Per person phosphorus addition in pounds per day is approximately:

• A. 0.00048 lbs
• B. 0.048 lbs
• C. 0.012 lbs
• D. 0.0048 lbs

Answer: (D)

Phosphorus loading from each person per day is a small, fixed mass used in wastewater design. A typical rule of thumb is about 2 grams of phosphorus per person per day, which works out to roughly 0.0048 pounds per person per day (since 1 pound is 453.6 grams, 2 g ≈ 0.0044 lb, and 0.0048 lb is about 2.18 g). This is why the correct value is the 0.0048 lb option.

Compare the others by scale: 0.00048 lb is about 0.22 g, far too low for daily human phosphorus excretion; 0.012 lb is about 5.4 g, which is higher than typical daily per-person load; 0.048 lb is about 21.8 g, which is far too high for daily per-person contribution.