WASTEWATER
By Rick Lallish
The MPN method for fecal coliform testing has become one the most common methods for testing. What is a disadvantage for MPN fecal coliform analysis?
A. Sample toxins are diluted
B. Samples cannot be analyzed by membrane filtration
C. Difficult to interpret, either by observation or gas emission
D. Results are not very accurate and have a high probability of false positives
Answer: D. It is important for operators to understand the many types of laboratory procedures and analysis so that they can properly operate a wastewater treatment facility. Fecal coliform testing is required on most if not all NPDES permits. MPN has become
