San Francisco’s Public Utilities Commission Treats its own Building Wastewater

I. Introduction – Why you should read this:

In July 2012, the new green headquarters of San Francisco’s Public Utilities Commission (SFPUC) was completed. It is one of the growing number of buildings with a Living Machine® System that is able to treat wastewater onsite. The treated wastewater is then reused for a number of non-drinkable (non-potable) purposes, such as toilet flushing and irrigation. Since its ribbon-cutting ceremony last year, the SFPUC building has received considerable attention for its innovative resource management. This building’s example redefines the way our infrastructures are conceived and created, and stretches the limits of what was once thought as “not possible.” The story of the SFPUC’s new headquarters offers an example of what is achievable for any organization interested in making sustainable long-term building changes.

SFPUC_building_sm_2

II. Basics of SFPUC’s New Headquarters:

  1. 13-story Class A office building totaling 277,500 square feet.
  2. Houses over 900 employees.
  3. Onsite treatment of gray and blackwater – the “Living Machine® technology” reclaims and treats all the building’s wastewater to satisfy 100% of the building’s demand for low-flow toilet and urinal flushing.
  4. Rainwater is kept in a 25,000-gallon rainwater harvesting system for onsite landscaping.

III. Savings in terms of $$ and water:

It is too soon to report on exact savings, but projections show that the lifespan of the SFPUC building is 100+ years, and its current energy and water reuse technologies should result in $3.7 billion in taxpayer savings. An average of 5,000 gallons of wastewater is treated per day, which enables a reduction in consumption from the average of 12 gallons per person per day (typical for a conventional office building) to 5 gallons per person per day. Overall the building consumes 60% less water than a similarly sized building.

IV. Basics of the Wastewater Treatment Technology:


SFPUC_building_interior_3SFPUC_diagram_Sm_1

The technology used to treat wastewater onsite is called the Living Machine® System, a 3-stage system that replicates the natural filtration processes in a wetland. The Living Machine® System in the SFPUC building consists of two tidal-flow stage 1-treatment cells and three vertical-flow stage 2-treatment cells.

In both stages the wastewater is filtered through a media that allow microbial organisms to grow, which facilitates wastewater treatment. The third and final stage involves chlorine disinfection and UV filtration, achieving reusable 

water quality standards. The Living Machine® System is an effective ecological wastewater treatment system with a small footprint.

V. Call to Action – Lessons Learned from SFPUC:

The first steps the SFPUC took before accepting the project was making the decision to take the road less travelled and commit to implementing new technologies. The changes SFPUC wanted to implement transgressed traditional building codes at the time of planning. Therefore, collaboration with the right public agencies, like the city’s Department of Public Health and Building Inspection Department, was key to the planning process. After the completion of SFPUC’s new headquarters, the City and County of San Francisco’s Building and Health Departments updated their codes for handling onsite wastewater treatment.

  1. Asking the Right Questions: SFPUC asked themselves - What can be done with treated water within a building? What technology is out there to do so?
  2. Collaboration: Collaborate early on with right local government agencies, in particular those who issue the relevant building and health code permits.
  3. Research: Due diligence of investigating which technologies would make sense for your project. In the case of SFPUC, they executed sustainability measures on a larger scale by having their new headquarters reflect their commitment to sustainability. They did this in consultation with Sustainable Water and the application of the Living Machine® technology.
  4. Learning Attitude: It’s been one year since the construction of the new SFPUC headquarters, and although the first year has been a success there have been some moments of pause and reflection along the way. In the case of SFPUC, one oversight that was not considered was that the Living Machine® requires water 24-7 to function, so for weekends and/or long weekends adaptations had to be made.

VI. Call to Action – Steps you can Take:

  1. Check out the SFPUC’s new headquarters! For more information about tour dates, click here.
  2. Determine what changes you want to make on a large or small scale. If creating a brand new headquarters building is not part of the plan, consider effective small-scale alternatives:

1. Low-flow toilets

2. Landscaping with recycled water

  1. Interested in speaking with Sustainable Water? Contact them here.

 

Other Water Recycling and Design Consultants that Service the Bay Area:

  1. RMC (San Jose/San Francisco) - http://www.rmcwater.com/
  2. Weiss Associates (Emeryville) - http://www.weiss.com/
  3. Hyphae Design Lab (Oakland) - http://www.hyphae.net/
  4. Water Recycling Systems (Redondo Beach) - http://reusegraywater.com/

By Joanna Portillo-Hsu

Aug 30, 2013

 
 
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