Japanese Journal of Water Treatment Biology
Online ISSN : 1881-0438
Print ISSN : 0910-6758
ISSN-L : 0910-6758
Volume 33, Issue 2
Displaying 1-5 of 5 articles from this issue
  • [in Japanese], [in Japanese], [in Japanese]
    1997 Volume 33 Issue 2 Pages 47-54
    Published: June 15, 1997
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1997 Volume 33 Issue 2 Pages 55-63
    Published: June 15, 1997
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
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  • In the River Nabetani, Ishikawa Prefecture
    MICHIAKI SUMITA, TOSHIHARU WATANABE
    1997 Volume 33 Issue 2 Pages 65-80
    Published: June 15, 1997
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    In the upperstream basin of the River Nabetani, Ishikawa Prefecture, there are deposit areas of pottery stone containing pyrites as one of the inpurites. This mineral used to make the river water in the upperstream strongly acidic (pH 3.6) . And the effect of this waste water from the mine extended to considerbly wide dowmstream areas.
    The water of the R.Edadani, one of the tributaries of the R, Nabetani was also weekly acidic, although there is no working mine in its vicinity.
    Hattori Ltd. in order to neutralize the effect of the mine waste water installed mine waste water treatment facilities which started to operate in December 1993.
    This six-year survey of R. Nabetani and its tributaries was made to evaluate the effect of the tratment facilities; before the operation of the facilities from 1990 to 1993 (Survey I) and after its operation from 1994 to 1995 (Survey II) .
    In each sampling site, the attached diatom assemblage on river bed was collected and some physicochemical variables of the river water measured. The result are summarized as follows:
    1. pH values of Sites 1-5 in Survey II showed slightly increasing tendency when compared with those of Survey I.
    2. In Survey I the SO42- values of river water decreased in order from upperstream to downstream.
    3. After the operarion of the treatment facilities, T-Fe and EC valu es showed a distinctly clear reduction.
    4. As shown Fig.7, the specific composition of diatom assembiage in each sampling site in the main stream, the R.Nabetani showed a distinct change after the operation of the treatment facilities.
    In areas about 5km between Site 1 and Site 4, diatom assemblages resistant to mine pollution appeared before the operation of treatment facilities on November 1990 (Surbey I) . But after the operation on August 1995 (Survey II) such diatom assemblages were reduced to with in the range of ab. 2km from Site I to Site 2, and replaced by common species usually occurring in comparatively pollution-free water area. Such a change of specific composition of diatom assemblages seems to suggest that range of ab. 3km from Site 3 to Site 4 was made free from the effect of mine pollution and recovered to ordinary pollution-free water course.
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  • NOBUTADA NAKAMOTO, DAISUKE IKEDA, KAYO TAGUCHI, MASUO YAMAMOTO, KENTAR ...
    1997 Volume 33 Issue 2 Pages 81-90
    Published: June 15, 1997
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Seasonal changes of developmental patterns of algal mats of slow sand filters (Someya water works, Ueda city, Wakata water works, Takasaki city and Nabeya-ueno, Nagoya city) were examined. The water sources of Someya water works and Wakata water works were a surface water of a stream and the water source of Nabeya-ueno was a reservoir water. In the cases of slow sand filters which water sources were stream water, an algal mat of filamentous diatom of Melosira grew well due to high nutrient concentration in raw water. It was remarkable in summer when there was high nutrient concentration. However in the case of a slow sand filter which water source was a reservoir water, the developmental rate of algal mat was extremely slow. The dominant species of algal flora on the algal mat on the filter bed were almost same as the flora in the inflow water from the reservoir. Algal mat on the filter bed was just accumulated with phytoplankton which was grown in the reservoir. The low growth rate of algal mat was due to lack of available phosphorus in the inflow water.
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  • MASUO YAMAMOTO, NOBUTADA NAKAMOTO
    1997 Volume 33 Issue 2 Pages 91-96
    Published: June 15, 1997
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    This research was carried out to appreciate a slow sand filtration treatment by an investigation of suspended matter distribution in sand layer at Ashford Common water works, London, UK.and Someya water works, Ueda, Japan.
    The following results were obtained.
    1) Most of the suspended matter was trapped in the upper layer of the sand bed and remainder, which had penetrated through the surface mud, was also retained in several centimetersdepth from the surface.
    2) From the vertical profiles of Chlorophyll/Total Organic Carbon ratio and that of Pheophytin/Total Organic Carbon ratio, there was shown that the matter derived from algae was much easier to enter into the deeper sand layer at Ashford Common water works than at Someyawater works.
    3) The order of the decrease rate of the suspended matter in the sand layer was Chlorophyll>Pheophytin>Total Organic Carbon.It could be considered that the decomposition rate in the sand layer varies with the different substance.
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