engineering recuitment BHEL Engineer Trainee Mock Test 2025 Environmental Engineering Water Treatment
Cleaning is done by
(i) Scraping and removal of top layer in slow sand filter;
(ii) Back washing in slow sand filters;
(iii) Scraping and removal of top layer in rapid sand filter;
(iv) Back washing in rapid sand filters.
The correct answer is
1
(i) and (iv)
2
(ii) and (iii)
3
(ii) and (iv)
4
(i) and (iii)