01 Reverse osmosis membrane element structure
The desalination layer is very thin (about 200 nm).
The desalination layer is applied to a support layer (approx. 45 microns thick) of polysulfone material
The polysulfone support layer adheres to the base layer of the polyester nonwoven fabric (approx. 100 microns thick).
The pressurized inlet water passes through the inlet water grid in the direction of the axis.
The pressure forces some of the influent water to pass through the membrane, and most of the dissolved salts remain on the inlet side of the membrane, and the water that permeates the membrane is called permeate water.
Permeate is collected by a fresh water separator.
The freshwater separator is located between two flat reverse osmosis membranes.
The permeate eventually flows to the central permeate pipe.
An 8-inch membrane element consists of many sheets.
02 Reverse osmosis membrane module
Membrane Module, Membrane Element, Pressure Vessel.
In a reverse osmosis system, many membrane elements are connected in series in a pressure vessel through connectors, usually one.
The pressure vessel is equipped with 6-7 reverse osmosis membrane elements.
The pressure vessel has a water inlet, a concentrated water outlet, and a central water outlet.
03 ** rate and concentration rate
With a highly desalination membrane element, the concentration factor gives us an intuitive impression of how many times the salt in the concentrated water has been concentrated. 04 Permutation
The combination of pressure vessels equipped with membrane elements is commonly known as arrangement. The stage refers to how many times the concentrated water has been filtered by a pressure vessel, and the stage refers to how many times the produced water has been filtered and separated.
1-stage system:Low ** rate SWRO (45).
2-stage system:bwro（＜80％）；High ** rate SWRO (60);Level 2 high rate system (90).
3-segment system:High ** rate BWRO (90);Level 2 High Yield System (95).
05 Inter-section booster pump
The inter-section booster pump is used to balance the inter-section flow rate and the best rate. 
06 Permeate back pressure
When the water level of the production tank degassing tower is higher than that of the RO system, it is easy to produce water back pressure.
Permeate back pressure can also be used to balance the permeate flux and rate of each section, the common method is to adjust the water permeate of the first and second stages of the membrane element, which can be achieved by installing a regulating valve on the first and second sections of the permeate pipeline.
07 Throughput
The average system flux and the maximum flux of the membrane element are important factors influencing the good operation of the RO system. Different permeate fluxes are recommended for different raw water and pretreatment methods. 08 Desalination rate
Removal is the ability of specific dissolved ions and compounds to be retained on the inlet side of the membrane element.
Salt permeability is defined as the ratio of the concentration of dissolved ions or complex salts in osmotic to the concentration of the same ions or compounds in the influent water.
09 Differential pressure
Differential pressure = inlet pressure Concentrated water pressure.
An increase in the normalized differential pressure indicates that the membrane system is contaminated.
Causes of the increase in differential pressure:
1) Front: membrane contamination (staining of suspended solids, colloids, bacteria, silt, clay, iron corrosion and pretreatment coagulants).
2) Rear: Scaling.
3) Any part: biological contamination (this article ** New Vision of Water Treatment, for your reference only, learn Xi, if there is any infringement trouble, please contact to delete, thank you).