Abstract: A device for purifying flue gas containing nitrogen oxides, in which the flue gas is scrubbed with a circulating scrubbing liquid which contains a transition metal chelate such as Fe(II) EDTA and the complex formed from nitrogen oxide and transition metal chelate and/or spent transition metal chelate is regenerated biologically in the presence of an electron donor, nitrogen oxide being reduced to molecular nitrogen. The biological reactor can be combined with the gas scrubber. The electron donor is, for example, hydrogen or methanol, but may also be sulphite which originates from sulphur dioxide in the flue gas.

Abstract: A new sulfur-reducing bacterium denoted as KT7 is described. It is a low-GC Gram-positive bacterium related to the genus Desulfotomaculum, capable of reducing sulfite and sulfate to sulfide, having an optimum growth at a temperature between 48 and 70° C. at a pH of between 5 and 9 and at a conductivity of the liquid medium between 0 and 40 mS/cm. It can be used in a process for removing sulfur compounds from water, wherein the sulfur-containing water is subjected to anaerobic treatment with the new sulfur-reducing bacteria, with the addition of an electron donor. The sulfur-containing water can be spent scrubbing liquid from a flue gas desulfurization step.

Abstract: A process and a device for purifying flue gas containing nitrogen oxides, in which the flue gas is scrubbed with a circulating scrubbing liquid which contains a transition metal chelate such as Fe (II) EDTA and the complex formed from nitrogen oxide and transition metal chelate and/or spent transition metal chelate is regenerated biologically in the presence of an electron donor, nitrogen oxide being reduced to molecular nitrogen. The biological reactor can be combined with the gas scrubber. The electron donor is, for example, hydrogen or methanol, but may also be sulphite which originates from sulphur dioxide in the flue gas.