著者

藤田 豊 中村 玄正

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.30, no.4, pp.197-203, 2007 (Released:2010-01-09)

参考文献数

26

被引用文献数

2 3

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Historically the water quality of Lake Inawashiro has been kept very good in terms of COD and other variables. The reason for this is due to the very low concentration of phosphorus in the lake for example, 0.003mg · l-1. Additionary, the primary production of phytoplankton is controlled at very low level. The authors studied the mechanism by which floc removes phosphorus that is produced in the acidic Nagase River. The major results obtained from this study are as follows : (1) The floc produced in the Nagase River coagulate and then settle as phosphorus sediment. (2) The floc has a particle size distribution that is effective for coagulation and then for phosphorus sedimentation. (3) The main components of the floc are Fe, Ca and Al. (4) When floc was added to the river water, the concentration of phosphorus decreased and the AGPM also decreased.

著者

黒澤 幸二 中村 玄正 高橋 幸彦 松本 順一郎

出版者

Japan Society of Civil Engineers

雑誌

環境工学研究論文集 (ISSN:13415115)

巻号頁・発行日

vol.34, pp.111-120, 1997-11-28 (Released:2010-06-15)

参考文献数

9

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From the view point of water supply stability, lakes and reservoirs are expected to be important water resources. Lake Inawashiro is the most important water resource not only for the Aizu districts but also for Koriyama city and the surrounding area. Lake Inawashiro has 104km2 of surface area, 3, 859, 000, 000m3 of volume and is classified as an oligotrophicated but acid-eutrophicated lake. The water quality of Lake Inawashiro has been at very high level. We considerthat the water quality of lake Inawashiro should be effectedby the Nagase river.Water quality was investigated at fifteen points of the Sukawa river and Nagase river. The pHvalue of the water is about 2-5 because of sulfuric acid flow out from out abandoned mind. As ferric, aluminium and phosphorus concentration decrease with flow down travel, it had been concludedthat the river had been undergoing self purification concerning to phosphorus. Sulfuric acidwater, which flows into Lake Inawashiro from the Nagase River has possibility of dissolving ferricand aluminium which have the ability of the flocculating and sedimenting of phosphorus.Thus, in the Nagase river, phosphorus concentration which causes eutrophication is very low, comparing to the other rivers which flow into Lake Inawashiro.