COD)/l day with soluble sugar wastewater (2500 mg COD/l). Maximum removal rates of 34 g COD/l day and CH/sub 4/ production rates of 7 vol/vol day (standard temperature and pressure (STP)) were obtained. The biomass activity was about 1.2 g COD/g volatile suspended solids per day. Conversion (based on effluent soluble COD) was over 93% with loading rates up to 26 g COD/l day. At higher loading rates conversion decreased rapidly. The packing was very efficient in retaining biomass. 11 references.