High salinity in wastewater is a significant challenge for water reuse, often requiring advanced treatments like reverse osmosis (RO). However, RO can create additional issues, including a waste stream that’s difficult to manage. In a recent interview with Treatment Plant Operator, Dr. Eva Steinle-Darling, water reuse technical practice director at Carollo Engineers, shared how Ion-Exchange-Based Advanced Treatment (XBAT) is offering a promising alternative.
An Innovative Alternative to Reverse Osmosis for Salinity Reduction
“Salinity is an Achilles’ heel for potable reuse,” Eva explains. While RO effectively reduces salinity, she notes, “it comes with the downside of a 15-20% brine concentrate that has to be managed.” For communities where brine disposal options like deep-well injection or ocean discharge are limited, this creates major obstacles.
Eva says XBAT provides a completely different approach. “It removes up to 50% of the salinity in the water while also addressing TOC, nitrate, bromide, and other anionic species. This makes it a versatile solution for a variety of water-quality challenges.”
How Ion-Exchange-Based Advanced Treatment (XBAT) Improves Potable Reuse
Describing the process, Eva highlights that XBAT uses suspended ion exchange (SIX® – developed by PWNT)—a fluidized version of traditional ion exchange—combined with softening. Unlike conventional systems, the resin beads in XBAT are regenerated continuously using a bicarbonate solution. “We regenerate the beads with bicarbonate… that enables us to do ion exchange without adding salinity to the water,” Eva says.
This innovative process doesn’t just reduce salinity. According to Eva, “It removes nitrate, phosphate, and bromide, solving problems that other treatment technologies often can’t address. And with a waste stream that’s less than 1% of the total flow, XBAT offers a more sustainable option.”
Sustainable Water Treatment: Reducing Waste While Improving Water Quality
While XBAT is still in the pilot phase, Eva shares promising results from bench-scale and pilot-scale testing. “We’ve achieved about 50% salinity reduction and 50% TOC reduction in several wastewater applications. Depending on the water, we’ve seen reductions of 60% for chloride and bromide, 70% for nitrate, and over 90% for sulfate,” Eva explains.
The potential of XBAT technology is setting the stage for a new era in sustainable water reuse. Learn more about the technology, its applications, and the pilot testing process by reading the full interview in Treatment Plant Operator magazine.