| 摘要 |
<p>Organic material in waste water is treated by aerobic digestion by bacteria in a reaction vessel. A proportion of the bacteria in the reaction vessel are deactivated to modify the concentration of active bacteria. This deactivation is accomplished by providing a region of high mechanical shear stress in the liquid so that flocs of bacteria are broken up. Resulting loose bacterial cells and small doc particles encourage an increase in the population of higher life forms, protozoa and rotifers, which predate on these lone cells and small particles. By controlling the level of predation by higher life forms, the effective death rate of bacteria is increased so that the overall biomass in the reaction zone can be maintained constant even though sufficient organic material is supplied in the waste water for the bacterial population to respire as in a growth phase. The resulting high respiration rate minimises the overall production of sludge without excessive residence times in the reaction zone.</p> |
