Which value best represents the total daily load of suspended solids at the plant if the influent is 100 mgd and 110 mg/L, ignoring the side-stream?

Which value best represents the total daily load of suspended solids at the plant if the influent is 100 mgd and 110 mg/L, ignoring the side-stream?

• A. 101,750 lb/d
• B. 91,000 lb/d
• C. 115,000 lb/d
• D. 120,000 lb/d

Answer: (A)

The daily load of suspended solids is found by multiplying the plant flow by the solids concentration, with a convenient conversion factor: lb/d = Q(MGD) × S(mg/L) × 8.34. Using 100 MGD and 110 mg/L: 100 × 110 × 8.34 = 91,740 lb/d, or about 91,700 lb/d. So the daily load is roughly 91,000 lb/d. This matches the value closest to 91,000 lb/d among the given options. Ignoring the side-stream means we don’t add any extra load beyond the influent.

The daily load of suspended solids is found by multiplying the plant flow by the solids concentration, with a convenient conversion factor: lb/d = Q(MGD) × S(mg/L) × 8.34.

Using 100 MGD and 110 mg/L:

100 × 110 × 8.34 = 91,740 lb/d, or about 91,700 lb/d.

So the daily load is roughly 91,000 lb/d. This matches the value closest to 91,000 lb/d among the given options. Ignoring the side-stream means we don’t add any extra load beyond the influent.