|The Audubon Nature Center.
Audubon Nature Center - 4700 North Griffin Avenue, Los Angeles
The Audubon Nature Center is a LEED-Platinum certified "green" development consisting of a nature center building complex with adjoining garden and courtyard areas. EPD helped the Audubon Society meet its sustainable development goals by designing a system that treats the building's wastewater for onsite reuse. Because the city does not yet permit the reuse of even highly treated wastewater within a building, the water is presently being used for subsurface irrigation. However, the system is designed to be easily modified to use this water for toilet flushing and other building processes such as cooling once the State Department of Health Services verifies continuous acceptable water quality.
The Audubon's wastewater treatment and reuse system consists of
* Orenco Advantex hybridized anaerobic/aerobic treatment and
* Peracetic acid / ultraviolet light advanced oxidation disinfection
* Discharge to a Geoflow subsurface irrigation system
Once the city/state approves reuse of the treated water inside the building, there will be an estimated 70 percent water savings over a comparable conventionally-plumbed building.
The Natural Resources Defense Council Santa Monica.
Natural Resources Defense Council Santa Monica Office
1314 2nd Street, Santa Monica, California
The Natural Resources Defense Council Santa Monica office is a LEED-Platinum certified "green" building that has focused heavily on water conservation. EPD designed a system for this project that reuses storm water and gray water for toilet flushing and landscape irrigation. This water reuse system, in conjunction with waterless urinals, dual flush toilets, and high efficiency lavatories, reduces the building's total water use by more than 50 percent.
EPD's water reuse system collects gray water from sinks and showers and storm water from the roof; treats, filters, and disinfects the water; then reuses it for toilet flushing and highly efficient subsurface irrigation. The treatment process involves
* Settling, aerobic pretreatment and ozone disinfection.
* Multi-stage filtration including reverse osmosis in an Equaris Infinity
final ozone and ultraviolet light disinfection
The resulting product meets California Title 22 unrestricted non-potable reuse standards. The entire system is free of PVC, a material whose manufacture and disposal has been linked to health risks and environmental degradation. The system maximizes the efficiency of its reverse osmosis filter -- which can typically reject 3 gallons of water for every gallon produced -- by recycling the concentrate back into the system and rejecting it only when the water exceeds a high threshold.
One gallon of purified water per minute is produced at a cost of about 1/2 cent per gallon.