Describe the function of online and offline water treatment.

The correct answer states that online treatment addresses water quality during operation, while offline treatment involves purging and conditioning during maintenance. This distinction is essential in understanding how water treatment systems function.

Online treatment refers to processes that take place when the system is operating, ensuring that water quality remains at the desired level. This typically involves continuous monitoring and chemical dosing to control parameters such as pH, dissolved oxygen, and other contaminants. The goal of online treatment is to maintain the system's efficiency and prevent issues such as scaling, corrosion, and biological contamination.

In contrast, offline treatment is conducted when the system is shut down. This process is crucial for maintenance activities; it includes purging the system of any stagnant water, cleaning, and conditioning the components to ensure they are free from deposits or contaminants that may have accumulated during operation. Offline treatment ensures that when the system is restarted, it is in optimal condition for performance.

This classification between online and offline treatment processes encompasses their specific roles in maintaining water quality and ensuring the reliability and efficiency of the equipment involved in feedwater systems.