Which method includes Presumed, Confirmed, and Completed tests?

The method that includes Presumed, Confirmed, and Completed tests is the MTF (Most Probable Number) method. This approach is used for assessing the presence of coliform bacteria in water samples, which is crucial for determining water quality and safety.

In the MTF method, the testing process is divided into these three stages:

• Presumed Test: This initial stage looks for a positive indication of coliform presence in a sample, typically using a selective growth medium and observing for gas production or color change.

• Confirmed Test: If the presumed test shows positive results, a confirmed test is conducted to verify the presence of coliforms. This usually involves sub-culturing to a different medium to provide more reliable identification of the bacteria.

• Completed Test: This stage confirms that the isolated organisms from the confirmed test are indeed coliform bacteria by conducting further identification tests, establishing the legitimacy of the findings.

Understanding the MTF method and its structured testing process is essential for water treatment professionals in monitoring and ensuring safe drinking water quality. The other methods listed do not involve this specific tiered testing approach focused on bacterial quantification and confidence in water quality assessments.