Besides disinfection, what is a primary use of chlorine in a water treatment plant?

Chlorine is primarily used in water treatment plants not only for disinfection purposes but also to prevent algal growth. Algae can cause various operational problems in water treatment processes, including taste and odor issues, clogging of filters, and even the production of harmful by-products. By introducing chlorine into the water, treatment plants can effectively inhibit algal growth, ensuring that the water stays clear and free from these unwanted organisms.

Using chlorine as an algicide is vital for maintaining the quality of the water supply. It helps to control algae and other biological growth in reservoirs, pipes, and treatment facilities, contributing to more efficient and effective water treatment. The prevention of algal blooms is crucial for protecting the ecological balance of bodies of water, enhancing the overall efficiency of the treatment process, and safeguarding public health.

The other options—like increasing pH levels, decreasing mineral content, or increasing turbidity—do not align with chlorine's recognized functions in water treatment. Chlorine is not used to alter pH levels significantly or to decrease mineral concentrations; in fact, its application generally does not involve modifying turbidity positively. Thus, the primary use of chlorine in relation to preventing algal growth stands out as the correct response.