[Chinese Mainland] CHN Energy's Saline Water Reverse Osmosis Patent Wins China Patent Excellence Award: Cascade Concentration Process Solves the Challenge of Zero Liquid Discharge for High-Salinity Wastewater

CHN Energy Research Institute's "Reverse Osmosis Treatment Method and Reverse Osmosis System for Saline Water" invention patent won the 26th China Patent Excellence Award. Based on the principle of osmotic pressure-assisted pressure-driven membrane processes, this patent proposes a cascade ultimate concentration process, achieving deep concentration of high-salinity brine under low operating pressure. It has been promoted to more than 10 users inside and outside the Group in scenarios such as desulfurization wastewater, chemical wastewater, mine water, coking wastewater, and electronic wastewater.

I. Patent Award: Solving the "Bottleneck" Problem of Reverse Osmosis Concentration of High-Salinity Brine

2026 年 8 月 28 日, the China National Intellectual Property Administration announced the award decision for the 26th China Patent Award. The invention patent "Reverse Osmosis Treatment Method and Reverse Osmosis System for Saline Water" of Guoneng Science and Technology Achievement Transformation (Beijing) Co., Ltd., affiliated with CHN Energy Research Institute (Low Carbon Institute), won the China Patent Excellence Award. This is a landmark intellectual property achievement of CHN Energy in the field of advanced industrial wastewater treatment and zero liquid discharge, and has significant demonstration significance for China's high-salinity wastewater treatment industry.

Currently, typical domestic brine zero liquid discharge process routes mostly adopt a three-stage architecture of "pretreatment—membrane concentration—evaporative crystallization," in which the membrane concentration unit mostly uses traditional reverse osmosis technology. Limited by operating pressure, the concentration limit of traditional reverse osmosis is relatively low, and large amounts of concentrated water cause excessively high loads on the terminal evaporative crystallization unit. For a long time, the industry has generally relied on "increasing operating pressure" to achieve high-salinity brine concentration, resulting in problems such as high investment and operating costs, short membrane element lifespan, and high safety risks. This patent proposes a solution precisely for this "bottleneck" problem.

II. Technical Route: Osmotic Pressure-Assisted Pressure-Driven + Cascade Ultimate Concentration

The core innovations of this patent include two aspects:

• Membrane material innovation—Based on the principle of osmotic pressure-assisted pressure-driven membrane processes, a series of high-salinity reverse osmosis membrane products with precisely controllable separation performance has been independently developed, providing differentiated rejection rates and flux performance for different salt concentration gradients.
• Process innovation—A cascade ultimate concentration process based on reverse osmosis units with different salt fluxes is innovatively proposed. Through the series combination of multi-stage reverse osmosis units, the operating pressure and membrane separation performance are precisely regulated at each stage according to the salinity level of the feed water at that stage, thereby achieving efficient deep concentration of high-salinity industrial wastewater under low operating pressure, greatly reducing the discharge volume of concentrated brine and effectively alleviating the cost burden of enterprise wastewater treatment.

The engineering significance of cascade concentration lies in the following: the low-pressure stage retains the low-energy-consumption advantage of conventional reverse osmosis, while the high-pressure stage only pressurizes the small amount of high-concentration water that is most difficult to concentrate. Overall energy consumption, membrane replacement costs, and the scale of the evaporative crystallization unit are significantly reduced, providing a more economical engineering path for zero liquid discharge of high-salinity wastewater.

III. Engineering Progress: From 2020 年 Demonstration to Promotion to More Than 10 Users

Since 2020 年 completed the first industrial demonstration project at Guoneng Changyuan Hanchuan Power Generation Co., Ltd., this patented technology has successfully achieved large-scale application across industries and fields. It has currently been promoted to more than 10 users inside and outside the Group, covering typical high-salinity scenarios such as desulfurization wastewater, chemical wastewater, mine water, coking wastewater, and electronic wastewater. Among them, the Guoneng Changyuan Hanchuan Power Generation project is one of China's first engineering demonstrations applying "cascade reverse osmosis + evaporative crystallization" to zero liquid discharge of desulfurization wastewater from power plants, verifying the engineering feasibility of achieving a recovery rate of more than 70% under low operating pressure and reducing the terminal evaporative crystallization load by nearly half.

This patented technology has incubated a startup enterprise through a technology licensing model—Beijing Nasiliwan Environmental Protection Technology Co., Ltd.—promoting the transition of this patented technology from the laboratory to industrialization, further expanding the market coverage of the technological achievements and significantly enhancing market competitiveness.

IV. Implications for TIANYI TECH's High-Salinity Wastewater Process Package

TIANYI TECH has long been engaged in industrial wastewater advanced treatment and zero liquid discharge process packages. The engineering progress of CHN Energy's cascade reverse osmosis patent brings three implications for the company:

• Process Combination Upgrade — The two-stage membrane concentration combination of cascade Reverse Osmosis + evaporative crystallization can replace the traditional "high-pressure RO + multi-effect evaporation" pathway, with the per-ton water operating cost expected to decrease by 15%—25%. The company can introduce this type of process combination in high-salinity scenarios such as chemical, coal chemical, power plant desulfurization, and electronics.
• Membrane Element Localization Synergy — The window for localized substitution of high-salinity Reverse Osmosis series membrane products has opened. The company can collaborate with domestic membrane manufacturers to carry out "process + membrane element" synergistic optimization, forming more cost-effective process packages.
• Zero Liquid Discharge and Carbon Footprint — Cascade Reverse Osmosis directly reduces power consumption by lowering operating pressure, and combined with the reduced evaporative crystallization load, indirectly lowers steam consumption. The company can highlight the "membrane cascade + waste heat utilization" synergistic pathway in low-carbon Zero Liquid Discharge project proposals, enhancing project carbon footprint competitiveness.

Source: Toutiao "Voice of National Energy" 2026-09-04 "An Invention Patent from CHN Energy Research Institute Won the China Patent Award".

About TIANYI TECH

TIANYI TECH is an international water service provider specializing in the R&D, engineering general contracting, and operation & maintenance services of wastewater treatment and Reclaimed Water Reuse equipment. Its business covers the full chain of scenarios including advanced Industrial Wastewater treatment and Zero Liquid Discharge, centralized Domestic Sewage and Industrial Park wastewater treatment, Reclaimed Water utilization, seawater desalination pretreatment, and sludge resource utilization. With "TIANYI LIMITED" as its unified brand identity, the company has deeply cultivated markets along the "Belt and Road" in Southeast Asia, the Middle East, and Africa, providing customers with full-cycle solutions from feasibility study, design, equipment manufacturing, installation and commissioning to operation trusteeship.