Title
Asset Management Program Update - Water and Wastewater Treatment Plants and Remote Facilities - Citywide
Description
This report provides the Transportation, Infrastructure, and Planning Subcommittee with information on the Water Services Department’s Asset Management Program for Water and Wastewater Treatment Plants and Remote Facilities.
THIS ITEM IS FOR INFORMATION AND DISCUSSION.
Report
Summary
Asset Management Program
The Water Services Department (WSD) is committed to an asset management program to support its mission of providing high quality, reliable, and cost-effective water services that meet the public needs and maintain public support. Asset management is an intentional, proactive approach to maximize the useful life of assets while minimizing life cycle cost. This means asset renewal that is based on age, condition, criticality, and risk value. Within the WSD, each asset is identified, and catalogued according to strict naming conventions in the asset database. The condition of the asset is also recorded in the asset database. Proper preventive maintenance procedures are identified and noted for each asset allowing work orders with proper maintenance activities to be assigned to employees. Standardizing work management processes using a modern computer maintenance management system (CMMS) ensures proactive maintenance on the right assets at the right time.
Risk analysis is also part of asset management. Risk is defined as the Probability of Failure times the Consequence of Failure. The Probability of Failure is dependent on the condition and reliability of the asset, the asset age and effective life, and redundancy of the asset. The Consequence of Failure factors the impact on service and duration of failure, higher replacement cost and repair difficulty, potential for staff and public injuries, and the importance of the asset.
Age, condition, criticality, and risk value are used to forecast the asset's end of life. The risk analysis is used in determining the replacement timeline of the asset, allowing for proper planning of the capital improvement program. The overall goal is to align maintenance and replacement programs so assets will have longer useful lives, resulting in longer replacement cycles. This alignment ensures that capital improvement programs for replacement and rehabilitation budgets are adequately funded and prioritized to replace the department’s critical assets at the end of their useful life. The right assets are replaced at the right time and cost.
Water Treatment Plants
Background
The City of Phoenix (Phoenix) owns five water treatment plants (WTPs), which are used to supply high quality water to customers in the City's water service area.
24th Street WTP: located near the intersection of 24th Street and Lincoln Drive. This plant receives water from the Salt and Verde Rivers delivered through the Salt River Project (SRP) canal system. The plant was originally constructed in 1953 and has a treatment capacity of 140 million gallons per day (MGD).
Deer Valley WTP: located near the intersection of 31st Avenue and Dunlap Road. This plant receives water from the Salt and Verde Rivers delivered through the SRP canal system. The plant was originally constructed in 1964 and has a treatment capacity of 100 MGD.
Val Vista WTP: a jointly-owned facility with the City of Mesa. The plant is located on McDowell Road between Lindsay and Val Vista roads in Mesa, and also receives Salt and Verde River water delivered through the SRP canal system. The plant was originally constructed in 1975 and has a treatment capacity of 220 MGD.
Union Hills WTP: located near the intersection of Deer Valley and Cave Creek roads. This plant receives Colorado River water delivered through the Central Arizona Project (CAP) canal system. The plant was originally constructed in 1986 and has a treatment capacity of 160 MGD.
Lake Pleasant WTP: located along New River Road, north of Carefree Highway. This plant also receives Colorado River water delivered through the CAP canal system. The plant was originally constructed in 2007 and has a treatment capacity of 80 MGD. This plant is owned by City of Phoenix; however, it is currently operated and maintained by Veolia. City Council approved returning plant operations and maintenance to the City's Water Department starting July 2025.
Water Remote Facilities
Booster Pump Stations
The Phoenix water system includes 109 active booster pump stations which help to maintain adequate water pressure, move water from lower elevations to higher elevations at a consistent pressure, and move water during peak demand events such as fire suppression. The booster pump stations range in pumping capacity from 40,000 gallons per day to 160 MGD. The total pumping capacity for the water system is 1.1 billion gallons per day. These facilities are located at remote sites and water treatment plants throughout the 540 square-mile water system. The average life span of a booster pump station is 25 years with proper maintenance.
Storage
The Phoenix water system includes 57 water storage reservoirs which maintain adequate water pressure and provide water for peak customer demand periods throughout the day and during other peak demand events, such as fires. They also provide redundancy within the system in times of localized water system outages, such as water main breaks. The storage reservoirs in the Phoenix water system are constructed of either concrete or steel and range in size from 10,000 gallons to 40 million gallons. They are located at water treatment plants as well as other remote facility locations throughout the water system. The average life span of a concrete reservoir is 50 years with proper maintenance. The average life span of a steel tank is 25 years with proper maintenance.
Wastewater Treatment Plants
Phoenix owns and operates three wastewater treatment plants (WWTP).
91st Avenue WWTP: located near the intersection of 91st and Southern avenues. It was constructed in 1958 and after multiple expansions, it now has a capacity of 230 MGD. This plant is the largest wastewater treatment plant in Arizona. It is jointly owned with four partner cities: Glendale, Mesa, Scottsdale, and Tempe. Phoenix operates the facility on behalf of the partners.
23rd Avenue WWTP: located near the intersection of 23rd Avenue and Lower Buckeye Road was initially constructed in 1932. This facility treats flows from central Phoenix and has a capacity of 66 MGD.
Cave Creek Water Reclamation Plant: located near the intersection of Cave Creek and Deer Valley roads. This facility began operating in 2002 but was taken out of service in 2009 due to the downturn in the economy. The facility is currently under construction to bring the plant back online to treat flows in the area. Upgrades are expected to be completed in 2026 with a treatment capacity is 8 MGD.
Wastewater Remote Facilities
Lift Stations
The Phoenix system includes 29 lift stations ranging in size from 200,000 gpd to 14 MGD. The lift stations move wastewater from low points to higher elevations. The average life span of a lift station is 20 years, but some pieces of equipment will need to be rehabilitated or replaced sooner due to the harsh environment.
Force Mains
Lift stations pump wastewater through force mains to move the flow to a higher elevation. Force main lengths range from a few hundred feet to three miles. Force main sizes range from eight-inch to 24-inch and each lift station has at least one force main leaving the station. Over half of the stations have two or more force mains leaving the site. This could either be for redundancy or flow quantity. The average life span of a force main is 75 years. There are many factors that impact a force main condition such as soil conditions, wastewater composition, and sewer gasses.
Odor Control
Phoenix has 33 odor control stations in the system. There are two major options to treat odors in the collection system. We can either treat the vapor phase (or air) by processing the fowl air through a filter or we can treat the liquid phase by using chemicals. Phoenix utilizes both options and both options require a facility. There are 21 liquid phase treatment sites and 12 lift stations with biofilters installed.
Infrastructure Renewal
WSD has ongoing programs to rehabilitate and replace aging assets at treatment plants and remote facilities. Over the next six years, WSD has budgeted in the Water Capital Program $227M for water storage reservoirs, $212M for booster pump stations, and $756M for water treatment plants. Over the next six years, WSD has budgeted in the Wastewater Capital Program $135M for remote facilities, $13M for odor control, and $1,248M for wastewater treatment plants.
Department
Responsible Department
This item is submitted by Deputy City Manager Ginger Spencer and the Water Services Department.