| 摘要 |
<p>1521258 Dispersing gases in liquids IMPERIAL CHEMICAL INDUSTRIES Ltd 19 Sept 1975 [3 Oct 1974 8 Jan 1975 13 March 1975] 42923/74 763/75 and 10456/75 Heading B1C [Also in Division Cl] A gaseous liquid containing biologically degradable material in solution and/or suspension is treated with an oxygen-containing gas, and a culture of microorganisms is maintained therein. For a period of time not greater than 5 minutes the liquid is subjected to a low DOT of less than 30 millibars, and/or for a period of time not greater than 10 minutes the liquid is subjected to a high DOT of at least 450 millibars. In this way the ratio of carbon dioxide to cellular material produced by the culture is increased during the process. There is also a period during which the liquid is subjected to DOT between 30 and 450 millibars. The microorganisms are not detrimentally affected by this treatment. The term DOT means dissolved oxygen tension i.e. partial pressure of oxygen in the liquid. This process is useful as a stage in the biological treatment of sewage as described in U.K. Specification 1473665. In Fig. 6 a downcomer (14) and riser (15) are located in the same shaft A-A, separated by partition (23). The upper ends of partition and downcomer are bent over within basin (13) to give deflectors (25) which produce a circulation as indicated by the arrows. Initially air is injected into the riser via sparger (17) in order to start the air lift, but the bulk of the air may subsequently be fed to the downcomer via sparger (16) while the whole system continues to function as an air lift pump.</p> |
