著者

松永 信博 増田 壮佑 中牟田 大嗣 徳永 貴久 矢野 真一郎 押川 英夫 橋本 彰博 藤田 和夫 古賀 雅之 岩下 智明 原田 敦彦

出版者

Japan Society of Civil Engineers

雑誌

水工学論文集 (ISSN:09167374)

巻号頁・発行日

vol.51, pp.1415-1420, 2007 (Released:2010-08-25)

参考文献数

11

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Laboratory experiments were carried out on water quality purification by a porous concrete block including Bacillus subtilis natto group. The block is called EcoBio-Block (EBB). The time variations of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were obtained experimentally under the aerated condition by changing the weight ratio of EBB to water. The time variations of BOD and COD were expressed universally by normalizing the data. The reduction rate of BOD increases with the weight ratio. On the other hand, that of COD takes the maximum value at the weight ratio of 0.01 and decreases after that. The rapid reduction of BOD and COD seen in the early stage may be due to the adhesion or adsorption of organic matter by EBB. The mineralization of organic matter and the nitrification of NH4-N by EBB become active at the later stage and the activity increases with the weight ratio. It was experimentally revealed that EBB has also the very high ability for the water quality purification in the DO-saturated water and it depends strongly on the weight ratio of EBB to water.

著者

松永 信博 増田 壮佑 中牟田 大嗣 徳永 貴久 矢野 真一郎 押川 英夫 橋本 彰博 藤田 和夫 古賀 雅之 岩下 智明 原田 敦彦

出版者

Japan Society of Civil Engineers

雑誌

水工学論文集 (ISSN:09167374)

巻号頁・発行日

vol.52, pp.1291-1296, 2008 (Released:2010-08-25)

参考文献数

8

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Laboratory experiments were carried out on water quality purification with EcoBio-Block (EBB). EBB is a porous concrete block including Bacillus subtilis natto group. In this study, we examined experimentally denitrification effect of EBB by letting it live together with denitrification bacteria in soil. The time variations of TN, ON, DIN, NH4-N, NO2-N, and NO3-N were obtained under the aerated condition by changing the weight ratio of EBB to water. On the basis of those data, the denitrification rate, the mineralization rate, and the decreasing rate of DIN were obtained. As a result, we confirmed that the processes of organic matter decomposition, nitrification, and denitification were performed effectively by the symbiosis of useful microbial group and denitrifying bacteria.

著者

矢野 真一郎 北川 洋平 谷口 弘明 西村 圭右 堂薗 俊多

出版者

公益社団法人 土木学会

雑誌

土木学会論文集B1(水工学) (ISSN:2185467X)

巻号頁・発行日

vol.71, no.4, pp.I_721-I_726, 2015 (Released:2016-01-29)

参考文献数

10

被引用文献数

2

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The Northern Kyushu Heavy Rain in July, 2012 caused very serious damages. The event also caused many drift woods disasters in river basins and coastal areas. This research focuses on transport of drift woods in the Ariake Sea due to the rain event. Numerical simulation of their transport by 3D hydrodynamic model (DELFT3D) combined with assumed drift woods tracking model and comparison between the calculation result and collection data by Ministry of Land, Infrastructure Transport and Tourism were conducted. From the result, the followings were clarified: 1) total drift woods volume of discharged from all rivers into the sea was estimated as 17,500m3; 2) volume of discharged drift woods from each A-class river was estimated; 3) relationship between the volume and specific maximum river discharge was evaluated.

著者

矢野 真一郎

出版者

九州大学

雑誌

基盤研究(C)

巻号頁・発行日

2006

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筑後川から有明海に流入した淡水の挙動を把握するために,GPS付き漂流ブイを利用したLagrange的観測を実施した.潮汐条件が中潮と大潮,筑後川の河川流量が平水時の55m^3/sから中規模出水時の1,678m^3/sまでの種々の組み合わせ条件下であった,2006年6/7と7/21,2007年7/17と7/28に現地観測を実施した.観測項目は,淡水塊の座標,流速,海洋構造(塩分・水温),水質(濁度・クロロフィルa・Ph),風向・風速である.観測は一潮汐(約13時間)もしくは半潮汐間(約8時間)に連続的に行った.観測結果より得られた主な知見は,以下の通りである.(1)風が弱い時,筑後川から有明海に流入した河川水の南北方向の運動に対しては圧力傾度力が,東西方向にはコリオリカが支配的である.(2)風が弱い時,筑後川から流入した河川水は一潮汐で西へ輸送され,移動距離は河川流量に依存する.特に,出水時は対岸の太良地先まで輸送され,一潮汐で諌早湾まで到達できる.(3)南風が強い場合,表層流が風の影響を強く受け,河川水が東岸に停滞する.次に,水平方向と鉛直方向の乱流拡散係数を推定するために,漂流ブイを複数浮かべる観測と乱流微細構造プロファイラーによる現地調査をそれぞれ4回と2回ずつ実施した.これらの観測結果より,水平乱流拡散係数は河川水の流入などの局所的な条件で異なり,1〜10^2m^2/sのオーダーをとることが分かった.さらに,鉛直乱流拡散係数は成層度,潮汐,潮時により大きく変動し,10^<-7>〜10^<-3>m^2/sのオーダーで変化していた.これらの成果は,有明海における流れの数値シミュレーションで未知のファクターである乱流粘性係数・拡散係数の評価と河川から流入する物質の湾内での輸送構造について,重要な知見を与えたものと考えられ,今後の計算精度の向上に寄与できる.