Tips Of Selecting The Valve For Brackish Water Treatment

Brackish water is when the chloride in a water source exceeds the normal range. Brackish water is formed mainly due to excessive water use, or when the water level is below sea level due to changes in the earth’s crust, when seawater is backed up, or when surface water flows through saline areas. Since chloride is different from other substances, it can be removed by using some kind of filter media, and the process of removing chloride is generally treated by reverse osmosis technology, which is a water treatment technology developed in recent years, especially for the treatment of chloride in water, so that the salt water can be desalinated or treated to meet the drinking water standards. Brackish water contains many heavy metals and harmful impurities, bitter taste, it is difficult to drink directly, long-term consumption leads to gastrointestinal disorders, low immunity. Therefore, brackish water treatment is necessary.

At present, most of the brackish water desalination method uses distillation, reverse osmosis and electrodialysis method.

● Distillation method: Distillation is the process of heating brackish water or seawater to make it boil and evaporate, and then condensing the steam into fresh water. There are many kinds of distillation methods, such as multi-effect evaporation, multi-stage flash distillation, pressure vapor distillation, membrane distillation, etc.

● Electrodialysis: Electrodialysis is a separation technique that uses ion exchange membranes to separate anions and cations in brine under the action of an electric field, thereby reducing the concentration of salt in the freshwater chamber and obtaining fresh water.

● Reverse osmosis: Reverse osmosis is a widely popular water treatment method in the world today. Under the action of external force, the solute in the solution is forced to separate from the solvent with the help of the retention effect of semi-permeable membrane, thus achieving the purpose of concentration, purification or separation. Not only can remove various ions in water, but also particles larger than ions, such as most of organic matter, colloids, viruses, bacteria, suspended matter, etc. Therefore, reverse osmosis separation method is also known as broad-spectrum separation method. Reverse osmosis brackish water desalination method can remove more than 90 % of dissolved salts and more than 99 % of colloidal microorganisms and organic matter, etc. from water.

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Types Of Valves For Brackish Water Treatment

Regardless of the purification method, valves can help regulate the flow of water, thereby increasing project capacity.

Shut-Off Valves

Shut-off valves are valves that allow the flow of media or shut-off by opening or closing a shut-off part. Ball valves, butterfly valves, gate valves and globe valves are all shut-off valves. They are used in a wide variety of water treatment facilities and help regulate water flow. They are easy to operate, easy to maintain, and can effectively increase project capacity.

Can be used with electric or pneumatic actuators to achieve the purpose of remote control and reduce labor costs.


The Y-strainer contains a strainer for filtering impurities in the pipeline, making the medium purer and thus extending the service life of industrial fittings such as pipes, valves and pumps.

Check Valve

Check valve is a valve that relies on the pressure of the pipeline to start, to prevent the backflow of media. They are generally used next to pumps, water meters, or other electrical equipment to prevent backflow of media back into the electrical equipment and reduce maintenance costs.

Choosing the right valve for a brackish water treatment plant will allow the system to operate well and increase capacity. Any demand for valves, feel free to consult us for a free valve solution.

Tips For Selecting The Valve For Surface Water Treatment

Surface water refers to the water that exists on the surface of the earth’s crust and is exposed to the atmosphere. It is one of the important sources of water for human life and the main component of water resources in various countries. But surface water contains a variety of impurities, including algae, sediment, suspended solids, colloids, bacteria, viruses, heavy metals, antibiotics, and more. Through surface water purification treatment, after reaching the drinking standard stipulated by the state, it can be used as drinking water.

