BIOTREATMENT OF A SULFATE-CONTAINING WASTE STREAM IN ANANAEROBIC UP-FLOW PACKED-BED BIOREACTOR

摘要

The kinetics of anaerobic sulfate reduction was studied in a continuous up-flow packed-bedbioreactor, containing active biofilms. Using a variable speed pump, feed with preset concentrations ofsulfate (1 g/L) and Na-lactate as electron donor was introduced to the bottom of the bioreactor. Initially alow flow rate of the feed was used. This was increased stepwise during the course of the experiment. Ateach flow rate (corresponding to a particular residence time) kinetics of sulfate reduction was assessedunder steady state conditions. Operating the bioreactor at residence times higher than 20 hours, completesulfate reduction was observed throughout the bioreactor. With shorter residence times (as low as 1.8 h)the conversion of sulfate in the bottom, middle and upper parts of the bioreactor were 72, 97 and 100%,respectively. The highest reaction rate achieved in the immobilized cell bioreactor, 0.57 g/L-h (conversion100%), was significantly higher than that observed in the stirred tank bioreactor with freely suspendedcells (0.007 g/L-h, with 61% conversion). Currently the effects of sulfate concentration and its volumetricloading on the kinetics of anaerobic sulfate reduction in the biofilm system are being investigated.