Analysis of immobilised cell bioreactors for desulfurisation of flue gases and sulfite/sulfate laden wastewater

Sulfur dioxide (SO), the most abundant air pollutant in the United States, is one of the major constituents that cause acid rain. The quantity emitted in the United States in 1992 was estimated to be 22.73 million tons [1]. Nearly two-thirds of the SO₂ emission arises from fossil fuel combustion, mainly from coal-fired power plants. In the atmosphere, SO₂ reacts photochemically or catalytically with other constituents to form sulfuric acid. Conventional flue gas desulfurisation (GFD) processes use either disposable sorbents, such as limestone, or regenerable sorbents, such as copper oxide. A microbial process of reducing SO₂ to hydrogen sulfide and then elemental sulfur has been considered as a promising technology that can replace a part of the conventional GFD processes economically and efficiently.