Question

If Alum is required to treat water up to the extent of 10 ppm, how much alum in quintals per day would be needed to treat 10 MLD of water?
1. 10 quintals
2. 1 quintals
3. 100 quintals
4. ​1000 quintals

Answer 1

Correct Answer - Option 2 : 1 quintals

Concept:

1 PPM stands for 1 part per million

1 PPB stands for 1 part per billion

1 PPM = 1 mg/l

Calculation:

Given,

Alum treatment to the extent of 10 PPM.

Amount of water to be treated = 10 MLD

10 MLD = 10 × 106 l/day

Alum required = 10 mg/l

Total alum required = 10 × 10 × 106 mg/day = 108 mg/day = 1 quintal/day

1 quintal = 100 kg = 100 × 106 mg = 108 mg

So 1 quintal/day alum is required.