| The properly designed underdrain must: |
| • |
Be structurally sound |
| • |
Allow maximum vessel capacity of granular media |
| • |
Uniformly support the load over its entire surface area
|
| • |
Retain the finest granules and resist clogging |
| • |
Provide minimum pressure loss and/or uniform drainage |
| • |
Be of corrosion-resistant material to insure long
service life, especially in inaccessible locations or hazardous service |
| • |
Permit backwash, regeneration in place or hydraulic
discharge |
| • |
Eliminate the need for subfill |
