報告書番号

U97094

タイトル（和文）

排水中の窒素除去に関する研究４．－脱窒のエネルギー源として水素ガスを用いたバイオリアクター－

タイトル（英文）

DEVELOPMENT OF BIOLOGICAL WASTEWATER TREATMENT SYSTEM FOR NITROGEN REMOVAL 4. -BIOREACTOR USING HYDROGEN AS ENERGY SOURCE FOR DENITRIFICATION-

概要 （図表や脚注は「報告書全文」に掲載しております）

チューブ状ゲルの脱窒反応のエネルギー源として，ガス状水素が利用可能であり，エタノールなどの溶液を流す場合と同様に，アンモニア，亜硝酸，硝酸の無機態窒素を窒素ガスとして除去できることが分かった。この事は，排水処理の他，飲料水として使われる地下水などの浄化にも使用でき，適用範囲の拡大につながるものと考えられる。さらに，水素ガスを用いた場合，Ｎ．ｅｕｒｏｐａｅａのコロニーはチューブの外側表面に近い領域に，Ｐ．ｄｅｎｉｔｒｉｆｉｃａｎｓのコロニーはチューブの内側表面に近い領域に分布しているのが観察された。従って，Ｎ．ｅｕｒｏｐａｅａとＰ．ｄｅｎｉｔｒｉｆｉｃａｎｓの分布の重なりがないため，両菌株が効率よく働ける環境が維持され，チューブ状ゲルの硝化速度（ＮＨ４＋－＞ＮＯ２－）がエタノールを用いた場合の硝化速度よりも約２５％高い値を示したと考えられる。

概要 （英文）

ARTIFICIAL WASTEWATER CONTAINING 100 MG-N/L OF AMMONIA WAS TREATED AEROBICALLY BY A TUBULAR POLYMERIC GEL CONTAINING NITROSOMONAS EUROPAEA AND PARACOCCUS DENITRIFICANS. GASEOUS HYDROGEN WAS USED AS THE ELECTRON DONOR FOR DENITRIFICAITON. THE HYDROGEN GAS WAS LED DIRECTLY THROUGH AN INTERNAL HOLE IN THE TUBE. AMMONIA IN THE WASTEWATER WAS REMOVED WITHOUT ACCUMULATING NITRITE,NITRATE,OR NITROUS OXIDE. THE NITRIFICATION AND DENITRIFICATION RATES OF THE TUBE INCREASED WITH ACCLIMATION. AFTER ACCLIMATION,THE BACTERAL DISTRIBUTIONS IN THE TUBULAR GEL WERE EXAMINED BY FLUORESCENT ANTIBODY LABELING. COLONIES OF N.EUROPAEA WERE DISTRIBUTED CLOSE TO THE EXTERNAL SURFACE OF THE TUBE,AND P.DENITRIFICANS COLONIES WERE DESTRIBUTED CLOSE TO THE INTERNAL SURFACE. THE SEPARATION OF THE NITRIFICAITON AND DENITRIFICATION ZONES ENEBLED AN INCREASE IN THE NITRIFICATION RATE FROM 1.6 TO 6.9 G OF N PER DAYFOR 1 M2 OF GEL SURFACE. THE SEPARATION FACILITATED COOPERATION BY THETWO BACTERIA SPECIES. HYDROGEN GAS IS SUITABLE FOR A TUBULAR REACTOR FOR NITROGEN REMOVAL. A TUBULAR REACTOR USING HYDROGEN GAS CAN REMOVE NITROGEN COMPOUNDS FROM BOTH WASTEWATER AND DRINKING WATER SUCH AS GROUNDWATER SAFELY AND EFFECTIVELY,BECAUSE RESIDUAL H2 IN THE TREATED WATER IS NON-TOXIC AND DOES NOT AFFECT THE CHEMICAL COMPOSITION OF THE WATER.FURTHERMORE,THE BACTERIAL DISTRIBUTION IN THE TUBULAR GEL CAN BE CONTROLLED USING THE BYDROGEN GAS. AN OPTIMUM DISTRUBUTION OF THE TWO BACTERIA SPECIES IN THE GEL WOULD INCREASE THE NITROGEN REMOVLA RATE.

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