Biological sulfate removal in an acidogenic bioreactor with and ultrafiltration membrane system

The biological sulfate removal in the acidogenic bioreactor with an ultrafi ltration membrane system was investigated at 35 degrees%. Sucrose was used as the sole organic substrate. The sulfate concentration in the substrate r anged from 0 to 600mgS-l(-1). The chemostat reactor was operated to compare with the membrane bioreactor. The fouling phenomenon caused by FeS precipi tate was observed at higher concentration of sulfate. However, it was possi ble to continuously operate the membrane bioreactor by cleaning the membran e. The efficiency of sulfate removal by sulfate reduction reached about 100 % in the membrane bioreactor, and 55 to 87% of sulfide was removed from the permeate by the membrane filtration. The composition of the metabolite was remarkably changed by the change in sulfate concentration When the sulfate concentration increased,ac significantly increased while n-butyrate and 3- pentanol decreased. The sulfate-reducing bacteria play the role as acetogen ic bacteria consuming volatile fatty acids and alcohols as electron donors under sulfate-rich-conditions. The results show that the acidogenensis and sulfate reduction simultaneousl y proceed in the membrane bioreactor. (C) 1998 Published by Elsevier Scienc e Ltd. All rights reserved.