Sludge Treatment

At the Throop plant, anaerobic digesters are used to break down organic material in both primary and waste activated sludge. “Anaerobic” refers to the absence of oxygen in the treatment tank during this process. As bacteria break down the sludge, they generate methane gas, which can be burned as fuel to heat the sludge.

In contrast, the Archbald plant uses aerobic digesters, where air is bubbled through the tanks. This provides oxygen to microorganisms that decompose the sludge efficiently.