The Moscone Center, located in San Francisco, California, currently generates more than 20 percent of the city’s 16.9 million annual visitors, making it a main driver for local economic growth. Since the city and the its convention needs continue to grow, the Moscone Center is undergoing an expansion project to prepare for the future. Southland Industries was selected as a contractor of choice to perform design-assist mechanical and plumbing services, including both wet and dry HVAC, controls, and plumbing systems.
Once completed, the improved Moscone Center will create less carbon emissions per visitor than any major convention center in North America. The systems Southland installed will save more than five million gallons of water annually and the project will generate clean energy with the largest rooftop solar installation in San Francisco. The San Francisco Green Building Ordinance requires that the project achieves LEED® Gold–but with strong focus on sustainability, the center is going above and beyond to seek LEED® Platinum certification.
The need for on-site water treatment
(Image from www.sfwater.org)
One of the most complex plumbing systems installed on the project is the fully automated on-site water treatment plant (WTP). The WTP is the common-sense solution to a real problem of the San Francisco built environment: it is the only coastal city in California with a combined sewer system that collects and treats both wastewater and stormwater in the same system of three treatment plants and over 1,000 miles of piping. Even though water flows through most of the sewers using gravity, and the city’s unique rolling geography reduces the costs associated with mechanical pumping, one of the challenges is that the city watershed is mostly paved or has hard surfaces, so rain has no place to go other than the city’s combined sewer system before being discharged to the bay or ocean. San Francisco treats about 70 million gallons of water on a clear day, versus about 575 million gallons on a rainy day – that’s over eight times the normal volume!
Building the treatment plant
In October 2017, Southland Industries completed construction of Moscone’s new fully automated on-site WTP. The plant can collect, treat, and re-use on-site water to address the need for both on-site storage during heavy rain days and to offset potable water used by the facility when reclaimed water could be used instead. “It’s satisfying to see a system this complex come together,” says Brett Russon, plumbing project engineer.
Inbound collection sources include foundation dewatering (a constant necessity this close to the Bay), rainwater runoff from about 217,000 square-feet of hardscape (not constant, but quite impactful), and steam heat condensate return. Outbound uses of the treated reclaimed water, or water exiting the treatment plant, include a projected 1.4 million gallons of annual toilet and urinal flushing throughout the facility, over two million gallons per year of irrigation and fountains throughout the campus, and over two million gallons per year of street cleaning trucks that utilize a digital screen and keypad to receive metered amounts of reclaimed water dispensed into the truck. The raw water tank, taking the inbound water prior to treatment, is approximately 70,000 gallons and the treated water tank is approximately 40,000 gallons.
The Moscone expansion project was plumbed by Southland for purple-pipe on-site reclaimed water use. During heavy rain days, the WTP can intelligently retain water on-site to avoid contributing to the city’s combined storm and sewer system, ultimately preventing overflow.
At the time of publication Southland is testing and commissioning the new water treatment plant to Department of Public Health standards. After a testing period where quality is monitored, Southland will transition certain systems over to treated water.
Stay tuned for more information about Moscone’s WTP’s predicative weather algorithm, customized by Envise. If you have any additional thoughts, we’d love to hear about them in the comments!