engineering recuitment UKPSC AE Civil 2021 Mock Test (Re-Exam) Environmental Engineering Water Treatment Filtration
Select the correct statement with respect to a slow sand filter.
1
The rate of filtration is in the range of 100-150 m3/m2/day.
2
The effective size of sand particles shall be 0.15 to 0.3 mm, and their uniformity coefficient shall be preferably below 3.
3
Backwashing daily or on alternate days is necessary for cleaning.
4
The filtering medium has effective size 0.45 to 0.7 mm, uniformity coefficient 1.3 to 1.7, multiple graded layers of sand with bacteria and odour removal.