Which method would NOT be used to feed liquid chemicals?

The method that would NOT be used to feed liquid chemicals is a screw pump. While screw pumps are excellent for transferring liquids, especially those that are viscous or require continuous flow, they are typically not classified under chemical feeding methods used for the precise delivery of liquid chemicals in wastewater treatment processes.

In contrast, vibrating troughs, rotating feeders, and plunger feeders are all designed specifically for metering and feeding chemicals into various processes. The vibrating trough utilizes vibrations to transport materials, ensuring a consistent and controlled delivery rate, while rotating feeders and plunger feeders regulate the flow of chemicals effectively to ensure that the correct dosage is introduced into the system.

The distinction lies in the intended purpose and functionality of these devices in the context of wastewater treatment. Understanding how each method works and what it is best suited for helps clarify why a screw pump is less appropriate for metering liquid chemicals compared to the other options.