生物亜硝酸化と水熱反応の組合せによる高濃度排アンモニア除去  [in Japanese] <b>High-concentration Nitrogen Removal in Industrial Wastewater </b><b>Combining Biological Nitrite Reactions and </b><b>Subcritical Hydrothermal Reactions </b>  [in Japanese]

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Abstract

本報では工業排水中の高濃度アンモニア態窒素(NH<sub>4</sub>-N)と,NH<sub>4</sub>-Nの生物亜硝酸化反応より得た高濃度亜硝酸態窒素(NO<sub>2</sub>-N)を用いた亜臨界水熱反応を検討するため,反応温度を140,160,180,200℃の4種,NH<sub>4</sub>-N とNO<sub>2</sub>-N 濃度を等モルに調整した各1,500,3,000,5,000 ㎎/L の3グループの模擬排水を,無触媒による振とう攪拌下で,耐圧容器内にて1hの反応に供した.<br>反応温度が180と200℃の場合,全濃度領域で総合除去率は90%以上に達した.そして,反応温度が140℃と低い場合でも,NH<sub>4</sub>-N とNO<sub>2</sub>-N の初期濃度が5,000 ㎎/L 以上では,総合除去率が90%以上に到達した. 一方,生物処理水を用いた場合は,90%以上の総合除去率を達成するのにNO<sub>2</sub>-N 初期濃度がNH<sub>4</sub>-N のそれの1.6~2.2倍モル必要であった.<br>生物反応に化学・物理反応を組み合わせた本研究の成果は,汚泥排出量などの生物処理でのデメリットを軽減した,効率の良い,消滅型の工業排水中の高濃度窒素除去システムの構築につながるものと期待される.

The removal of high-concentration nitrogen using subcritical hydrothermal reactions of equivalent mixtures of NO<sub>2</sub><sup>-</sup> converted from the original NH<sub>4</sub><sup>+</sup> and NH<sub>4</sub><sup>+</sup> without a catalyst was studied. This reaction was carried out in a pressure bottle shaken for 1h with three kinds of initial substrate concentrations: 1,500, 3,000, and 5,000 ㎎/L of either NH<sub>4</sub>-N or NO<sub>2</sub>-N while setting the temperature at 140, 160, 180, or 200℃.<br>In the cases where the reaction temperatures were 180 and 200℃, over 90% of the total nitrogen successfully decomposed at the initial concentrations in the artificial water. Even if the reaction temperature was lowered to 140℃, over 90% was removed when the concentration of NH<sub>4</sub>-N and NO<sub>2</sub>-N were over 5,000 ㎎/L.<br>On the other hand, it was necessary to achieve above a 90% total nitrogen decomposition value when the initial concentration of NO<sub>2</sub>-N was 1.6 to 2.2 times higher than that of NH<sub>4</sub>-N when biologically treated water were used.<br>The combined treatment of a subcritical hydrothermal reaction followed by a biological nitrite reaction, can effectively remove high concentrations of nitrogen in industrial wastewater.

Journal

  • Journal of Environmental Conservation Engineering

    Journal of Environmental Conservation Engineering 44(10), 568-573, 2015

    Society of Environmental Conservation Engineering

Codes

  • NII Article ID (NAID)
    130005132225
  • NII NACSIS-CAT ID (NCID)
    AN00046213
  • Text Lang
    JPN
  • ISSN
    0388-9459
  • NDL Article ID
    026818000
  • NDL Call No.
    Z16-834
  • Data Source
    NDL  J-STAGE 
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