Tennessee Wastewater Operator Practice Exam

What is the maximum allowable temperature variance in degrees C for a fecal coliform incubator using the membrane procedure?

1. 0.1 degree C

2. 0.2 degree C

3. 0.3 degree C

4. 0.4 degree C

The correct answer is: 0.2 degree C

The maximum allowable temperature variance for a fecal coliform incubator using the membrane procedure is set at 0.2 degrees Celsius. This specification is crucial in ensuring accurate and reliable results during the testing process. Maintaining a consistent and precise temperature is essential because any fluctuation may lead to variations in bacterial growth and replication rates, thereby affecting the test outcome. In microbiological testing, especially for fecal coliforms, the incubation temperature is critical for promoting the optimal growth of the target organisms while inhibiting unwanted microbial activity. A variance of 0.2 degrees Celsius provides a narrow limit that helps ensure that the results are within a standardized range, aligning with regulatory guidelines and ensuring that the laboratory's findings are deemed valid. This strict control limits ensure quality assurance in the testing process, reflecting good laboratory practice. Therefore, the choice of 0.2 degrees Celsius is supported by both the need for meticulous control of testing conditions and adherence to established standards in water quality testing.