Abstract
Several bacteria in the ambient surroundings were examined for biological removal of hydrogen sulifide. Dry pig feces was shown to be a good source of the bacteria removing hydrogen sulfide. The bacteria were cultivated in the presence of hydrogen sulfide, and then the capability of removing hydrogen sulfide was examined with apparatuses of aerating process and scrubber process. The aerating process showed a good result that about 13 ppm of hydrogen sulfide was almost completely removed at the flow rate of 940 mLmin-1. At higher flow rate, the removal efficiency decreased. The scrubber process did not work well. The gas-liquid contact time was supposed to be the main reason of the low efficiency. In the aerating process, long time operation resulted in the decrease in the removal efficiency with the decrease in the amount of bacteria. Addition of nutrient recovered the efficiency as well as the amount of living bacteria. Thus, the bacteria removing hydrogen sulfide ware heterotrophic. Complete isolation of the bacteria has not been succeeded. Two types of bacterium were observed even after repeated streak on nutrient broth agar media. One of those was Gram-negative bacillus (0.4μm ×1.3μm) and the other was Gram-negative cocuss (0.4μm).
