state gov APPSC (ఆంధ్రప్రదేశ్) Group 2 (Pre + Mains) Mock Test 2023 People Development & Environment Environmental Issues Waste
Consider the following tertiary treatment methods for treatment of waste water:
1. Ion-exchange method
2. Reverse osmosis
3. Chemical oxidation method
4. Activated sludge process
Which of the above methods are correct ?
1
1, 2 and 4
2
1, 3 and 4
3
2, 3 and 4
4
1, 2 and 3