Two-stage reverse osmosis equipment is also called two-stage reverse osmosis. The raw water is pressurized and sent to the pretreatment system for coarse filtration, and then filtered through the precision filter, and then sent to the first-stage reverse osmosis system under pressure by a high-pressure pump. The output water is pressurized by a two-stage high-pressure pump to the two-stage reverse osmosis system to produce product water, which is called two-stage reverse osmosis.

Two-stage reverse osmosis is a process in which the permeated water of the first stage of reverse osmosis is adjusted to its PH value and then sent to the second stage of reverse osmosis system by the second stage of high-pressure pump for treatment, thereby obtaining permeated water.
The desalination rate of the first-stage reverse osmosis system is ≥99.5%. In this way, raw water with a salt content of less than 1000 ppm can be directly processed without ion exchange to reach the level 3 water standard of "GB6682-2008" used by the National Laboratory of China.

Main configuration of two-stage reverse osmosis:  

1. Pre-system: raw water pump, multi-media filter, activated carbon filter, automatic water softener, pipe, valve 

2. DRO reverse osmosis system: primary high pressure pump, secondary high pressure pump, reverse osmosis membrane, reverse osmosis membrane shell, membrane frame, control system water inlet, solenoid valve, flush solenoid valve, pressure regulating valve, high pressure switch, low pressure switch, precision Filters, wire mesh, valves.

3. Storage system: liquid level controller, water tank.