Purifying Waste Water with a Freeze-concentrating and Rarefying Technique, Using Outdoor Coldness(Part 1). Purifying Milking Waste Water.

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Other Title
  • 寒冷外気利用による凍結濃縮・希薄化に関する研究（第１報）　搾乳廃水の希薄化
  • Purifying Milking Waste Water
  • 搾乳廃水の希薄化

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Description

This study was carried out to determine the feasibility of purifying milking waste water by using a freeze-concentrating technique that makes use of cold outdoor air. After partially freezing the waste water, the upper layer of ice contains less waste, as the waste is naturally concentrated in the lower unfrozen layer of waste water.<br>In this study, waste water contained in a vessel (70mm in diameter and 210mm deep) was frozen from the top downwards by blowing cold ambient air horizontally across the water surface in a freezing room.<br>The results are summarized as follows:<br>1) As the cold ambient air temperature decreased and the air velocity increased, the freezing rate of the ice layer increased.<br>2) As the freezing rate increased, the COD concentration in the frozen layer increased and the purifying rate (i. e., COD concentration in the waste water/COD concentration of frozen layer) decreased. This is due to the fact that when the freezing rate is too high, the waste is trapped during the ice crystallization process.<br>3) As the ice layer grew in thickness, the COD concentration of the newest ice also increased. As a result the COD concentration within the ice layer varied with the location within the ice layer, such that the concentration was lowest at the ice surface and increased with ice depth.<br>4) Based on the results of this experiment, we were able to develop a predictive equation that relates the COD concentration in the ice layer to the known ambient cold air temperature, the air velocity and the freezing rate.

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Details 詳細情報について

  • CRID
    1390282679327670144
  • NII Article ID
    130004280052
  • DOI
    10.11449/sasj1971.27.225
  • ISSN
    21860122
    03888517
  • Text Lang
    ja
  • Data Source
    • JaLC
    • CiNii Articles
  • Abstract License Flag
    Disallowed

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