When alum is added to the waste water containing calcium ions which compound is formed as a precipitate?

Al(OH)₃

CaCO₃

Ca(OH)₂

Al₂ (SO₄)₃

Correct Answer : Al(OH)₃

Explanation : When alum is added to a waste water containing calcium salts Al(OH)₃ is precipitated. This sis a gelatinous floc. This reaction sweeps out suspended particles

Recently Updated in Waste Water Engineering Questions

What is the growth of huge amounts of algae and other aquatic plants leading to the deterioration of the water quality called?

Algae growth

Eutrophication

Denitrification

Nitrification

Correct Answer : Option (B) : Eutrophication

Explanation : Eutrophication is the growth of huge amounts of algae and other aquatic plants leading to the deterioration of water quality. The untreated wastewater is rich in organic matter which demands oxygen.

5 days-biochemical oxygen demand (BOD₅) is taken at a temperature of

0°C

15°C

20°C

25°C

Correct Answer : Option (C) : 20°C

Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for

unexpected increase in the population

under estimates of maximum and average flows

unexpected large scale infiltration of stream water

All of the above

Correct Answer : Option (D) : All of the above