What is essential for effective chlorine disinfection?

Effective chlorine disinfection in water treatment relies heavily on the correct dosage of chlorine and adequate contact time. The dosage refers to the concentration of chlorine being added to the water, which must be sufficient to eliminate pathogens and disinfect the water effectively. If the dosage is too low, it may not successfully kill harmful microorganisms, leading to unsafe drinking water.

Contact time is equally important; it is the amount of time that chlorine remains in contact with the water to exert its disinfecting effect. This duration allows the chlorine to interact with microorganisms, ensuring their inactivation. Insufficient contact time can result in inadequate disinfection, even if the dosage is appropriate. Therefore, both factors are critical for achieving effective disinfection and ensuring the water is safe for consumption.

Other choices, while related to water quality management, do not specifically address the primary requirements for chlorine disinfection. Temperature can influence the effectiveness of chlorine, but it is not a primary factor like dosage and contact time in the context of chlorine disinfection.