Improve Water Purity with Dual-Stage Ro Systems

 In high-end industrial fields such as electronic chip manufacturing and biomedical research and development, the purity of water directly determines the yield and safety of products. Double-stage reverse osmosis process through two-stage tandem membrane separation technology, the water ions, organic matter and microorganisms in the removal rate increased to more than 99.7%, becoming the core process of high-purity water preparation.

Process: Precision purification from raw water to ultrapure water

 The two-stage reverse osmosis system adopts the tandem structure of “pretreatment + two-stage membrane filtration”:

1.Pre-treatment stage: the raw water first enters the raw water tank, pressurized by the raw water pump, and then passes through the multi-media filter (quartz sand layer to retain suspended solids), activated carbon filter (adsorption of residual chlorine and organic matter), softener (sodium ion exchange to remove calcium and magnesium ions), and finally through the precision filter (5 μm PP cartridge to intercept particles) to complete the initial purification.

 2.First-stage reverse osmosis (RO): pre-treated water is pressurized to 15-25 bar by a high-pressure pump and enters the first-stage RO membrane module. The use of polyamide composite membrane (such as CPA3 type), can remove 90% -95% of dissolved salts, organic matter and microorganisms, water conductivity down to 10-15 μS/cm.

 3.Secondary reverse osmosis (RO): the first RO produced water by pH adjustment (adding NaOH neutralization of CO₂), by the second high-pressure pump pressurized to 12-15 bar, into the second RO membrane module. Using ultra-low pressure membrane (such as ESPA2 type), to further remove residual ions, the conductivity of produced water is stable ≤ 0.8 μS/cm, desalination rate ≥ 99.5%.

 4.Post-treatment and storage: After the secondary RO produced water is sterilized by UV (254nm wavelength) or ozone, it enters the pure water tank for storage, and is finally transported to the point of water consumption through the pure water pump.

Technical Advantage: Balance of Efficiency, Cost and Reliability

 1.High-efficiency Desalination: The two-stage filtration makes the system's retention rate of monovalent ions reach 99.7%, and the retention rate of divalent ions exceeds 99.9%, which is far more than that of the single-stage RO system.

 2.Cost optimization: After upgrading the two-stage RO of a photovoltaic enterprise, the dosage of mixed-bed resin is reduced by 80%, which saves 500,000 RMB annually; the energy consumption of the system is reduced by 40%, and the cost of the unit of produced water is reduced from 8 RMB/ton to 3 RMB/ton.

 3.Stable operation: through redundant pump configuration and split water supply strategy, 70% of the capacity can still be maintained when a single pump fails; membrane element grouping control to achieve online cleaning (CIP), the system availability rate of more than 99.5%.

Application scenarios: full chain coverage from laboratory to industrialization

 Electronics industry: providing ultrapure water for 12-inch wafer cleaning to ensure that photoresist coating is free of impurity defects;

 Pharmaceutical field: preparing water for injection (WFI) to meet the stringent standard of endotoxin <0.25 EU/mL;

 New energy field: cleaning electrode materials of lithium batteries, to avoid the degradation of battery capacity caused by metal ion contamination.

 From the microscopic molecular sieving to the macro industrial upgrading, two-stage reverse osmosis process is “invisible precision” to support the modern industrial “water quality lifeblood”. With the breakthroughs of graphene membrane, intelligent monitoring and other technologies, this system will continue to evolve to provide purer and more efficient water quality solutions for high-end manufacturing.