著者

田井 明 久保 奈央 橋本 彰博 小松 利光

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.68, no.4, pp.I_1057-I_1062, 2012 (Released:2013-03-26)

参考文献数

13

被引用文献数

3

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In order to analyze regional changes frequency of torrential rain that defined hourly precipitation of 50 mm, 75 mm and 100 mm, we represented the spatial distributions of frequency of torrential rain. Secondly, we analyzed relationship of human damage and precipitation pattern in past flood and sediment-related disasters. Number of candidate disaster which more than five persons are killed or went missing in is 49 since 1976. We used total precipitation, total precipitation and maximum hourly precipitation during a disaster period as indicators of precipitation pattern.The results of the present research are summarized as follows:(1)From the 1980-1989 decade to the 2000-2009 decade, frequency of torrential rain had increased in Shikoku area, Kyushu area, Tohoku area and Hokuriku area. In particular, in Tohoku and Hokuriku area, torrential rain did not occur about 30 years ago, but in resent years, torrential rain occurs (2)Relationship of human damage and precipitation are studied by means of the statistical hypothesis test. The results show that Kyushu area has a higher resistibility for disasters than Setouchi area.

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.