Bioremediation of hydrogen sulfide from gas stream in continuous culture with cell recycle

摘要

Biodesulfurization of sour gas has been carried out in a continuous stirred tank bioreactor (3.5 L)equipped with absorption tank (1.5 L) and cell recycle unit (1 L). Pure culture of sulfur oxidizedbacteria was isolated from native sulfur hot spring. Continuous biodesulfurization was conducted withcell decanter as cell separator. Cell concentration was increased from 1.35 to 1.96 g.L-1 as cell recycleratio was increased from 0 to 0.6. Maximum hydrogen sulfide transfer rate and volumetric masstransfer coefficient (kLa) was determined to be 0.0463 mol.m-3h-1 and 0.0202 h-1 at 36oC and 250 rpm,respectively. Application of absorption tank improved sulfide removal rate under cell recyclinganaerobic conditions approximately by 18%. The optimal dilution and gas flow rate were achieved at0.0186 h-1 and 2 mL.min-1. The removal of H2S at high concentration in the sour gas (5% v/v H2S, 5%v/v CO2, 10% v/v Ar, 80% v/v CH4 ) was determined to be 98%.