What is the primary purpose of testing for residual chlorine?

Testing for residual chlorine is primarily focused on evaluating the effectiveness of disinfection in water treatment processes. Chlorine is widely used as a disinfectant to eliminate pathogenic microorganisms in drinking water and wastewater. The level of residual chlorine indicates whether sufficient chlorine is present to ensure that the water has been effectively treated and remains safe for consumption or use.

When residual chlorine levels are maintained within the appropriate range, it signifies that the disinfection process has been effective in killing harmful bacteria and viruses. If residual chlorine is too low, it can raise concerns about potential recontamination or inadequate disinfection. Monitoring residual chlorine is therefore essential for confirming that water meets safety standards and is free from harmful pathogens.

The other options address different aspects of water quality and treatment. Testing for pH balance is crucial for understanding acidity or alkalinity, which can affect chemical reactions in the water but is not related to disinfection efficacy. Determining mineral content involves analyzing the presence of various ions and compounds in water, which is significant for assessing overall water quality but not specific to disinfection. Assessing water clarity pertains to the physical appearance of water, which can be influenced by turbidity or suspended particles but does not provide direct information regarding water safety from microbial contaminants.