In classical fluid dynamics, the flow through a pipe whose cross-section is traversed at almost the same velocity is called plug flow. The medium moves through the pipe like a solid plug. Only at the pipe wall there are strong flow losses.

This model is also used for waste water technology in aeration tanks (see activated sludge process). In this case the tank is operated without agitators and internal recirculation, in contrast to conventional processes such as upstream denitrification. Thus, the wastewater is pushed through the basin in a similar way as in a pipe and only aerated and non-aerated phases are changed. To increase this effect, the tanks are often designed as cascades.

This method is also applicable for the S::Select^® process, because despite the good settling behaviour of the aerobically granulated sludge, it is brought back into suspension during aeration and shows its advantages over conventional activated sludge systems.


« back