| 摘要 |
<p>PROBLEM TO BE SOLVED: To sufficiently feed oxygen necessary for biological desulfurization to effectively subject digestion gas to biological desulfurization by aerating waste water of a biological desulfurization column in an aeration tank before subjecting it to membrane filtration by a membrane filter and spraying concentrated water to a packed bed of the biological desulfurization column. SOLUTION: A packed bed 2 in which microorganisms to oxidize and decompose hydrogen sulfide are deposited is installed in a biological desulfurization column 1, and above it, a water spray nozzle 3 is fitted. Gas to be treated such as digestion gas is introduced into the lower part of the biological desulfurization column 1 to oxidize and decompose most part thereof into sulfuric acid. When the sulfuric acid and the undecomposed hydrogen sulfide are introduced as biological desulfurization waste water into an aeration tank 6 to subject them to aeration treatment, the undecomposed hydrogen sulfide is oxidized and decomposed. After that, when the aeration treated liquid sufficiently containing dissolved oxygen is introduced into a membrane filter 9 to subject it to membrane filtration, microorganisms are concentrated and sulfuric acid and other dissolved components are concentrated. The concentrated water containing a large amount of dissolved oxygen is circulated in the desulfurizer 1 and is sprayed by the water spray nozzle 3.</p> |
