Eco-Engineering
Online ISSN : 1880-4500
Print ISSN : 1347-0485
ISSN-L : 1347-0485
Volume 14, Issue 2
Displaying 1-4 of 4 articles from this issue
Original Papers
  • Katsunori Omori, Toshio Takeuchi, Mitsuo Oguchi
    2002 Volume 14 Issue 2 Pages 2_3-2_8
    Published: 2002
    Released on J-STAGE: June 08, 2006
    JOURNAL FREE ACCESS
    The recirculating zooplankton-culture system is indispensable to the culture of the fish in space. So, as the first step, the trial model of this system was designed and manufactured. This model consists of three parts: the zooplankton-rearing tank, the filtration unit and the water-purification tank. In the culturing experiment of Moina macrocopa (Cladcera) using this model, it succeeded in high density culture of M. macrocopa. However, 120 hours after the experiment start, operation became impossible because of the fall of the filtration capability of the filtration unit. From the results of the experiment, it was showed that long-term culture is difficult in this model, and in order to make it possible, reconsideration of the filtration unit must be required.
    Download PDF (497K)
  • — Effects of Film-Diffusional Resistance and Penetration of UV Light on Decomposition Rates —
    Shinpon Wang, Fumihide Shiraishi
    2002 Volume 14 Issue 2 Pages 2_9-2_17
    Published: 2002
    Released on J-STAGE: June 08, 2006
    JOURNAL FREE ACCESS
    Photocatalytic decompositions of formic acid were performed by use of two types of photocatalytic reactors (Reactor I and II) and the influences of film-diffusional resistance and UV-light penetration on the reactor activity were studied both experimentally and theoretically. Reactor I is an annular-flow type with a 6-W blacklight blue fluorescent lamp (BL). In Reactor II, four glass tubes of 23 mm in inside diameter, each of which has an insertion of 6-W BL, are arranged in parallel in a glass tube of 92 mm in inside diameter. The inside or outside surfaces of these glass tubes are coated with a thin film of TiO2. All the reaction experiments were carried out in a batch-recirculation mode. The experimental result shows that in Reactor II, the UV light that penetrated through the glass tube and then the flowing reaction mixture acted on the photocatalyst immobilized on the surfaces of the neighboring glass tubes and greatly contributed to an enhancement in the reactor activity. In Reactor I, the film-diffusional resistance was certainly reduced with the increase of flow rate because it was easy to operate the reactor at a very high flow rate (2888 m h-1). The simulated result indicates that if Reactor II is possible to operate at a high flow rate, the reactor activity is increased by about 7.5 times compared with that of the present reactor and also by 2.2 times compared with that of Reactor I.
    Download PDF (1353K)
  • Yasuhiro Yamamoto, Masaki Moriizumi, Mitsuru Inoue, Naoshi Fujimoto, Y ...
    2002 Volume 14 Issue 2 Pages 2_19-2_25
    Published: 2002
    Released on J-STAGE: June 08, 2006
    JOURNAL FREE ACCESS
    This study examined the effects of differences in hydraulic loading and recirculated ratio on the efficiency of removing BOD, T-N and T-P, as well as on sludge produced, in the anaerobic filter bed-biological filtration process combined electrolysis of iron system. The use of an apparatus for removing phosphorus by electrolysis of iron in the anaerobic filter bed-biological filtration process increased its T-P removal efficiency. Stable BOD and T-N removal efficiency was achieved despite different hydraulic loading and recirculated ratio. The optimum recirculated ratio required to remove both nitrogen and phosphorus was 2.8 at a hydraulic loading of 1,000 l·d-1, and 2.8 at a hydraulic loading of 2,000 l·d-1. At the lower hydraulic loading the process had the following domestic wastewater treatment capabilities when the optimum recirculated ratio was set to 2.8: BOD was reduced 10 mg·l-1, T-N 10 mg·l-1, T-P 1 mg·l-1 and SS 10 mg·l-1. The use of electrolysis of iron system in the process resulted in a 25-30% increase in the amount of sludge produced; however, neither its amount nor its properties were affected by differences in hydraulic loading or recirculated ratio, and phosphorus did not dissolve into the surrounding medium again even when the sludge was stored in the anaerobic filter bed tank. In addition, the experiment confirmed that the sludge produced had good sedimentation properties, and so an anaerobic filter bed tank with smaller storage capacity could be used. Thus, this process offers advantages in terms of maintenance and control of the sludge produced.
    Download PDF (607K)
Explanation
feedback
Top