The surface water purification process is as follows:

● Pre-oxidation: deodorization, algaecide, sterilization, pre-oxidation or conversion of pollutant

● Air flotation: micro-bubbles catch and adsorb fine particles of sticky matter, reducing turbidity

● Coagulation and precipitation: adding coagulant to water, destabilizing and coalescing of colloid in water through its hydrolyzate, or hydrolyzing and polycondensing coagulant to form high polymer, which binds colloid through adsorption and bridging. Precipitate large particles and reduce turbidity

● Filtration: Absorb suspended particles, colloidal impurities, bacteria and fine flocs in water

● Disinfection: The purpose of disinfection is to prevent the transmission of diseases through drinking water and to eliminate the pathogenic effects of pathogenic microorganisms in the water. Pathogenic microorganisms include bacteria, viruses and protozoan cysts. Disinfection also has the function of preventing secondary pollution during water distribution and short-term storage of water tanks

● Advanced treatment: In order to ensure the safety of water quality, we also use main ozone, activated carbon filtration and other methods for advanced treatment of water quality

● Large-scale municipal water supply equipment: the horizontal centrifugal pump in the secondary pump room delivers the clean water that meets the standard to thousands of households

Application Of Valve In Surface Water Treatment

Valves are essential in surface water purification systems. Valves can help transport water and various chemicals, and build integrated surface water purification systems, increasing production capacity and reducing operating and maintenance costs.

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Type of Valves

Shut-Off Valves

Shut-off valve is a valve used to circulate and shut off flow. By controlling the opening/closing of the opening and closing parts, the purpose of regulating the flow is achieved. Ball valves, butterfly valves, gate valves and globe valves are all shut-off valves and are widely used in various pipelines. Ball valves and butterfly valves are quarter-turn valves, which can be opened or closed by simply rotating the opening and closing parts by 90 degrees. Gate valves and globe valves are linear-operated valves, and the opening and closing parts move up or down in a straight line to open or close the valve.

Whether it is quarter-turn valves or linear-operated valves, they all have their own advantages and can be well matched with various types of pipes to meet your flow regulation needs. The Shut-off valve can also be remotely driven by an electric actuator or a pneumatic actuator, increasing the water production efficiency by 20%.

Check Valves (Non-return Valves)

The check valve is a valve used to prevent the backflow of the medium, which is self-starting by relying on the internal pressure of the pipeline. It is generally used next to electrical equipment such as pumps, water meters, motors, etc. to ensure the safety and normal use of electrical equipment, so as to avoid higher maintenance costs due to downtime.


The Y-Strainer is a valve used to filter impurities, allowing the system to run more smoothly.

Choosing a suitable valve can make the surface water treatment system run more smoothly, let humans have more drinking water, and make our living environment better. Any demand for valves, feel free to consult us at

Tips For Selecting The Valve For Coal Mine Water Treatment

Coal mine water refers to all the water that penetrates into the underground mining space during the coal mining process, and sometimes also contains a small amount of infiltrated surface water. Coal mine water treatment technologies mainly include neutralization of acidic water, flocculation treatment to remove suspended particles, reverse osmosis to remove soluble salts and other technologies and combinations. Take various methods to remove or reduce harmful substances in mine water to make it meet the discharge standard and meet the requirements of the environmental quality standard of the receiving water body, or treat the target water quality of various needs. Mine water generally contains suspended solids mainly composed of coal rock powder and soluble inorganic salts, with less organic pollutants and generally no toxic substances. Therefore, the purification treatment and utilization of mine water will produce huge economic and social benefits.

Clean mine water. Special water pipelines can be set up to lead out for use, and disinfection treatment is required for drinking water.

General mine water. Suspended solids are removed underground or on the ground by sedimentation. One is to use the underground water tank for treatment, divide the water tank into several sections, add flocculant before the mine water enters the water tank, settle and overflow through each section of the water tank, and finally meet the discharge standard. The other is to build a sedimentation tank on the ground, and the mine water is discharged into the sedimentation tank after sedimentation.
When the mine water treatment capacity is small, a combined water purifier is also used. It is equipment that integrates coagulation, sedimentation, filtration and other processes. It has the characteristics of saving one-time investment, small footprint and convenient operation.

High salinity mine water. Commonly used treatment methods are distillation, electrodialysis and reverse osmosis. Electrodialysis is generally used. The electrodialyzer must be strictly pre-treated, the turbidity of the water entering the electrodialyzer should be controlled below 3°, and it should be ensured that Fe, Mn, Cl, etc. meet the specified requirements.

