Environmental E...

Consider the following statements for Sewers

1. Maximum Daily Discharge is two times average daily discharge

2. Maximum Hourly Discharge is three times average daily discharge

3. Minimum Daily discharge is Half of the average daily discharge

4. Minimum Hourly discharge is \({\frac{2}{3}^{{\rm{rd}}}}\;\)of the average daily discharge.

The COD/BOD₅ ratio of two wastewater samples form different sources was measured as 1.5 and 3.0 respectively. Based on this information the following conclusion may be arrived at.

An industry produces 240 m³/day of wastewater with a BOD₅ of 1500 mg/L. The population equivalent of the industrial sewage considering average standard BOD of domestic sewage as 80 gms per person per day is

A combine sewer is to be designed for a catchment area of 100 hectare. The time of concentration for the area is 25 minutes. The total population of the area is 50000 and the water supply rate is 200 lpcd. If 75% of the water goes into the drain and the impermeability factor for the catchment is 0.6, then the sewer capacity designed to carry three times of average discharge is _____.

The theoretical oxygen demand of a water sample containing 240 mg/ℓ of C₈H₁₆O₈ is (in mg/L)_____

A 300 ml bottle diluted with seeded water (30 ml waste-water and remaining seeded) has an initial D.O of 9 mg/ℓ. After 5 days, the remaining D.O of the bottle is 3.6 mg/ℓ. The drop in the D.O of seeded control sample over 5 days is 2 mg/ℓ. The BOD₅ of the sample (in mg/L) is