摘要 |
An improvement is provided in the operation of a long vertical shaft bioreactor in the treatment of waste which comprises circulating waste liquor and oxygenating gas through the bioreactor in which the uppermost portion of the shaft (the surface basin) is under supra-atmospheric pressure. The use of a pressurized surface basin subjects the waste to improved oxidizing conditions in a critical zone of the bioreactor and results in more effective biodegradation of the waste. By precise control of surface basin pressure, adequate levels of oxygen in the waste are maintained for biodegradation purposes while unwanted gas, such as carbon dioxide and nitrogen, are disengaged. The pressure on the surface of the waste in the basin is controlled so as to ensure that the concentration of oxygen in the waste is subsaturated and retained while the unwanted gas concentration is super saturated and becomes disengaged.
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