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The city of San Diego’s Alvarado Water Treatment Plant (AWTP) is more than just a drinking water system—the plant has been a monument to the city since 1951 and was designated as an American Water Landmark in 2002 by the American Water Works Association.
By 1998, the AWTP was facing increasing water needs in its service area, which currently spans approximately 36,366 acres, or more than 54 sq miles, and provides drinking water to more than 500,000 residents. Additionally, changes in state and federal drinking water quality regulations, specifically the Stage 2 Disinfectants and Disinfection Byproduct Rule from the U.S. Environmental Protection Agency, set forth stricter standards for all treatment plants.
In light of these circumstances, the historic plant is in the midst of the comprehensive AWTP Expansion and Improvement Project, which began in 1998 and involves constructing eight new filters, sedimentation and flocculation basins, implementing ozone as an alternative disinfectant, upgrading the Lake Murray and College Ranch pump stations and remodeling the existing operations building.
The entire project is scheduled to be completed by the end of fall 2010 and will enable AWTP to produce 65% more water with a safer, modernized facility and equipment that offers the latest in water quality monitoring, according to Darren Greenhalgh, deputy director, Architectural Engineering and Parks Division.
A large-scale project such as the AWTP expansion presents unique challenges and hurdles to overcome.
“Applying massive structural, architectural and engineering changes to a facility that needs to continue operating 24 hours a day, seven days a week while being upgraded and expanded has posed many challenges,” Greenhalgh said.
The sheer size and complexity of the project is one such challenge. A number of governing bodies and groups have input, including the state of California; the California Department of Public Health; the California Department of Water Resources Division of Safety of Dams; the city of San Diego Mayor’s Office, City Council, Development Services Department and Water Department; the city of La Mesa; Friends of Lake Murray; the Lake Murray Recreation Council; the Mission Trails Regional Park Task Force; the Navajo Community Planning Group; and the Maintenance of Plant Operations (MOPO) Task Force.
The AWTP engineering project management team leads efforts to mediate project input by holding frequent meetings to make sure requirements from regulatory agencies, public groups and city departments are met, according to Iraj Asgharzadeh, senior civil engineer.
The project management team also looked to water treatment plant experts to help coordinate the large, complex project.
“Staff met with stakeholders frequently, surveyed local contractors regarding market conditions and analyzed ways to reduce construction costs,” Asgharzadeh said. “Workshops and value engineering processes were utilized to resolve many challenges during design and construction phases of the project.”
Faced with a lack of funding in previous years, the city had to divide the project into smaller phases with longer construction periods. This has helped them satisfy stakeholders and stay in line with the allocated city budget while still providing high-quality construction services.
Cooperation is Key
To deal with ongoing challenges, the MOPO Task Force was developed. The force is made up of design engineers, project managers, contractors, operators and construction managers. They examine the design and specific job needs relative to plant operations, evaluate the schedule and water use requirements for the city and determine contractor requirements.
“To date, the coordination work done by the MOPO Task Force has been invaluable to ensuring a smooth project and has led to transparent water distribution to customers,” Greenhalgh said. “All the MOPO operations have been completed successfully with no disruption in water service.”
The Next Phase
Phase II of the project was completed in 2007 and the project is now moving on to Phase IV, which includes the construction of the new ozone generation facility beginning in summer of 2008.
“The new ozone generating facility will include the construction of a very large building designed to protect the ozone contactor and equipment (complex mechanical, electrical and automated components),” Greenhalgh said.
Both the new ozone facility and Phase III, the rehabilitation of the two original flocculation and sedimentation basins, are scheduled to be completed by the end of 2010. The same kind of cooperation and teamwork utilized in past phases will be necessary for successfully completing the remaining portions of the project.
“Engineers and members of the community are committed to ensuring a smooth process for the completion of Phase III and IV,” Asgharzadeh said. “Strong oversight by staff during construction will be given a priority to ensure proper installation. Also, once the new ozone facility is complete, the water operations staff will go through extensive training regarding ozone technology.”