Acid mine water. The neutralization method is adopted, and lime or limestone is used as the neutralizing agent. Usually, there are three technological processes: direct lime addition method, limestone neutralization drum method and open-flow variable filtration rate expansion neutralization method, and the precipitate is formed and then filtered.

Therefore, different treatment processes require different pipes and valves in order to build a suitable mine water treatment pipeline system to maximize the treatment effect. For mine water treatment, the valve materials are stainless steel, carbon steel, duplex steel, UPVC, CPVC or PVDF to meet the needs of various processing technologies.

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Shut-Off Valves

Ball valves, butterfly valves, gate valves and globe valves belong to shut-off valve types. They all have an opening and closing part, which could transport or cut off the water flow by opening or closing the opening and closing parts. They are commonly used valves in water treatment and processing pipelines. Ball valves and butterfly valves are both quarter-turn valves, easy to open and close and easy to operate. Gate valves and globe valves are both linear-operated valves, with large sizes and wide application ranges.
Regardless of the type of shut-off valve, it can be operated with electric actuators, pneumatic actuators or manual actuators.

Check Valves

The check valve is a valve that automatically opens or closes depending on the pressure of the pipeline. It is used to prevent the backflow of the medium in the pipeline and ensure the normal operation of the pump, water flow meter, or other motors.


The Y-strainer is a valve used to filter impurities in the pipeline, making all the fittings in the pipeline work more smoothly, and reducing the downtime and maintenance cost of the pipeline system.

Choosing the right valve can increase the productivity of the entire system and reduce losses due to downtime. Any demand for valves, feel free to consult us for a free valve solution.

Tips For Selecting The Valve For Reverse Osmosis Equipment

What Is Reverse Osmosis Equipment?

Reverse osmosis is a relatively advanced and energy-efficient membrane separation technology in the world today. It mainly uses the osmosis principle of the semi-permeable membrane, and applies a pressure to it in a certain way, which is opposite to the force of the natural osmosis direction, so that the water in the concentrated solution penetrates into the dilute solution. This method is called reverse osmosis. The device composed of reverse osmosis elements is a reverse osmosis device. Since the pore size of the reverse osmosis membrane is very small, it can effectively remove dissolved salts, colloids, microorganisms, organic substances, etc. in water. The system has the advantages of good water quality, low energy consumption, simple process and easy operation.

Reverse osmosis equipment is suitable for water treatment equipment in food, beverage, chemical, electronic and other industries, and can also be used as core equipment for water purification in communities, industrial areas, and oil fields.

Valves Types Used On Reverse Osmosis Equipment

In this system, it is usually applied to butterfly valves, ball valves, check valves, regulating valves, etc. Different pipelines will have different valve requirements.

● Ball valves, butterfly valves, or gate valves will be used at the water inlet to function as circulation or cut-off
● Control valves, check valves, and hard-sealing butterfly valves are used at the pump outlet
● Shut off valve will be used in the concentrated water pipe and product water pipe

In the above three situations, there will be high-pressure pipelines and low-pressure pipelines, and corrosive media will also be generated. Therefore, it is very important to choose the appropriate valve and valve material. According to the characteristics of reverse osmosis equipment, the valve materials used are mainly duplex steel, nickel aluminum bronze, stainless steel, UPVC, CPVC or PVDF to meet the needs of various media.

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Shut-Off Valves

Ball valves, butterfly valves, gate valves and globe valves are shut-off valves. Ball and butterfly valves are quarter-turn valves, while gate valves are linear valves. All three can be used for circulation and cut-off flow, and are used in various types of water supply pipelines.

Check Valves

The check valve is a valve that prevents the backflow of the medium, which is used to protect the normal operation of the system and prevent the pump or motor from being corroded by the backflow of the medium. It helps to increase system uptime and reduce downtime maintenance costs.

Actuator Types Used On Reverse Osmosis Equipment

Today’s manufacturing industry pays attention to production capacity, and in order to increase water production, more and more water treatment equipment will use automatic valves. So how should we choose the right automation actuator?

Drive Method

The electric actuator is driven by current, and can receive and feedback control signals, and is compatible with various control systems, so as to achieve the purpose of remote control of the valve. Pneumatic actuators are driven by gas and need to be equipped with a set of air supply parts, and it is necessary to ensure that the air supply is clean. Pneumatic actuators need to be equipped with positioners to achieve the effect of remote control.

