Which piece of equipment injects treatment chemicals into a water system?

The equipment responsible for injecting treatment chemicals into a water system is the chemical feed pump. This device is specifically designed to accurately and reliably introduce various treatment chemicals into the water, ensuring proper dosage and distribution throughout the system. Chemical feed pumps can be manually adjusted or set on a timer to deliver chemicals at certain intervals, enhancing the effectiveness of water treatment processes such as disinfection, conditioning, or pH adjustment.

In contrast, other options serve different functions within a water treatment system. The contact tank is primarily used for allowing chemicals to react with the water before it continues through the system. The brine tank float control is involved in regulating the level of brine in a brine tank used for regeneration in softening processes. Twin alternating systems refer to setups that switch between two tanks or systems to maintain continuous operation but do not inject chemicals directly. Understanding the specific roles of these components helps clarify why the chemical feed pump is the correct choice for this question.