Activated sludge continuous reactor

Figure 8. Response of first order biotransformation rate constants for naphthalene oxidation to naphthalene perturbation frequency in a continuous activated sludge biotreatinent reactor.

ASCSTR - Continuous Stirred Tank Reactor Model of Activated Sludge System... 

Fig. 2 Startup of the continuous activated sludge reactor with recycle ratio R = 0.3.

Usually, the typology of batch reactors also includes the semi-batch gas-liquid reactors, in which a gaseous phase is fed continuously in order to provide one of the reactants. A typical example is given by the reactors used both in different oxidative industrial processes and in the active sludge processes for the treatment of wastewater. It is possible to distinguish between the bubble columns (Fig. 7.1(c)), in which the gas rises undisturbed in the liquid phase, and the bubble stirred reactor, in which a mechanical mixer is added. Finally, the slurry reactors can be considered, in which the liquid phase contains a finely dispersed solid phase as well, which can act as a reactant or as a heterogeneous catalyst these reactors assume in general the features of Fig. 7.1(d). 

In the activated sludge process, single- or multi-stage continuous-flow aerated reactors are used (Fig. 4). Effluent from the bioreactor is separated in a settling tank and a portion of sedimented sludge is usually recycled to the reactor providing a continuous sludge inoculation. 

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