Plans for Pleasant Water

By K. Robert Wendel

Better tasting water is on tap for Phoenix residents.

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Phoenix, along with other Valley cities, has long struggled with poor- tasting tap water, but a new, 320-million-gallons-a-day water treatment plant on Lake Pleasant Road will change that.

The new plant is being constructed in phases. The first, an 80-mgd project, is under construction. The $228 million project is scheduled for operation in February 2007, with construction finishing in mid-2006 followed by a startup period. Total contract value is $330 million

The new treatment plant incorporates several systems that usually stand alone.

"Essentially, this is the first time in the United States that all the different processes have been put together in one system," said Troy Hayes, the plant-engineering leader for the city of Phoenix. "All the systems work together to meet any current or foreseeable regulations, so we are going above and beyond any standards we have now and are even exceeding future regulations."

The project employs a series of five processes to treat water: An active ballasted flocculation system where sediment is separated; an ozone treatment system; a deep- bed filtration through granular activated carbon; an ultraviolet treatment process; and chlorination. Once the water is finished, it will be stored in a 40-million- gallon basin.

"Central Arizona Project water is a difficult water to treat," said John Quarendon, American Water project director. "With all these processes, you are going to get a much better water aesthetic and you will really be able to taste the difference."

Started in the 60s, the CAP is a system of canals that bring water to cities around Arizona from the Colorado River. The water picks up minerals and sediment on its journey from the snow packs of the Rocky Mountains, making it difficult to treat.

The Lake Pleasant Water Treatment Plant is the largest design-build-operate project in North America, with New Jersey-based American Water Services as the prime contractor. The Phoenix offices of Black and Veatch and McCarthy Building Cos. are providing design and construction services.
American Water Services has a 15-year contract to operate the project, with a five-year option available. American Water Services is a division of London-based Thames Water.

City of Phoenix officials went with the design-build-operate contract for a variety of reasons. As the prime contractor and operator, American Water Services is expected to deliver a higher- quality construction because it will operate the plant for at least 15 years.

"We figured we could get a better handle on costs and schedules by going with a builder/operator," Hayes said. "There are also cost savings associated, and we can get the project delivered quicker by going with one design and building team."

The project is requiring a massive amount of earthwork, with the Peoria office of Ames Construction Inc. moving more than 400,000 cu. yds of dirt. The soils on the 285-acre site were also a challenge, with much of the excavation done by blasting. BCS Enterprises of Phoenix performed the demolition.

"It's been one big dirt job," said McCarthy project manager Rich Distler. "We had a mix of soils, with some river rock, but we blasted most of the structural sites and we had a lot of hard rock trenching."

The plant actually sits nearly 2 mi. away from its water source, the CAP canal, south of Lake Pleasant.

To connect the plant with the water source, crews constructed an 11,500-ft.- long, 90-in. pipeline from the canal to the treatment plant's intake. Crews are in the process of building a giant head works at the canal to intake the water.

The canal's pump station is 45 ft. below grade.

Because of the site's size and location, permitting was a major headache for the team. Part of the project lies in Phoenix, with the intake in Peoria, so permitting from two cities was needed, along with the Arizona Department of Environmental Quality, the U.S. Army Corps of Engineers, The Arizona Historical Preservation Department, Maricopa County, the CAP and APS.

And don't forget the BLM, Bureau of Reclamation and EPA. Although the project uses an impressive 63,000 cu. yds of concrete, most of it will be covered and below grade. There also are 18 different buildings such as pump houses and equipment rooms. The project even has its own 67-kV substation to electrify the plant.

Ludvik Electric Co. of Peoria is the electrical contractor, with Able Steel of Mesa erecting and fabricating steel. Harris Rebar of Phoenix is tying the rebar, while Coreslab Structures is providing the precast concrete. Tempe's TriCity Mechanical is performing the plumbing, piping and mechanical work.

There are also plans for a 7,600-sq.-ft. operations center.

"The architecture is going to be significant, with poured-in-place concrete, core 10 steel and a lot of natural material," said architect Nader Kavakeb of Scottsdale's Swaback Partners. "In the past, neighborhoods rejected these projects, so municipalities have decided to make an art form for these building types."

In addition to the poured concrete and steel, plans also call for gabion walls, tensile structures and high-end masonry. The masonry block features two finishes, with a rough-cut "mesa" stone on the exterior and a burnished and sealed block on the interior.

Maverick Masonry, which is based in nearby Glendale, will use more than 115,000 units on the project.

"It's one block with two different finishes, so that is unique," said Gary Tieman, president of Maverick Masonry. "Even though the units are more expensive, it will save the city money because you won't have to do tile or gypsum board on the interior."