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

RO Treatment System Project in Greece

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?

Waste Treatment System Project In France

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.