Budget Cost

The procurement cost of electric actuators is about twice that of pneumatic actuators. If your budget is limited, then pneumatic actuators will be one of your first choices.

In conclusion, the choice of actuator needs to be based on project requirements and budget. Choosing the right valve for use in reverse osmosis equipment can double your effect and increase your production capacity. If you have any needs for valves, welcome to consult us. We will be happy to provide you with the right water treatment valve solution.

Tips For Selecting The Valve For Desalination

With the continuous improvement of the level of global industrialization, freshwater resources are increasingly scarce, and the lack of water resources has led to slow global industrial development. Desalination has become an important option for coastal cities to solve such problems. Valves are widely used in seawater desalination plants. As important control components in various processes, their selection and application are particularly important. The right valve can help seawater treatment plants build fluid pipelines to regulate water flow and increase production capacity.

In the process of seawater desalination, it is necessary to pay attention to the corrosion of chloride to equipment. Seawater temperature affects the corrosion rate, the higher the temperature, the faster the corrosion. Solid contaminants can damage the protective film of the material and cause erosion corrosion. Various chemical contaminants also increase the probability of corrosion. The addition of ingredients can also cause corrosion. Therefore, in seawater desalination, media with different degrees of corrosion will be encountered. We need to decide which style of valve to choose according to the processing technology.

Because seawater is highly corrosive, and seawater desalination requires uninterrupted and stable operation, corrosion resistance has become the main consideration. Valves used in seawater desalination mainly include nickel aluminum bronze, stainless steel, carbon steel, ductile iron, dual-phase steel, UPVC, CPVC and PVDF. Commonly used in seawater desalination are butterfly valves, ball valves, gate valves, globe valves, check valves and diaphragm valves.

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Butterfly Valves

Butterfly valves are mainly used in the process of separating salt and water in seawater. The advantages of butterfly valves include convenient and rapid opening and closing, torque saving, small fluid resistance, and many styles, which can meet the needs of various processing processes. The body material, valve plate material and seal material of the butterfly valve can be replaced according to the requirements of the processing process. Such as replacing with duplex steel, nickel aluminum bronze and other materials that can withstand higher corrosion.

Ball Valves

Ball valves are mainly used for exhaust and dosing pipelines. The advantages of ball valves include good sealing performance, pressure resistance, corrosion resistance, and zero leakage. Due to the process of seawater desalination, there will be low-pressure pipelines and high-pressure pipelines. The ball valve can meet this demand. The ball valve has good pressure resistance and can withstand pressures up to Class 2500.

Gate Valves

A gate valve is a shut-off valve commonly used to circulate or block flow. The applicable pressure range and temperature range are relatively wide, and it will not be restricted by the flow direction, and the sealing performance is good.

Globe Valves

A globe valve is a valve commonly used to regulate, circulate and cut off flow. The globe valve has small friction on the sealing surface during the opening and closing process, is durable, easy to maintain, and is suitable for a wide range of pressures.

Check Valves

A check valve is a valve used to prevent backflow of media. Check valve can be divided into swing check valve, lift check valve, disc check valve and so on. It can prevent the reverse rotation of the pump and the motor and the leakage of the container medium.

The most important thing in choosing a valve for desalination is to choose the appropriate valve material and pressure bearing capacity. At the same time, routine maintenance and regular replacement of wearing parts and erodible parts will help reduce the unit consumption of some seawater desalination and unnecessary downtime. If you have any needs for valves, welcome to consult us. We will do our best to provide you with the right valve solution.

Tips For Selecting The Valves For Sewage Treatment Plants

The global water pollution situation is becoming more and more serious, and sewage treatment and other water treatment industries have received unprecedented attention. In the sewage treatment pipeline system, the valve plays a very important role in building the fluid conveying system and controlling the direction, flow, pressure, etc. of the fluid. It is convenient to increase the production capacity of water treatment equipment and obtain more pure water for human life.

What Is Sewage Treatment?

