After primary treatment, the primary effluent (or wastewater from primary treatment) is sent to:

Secondary reactors where the wastewater is mixed with pure oxgyen, sent from the cryogenic oxygen facility, which stimulates the rapid growth of beneficial microorganisms (e.g. bacteria, ciliates, and rotifiers). These microorganisms consume more solids and breaks down more contaminants in the wastewater.

From the secondary reactors, the wastewater flows into:

Secondary clarifiers where more sludge and scum are separated. A portion is used as secondary sludge which is returned to the secondary reactor to help rebuild the organic material. The other portion, the waste sludge, is sent for further sludge processing. The remaining liquid is sent to a disinfection system.