Lab results for following problems

Influent BOD – 250 mg/L
Influent TSS – 264 mg/L
Primary clarifier effluent BOD – 160 mg/L
Primary clarifier effluent TSS – 112 mg/L
Final clarifier effluent BOD – 10 mg/L
Final clarifier effluent TSS – 25 mg/L

1. Find overall plant efficiency for TSS

2. Find activated sludge/final clarifier BOD removal efficiency.

3. Find primary TSS removal efficiency.

4. Find total plant BOD removal efficiency.

5. Find final clarifier TSS removal efficiency.

Answers:
Formula = (In – Out) / (In) X 100 %

1. 90 %
* (264 mg/L – 25 mg/L) = 239 mg/L
* (239 mg/L) / (264 mg/L) = 0.90 mg/L
* Convert from Decimal to Percent = 0.90 mg/L X 100 % =
(OR shuffle the decimal 2 places to the right)

2. 94 %
* (160 mg/L – 10 mg/L) = 150 mg/L
* (150 mg/L) / (160 mg/L) = 0.94 mg/L
* Convert from Decimal to Percent

3. 58 %
* (264 mg/L – 112 mg/L) = 152 mg/L
* (152 mg/L) / (264 mg/L) = 0.58 mg/L
* Convert from Decimal to Percent

4. 96 %
* (250 mg/L – 10 mg/L) = 240 mg/L
* (240 mg/L) / (250 mg/L) = 0.96 mg/L
* Convert from Decimal to Percent

5. 78 %
* (112 mg/L – 25 mg/L) = 87 mg/L
* (87 mg/L) / (112 mg/L) = 0.777 mg/L
* Convert from Decimal to Percent