According to the classification of sewage sources, sewage treatment is divided into production sewage treatment and domestic sewage treatment.

Production sewage includes industrial sewage, agricultural sewage and medical sewage. Domestic sewage is sewage produced in life, which refers to a complex mixture of inorganic and organic substances in various forms, including floating suspended solid particles, colloid and gel diffusion, and pure solutions.

According to the nature of water pollution, there are two types of water pollution, one is natural pollution and the other is man-made pollution. Most of the current damage to water is man-made pollution. According to the different pollutants, water pollution can be divided into chemical pollution, physical pollution and biological pollution. The main pollutants are:

● Untreated industrial wastewater
● Untreated domestic sewage discharged
● Large-scale use of chemical fertilizers, pesticides, and herbicides in farmland sewage
● Industrial waste and domestic garbage piled along the river
● Soil erosion
● Mine sewage

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Types Of Valves Use For Sewage Treatment

Sewage treatment technology can be divided into primary treatment, secondary treatment and tertiary treatment according to the degree of treatment. The degree of sewage treatment can be determined according to the water quality and the flow direction of the treated water. The valves required for each stage are also different.

2.1 Primary Processing

It mainly removes suspended solid pollutants, and most physical treatment methods can only meet the requirements of primary treatment. After the primary treatment, the BOD removal rate is generally around 30%, which does not meet the emission standard. The primary processing belongs to the preprocessing of the secondary processing. Valves include knife gate valves, triple eccentric butterfly valves, filters, etc.

2.2 Secondary Processing

It mainly removes colloidal and dissolved organic pollutants (BOD and COD substances) in sewage, and the removal rate can reach more than 90%, so that the organic pollutants can meet the discharge standard, and the suspended solids removal rate can reach 95%. The valves used include soft sealing butterfly valves, gate valves, ball valves, check valves, etc.

2.3 Tertiary Treatment

Further treatment of refractory organics, nitrogen and phosphorus can lead to eutrophication of soluble inorganics in water. The main methods are biological denitrification and phosphorus removal, coagulation sedimentation, sand filtration, activated carbon adsorption, ion exchange and electrodialysis. The valves used are butterfly valves, gate valves, ball valves, check valves, etc.

Types Of Actuators Use For Wastewater Treatment Plants

Nowadays, people are more and more pursuing high efficiency and high production capacity. Then automated actuators are the best choice. So how do we pick the right actuator for us?

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3.1 Driving Method

Actuators are divided into electric actuators and pneumatic actuators. The difference between them is that electric actuators are driven by power supply, while pneumatic actuators are driven by air source and need to be equipped with air source parts. Therefore, you can choose a suitable actuator for the equipment according to the conditions of the control system.

3.2 Switching Frequency And Switching Speed

Different systems, as well as different treatment processes, will have different requirements for the switching frequency and speed of the valve. The switching speed of the electric actuator is relatively slow, and generally it takes more than 5 seconds to fully open/close. However, the switching speed of the pneumatic actuator is faster, under normal circumstances, it only takes about 2 seconds to fully open/close. Therefore, if your system requires a valve that can be switched frequently and quickly, then choosing a pneumatic actuator will be your first choice.

3.3 Remote Control

The electric actuator has its own signal module, which is compatible with various control systems and realizes remote control. However, the pneumatic actuator needs to be equipped with a positioner because it is not electrified, so as to realize the remote control of the valve.
Both can be remotely controlled.

3.4 Pipeline Working Pressure And Working Temperature

The working pressure and working temperature of the pipeline will indirectly affect the selection of the actuator. However, when the working pressure and working temperature are high, we recommend the use of electric actuators to ensure that the valve can be opened or closed safely and smoothly.
Therefore, when you are making a project plan, please inform the working pressure and temperature of the pipeline in advance, so that the valve manufacturer can match the appropriate valve for you.

Choosing a valve isn’t easy, but it’s not difficult either. COVNA has more than 20 years of experience in the valve field and has helped as many as 500 water treatment projects build fluid control pipelines. If you have any needs for the valve, please let us know. We will do our best to provide you with the right valve solution.