Consider the statements for trickling filter
S1: Greater is the loading, lesser is the efficiency and thus lesser is the BOD removed when there is no circulation.
S2: Design of trickling filter is done for average flow.
S3: The organic loading decides the area of the filter required.
S4: The hydraulic loading decides the volume of the filter.
The correct statements are:
1
S1 & S2
2
S1 & S3
3
S2 & S3
4
All are correct.