Which of the statements are true for a Rapid Gravity Filter? i. The amount of water required for washing a rapid gravity filter is around 2-5 per cent of the total amount of water filtered ii. The rapid gravity filters are washed once in 3 months
- AOnly (i)Correct
- BOnly (ii)
- CBoth (i) and (ii)
- DNeither (i) nor (ii)
Solution
Concept
Backwashing of RGF
Step-by-step solution
1. Backwash water is about 2–5% of the filtered water (i true). 2. RGFs are backwashed every 24–48 hours, not every 3 months (ii false).
Explanation
Only (i) is correct.
Shortcut
RGF wash every 1–2 days.
Correct answer: A) Only (i)