 
			 
			MCQOPTIONS
 Saved Bookmarks
				| 1. | Air binding in rapid sand filters is encountered when | 
| A. | the water is subjected to prolonged aeration | 
| B. | the water contains high dissolved gases | 
| C. | the filter bed comprises largely of coarse sand | 
| D. | there is excessive negative head | 
| Answer» E. | |