2 Stage Reverse Osmosis System

2 stage reverse osmosis systems, with their two-stage series deep desalination process, have become essential water treatment equipment in the fields of industrial pure water and ultrapure water production.

Overall, a 2 stage reverse osmosis system integrates five major units: pretreatment, first-stage reverse osmosis, interstage buffering, second-stage reverse osmosis, and intelligent electronic control. It relies on two-stage membrane separation filtration to achieve double-layer interception of impurities in the water, producing stable, low-conductivity, high-purity water.

1. Overall desalination rate: ≥99.5%
2. Secondary product water conductivity: 0.5–5 μS/cm (at room temperature, 25℃)
3. System overall recovery rate: 70%–85%
4. Feed water requirements: SDI (sludge density index) <5, residual chlorine <0.1 mg/L, turbidity <1 NTU
5. Operating pressure: Stage 1 0.8–1.2 MPa, Stage 2 1.5–2.0 MPa
6. Operation mode: 24-hour continuous fully automatic water production, supporting intermittent start/stop
7. Applicable raw water TDS: ≤3000 mg/L (municipal tap water, groundwater, surface water)

In comparison, 1 stage reverse osmosis has an overall desalination rate of 90%-98%, and its product water conductivity is mostly between 5–50 μS/cm. The overall desalination rate of a 2 stage reverse osmosis system can be stably maintained at ≥99.5%, and the conductivity can be stably controlled within 0.5–5 μS/cm. Therefore, a 2 stage reverse osmosis system must be selected in areas with poor water quality or when higher water quality is required.

The pretreatment unit of the 2 stage reverse osmosis system manufactured by Foren is equipped with a quartz sand filter, activated carbon filter, and softening system, along with an online antiscalant dosing system to inhibit scale formation on the membrane surface in real time. The final precision filter intercepts particles leaking from the pretreatment process, significantly extending the lifespan of the reverse osmosis membrane and making it suitable for complex raw water conditions such as high-hardness well water and high-turbidity surface water.

The equipment is equipped with dedicated high-pressure vertical booster pumps for both stages, ensuring stable pressure output. The membrane elements are low-pressure, fouling-resistant reverse osmosis membranes, supporting customized flow rates from 0.25t/h to 100t/h. Both stages are equipped with independent permeate and concentrate flow meters and online conductivity monitoring instruments, allowing for real-time and intuitive monitoring of the purification effect of each stage.

The entire system features an integrated stainless steel frame, with optional UPVC industrial piping and 304 food-grade stainless steel piping. Key components are selected from mature and durable industry models, eliminating the use of cheap, non-standard parts. The unit is equipped with an integrated electrical control cabinet and a touchscreen interface, incorporating automatic flushing, high and low pressure protection, water shortage shutdown, automatic concentrate adjustment, water quality exceeding alarm, and fault code display functions. It also features automatic flushing upon startup and timed membrane cleaning programs, reducing the frequency of manual operation. And, we can add an ultraviolet sterilizer and a microporous precision filter after the 2 stage reverse osmosis system to inhibit bacterial growth in the pure water tank and meet sterile water standards.

Qingzhou Foren Water Treatment Equipment Co., Ltd. has over ten years of experience in manufacturing reverse osmosis water treatment equipment. We consistently adhere to the principle of "focusing on products and putting customers first," and have won unanimous praise from our customers with excellent products and a comprehensive service system.