Table 1. Comparison of H2S oxidation rates using pilot-scale desulfurization units.
| 65 L vertical barrel | 65 L horizontal barrel | 104 L barrel no fabric | 104 L barrel with fabric | 10 L desulfur-ization unit [7]1 | 50 L digester [13]2 | |
|---|---|---|---|---|---|---|
| Headspace volume (L) | 59 | 59 | 74 | 74 | 9 | 20 |
| Liquid/wetted surface area (m2) | 0.099 | 0.150 | 0.146 | 0.224 | 0.049 | 0.126 |
| Biogas H2S (ppmv) | 3500 | 3500 | 3500 | 3500 | 3000 | 6000 |
| Biogas H2S (g m-3) | 4.88 | 4.88 | 4.88 | 4.88 | 4.18 | 8.38 |
| Biogas flow rate at maximum H2S oxidation rate2 (LPM) | 1.5 | 1.5 | 2.0 | 2.5 | 0.15 | 0.027 |
| Biogas retention time (min) | 39 | 39 | 37 | 30 | 60 | 740 |
| Maximum H2S oxidation rate3(g S d-1) | 4.3 ± 0.3 | 12.4 ± 1.3 | 15.3 ± 0.5 | 22.4 ± 0.3 | n.d. 4 | n.d. 4 |
| Maximum H2S oxidation rate3(g S d-1 m-2) | 43 ± 3a | 83 ± 7b | 104 ± 5c | 101 ± 2bc | n.d. 4 | n.d. 4 |
| Maximum H2S input rate for effluent content <500 ppmv H2S (g S d-1 m-2) | n.d. | 24 (29%)5 | 27 (26%) | 44 (43%) | 25 | n.d. 4 |
| Maximum H2S input rate for effluent content <100 ppmv H2S (g S d-1 m-2) | n.d. | 6.6 (8%)4 | 9.3 (9%) | 18 (18%) | n.d. | 2.6 |
1Experiments used a 10 L (25 cm diameter) plastic container and achieved effluent biogas H2S values of 100 to 200 ppmv. Maximum H2S oxidation rates were not determined.
2Experiments used a 50 L (40 cm diameter) digester and achieved effluent biogas H2S values of 30 ppmv. Maximum H2S oxidation rates were not determined.
3Values are means ± SE of 6 or 7 daily measurements from duplicate barrels. Treatment means with different letters are statistically significant at the 0.05 significance level.
4n.d.: not determined.
5Values in parentheses indicate theoretical H2S input rate with effluent content <500 ppmv or < 100 ppmv H2S as a percentage of the maximum oxidation rate.