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  • Treatment Facilities

    The Treatment Division operates and maintains the treatment facilities that receive, treat, and dispose of over 62 million gallons per day (MGD) of sanitary sewage. Two major facilities handle sewage from the metropolitan Tucson area, and seven facilities serve remote areas scattered throughout several areas of eastern Pima County.

    Weather information at the Treatment Plants

    Metropolitan Facilities

    Roger Road Water Reclamation Facility (WRF)

    The Roger Road WRF was established in 1951. It had a capacity to treat 41 MGD and served the urban Tucson area that lies southerly of the Rillito Creek for more than 60 years.

    After more than 60 years of service, the Roger Road Wastewater Reclamation Facility (WRF) will no longer be treating Pima County wastewater. As of January 8, 2014 the last flows to the Roger Road WRF were diverted from the old plant to the new facility, Agua Nueva WRF.

    Agua Nueva Water Reclamation Facility (WRF)

    Since December 16, 2013, the Pima County Regional Wastewater Reclamation Department (RWRD) has been diverting flows from the Roger Road WRF to the Agua Nueva Water Reclamation Facility (WRF).

    The Agua Nueva WRF is a new state-of-the-art water reclamation facility that will allow Pima County to meet new strict environmental standards for effluent discharges into the Santa Cruz River.

    Tres Rios Water Reclamation Facility (WRF)

    The Tres Rios WRF has a current capacity of 25 MGD. Work to increase the facility's capacity to 37.5 MGD is underway; construction began in January 1998. This facility, established in 1977, serves the northern parts of the Tucson metropolitan area, Oro Valley, and a major portion of the Town of Marana.

    Randolph Park Water Reclamation Facility (WRF)

    Originally placed into operation in 1975, the Randolph Park WRF was temporarily removed from active service in 1995. As part of RWRD's commitment to providing safe and efficient sewage treatment to our community, a project is currently underway to replace the Randolph Park facility with a new, modern system.

    Sub-Regional Facilities

    Six outlying facilities serve smaller towns and rural areas of Pima County:

    • Arivaca Junction WRF
    • Avra Valley WRF
    • Corona de Tucson WRF
    • Green Valley WRF
    • Mt. Lemmon WRF
    • Pima County Fairgrounds WRF

    Illustrations of the Treatment Process



    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 separate sludge and scum from the sewage before biotreatment.






    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.



    Recirculation System

    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


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    Wastewater Reclamation

    Agua Nueva WRF
    2955 W. Calle Agua Nueva
    Tucson, AZ 85745

    (520) 724-6500

    Tres Rios WRF
    7101 N. Casa Grande Hwy.
    Tucson, AZ 85743

    (520) 724-6100

    Randolph Park WRF
    3805 E. 22nd St.
    Tucson, AZ 85713

    (520) 319-0139

    Sub Regional Facilities Admin Office
    4527 W. Walker Rd.
    Tucson, AZ 85743

    (520) 724-6170

    Avra Valley WRF
    10000 W. Snyder Hill Rd.
    Tucson, AZ 85735

    (520) 578-7341

    Corona de Tucson WRF
    1100 W. Sahuarita Rd.
    Corona de Tucson, AZ 85641

    (520) 762-0593

    Green Valley WRF
    19600 S. Old Nogales Hwy.
    Green Valley, AZ 85614

    (520) 625-0025

    Mt. Lemmon WRF
    12633 N. Sabino Canyon Pk.
    Summerhaven, AZ 85619

    (520) 576-1225

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