When you think of a wastewater treatment plant, you probable picture a vast, unsightly pool surrounded by a concrete facility. You probably do not picture a serene wetland in the lobby of an office building, but that’s exactly how sewage will be treated in the new building of the San Francisco Public Utilities Commission. Design by Worrell Water Technologies, the constructed wetland, called Living Machine, will clean the building’s wastewater to make it suitable for reused in toilets, irrigation, and maintenance.
The constructed wetland will be integrated into the building’s lobby and outside landscaping, using Worrell’s advance ecological engineering to clean all of the building’s black and gray water. The system can treat up to 5,000 gallons of watewater each day and requires only 1,000 square feet. Wastewater will flow into watertight basins below the wetlands’ surface so there is no smell, no mosquitos, and no health hazards. The end result is a lush green space and natural habitat that will save the Public Utilities Company up to 750,000 gallons of water every year. An additional 900,000 gallons will be saved for nonpotable future uses.
A Living Machine system mimics a tidal wetland, one of nature’s most productive ecosystems. The computer-controlled system treats wastewater in a more energy-efficient and cost-effective way than traditional wastewater plants. Inside the watertight basins, a biofilm grows on a special gravel. When the basins fill, the microorganisms in the biofilm begin eating the nutrients in the wastewater. The water is then drained and the basins are filled with atmospheric oxygen, which rapidly consumes and converts any remaining nutrients.
The constructed wetland is just one of many green technologies that the San Franscisco Public Utilities Commission will be implementing in its new 13-story building. The structure will also generate its own energy through solar panels and wind turbines.