In disinfection verification, which type of bacteria is commonly used as an indicator?

In disinfection verification, which type of bacteria is commonly used as an indicator?

• A. Coliform bacteria
• B. E. coli
• C. Staphylococcus aureus
• D. Pseudomonas aeruginosa

Answer: (A)

Indicator organisms used to verify disinfection are chosen because their presence signals whether the treatment is effectively reducing microbial load. Coliform bacteria are the traditional indicator group in wastewater disinfection verification because they are abundant in sewage, easy to detect and quantify with standard lab methods, and their removal during disinfection reflects the overall performance of the process. A reduction or absence of coliforms after treatment gives a practical, conservative measure that the disinfection step is working. Escherichia coli is a specific member of the coliform group and can be used as a more precise fecal indicator, but the general coliform group is the common indicator. The other organisms—Staphylococcus aureus and Pseudomonas aeruginosa—are not routinely used as general indicators for disinfection because they do not represent fecal contamination levels in wastewater and their presence does not reliably reflect the effectiveness of the disinfection process.

Indicator organisms used to verify disinfection are chosen because their presence signals whether the treatment is effectively reducing microbial load. Coliform bacteria are the traditional indicator group in wastewater disinfection verification because they are abundant in sewage, easy to detect and quantify with standard lab methods, and their removal during disinfection reflects the overall performance of the process. A reduction or absence of coliforms after treatment gives a practical, conservative measure that the disinfection step is working. Escherichia coli is a specific member of the coliform group and can be used as a more precise fecal indicator, but the general coliform group is the common indicator. The other organisms—Staphylococcus aureus and Pseudomonas aeruginosa—are not routinely used as general indicators for disinfection because they do not represent fecal contamination levels in wastewater and their presence does not reliably reflect the effectiveness of the disinfection process.