The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by

Which of the following values of pH represents a stronger acid?

A. 2

B. 5

C. 7

D. 10

The distribution mains are designed for

A. Maximum daily demand

B. Maximum hourly demand

C. Average daily demand

D. Maximum hourly demand on maximum day

Sewage treatment units are designed for

A. Maximum flow only

B. Minimum flow only

C. Average flow only

D. Maximum and minimum flow

For satisfactory working of a sludge digestion unit, the pH range of digested sludge should be maintained as

A. 4.5 to 6.0

B. 6.5 to 8.0

C. 8.5 to 10.0

D. 10.5 to 12.0