1 Microbial removal of SO2 and NOx from flue gas; (2) Microbial by-product recovery from regenerable processes for the simultaneous removal of SO2 and NOx from flue gas. Final report
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The objective of this project has been to investigate the reduction of SO(sub 2) to H(sub 2)S by Desulfovibrio desulfuricans in coculture with mixed fermentative heterotrophs and the reduction of NO to elemental nitrogen by Thiobacillus denitrificans. The ultimate goal has been the development of a viable process concept whereby a microbial process could impact on the problem of flue gas desulfurization and NO(sub x) removal. It was observed that molasses will support the reduction of SO(sub 2) to H(sub 2)S by working cultures of D. desulfuricans. However, the sulfur contained in the molasses resulted in H(sub 2)S production in excess of that expected based on the SO(sub 2) feed. We demonstrated the reduction of nitric oxide (NO) to elemental nitrogen (N(sub 2)) by Thiobacillus denitrificans. We also investigated the simultaneous removal of SO(sub 2) and NO from a gas by contact of the gas with either D. desulfuricans and T. denitrificans reactors-in-series or in co-culture. An economic evaluation of the microbial reduction of SO(sub 2) was performed comparing the microbial process to a conventional catalytic SO(sub 2) hydrogenation (with H(sub 2) generation from methane). Microbial SO(sub 2) reduction and conventional SO(sub 2) hydrogenation were estimated to have similar costs in terms of capital investment. However, annual operating costs for the microbial process were much higher than the conventional process, due primarily to the cost of raw materials. 52 refs., 38 figs., 20 tabs.
1 Microbial removal of SO2 and NOx from flue gas; (2) Microbial by-product recovery from regenerable processes for the simultaneous removal of SO2 and NOx from flue gas. Final report