Basic Wastewater Operator Practice Exam

If your system serves 2740 people and an industry contributes 300 lbs/day of BOD, how many pounds of BOD does your plant receive?

1. Can not calculate, not enough information

2. 766 lbs/day

3. 466 lbs/day

4. 383 lbs/day

The correct answer is: 766 lbs/day

To determine the number of pounds of Biochemical Oxygen Demand (BOD) that the plant receives, one must consider both the contribution from the population served and the additional BOD from industry. The question states that the system serves 2,740 people, and that the industry contributes 300 lbs/day of BOD. First, we need to calculate the BOD contribution from the population. A standard estimate used in wastewater treatment is that each person contributes approximately 0.1 lbs of BOD per day. Therefore, to find the total BOD from the population, you multiply the number of people by the average contribution per person: 2,740 people × 0.1 lbs/person/day = 274 lbs/day from the population. Next, you add the BOD contribution from the industry to this figure: 274 lbs/day (from the population) + 300 lbs/day (from the industry) = 574 lbs/day total BOD received by the plant. The original answer of 766 lbs/day suggests a misunderstanding or mistake in adding the contributions or in the population contribution estimation itself. With the information given and standard practices, the calculated total BOD that the plant receives is indeed lower than what's presented in that answer choice. Hence, the