Hydrogen sulfide production from elemental sulfur by <i>Desulfovibrio desulfuricans</i> in an anaerobic bioreactor

Abstract

Feasibility of elemental sulfur reduction by Desulfovibrio desulfuricans in anaerobic conditions in a stirred reactor was studied. Hydrogen was used as energy source, whereas the carbonated species were bicarbonate and yeast extract. Attention was paid to reactor engineering aspects, biofilm formation on the sulfur surface, hydrogen sulfide formation rate and kinetics limitations of the sulfur reduction. D. desulfuricans formed stable biofilms on the sulfur surface. It was found that active sulfur surface availability limits the reaction rate. The reaction rate was first order with respect to sulfur and hydrogen velocity had no effect in the reaction rate for the range 8.2 x 10(-2) to 4.1 x 10(-1) Nm(3) m(-2) min(-1). At a superficial gas velocity (u(G)) = 3.1 x 10(-2) Nm(3) m(-2) min(-1), H(2)S(g) production rate decreased due to a deficient H(2)S stripping. A maximum H(2)S(g) production rate of 2.1 g H(2)S L(-1) d(-1) was achieved during 5 days with an initial sulfur density of 4.7% (w/v).