Which type of wastewater treatment functions during the endogenous bacteria growth phase?

The extended aeration process is designed to maintain a long detention time for the wastewater, allowing the microorganisms to thrive for an extended period. During this extended period, the bacteria enter the endogenous growth phase, which occurs after the substrate (organic matter) is depleted. In this phase, bacteria begin to use their own cellular materials for energy, leading to a stabilization of the biomass.

This is contrasted with other treatment methods like activated sludge and trickling filters, which have different operational parameters and do not typically sustain conditions for the endogenous phase to be a significant part of their treatment process. While activated sludge does involve biological growth, it generally operates under conditions that encourage active growth rather than maintaining the prolonged phase where endogenous conditions prevail. Trickling filters also rely on biofilms that may not provide the same environment for endogenous growth. Rotating biological contactors, while they encourage biological treatment, focus on aerobic conditions that support active microbial reproduction rather than the sustained endogenous phase.

The extended aeration approach thus allows for an efficient treatment process by leveraging this unique phase of bacterial activity, leading to superior effluent quality and the stabilization of organic content.