Coliform bacteria are

Coliform bacteria are

• A. More resistant to chlorination than pathogenic bacteria
• B. Less resistant to chlorination than pathogenic bacteria
• C. Equally resistant to chlorination as pathogenic bacteria
• D. Not affected by chlorination

Answer: (A)

Coliform bacteria are used as indicators of fecal contamination, and their behavior under chlorination helps gauge disinfection effectiveness. When chlorine is used to inactivate microbes, many pathogenic bacteria are killed more readily than coliforms, so coliforms tend to be more resistant to chlorine. This means that if coliforms are eliminated, you can be reasonably confident that the more chlorine-resistant organisms are also inactivated. If coliforms persist after disinfection, it signals that the chlorine dose or contact time may be insufficient and adjustments to CT are needed. It’s also worth noting that some other organisms (like certain viruses or protozoa) can be more resistant in different circumstances, but for typical chlorination conditions, coliforms are among the more chlorine-resistant indicator organisms.

Coliform bacteria are used as indicators of fecal contamination, and their behavior under chlorination helps gauge disinfection effectiveness. When chlorine is used to inactivate microbes, many pathogenic bacteria are killed more readily than coliforms, so coliforms tend to be more resistant to chlorine. This means that if coliforms are eliminated, you can be reasonably confident that the more chlorine-resistant organisms are also inactivated. If coliforms persist after disinfection, it signals that the chlorine dose or contact time may be insufficient and adjustments to CT are needed. It’s also worth noting that some other organisms (like certain viruses or protozoa) can be more resistant in different circumstances, but for typical chlorination conditions, coliforms are among the more chlorine-resistant indicator organisms.