WaterSurplus, a company focused on sustainable water treatment technologies, announced that its NanoStack membrane coating has been certified under the NSF/ANSI/CAN 61 standard. Certified by IAPMO R&T, North America’s leading agency for plumbing and mechanical product compliance, the NanoStack coating is now confirmed to be safe for use in drinking water applications.

This milestone is significant for NanoStack technology, as it is a key component of WaterSurplus’s ImpactRO brackish water reverse osmosis (BWRO) platform. This platform combines multiple advancements to improve performance and efficiency in high-fouling environments.

Technology review

NanoStack is based on a bio-inspired polymer that generates an ultra-hydrophilic membrane surface that is resistant to fouling and scaling. This coating allows contaminants to naturally wash away during operation, thereby extending the time between cleaning cycles. When cleaning is required, NanoStack-coated membranes nearly fully recover their original permeability and performance. This results in higher uptime, longer membrane life, and more stable operation across BWRO systems.

Conventional uncoated RO membrane elements, according to the company, often experience rapid flux decline and require frequent cleaning in challenging feedwater conditions. This reduces both service life and long-term efficiency.

System performance and applications

NanoStack-coated membranes used in the ImpactRO system have demonstrated up to 96% product recovery, a fourfold reduction in fouling and downtime, and twice the membrane life compared to conventional multi-stage BWRO systems. These characteristics make the technology ideal for high-recovery, high-efficiency, and reuse applications where the potential for fouling is significant.

NSF/ANSI/CAN 61 compliance

NSF/ANSI/CAN 61 is the internationally recognized benchmark for drinking water product safety and quality. This certification involves a comprehensive evaluation of materials, manufacturing practices, and product performance, supported by ongoing audits and periodic retesting to verify sustained compliance.

“NSF certification is an important milestone in the commercialization of NanoStack membranes and other of our technologies. With NSF certification of our NanoStack coating, WaterSurplus now owns two products―NanoStack membrane coating and OxiPlus™ high-flow, catalytic filter media―that have achieved NSF/ANSI/CAN 61 certified status,” said Dileep Agnihotri, Chief Technology Officer of WaterSurplus.