Sludge thickening is commonly achieved by the following methods :
1. Gravity thickening
2. Air flotation
3. Centrifugation
Which of the above methods are correct ?
1
2 and 3 only
2
1 and 2 only
3
1 and 3 only
4
1, 2 and 3
Sludge thickening is commonly achieved by the following methods :
1. Gravity thickening
2. Air flotation
3. Centrifugation
Which of the above methods are correct ?