Actuators in Water Treatment Systems: Valve and Flow Control

For the last 100 years, actuator systems have played an integral role in water treatment systems. They control or divert the flow of water remotely in water treatment systems by converting pneumatic, electric, or hydraulic energy into linear or rotary motion in valves.

You can call them control devices because they essentially operate valves and flow control devices in water treatment plants. We will focus on discussing how actuators are used for valve operation and flow control. We will also explore how actuators are integrated into water treatment systems for automation and control to enhance water quality.

Actuators in Valve Control

Remote control of valves is a primary tasks at any water treatment plant, and actuator motors are the devices that fulfil this role. They can help control the movement of water by either opening or closing a channel.

These plants have different types of valves to operate, so this determines the kinds of actuators to be used. The different kinds of valves used include gate valves, ball valves, butterfly valves, globe valves, check valves, and pressure relief valves.

Each type of valve has its advantages and disadvantages, depending on its applications. For instance,  gate valves are well suited for stopping or isolating the water flow. Therefore, it may not be ideal for regulating or adjusting its flow.

Actuators can operate or manipulate the valves, so no human interaction is necessary to cycle at the operation site. This is because actuator systems are remotely controlled. One more advantage of this setup is that actuators can act as shutdown mechanisms in an emergency situation that would be dangerous for human intervention.

Actuators in Flow Control

Flow control is an essential parameter in a water treatment plant; therefore, many plants require that dampers and valves move constantly between two points. And actuators provide the mechanical means to do just that.

This back-and-forth movement of valves and dampers is necessary for all stages of water purification, from filtration to desalination and distribution. One advantage of using actuators in flow control is the precision they bring to the process. They enhance the accuracy and precision of flow measurement or regulation.

This, in turn, improves the performance and efficiency of water treatment systems, ensuring that both water quality and quantity meet standards and specifications. As an example, to add chemicals or disinfectants to the water, an operator can use actuators to adjust the necessary valves to control water and chemical flow rates accordingly to achieve the best optimal concentration and dosage.

Integration of Actuators in Water Treatment Systems

Water treatment systems cannot do without integrating actuator motors in almost all stages of the treatment process. In fact, actuators can integrate with automation and control systems for monitoring and managing the water treatment process remotely.

Control systems are simply computerized systems that monitor and control the activities of other devices in a mechanical system. In terms of water treatment, these systems can include:

• Control and data acquisition (SCADA), distributed control system (DCS)
• Programmable logic controller (PLC), and
• Human-machine interface (HMI).

Each level serves a purpose and application depending on the complexity and size of the water treatment system. For instance, SCADA monitors and regulates the water treatment system.

DCS is used for controlling processes or units within the water treatment system. PLCs are used to regulate devices or equipment within those processes or units. HMI serves as an interface that allows operators or users to interact with the water treatment system.

An advantage of incorporating actuators in water treatment systems is their ability to facilitate coordination among levels of automation and control systems. This coordination enhances the functionality and flexibility of the water treatment system enabling customization and optimization of the treatment process.

For instance, if there are changes in the water source or quality, SCADA can transmit signals to DCS for adjusting process parameters or unit settings.

Subsequently, DCS can send signals to PLCs instructing them to operate the actuator motor thereby altering valve positions or flow control device speeds. Additionally, PLCs can send feedback signals back to DCS and SCADA,  reporting device status and performance. The HMI then displays data and information from SCADA and DCS for operators or users to monitor and intervene as necessary.

Real-World Examples of Actuators in Water Treatment

Actuators have applications in water treatment systems across the globe. Let me provide you with some real-world examples:

• In Singapore, actuators play a role in the NEWater system. This system uses membrane technologies to produce high-quality water from treated wastewater. Electric actuators are responsible for operating valves there.

Flow control devices that regulate water pressure and flow during filtration, disinfection, and stabilization stages.

• In Australia, actuators are extensively used in the Gold Coast Desalination Plant. This plant uses reverse osmosis technology to convert seawater into water. Actuators are also used to control the valves.

Similar to Singapore, automation and control systems use these actuators to monitor and manage the desalination plant.

• Lastly, actuators find their application within the Lagos Water Corporation (LWC) in Nigeria. The LWC serves as a utility for providing water supply services to Lagos State.

Actuators play a role in regulating the flow and pressure of LWC’s water from the source. These actuators are seamlessly integrated with automation and control systems to facilitate monitoring and management of the LWC network.

Sustainable Practices in Water Treatment

Using actuators in water treatment systems can also contribute to sustainable practices in water management. Sustainable practices aim to conserve and protect water resources for present and future generations.

Some of the sustainable practices that actuators in water treatment systems can support are:

• Reducing water loss and leakage: Actuators can help reduce water loss and leakage by detecting and repairing faults or damages in valves or pipes using sensors and controllers. This can also save energy and money by reducing pumping and maintenance costs.

• Improving water efficiency: Actuators can help improve water efficiency by adjusting or optimizing the flow rate or volume of water according to demand or quality using flow controllers or regulators. This can also reduce waste and environmental impact by minimizing overuse or underuse of resources.
• Enhancing water reuse: Actuators can help enhance water reuse by facilitating the recovery and recycling of wastewater using valves and flow control devices. This can also increase water availability and security by diversifying water sources and reducing dependence on external supplies.

Conclusion

When next you open your tap for a cup of sparkling clean water, realise that actuators play a pivotal role in water treatment by operating valves and flow control devices. We hope you enjoyed reading our blog post on the role of actuators in making water safe for your use.