Two common desalination processes for reverse osmosis equipment

Reverse osmosis equipment is also called water purification equipment, there are many industries in the use of water purification equipment for the desalination rate requirements are extremely high, then today we will introduce you to two common desalination water treatment equipment process, I hope to be able to help you.


First, in the reverse osmosis equipment in electrodialyzer will be with other water treatment equipment joint desalination system

Electrodialysis is generally used for the local desalination of high salinity and high hardness brackish water for deep desalination depth treatment.

As electrodialysis desalination has its application range, in the application, it should be based on the requirements of raw water quality and desalination water quality, combined with ion exchange water treatment technology, to give full play to the advantages of each in the water treatment process, in order to achieve reasonable technical requirements. Economic efficiency and operational stability. The commonly used reverse osmosis equipment systems are as follows.

1, pretreatment electrodialysis ion exchange
The system combines electrodialyzer and ion exchanger, which has been early and widely used at home and abroad.
The combination principle is that when the resistivity of the water in 20 * 104 _ ucm or more, electrodialyzer is easy to polarize, can not continue to adapt; on the contrary, the ion exchange can be adapted to the treatment of low-salt content of the water can produce high purity water. Therefore, in this combined water treatment system, electrodialysis is used as a pretreatment for ion exchange water treatment to remove most (60%-90%) of the salt in the raw water, and a small portion of the remainder can be further removed by ion exchange to produce desalinated water.
According to the desalinated water quality requirements, ion exchange can be used in the form of single bed, double bed, mixed bed or other different combinations. The system has good water quality, stable operation, low regenerant dosage, and strong adaptability to the change of salt content of raw water. It is suitable for salty water or coastal areas affected by seawater recharge.
The joint desalination water treatment system has been widely used in electric power, chemical industry, light industry, electronics and other fields.

2、Pre-treatment ion exchange electrodialysis

3、Pre-treatment ion exchange (softening), electrodialysis ion exchange (softening)
In the reverse osmosis equipment combination system, electrodialysis before and after the ion exchange softening treatment, this is because the pre-softening can prevent the electrodialyzer scaling blockage, improve the efficiency of electrodialysis desalination. Ion exchange softening treatment after electrodialysis can further reduce the hardness and relative alkalinity of water to ensure the quality of medium and low pressure boiler feed water.
Application of electrodialysis in water treatment
Brackish water and seawater desalination, seawater concentration salt, pure water preparation, industrial wastewater (electroplating wastewater, paper wastewater, heavy metal wastewater), radioactive wastewater, reverse osmosis equipment, ionic membrane electrolysis and other treatment.

Second, reverse osmosis equipment in electrodialyzer body process system

Select economically rational reverse osmosis equipment electrodialysis process system (i.e., desalination) is an important part of electrodialysis desalination process design. Generally should be based on the raw water quality, water quantity and water quality requirements, determined by technical and economic comparison.
Reverse osmosis equipment commonly used in the desalination method of direct current method, cycle method and part of the cycle method.

1, reverse osmosis equipment direct current desalination: raw water by one or more tandem electrodialyzer, can achieve the required water quality. Applicable to the water and raw water concentration is constant. The advantage of this method is continuous water supply and simple piping. The disadvantage of this method is that the water quality of the output water of the stereotyped equipment changes with the change of the salt content of the raw water.

2, reverse osmosis equipment cycle desalination:
The raw water is recycled many times in the electrodialyzer and the water tank to achieve the ideal quality of the effluent water. Its advantage is that no matter how the concentration of raw water changes, the raw water can be treated to any required level, the flow rate is high, the desalination speed is fast, and the volume of electrodialyzer is small. The disadvantage is that it needs to set up circulating pump and water tank, only intermittent water supply, high power consumption. Suitable for small production of water, high salt content of raw water, water quality requirements of small equipment.

3, reverse osmosis equipment part of the cycle of desalination:
It is the combination of direct current desalination and circulating desalination. In the partial cycle desalination process system, electrodialyzer fresh water is divided into two ways, one is continuous water for users, the other is to return to the electrodialyzer and the water phase in the water mix to continue desalination. It is characterized by the use of stereotyped equipment, which can meet the requirements of different water quality and water quantity. When the salt content of the raw water changes, the circulation volume can be adjusted to ensure the stability of the effluent water quality, but the system is complex, high energy consumption. It is suitable for large-scale water treatment system.