A lot can go wrong in a large urban water system. Pumps malfunction. Valves break. Pipes leak. Infrastructure ages. By-products and contaminates like PFAS enter the freshwater sources.
Traditionally, cities have relied on centralized water systems that treat freshwater from a river or aquifer at a central facility, then distribute it through a large network of pipes. But that infrastructure becomes increasingly vulnerable to disruptions as it ages. And climate change, water scarcity, and population growth increase stress on the systems.
These issues are just some of the reasons why cities are beginning to experiment with distributed systems –– small-scale water treatment, reclamation, and recycling plants that are designed to collect, treat, and reuse water near both the source and user.
“Access to clean, safe, and affordable water is a fundamental human right,” says Lu Liu, an assistant professor in the Department of Civil, Construction and Environmental Engineering who is working to make decentralized water systems a reality for cities nationwide through innovative modeling. “People often don’t consider the reliability and resilience of urban water systems until faced with insufficient or poor-quality water.”
Liu answers a few questions on what could be the future of America’s water systems.
What are some examples of small-scale treatment?
Small-scale treatment can range from advanced filters inside individual homes to treatment at tanks serving clusters of homes or commercial, industrial, and agricultural facilities. A good example is the decentralized water system in San Francisco, where on-site water recycling systems in new buildings supplement the buildings’ water needs. In a few years, these buildings could become completely self-sufficient or water-neutral with on-site distributed water systems.
What are the benefits of cities investing in decentralized water systems?
It can be cost-effective: Reusing water can be more cost-effective than developing other alternative supplies, provided there is a robust business model and supportive governance. It’s environmentally sound: Reusing water reduces pressure on freshwater sources. It’s safe: Properly treated reclaimed water can be safe to drink and may even contain fewer toxins than current water sources. And it can be locally controlled: Communities gain more autonomy in meeting their water demands without relying on external sources.
How are citizens reacting to wastewater recycling?
Wastewater recycling for non-potable uses has been implemented to supplement local water supply in many U.S. cities. However, potable reuse often faces challenges due to public skepticism about its safety, reliability, and appropriateness. Direct potable reuse (DPR) remains a highly controversial water reuse system with low public acceptance, primarily due to the explicit connection between wastewater and drinking water.
What role does tech play in the future of reusable water?
Technology is crucial in ensuring that water meets safety standards and complies with environmental regulations. Developers need to focus on creating low-cost water treatment technologies that are affordable for underserved communities with limited resources.
What can people do at home to support our water systems?
Save and reuse water within your capacity. For example, use a rain barrel to collect rainwater for irrigation instead of using tap water. This reduces the burden on the city’s stormwater drainage system during storms and conserves water for daily activities.