Why should air binding in filters be avoided?
Air bound filters can lose media when backwashed
Effective removal of turbidity using a filtration process is based on the nature of the suspended particles, types and degree of pretreatment, the chemical characteristics of the water and what other factor?
The filter type and operation
What is the proper layering of media in a multi-media filter from top to bottom?
Anthracite, sand, garnet, gravel
Mudballs in the filter media, filter media shrinkage and cracking are all attributed to what cause?
Improper or ineffective backwashing procedures
A filter is 30 ft long and 30 ft wide, operates at a depth of 8.5 ft and has 24" of sand media. If the flow rate into the filter is 3,600 gpm, what is the filtration rate in gpm/sq ft?
4.0 gpm/sq ft
What is the rule requirement regarding turbidity when using the conventional or direct filtration process?
Less than or equal to 0.5 NTU in 95% of monthly measurements
The Surface Water Treatment Rule (SWTR) requires what percent (%) removal of Giardia cysts and enteric viruses?
99.9 and 99.99%
This filtration process relies on a loading rate of 2-10 gpm/sq ft of filter surface area.
Gravity filtration
Conventional filtration includes which processes in the treatment of water?
Coagulant addition, flash mixing, flocculation, sedimentation followed by filtration
What filtration process requires filter media to be added to the water being treated as slurry where it collects on a septum or other appropriate screening device?
Diatomaceous earth (DE) filtration