Double-Pass Reverse Osmosis Process
In a double-pass reverse osmosis (RO) system, raw water—such as tap water, surface water, or groundwater—is first pressurized and sent through the pretreatment system for coarse filtration.
After further filtration, the pretreated water is pressurized by the first-stage high-pressure pump and fed into the first-pass RO system. The permeate produced by the first RO stage is then pressurized by a second-stage high-pressure pump and treated again through the second-pass RO system.
This two-stage purification process is known as double-pass reverse osmosis, providing higher water purity and lower conductivity than a single-pass RO system.
Process Flow
Raw Water → Pretreatment → Filtration → First-Pass RO → Second-Pass RO → Purified Water
Double-pass RO systems are suitable for feed water with conductivity above 500 μS/cm.
Typical Product Water Conductivity: 1–10 μS/cm
The system is widely used in applications requiring high-purity water, including industrial manufacturing, electronics, pharmaceuticals, chemical processing, and other production processes.