Tracing our "Roots" in Pima County

Part 4:   1975 -- 1999


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Pima County started construction of a new, 25 mgd, pure oxygen Water Pollution Control Facility (WPCF) at its Ina Road site.

A 1.5 mgd Wastewater Reclamation Facility was put into operation by the City of Tucson at Randolph Park. Its purpose was to provide relief for overloaded sewer lines, and to provide effluent for irrigation at Randolph Park Golf Course.

1976 MUM was dissolved. An intergovernmental agreement was considered to provide a more workable liaison (merger) between the county and city.
1977 The Water Pollution Control Facility began operation at Ina Road. This facility generated all of its required electrical power on-site and was not connected to any off-site source of power.
1978 The Pima County Department of Sanitation was renamed the Pima County Wastewater Management Department (PCWWM). The department was responsible for the operation of both the county's sanitary sewerage facilities and its solid waste facilities.

PCWWM initiated the Slow-the-Flow Indoor Water Conservation Program.

On June 26, via an intergovernmental agreement between Pima County and the City of Tucson (known as "The Sewer Merger Agreement"), the Pima County Wastewater Management Department assumed responsibility for the operation of all the region's public sewage facilities. This included 2 WWTFs; 1600 miles of sewer main; and several wastewater pump stations within the City of Tucson. Facilities serving outlying incorporated areas were also included as well as those serving the unincorporated areas.


Additional upgrading and expansion of the Roger Road Wastewater Treatment Facility begins.

City of Tucson's population: 331,000.
Greater Metropolitan Area's population: 531,000.

The PCWWM developed the first capital improvement program in Pima County to provide long-range planning for improvements to the sewage facilities serving the greater Tucson Metropolitan area.


The first comprehensive Financial Plan was developed by the department. The Financial Plan has since been updated and adopted by the Board of Supervisors annually.

A newly modified Green Valley Wastewater Treatment Facility (serving the communities of Green Valley and Santo Tomas) began operation. It had been upgraded to 2.1 mgd capacity by replacing stabilization ponds.

1982 The department adopted the Industrial Wastewater Control Ordinance and implemented a program for addressing the management and proper disposal of industrial wastewaters.
1982 - 83 The Roger Road WWTF was improved to treat 30 mgd using bio-filter towers; an on-site, methane power plant; a modified digester system for better gas production and utilization; and single-point effluent discharge into the Santa Cruz River. The previous operational scenario of running 3 treatment trains in parallel was replaced, in essence, with one process. The quality of effluent was improved, but the overall capacity of the plant was reduced until the next expansion.

Pima County adopted a policy endorsing the beneficial use of treated sludge on area farmlands via subsurface injection. A program was established and design work was initiated to collect, convey and dewater the sludge in preparation for use on non-food chain crops.

Pima County initiated the Landfill Environmental Studies Program to investigate the quality of groundwater in the vicinity of county-owned landfills. The program provided for mitigation if landfill-caused groundwater quality degradation could be demonstrated.

March: the first modern-era environmentally sound (lined) sanitary landfill opened for service -- Pima County's Tangerine Road Landfill, located one mile west of Tangerine Road and I-10.

October rains brought massive flooding and inflicted approximately 5 million dollars worth of damage to Pima County's sanitary sewerage and solid waste facilities.

1984 Work began on yet another expansion of the Roger Road WWTF, including the design of additional systems to prepare solids for beneficial use.

The City of Tucson had previously acquired the rights to 90% of the effluent generated from the metropolitan area WWTFs via the 1979 Sewer Merger Agreement. The city, in April, placed into operation the first phase of a basin-wide reclaimed water filtration and distribution system. The filtration facility was positioned on a site immediately adjacent to Pima County's Roger Road WWTF.

Construction began on Contracts C-234 and C-235, Sludge Handling Facilities comprising new digesters and sludge pumping station at the Roger Road WWTF, and a five-mile sludge force main to the Ina Road WPCF. Ground was also broken on a sludge centrifuging facility at the Ina Road WPCF.

The Corona De Tucson Wastewater Treatment Facility was relocated and upgraded to .18 mgd capacity.

The final phases of the Southeast Interceptor were completed and put into service. This interceptor, consisting of approximately 10 miles of sewer line, provided service to the southeastern portion of the Tucson Metropolitan Area.


PCWWM's Technical Services Laboratory received certification from the Arizona Department of Health Services to perform organic, inorganic and microbiological analysis.

The 11 MGD Expansion Study and Design Contract was awarded to PRC Engineering for the expansion of the Roger Road WWTF.


