How much oxygen per day per person is typically needed by the biological community in wastewater treatment (BOD concept)?

• A. 0.05 lb
• B. 0.10 lb
• C. 0.25 lb
• D. 0.17 lb

Answer: (D)

The amount of oxygen the biological community needs to oxidize the organic matter in a person’s wastewater each day is what this question tests. In wastewater design, this daily oxygen demand is a practical way to represent how much oxygen must be supplied to treat the biodegradable matter from one person per day, using the BOD concept.

The standard design estimate used is about 0.17 pounds of oxygen per person per day. This figure comes from typical domestic waste loads and is widely used to size aeration equipment and estimate oxygen requirements. Values much lower would underpredict the oxygen needed to achieve proper treatment, while a figure like 0.25 pounds would be more conservative than necessary for typical conditions.