August 2025 What's on Tap Employee Newsletter

The NRRRF “ treats the wastewater to a high standard, but not a drinkable standard, ” Berglund says. Water from this facility is usable for non - potable purposes — such as flushing toilets, washing cars, irrigation, and filling decorative fountains and ponds. The NRRRF provides some reclaimed water for non - potable reuse through the Raleigh Reclaimed Water Distribution System but discharges most of the water into the Neuse River. “ Indirect potable reuse ” recycles water by introducing treated wastewater to an environmental buffer, such as a river, lake, or aquifer, then withdrawing and treating water again for distribution to a consumer base. “ Indirect potable reuse can provide more assurance in the mind of the consumer that the water is clean, ” Berglund says. But what about direct potable reuse? Directly Drinkable In a “ direct potable reuse ” approach, reclaimed water would directly be treated to drinking water standards and distributed without being stored in an intermediate water body. Once cleaned to the appropriate water quality standard, the water would then reenter the potable water supply. “ On the infrastructure side, direct potable reuse can be efficient, ” says Berglund. There is no need for a separate reservoir or a buffer, and unlike non - potable reuse dual systems, “ you don ’ t need a separate pipe system to deliver non - potable water. ” Instead, direct potable reuse is conveyed using the existing drinking water pipe network. One drawback of direct potable reuse, Berglund says, is that the process can be energy intensive, especially for direct potable reuse systems that rely on “ reverse osmosis ” — an advanced process that uses high pressure to push water through a semipermeable membrane. Berglund says that a direct potable reuse system can be effective when compared with non - potable or indirect potable reuse and that reclaimed water is a good alternative for a secondary source of water. Her team is working to demonstrate how this system would work on a laboratory scale, and Berglund says it will take time and testing to find the treatment approach that will scale up for the Raleigh water supply. The Pipeline to New Policy Given the risks to public safety, water reuse regulations and policy do not allow for distribution of direct potable reuse on a large scale, yet. Although the researchers haven ’ t found a perfect solution, “ there ’ s a potential pathway for direct reuse to happen in the city of Raleigh, ” Berglund says. “ Demonstrating that this technology works and demonstrating how much it ’ s going to benefit the community and our future water supply ” is the first step for crafting plans for policy and infrastructure. “ On the east coast, we ’ re water rich, ” Berglund says, “ so direct potable water reuse is something we haven ’ t thought a

lot about or implemented. ” So, to better understand what reuse could look like outside of the lab, the researchers have turned to policies from other states. “ California, Colorado, and Texas all have potable reuse programs, so we ’ ve explored what ’ s in their regulation, ” Berglund says. To craft solutions for North Carolinians, the researchers are working to identify the most im portant and relevant components. “ Since water supply planning happens in decades, it is important that we conduct this research now, ” says Wheeler about Raleigh Water ’ s collaboration with Berglund and Aziz ’ s team. “ I am confident that NC State ’ s Department of Civil, Construction and Environmental Engineering can lead the way for North Carolina. ” There ’ s only so much water to go around, Berglund says. “ And we need new sources. ” New dams and reservoirs aren ’ t always options, and direct potable reuse can help meet the needs of the present, protect supplies in times of crisis, and preserve resources for future generations. “ Reuse builds resilience, ” she says, “ not just sustainability. ”

(retrieved from: Soetebier, L. 2025, July 9. Waste Not, Want Not, Coastwatch. Summer 2025).