San Francisco’s Southeast wastewater treatment plant, the city’s largest and oldest such facility, handling up to 250 mgd in peak periods, will receive a major upgrade with an innovative biosolids digester unit to replace one more than 60 years old.

The estimated $1.4-billion project, to be built for the San Francisco Public Utilities Commission by a joint venture of Webcor Builders and MWH Constructors, a unit of Stantec, gained traction last month with a $699-million low-interest loan from the U.S. Environmental Protection Agency under the federal Water Infrastructure Finance and Innovation Act program (WIFIA), the agency’s largest such loan to date.

The more earthquake-resilient plant, which will generate reusable biosolids and biogas, also will maximize energy and water recovery and be sited farther from residences.

Flatiron Construction and Dragados North America also competed for the project. Leading the project design team is Brown and Caldwell.  Construction of the facility, in the city’s Bayview-Hunters Point section, is set to begin in early 2019 with facilities operating by 2025.

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