1. If an activated sludge plant discharges 1,500,000 gpd of wastewater with a BOD concentration of 15 mg/L, how many pounds of BOD are discharged each day?

2. If a trickling filter plant receives an influent total suspended solids of 250 mg/L with a flow of 880,000 gallons per day, what would the TSS loading be on this plant?

Using this information for the remainder of the problems:
Influent Flow Rate – 6.34 MGD
Influent BOD – 275 mg/L
Influent TSS – 350 mg/L
Effluent BOD – 20 mg/L
Effluent TSS – 25 mg/L

3. What is the average influent BOD loading in pounds per day?

4. Find the TSS loading for the average influent.

5. How many pounds per day of BOD are discharged each day?

Answers:

1. 187.65 lbs/day
* Pounds formula (is the Davidson Pie Chart) = Flow, MGD X Conc, mg/L X 8.34 lbs/gal
* Convert flow from GPD to MGD (with a decimal) = (1,500,000 gpd) / (1,000,000) = 1.5 MGD
(or just shuffle to the left 6 places since you are showing less digits)
* Work formula = 1.5 MGD X 15 mg/L X 8.34 lbs/gal =

2. 1,834.8 lbs/day
* Convert flow from GPD to MGD = 0.88 MGD
* Work formula = 0.88 MGD X 250 mg/L X 8.34 lbs/gal =

3. 14,540.79 lbs/day
* 6.34 MGD X 275 mg/L X 8.34 lbs/gal =

4. 18,506.46 lbs/day
* 6.34 MGD X 350 mg/L X 8.34 mg/L =

5. 1,321.89 lbs/day
* 6.34 X 25 mg/L X 8.34 lbs/gal =