Salinity poses a significant obstacle to reuse as wastewater effluents often contain elevated salinity levels compared to traditional water sources. Salinity removal typically relies on reverse osmosis (RO)-based advanced treatment (RBAT). This approach presents waste stream challenges, especially for inland communities where ocean discharge is inaccessible or deep well injection is restricted and where 8-15% water loss as a brine waste stream is deemed unacceptable.
Existing alternative advanced treatment methods, such as carbon-based advanced treatment (CBAT), do not produce a brine waste, but cannot address elevated influent salinity. Thus, both RBAT and CBAT advanced treatment approaches have significant salinity management limitations.
XBAT, for which Carollo holds two provisional patents, heralds a new era in water treatment by leveraging cutting-edge technology to simultaneously target salinity and other challenging water quality parameters. One such parameter, total organic carbon (TOC), is a crucial constituent that must be controlled to prevent the formation of disinfection byproducts or reduction in oxygen demand in receiving waters. XBAT also has the capacity to remove anions, such as nitrate, phosphate, and bromide, thus solving a wide range of pervasive and previously intractable water quality challenges.
By integrating suspended ion exchange (SIX) with lime softening processes, XBAT achieves unmatched performance in reducing salinity and TOC without relying on RO and its associated disposal challenges. Notably, XBAT's regeneration waste stream comprises only 0.8% of the total feed water flow, thereby minimizing environmental impact, while maximizing resource utilization.
Key features and benefits of XBAT include:
- Multi-contaminant removal without RO: XBAT's high TOC removal rates (averaging 50%), salinity reduction, and problem-anion removal capabilities ensure high-quality water production that meets stringent regulatory standards.
- Minimal waste with reuse potential: With a waste stream comprising only 0.8% of the total feed water flow, XBAT maximizes resource utilization while mitigating environmental impact. This waste stream is not a high-salinity brine and its high alkalinity opens opportunities for beneficial treatment of the brine or recycling within upstream wastewater treatment processes.
- Exceptional performance: XBAT achieves impressive removal rates, up to 90% for sulfate and 30-70% for chloride and bromide, with better performance if the respective starting levels are high or the overall total dissolved solids is low.
- Lime softening: XBAT achieves greater than 90% calcium and magnesium removal, further enhancing water quality.
XBAT can achieve required water quality goals while avoiding disinfection byproduct formation and minimizing waste streams. This enables inland communities to unlock the potential of reuse and achieve a diversified and secure water supply portfolio as described by Carollo's Water Reuse Technical Practice Director Eva Steinle-Darling: "XBAT signifies a transformative evolution in water treatment, particularly for communities facing moderate salinity obstacles. By providing an alternative to RO-based methods, XBAT empowers utilities to enhance efficiency, reliability, and sustainability while advancing the future of responsible water management."
Carollo is currently upscaling evaluations of XBAT with an advanced wastewater treatment pilot at the City of Tampa, Florida, and a direct potable reuse treatment feasibility assessment at Aurora Water, Colorado.
About Carollo Engineers
For 90 years, Carollo Engineers has provided a full range of innovative planning, design, and construction management services to address the water needs of municipalities, public agencies, private developers, and industrial clients. Carollo develops robust water management strategies that leverage collaboration, provide multi-benefit solutions, and achieve sustainability and resilience. Carollo has nearly 1,400 employees located across North America. To learn more about how Carollo is "Working Wonders With Water®" call (800) 523-5826 or visit www.carollo.com
SOURCE Carollo Engineers
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