Japanese Journal of Water Treatment Biology
Online ISSN : 1881-0438
Print ISSN : 0910-6758
ISSN-L : 0910-6758
Volume 32, Issue 4
Displaying 1-5 of 5 articles from this issue
  • KAZUHIRO TAKAMIZAWA, AKIRA TAKAGI, MASAHIRO HATSU
    1996Volume 32Issue 4 Pages 211-219
    Published: December 15, 1996
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    A new method for producing fine particles of cadmium sulfide using a bioreactor with sulfate-reducing bacteria was proposed. The reactor composed of three layers, i.e. sulfate-reducing bacteria layer to produce hydrogen sulfide, cadmium solution layer, and membrane filter layer on which cadmium sulfide was produced as the result of reaction between hydrogen sulfide and cadmium ion. Hydrogen sulfide gas began to produce at the first day of experiment and 6, 000-10, 000μl/l in average was produced. The characteristics of particle generated was depended on property and pore size of membrane filter used. Among filters, 0.2μm pore size of polycarbonate was best choise, resulting 0.5μm of fine particle of cadmium sulfide in uniform quality. In case of using pure hydrogen sulfide (5, 000μl/l and 10, 000, μl/l), not from sulfate-reducing bacteria, 0.2μm of fine particle of cadmium sulfide in uniform quality was accumulated.
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  • LIEPING ZHU, YUKI KOZAKI, YOSHIHIRO AGARI, TOSIO SATO, ISAO YOSIDA, TA ...
    1996Volume 32Issue 4 Pages 221-234
    Published: December 15, 1996
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    A laboratory scale study was undertaken to investigate the potential of decomposition of algae sludge by a thermophilic oxic process (TOP) . The characteristics of the thermophilic oxic process are that, a minute amount of excess sludge is formed, and organic materials are efficiently degraded, as well as all water is evaporated by the heat generated by bio-degradation.Feasibility of this study was assessed by determining the decomposition efficiency of added organic material, transference of organic carbon to CO2 and decrease efficiency of chlorophyll-a in media. By using cedar chips as media and waste food oil as an additional energy source, algae sludge could be decomposed by the thermophilic oxic process with the following conditions: total solid (TS) load of 1.5 kg⋅m-3⋅d-1, hydraulic volumetric load of 35l·m-3·d-1, waste food oil addition rate of 15% as added algae sludge and aeration rate of 200l⋅m-3⋅min-1.From above manipulation, more than 98% of chlorophyll-a in added algae sludge was decreased, more than 80% of total organic carbon was transferred into CO2, and due to it, low excess sludge production rate of 0.15 kg/kg-BOD treated has been certified in this process.
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  • SEIJI FURUKAWA, JUNJI HIROTSUJI, AKIRA IKEDA, SATORU SHIONO
    1996Volume 32Issue 4 Pages 235-245
    Published: December 15, 1996
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    A new operational support system for high nitrogen removal in the batch type activated sludge process using intermittent aeration has been developed. The system consists of: (i) the index to change the intermittent aeration pattern and (ii) the menu in which several patterns are lined up in the order of total aeration time. If the index becomes out of predetermined range, the system suggests to the operator exchanging the pattern being used for a next upper or lower one. The analysis of the nitrification and denitrification in the batch type activated sludge process using mathematical models lead to the validity to use the ratio of aerobic to anaerobic duration time as the index, and its optimum value was found to be around 1.The index is obtained from the output of a DO meter without complex calculation. The systemshows high nitrogen removal because the balance of nitrification and denitrification is optimizedby keeping the ratio of aerobic to anaerobic duration time around 1, and it has a very practicable advantage because of its simplicity. A laboratory experiment applying the system resulted in good nitrogen removal, indicating the reliability of the system.
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  • MYUNGSOOK JUNG, KAI-QIN XU, YUHEI INAMORI, RYUICHI SUDO
    1996Volume 32Issue 4 Pages 247-255
    Published: December 15, 1996
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    In order to evaluate treatment performance and biological effects of landfill leachate, we conducted bioassay procedure for the raw landfill leachate collected from an actual landfill disposal site and the effluent treated by the biological activated carbon fluidized bed (BACFB) process and ozone treatment using D. magna for acute and chronic exposure. The sublethal effects of landfill leachate and its effluent on the survival, reproduction and growth of D. magna were monitored for 24 hours and 21 days, respectively. The algae Chlorella sp.2×106cells⋅ml-1 was used to feed the daphnids. The results showed that the EC50, NOEC (No Observed Effect Concentration) and LOEC (Lowest observed Effect concentration) for raw landfill leachate were 6.0%, 2.5% and 10%, respectively, showing severe toxic. Reproduction as well as survival was significantly reduced if the raw leachate concentration is more than 10%. On the other hand, the effluent treated by BACFB and ozone showed little toxicity.
    These results suggest that the hybrid treatment system with BACFB and ozone treatment process is efficient to remove toxic substances from landfill leachate.
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  • MASANORI FUJITA, KEISUKE IWAHORI, YUKIO KAWAGUCHI, YOSHIO SAKAI
    1996Volume 32Issue 4 Pages 257-269
    Published: December 15, 1996
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    A questionaire survey was carried out in two trials to examine the overall situation on both the general operating problems of 785 sewage treatment plants in Japan and the corresponding solid-liquid failure caused by filamentous microorganisms. The results showed that operating problems had obviously occurred at about 80% of sewage treatment plants in Japan. About onethird of all operating problems experienced over the past five years was “filamentous bulking” followed by “abnormal foaming and scum”. The change of temperature, the sidestreams from the sludge treatment facilities, a large quantity of SS in pipes and the fluctuation of influent loading were regarded as the causes of “filamentous bulking”. The causes of “abnormal foaming and scum” were not as easily identified as those of “filamentous bulking”, but they were related to sludge level and nitrification in the aeration tank. From the point of the present situation of plants and their maintenance methods, the need for integrated management of both sewage and sludge treatment facilities was discussed in order to prevent the solid-liquid failure.
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