Texas Wastewater Class B Practice Exam

The Biochemical Oxygen Demand (BOD) of a sample is evaluated by measuring what?

1. Dissolved oxygen (DO) used

2. Solid waste content

3. Microbiological activity

4. pH balance

The correct answer is: Dissolved oxygen (DO) used

The Biochemical Oxygen Demand (BOD) of a sample is evaluated by measuring the dissolved oxygen (DO) that microorganisms consume while decomposing organic matter in the sample. This process takes place over a specific incubation period, typically five days, in a controlled environment. BOD is an important indicator of the organic pollution level in water, as it reflects the amount of oxygen required by microorganisms to break down the organic material present. A high BOD value indicates a high level of organic pollution, which can lead to oxygen depletion in water bodies, adversely affecting aquatic life. In contrast, assessing solid waste content, microbiological activity, or pH balance does not directly measure BOD. While each of these factors can influence water quality and are important parameters in wastewater analysis, they do not specifically quantify the amount of oxygen utilized by microorganisms during the decomposition of organic matter, which is the primary function of BOD assessment.