Treatment Plant Operator Exam Study Guide Answers

What laboratory tests must be done on grab samples? The answer to the question is B, pH. Proper sampling is necessary for accurate laboratory analysis. Tests such as pH and dissolved oxygen must done on grab samples as the samples degrade (change) drastically over a brief period. Some analysis such as BOD and TSS can be done on composite samples which are drawn over periods of time and do not change as much. If you are unsure of what tests require grab or composite, simply review your NPDES permit. Understanding the difference between grab and composite samples and what analysis requirements are