The Roger Road Sludge Management Facilities were completed. Stabilized sludge could now be transferred from the Roger Road WWTF to the Ina Road WPCF for further dewatering and thereafter, for agricultural application. The sludge drying beds at the Roger Road WWTF were taken out of service, and the disposal of biosolids into local landfills ceased.

The Wastewater Citizens Advisory Committee (WAC) was established by the Board of Supervisors.

The Camino del Cerro Landfill Environmental Study was initiated to determine how mitigation of contaminated groundwater would be achieved.

Construction of the Catalina Outfall Sewer was completed, which connected the Town of Catalina sewage conveyance system to the metropolitan sanitary sewerage system. The public Catalina WWTF was abandoned.

PCWWM instituted a computerized remote monitoring system to routinely measure the sewage flow at strategic points along the basin's trunk and interceptor sewers. This allowed the department to more accurately determine the system's available capacity, and (for CIP planning purposes) ascertain any need for physical augmentation.

Construction began on modifications to the Ina Road Water Pollution Control Facility. The rated capacity remained at 25 mgd (adwf).


PCWWM constructed the Water Hyacinth Research Project at the Roger Road WWTF site. This project eventually was renamed the Constructed Ecosystem Research Facility (CERF).

The department also began a program to automate sanitary sewer preventive maintenance scheduling. This effort required staff to input data about each public manhole and cleanout into a database for use by the scheduling software. The software issued work orders for maintenance activities. Upon completion, field crew comments could be recorded into the maintenance history portion of the database.

The design for the 11 mgd expansion of the Roger Road Treatment Facility was completed. This expansion would be implemented in phases as the availability of funding allowed. The capacity of the WWTF upon completion of this work was expected to be 41 mgd.


PCWWM opened a year-round Household Hazardous Waste Facility jointly with the City of Tucson. Waste that might otherwise be improperly discarded in public sewers or landfills could be brought here for safe handling and reuse.

City of Tucson's population: 405,000.
Greater Metropolitan Area's population: 667,000.

1991 PCWWM moved its administrative offices from the 3rd floor of the County Administration Building at 130 W. Congress to the new Public Works Center at 201 North Stone Avenue. This structure had recently been renovated in order to house offices for Pima County and the City of Tucson.
1992 The Wastewater Management Department began the process of converting hand-drafted sanitary sewer base maps to AutoCAD files. This process was completed by 1995.
1993 The newly elected Pima County Board of Supervisors instituted a massive reorganization of county departments. Through the reorganization, the Solid Waste Division became a separate county department, i.e., the Solid Waste Management Department.
1994 The final design was begun for a 12.5 mgd expansion (air-activated sludge/BNR) to the Ina Road WPCF.
1995 An oxidation ditch treatment process (capacity: 1.2 mgd) was placed into operation at the Avra Valley WWTF which replaced the existing, undersized treatment ponds.

PCWWM was awarded a five million dollar grant for the Arid West Water Quality Research Project. Pima County will work with EPA Region IX and others to improve the scientific basis for evaluating water quality in the arid and semi-arid West. The research will assist agencies and regulators in developing quality standards for ephemeral and effluent-dependent stream ecosystems.
1996 The Randolph Park WRF was removed from active service. The adjacent park and golf course now received effluent from the City of Tucson's regional reclaimed water distribution system.
1997 Pima County's Solid Waste Management Department was dissolved. All solid waste activities and employees were re-integrated with PCWWM.
1998 The latest phase of the Roger Road WWTF was completed. The overall capacity of the Roger Road WWTF was now 41 mgd (adwf).

The Field Operations Division of WWM began a program to locate hidden and buried public manholes and cleanouts and to record their position for future reference using GPS equipment.

A four-phase, 12.5 mgd expansion of the Ina Road WPCF was begun. The contract for phase 1 (a new headworks facility) was awarded, and a Notice-To-Proceed was issued to Ashton Construction on March 22.

A 2 mgd expansion of the Green Valley WWTF was started. The contract went to to Dogan Construction Company, Inc. (DCCI), of Castle Rock, Colorado. The estimated completion date is in 2001. hence.

November 16: The Board of Supervisors awarded a construction contract to CDM Engineers and Constructors, Inc., for the installation of odor control facilities at the headworks of the Roger Road WWTF.

The Septage Receiving Facility, at the Roger Road WWTF, began operation on July 1. Henceforth, septage will no longer be deposited in the public sanitary sewage conveyance system (at manholes).

2000 September, 20: The 100th anniversary of the first public sewers in the Tucson area.

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