Roger Road Wastewater Reclamation Facility -
Illustrations of Treatment Processes
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Headworks
The Headworks is the initial receiving area for raw sewage from the conveyance system. Screens filter out large materials and grit chambers allow heavy sand and rocks to settle before sewage is sent to the primary clarifiers. Note - the Headworks at the Roger Road WRF is now covered (part of the Odor Control Program).
Clarifiers
Clarifiers separate sludge and scum from the sewage before biotreatment.
Biotowers
The two biotowers at the Roger Road WRF remove suspended particles and pollutants by biological treatment. Sewage is distributed across a "zoogleal mass" filled with bacteria that eat waste products. After biological treatment, secondary clarifiers provide further treatment.
Secondary Clarifiers and Biotower Recirculation System
Filtered effluent from the biotowers flows to the secondary clarifiers, while excess sludge is pumped to the thickeners, then to the digesters. "Returned sludge" containing microorganisms is returned to the biotowers if needed to maintain moisture levels, or recycled through the secondary clarifiers again. Secondary effluent flows on to the Chlorine Facility.
Chlorination and Discharge
Chlorine Contact Chambers provide extended contact between effluent and chlorine. The chlorinated effluent is used for golf courses and other reuse, or dechlorinated and discharged into the Santa Cruz River.
Illustrations by Jan McDonald, Pima County Regional Wastewater Reclamation
