Experimental study of flue gas desulfurization using landfill leachate

Because of the complexity of landfill leachate's composition, the reaction mechanism of SO2 in flue gas with landfill leachate was studied. The experimental results indicated that the factors influencing SO2 efficiency absorption efficiency using landfill leachate as the scrubbing medium were, in decreasing order of importance, pH, Fe2+, Mn2+, and Cl- as catalysts and the concentration of toluene and ethanol. Experiments showed that the pH landfill leachate was the key factor governing both SO2 absorption and ammonia stripping. With the initial pH of 8.5, the terminal pH 6.0 and L/G ratio 3 L/m(3), experimental results showed that average absorption efficiency of SO2 and the stripping efficiency of ammonia were 85 and 44%, respectively. The use of catalysts such as Fe2+ and Mn2+ was important for SO2 absorption when the pH value as below 7.0. The catalytic activity of Mn2+ was greater than that of Fe2+ although the reaction steps were very similar. Ethanol inhibits HSO3-/SO32- oxidation. The HSO3-/SO32- oxidation process improves the solubility of organics such as toluene in the leachate. The solute products of organics were water soluble and biodegradable and could be used as substrates for bacteria in the post biotreatment. The factorial experiment results showed the effect of Cl-, Fe2+, and Mn2+ as catalysts on the HSO3-/SO32- oxidation has a greater positive impact than ethanol's inhibitory effect on the HSO3-/SO32- oxidation. (c) 2006 American Institute of Chemical Engineers Environ Prog, 26: 25-32, 2007.