Removal of Hydrogen Sulfide from Swine-Waste Biogas on a Pilot Scale Using Immobilized IParacoccus versutus/I CM1

Hydrogen sulfide (H[sub.2] S) is a toxic and corrosive component that commonly occurs in biogas. In this study, H[sub.2] S removal from swine-waste biogas using sulfur-oxidizing Paracoccus versutus CM1 immobilized in porous glass (PG) and polyurethane foam (PUF) biofilters was investigated. Bacterial compositions in the biofilters were also determined using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The biofilters were first tested on a laboratory scale under three space velocities (SV): 20, 30, and 40 h[sup.−1] . Within 24 h, at an SV of 20 h[sup.−1] , PG and PUF biofilters immobilized with P. versutus CM1 removed 99.5% and 99.7% of H[sub.2] S, respectively, corresponding to the elimination capacities (EC) of 83.5 and 86.2 gm[sup.−3] h[sup.−1] . On a pilot scale, with the horizontal PG-P. versutus CM1 biofilter operated at an SV of 30 h[sup.−1] , a removal efficiency of 99.7% and a maximum EC of 113.7 gm[sup.−3] h[sup.−1] were achieved. No reduction in methane content in the outlet biogas was observed under these conditions. The PCR-DGGE analysis revealed that Paracoccus, Acidithiobacillus, and Thiomonas were the predominant bacterial genera in the biofilters, which might play important roles in H[sub.2] S removal. This PG–P. versutus CM1 biofiltration system is highly efficient for H2S removal from swine-waste biogas.