報告書番号

U01010

タイトル（和文）

排水中の窒素除去に関する研究 （その６） --バイオリアクターの大型化に関する検討--

タイトル（英文）

Development of biological wastewater treatment system for nitrogen removal. Part 6. -Large-scale practice of bioreactor using packed gel envelopes-

概要 （図表や脚注は「報告書全文」に掲載しております）

膜状ゲルを用いた窒素除去バイオリアクターを発電所などの排水処理に適用することを目的として、膜状ゲルの作製条件と作製した大型の膜状ゲルの窒素除去能力について検討した。その結果、アンモニア酸化菌と脱窒菌を混合した高分子ゲルの塗布条件や硬化条件の違いによる窒素除去能力の差は認められず、大型の膜状ゲルを工業的に作製できる見通しが得られた。また、350L容量の実験装置を用いて、作製した大型の膜状ゲルの窒素除去能力を測定したところ、ゲル表面積1 m2当たり6.9 g-N/dayのアンモニア酸化速度（NH4+→NO2-）を、4.6 g-N/dayの窒素除去速度（NH4+→N2-）を有し、ビーカーレベルの実験と同等の高い活性を保持していた。さらに、この窒素除去能力は、脱窒菌のエネルギー源として安価なメタノールを利用した場合も、発電所の実排水を模擬した塩分濃度の高い排水に適用した場合も維持された。

概要 （英文）

The reactor using packed gel envelopes was capable of simultaneous nitrification and denitrification for nitrogen removal from wastewater. The packed gel envelope consisted of two plate gels with a spacer in between. The plate gels were made from polymeric gel containing nitrifying bacteria (Nitrosomonas europaea) and denitrifying bacteria (Paracoccus denitrificans). We examined the effect of the making conditions to the initial activity of the packed gel envelopes. When artificial wastewater containing 200 mg-N/L of ammonia was treated with a packed gel envelope made under various conditions, there was little difference among the experiments with various packed gel envelopes. The making conditions did not affect the activity of the packed gel envelopes. The result indicates that we can manufacture the packed gel envelopes under easy conditions. Further, we examined the activity of the large packed gel envelopes for practical application to the wastewater treatment system in coal power plants. When artificial wastewater containing 100 mg-N/L of ammonia was treated with a large reactor (water volume 350 L) using two large packed gel envelopes (1000 mm x 500 mm x 16 mm), the reactor showed 6.9 g-N/day of ammonia oxidation rate（NH4+→NO2-）and 4.6 g-N/day of nitrogen removal rate（NH4+→N2-）per 1 m2 of gel surface. These rates of large packed gel envelopes were similar to those of the tubular gel and small ones described in our previous papers. The packed gel envelopes could use economical methanol instead of ethanol as an electron donor for denitrification. The rates of the packed gel envelopes using ethanol were similar to those using methanol. When modified artificial wastewater containing ammonia and a little salt was treated with the large reactor, the packed gel envelopes showed similar activity. When artificial wastewater containing 100 mg-N/L of nitrate was also treated with the large reactor using two large packed gel envelopes, the reactor showed 6.5 g-N/day of nitrogen removal rate（NO3+→N2-）per 1 m2 of gel surface. The rate of the packed gel envelopes using ethanol was similar to that using methanol. When modified artificial wastewater containing nitrate and a little salt was treated with the large reactor, the packed gel envelopes showed similar activity. These results suggest that our reactor using the packed gel envelopes can treat both ammonia water and nitrate water originated from coal power plants.

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