Oxygen transfer and consumption in a thiosulfate oxidizing bioreactor with sulfur production

Abstract

Aims: To evaluate the contribution of oxygen transfer and consumption in a sulfoxidizing system to increase the elemental sulfur yield from thiosulfate oxidation. Methods and Results: A 10 l thiosulfate oxidizing bioreactor with suspended cells operating under microaerophilic conditions and a separated aerator with a variable volume of 0AE8-1AE7 l were operated with a consortium containing mainly Thiobacillus sp. that oxidizes several sulfide species to elemental sulfur and sulfate. From the gas-liquid oxygen balance, the k L a was estimated under different operation conditions. A k L a of around 200 h )1 favoured elemental sulfur production and can serve as scale-up criterion. It was further shown that more than 50% of the oxygen fed to the system was consumed in the aerator. Conclusions: The performance of the sulfoxidizing system can be improved by controlling oxygen transfer. Significance and Impact of the Study: The proposed method for the k L a determination was based on the oxygen balance, which incorporates the oxygen concentrations measured in the liquid in steady state, reducing the interference of the response time in the traditional non-steady state methods. This approach can be used to optimize reactors where microaerophilic conditions are desirable.

Development of a kinetic model for elemental sulfur and sulfate formation from the autotrophic sulfide oxidation using respirometric techniques

“…Thus, the elemental sulfur and sulfate mass balances into the LFS respirometer can be easily expressed by Equations 13 and 14 respectively. reported (Janssen et al 1997;Alcantara et al 2004;Gonzalez-Sanchez et al 2005) but restricted under the assumption of steady-state condition.…”