Basic Wastewater Operator Practice Exam

What does 'BOD' stand for in wastewater treatment?

1. Bacteriological oxygen demand

2. Biological oxygen demand

3. Biochemical oxidative demand

4. Biosolid oxygen demand

The correct answer is: Biological oxygen demand

The term 'BOD' stands for Biological Oxygen Demand. This measurement is crucial in wastewater treatment as it indicates the amount of oxygen that microorganisms will consume while decomposing organic matter in a water sample over a specific period, usually five days at a standard temperature of 20 degrees Celsius. A higher BOD value suggests a greater concentration of organic matter, which means that more oxygen is required by bacteria to break it down. This is significant in managing the treatment processes, as high BOD levels can lead to oxygen depletion in receiving water bodies, adversely affecting aquatic life. Understanding BOD helps operators assess water quality and determine the effectiveness of treatment processes in removing organic pollutants. The other terms in the choices may sound similar but do not accurately represent the accepted definition and concept of BOD in wastewater treatment. For example, "bacteriological oxygen demand" and "biochemical oxidative demand" do not capture the specific process that BOD measures, focusing instead on other aspects of microbial activity. Similarly, "biosolid oxygen demand" does not pertain to the broader measurement of organic matter within wastewater. Therefore, recognizing BOD as Biological Oxygen Demand is key to effectively managing wastewater treatment operations.