Question

1. Raw sewage is___________ hazard 2. In secondary treatment, sewage water is treated with _____________. 3. The sewage is carried by _____________ pipes or __________. 4. __________ is the solid matter that settles to the bottom of the settling tank. 5. Chlorination is done during __________ treatment. 6. Dried __________ is used as manure.
7th class
Fill in the blanks​

Answer 1

Answer:

1) healthy

2)grit and sand removal tank

3)small and big ,tubes

4)sludge

5)sewage

6)sludge