You don’t normally expect to learn about the true potential of blackwater on your way to getting a tree permit. That’s now likely to happen to attentive visitors to Austin’s new Permitting and Development Center (PDC). And it’s exactly what the city wants—developers confronting, face-to-face, the remarkable, cost-effective potential of water reuse technology.
Six years ago, the most likely reason to visit what’s now 6310 Wilhelmina Delco Drive, would be to find a parking spot on your way to good ol’ Highland Mall. That mall is now history and that parking spot has transformed into Austin’s newly-opened PDC—a one-stop shop for Austin residents and developers looking for permitting and development services AND a showcase of onsite water reuse methods, including the first onsite blackwater reclamation system in the state.
The two stars behind the facility’s water conservation efforts are OSCAR and CLARA—on-site water reuse systems that visitors must walk between on their way to the entrance lobby. By installing the systems (with ample educational signage) front and center, the facility offers an opportunity for developers to become acquainted with the reuse technologies they employ, ask questions about them, and see them in action.
Both OSCAR and CLARA take a fit-for-purpose approach to water reuse treatment, meaning water is only treated up to a standard required for its final end-use. This approach reduces the energy consumed during the treatment process by limiting unneeded treatment processes. Together OSCAR and CLARA tackle different streams of the facility’s water. OSCAR (On-Site Collection and Reuse) leads the collection and reuse of the greywater collected onsite for non-potable uses. Meanwhile, CLARA (Closed-Loop Advanced Reclaimed Assembly) treats the building’s wastewater up to non-potable water use standards. Together, OSCAR and CLARA can leverage the water that flows through the PDC facility while being intimately integrated into the landscape. Once fully online, they are estimated to reduce the facility’s potable water consumption by 75%.
OSCAR is the simplest of the two. His storage tanks collect up to 40,000 gallons of rainwater and condensate water. These tanks are located underground, hidden from view and making space for an outdoor patio. Before entering the tanks, the water is filtered through self-cleaning 350-micron filters. OSCAR then uses this water for landscape irrigation. He can also send water to CLARA to assist her treatment process by diluting solids.
CLARA’s role is a bit more complex. She treats the facility’s wastewater, also known as blackwater, which comes from toilets, urinals, sinks, and drinking fountains. The treatment process transforms the blackwater to a standard appropriate for use in toilets and urinals, thus requiring more rigorous treatment methods than OSCAR. Treating this water onsite diverts wastewater from being piped away to a treatment plant. Lessening the wastewater flow reduces the burden on local infrastructure. CLARA’s innovative approach can treat and recycle 5,000 gallons of wastewater per day, lowering the building’s demand for water and freeing up potable water supplies.
CLARA’s treatment process is a hybrid membrane system that uses biological, physical, and chemical treatment. The first step involves screening out solids from the wastewater and sending those to the city’s sewage collection system. The remaining effluent continues through the process to the pre-anoxic tank, where biological treatment begins. A membrane uses bacteria for nitrification and denitrification processes. Additionally, a hydroponic reactor is used for nitrification and preparing the effluent. The process depends on a diverse set of plant species whose roots extend deep into the water. These roots become the home for microorganisms to assist in the process.
Next, the water moves to a low oxygen environment in the post-anoxic reactor. This space allows microorganisms to remove nitrate from the wastewater before continuing into a membrane tank. The membrane tank conducts a final round of biological treatment and solid separation.
The final step removes any remaining pathogens. CLARA uses ultraviolet radiation (UV) and chlorine to disinfect the water. This final step controls for odor, bacteria regrowth, and biofilms. Finally, the treated water enters the reuse tank until it’s pumped into the building. This closed-loop recycling system allows water to be reused again and again.
The facility’s design seamlessly incorporates OSCAR and CLARA as part of the landscape with minimal interruption of one’s experience of the site. The spaces they create are both functional and aesthetically pleasing. Their location allows for easy access for maintenance, but also makes the systems visible enough to create a learning space for visitors. OSCAR’s storage tanks are tucked under a patio, opening up a green space to be enjoyed by employees and visitors. Here a water feature uses OSCAR’s water to produce a relaxing soundscape as water flows from the top of a rock down to a small pool of water. By using reclaimed water, facilities like PDC can utilize these features without consuming valuable potable water but still provide place-making features. Across from here, CLARA is neatly tucked behind an outdoor sitting area. If you walk over CLARA and look down you will see the plants that are part of the biological treatment process. You can also walk along the sides where you get an impression of the scale of CLARA. Through thoughtful design, onsite reuse systems can be meaningful parts of a site beyond their main functional role. They can be places for relaxation, learning, and building our relationship with water.
Efficient water management is only part of the building’s overall dedication to wellness. The PDC is the first city facility to be built and operated to WELL Building Standards. WELL Building Standards support well-being through various features such as natural lighting, good air quality, and healthy food options. These standards center the human experience of a building.
Such measures are increasingly needed. The COVID-19 pandemic has exposed the importance of healthy indoor environments. In regard to water, the WELL Building Standard oversees the quality and management of water in the building assuring that clean and adequate amounts of water are available for use. It also considers how water interacts with the building materials and infrastructure to avoid health risks from contamination and mold.
The experience and information gathered from OSCAR and CLARA will assist the City of Austin’s refinement of requirements and criteria for onsite water reuse systems. Moreover, the PDC facility takes on a pivotal role because of the recently adopted water reuse ordinances. These Water Forward ordinances set the stage for a water resilient city by requiring water budgeting, purple pipe connections, and onsite water reuse for certain projects. Passing these ordinances and investment in OSCAR and CLARA exemplify the city’s leadership and commitment to water resiliency. It specifically signals to developers that Austin is transitioning to water-conscious development. The new set of Water Forward ordinances motivates developers to be part of this change and the PDC exemplifies the possibilities of doing so.
The PDC is the first professional office development at Highland, a new Austin neighborhood built on the former Highland Mall. More than halfway completed, the project combines a walkable, mixed-use, transit-friendly environment with a new high-tech campus for Austin Community College:
Understanding the types of water in a building system
Alternative Water: Highly treated reclaimed water from wastewater treatment plants or onsite water sources. This includes rainwater, greywater, stormwater, wastewater, and air conditioning condensate.
Recycled/Reclaimed Water: Water that meets 90% of the criteria for drinking water but used for non – potable needs. Reclaimed water is clear, odorless, and harmless.
Stormwater: Rainwater that runs off impervious surfaces such as streets, sidewalks, parking lots, and rooftops.
Air Conditioning Condensate: Water from air conditioning systems.
Wastewater/Blackwater: Water from kitchen sinks, toilets, and dishwashers.
Graywater: water from showers, bathroom sinks, bathtubs, and laundry machines.
Rainwater: rainfall collected from a catchment system