3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is______________________?

Related Mcqs:

Pick up the correct statement from the following ?

A. Rate of digestion of sludge is more at higher temperature B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C D. All the above...

A five day B.O.D. at 15°C of the sewage of a town is 100 kg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is____________________?

A. 100 B. 1000 C. 5000 D. 10000...

The presence of free ammonia in sewage, is detected by___________________?

A. Boiling B. Adding potassium permanganate C. Adding sulphuric acid D. Phenol-di-sulphuric acid...

The gradient of sewers depends upon_________________?

A. Velocity of flow B. Diameter of the sewer C. Discharge D. All the above...

The suitable cross-section of sewers to carry combined flow, is__________________?

A. Circular B. Egg shaped C. Rectangular D. Horse shoe shaped...