Journal of Environmental Conservation Engineering
Online ISSN : 1882-8590
Print ISSN : 0388-9459
ISSN-L : 0388-9459
Volume 20, Issue 7
Displaying 1-13 of 13 articles from this issue
  • Takakazu NAKAMURA
    1991 Volume 20 Issue 7 Pages 417
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
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  • Juntaro TSURU
    1991 Volume 20 Issue 7 Pages 418-421
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
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  • Yoshiko HIROTA
    1991 Volume 20 Issue 7 Pages 422-426
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
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  • Joji ABE
    1991 Volume 20 Issue 7 Pages 427-431
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
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  • Tsutomu TAMAKI
    1991 Volume 20 Issue 7 Pages 432-436
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
    Refractory organic componds are remained even in the effluent of a conventional biological wastewater treatment process which intends to remove mainly BOD5, and attracts attention in respect to pollution of lakes and bays.
    Though a physicochemical treatment process may be applied to remove the refractory organics, it costs a lot for operation and maintenance. It was reported that PVC removal was accomplished by activated sludge process operated at a long SRT (30-50days) . It was also reported that refractory organics and halogenated organic compounds were effectively removed under denitrification conditions.
    A long-term experimental study was conducted using a pilot-scale single sludge predenitrification plant, in order to demonstrate the removal performance for refractory organics from municipal wastewater consisting chiefly tannery waste. The data suggest that the refractory organics measured as carbonaceous dissolved CODMn was effectively removed by single sludge predenitrification process with pure oxygen. The removal efficiency by the process was 12-16% higher than that by conventional oxygen aeration activated sludge process. The removal efficiency of BOD5, D-CODMn, SS and T-N by the process were 99%, 82%, 98% and 80-85% respectively.
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  • Konosuke NISHIDA, Kiyonari HINA, Masahiro OSAKO, Yoshichika NISHIDA, Y ...
    1991 Volume 20 Issue 7 Pages 437-444
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
    Recently, the utilization of reclaimed land by municipal wastes to the residential quarter is becoming the object of attention in many local governments, as the wastes under the ground would be completely decomposed within 10 or 20 years. However, many troubles have occurred by the generation of dangerous and offensive gases discharging from the waste layer when the ground was dug up.
    In this study, an investigation on the removal method of gases being in the waste layer under the ground was carried out and a suction model of gas from the central boring pipe was proposed. As a result, it was decleared that the distribution of gas flow rate in the waste layer and covered surface soil were obtained based on the ratio of gas permeability coefficient between waste layer and surface soil.
    And this model is applied to estimate the change of gas concentration in the waste layer, and it was confirmed that higher efficiency of gas suction will be obtained with the increasing of thickness or reducing the gas permeability coefficient of covered surface soil.
    And also, the suction rate of gases is proportional to the capacity of vacuum pump, and a higher efficiency of gas suction is obtained to increase the distance of ditch from central pipe, but this method increase the required time for the suction because the total volume of gases to be suck up become to four hold, when the radius makes double.
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  • Kiyoshi MOMONOI
    1991 Volume 20 Issue 7 Pages 445-450
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
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  • Masakazu ICHIKAWA
    1991 Volume 20 Issue 7 Pages 451-454
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
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  • Hiroshi TSUJIMOTO, Osamu ARIGA, Yoshiki SANO
    1991 Volume 20 Issue 7 Pages 455-459
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
    Alkaline decomposition of excess waste sludge was attempted. Effect of sludge concentration, alkaline concentration, sludge volume index (SVI) and temperature on digestibility of the sludge were investigated.
    Digestibility was increased with increasing alkaline concentration and temperature and decreased with sludge concentration and SVI. Digestibility was related with treatment time by the following equation; X=AtB
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  • Isao AOYAMA
    1991 Volume 20 Issue 7 Pages 460-463
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
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  • Tsutomu MIZUSIMA
    1991 Volume 20 Issue 7 Pages 464-473
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
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  • [in Japanese]
    1991 Volume 20 Issue 7 Pages 474-476
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
    JOURNAL FREE ACCESS
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  • Ronald BRIGGS
    1991 Volume 20 Issue 7 Pages 477-480
    Published: July 30, 1991
    Released on J-STAGE: March 18, 2010
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