| 摘要 |
PURPOSE:To reduce the dissolution of carbon dioxide into the liq. in a nitration vessel and to reduce the amt. of an alkali to be used for the regulation of the pH of the liq. in the nitration vessel by allowing the stream of a high-concn. oxygen-contg. gas used for oxygenation and the stream of a liq. in the nitration vessel to flow countercurrently. CONSTITUTION:Waste water 2 is charged into a denitrification vessel 1, and then introduced into a multistage nitration vessel 5 wherein BOD components, ammoniacal nitrogen, and org. nitrogen in the waste water are oxidized by oxygenation to nitric nitrogen or nitrous nitrogen. A part of water 6 discharged from the nitration vessel 5 is circulated to the vessel 1 as a circulating liq. 4. The remaining part of the discharged water 6 is introduced into a solid-liq. separator 7, and separated into sludge and treated water. The separated sludge is introduced into the vessel 1, and the nitric nitrogen or nitrous nitrogen in the liq. is denitrified. In the biological treatment of waste water, both streams of the high-concn. oxygen-contg. gas 9 and the liq. in the nitration vessel 5 are allowed to flow countercurrently. Consequently, the dissolution of CO2 into the liq. in the nitration vessel is reduced, and the amt. of an alkali to be used for the regulation of pH is reduced.
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