| S.No. |
Spirals |
Other Random Media |
| 1. |
Material of construction – PVC. |
Material of construction – PP in different shapes and sizes. |
| 2. |
Shape of spirals specially derived for fluidizing. |
Simple rings with serrations or with diagonals. |
| 3. |
Specific gravity 1.05 |
Specific gravity 0.98 |
| 4. |
Behavior of spirals similar to sludge |
Media lighter than sludge and water |
| 5. |
Spirals swirl and fluidize with slightest disturbance. |
Media floats on water. |
| 6. |
No fine bubble diffusers required. |
Fine bubble diffusers a must. |
| 7. |
8 – 10% of liquid volume would be the max. media requirement irrespective of the organic load. |
Minimum 25% of liquid volume required. Quantity dependent on organic load. |
| 8. |
Shut down and restart possible with ease as spiral support attached growth. |
Shut down and restart sluggish as media floats on water and wetting surface of media inadequate. |
| 9. |
Mass transfer efficiency high - Continuous shearing of bio mass from the media occurs to provide a large population of bio mass for treatment. |
Mass transfer efficiency low – tubular shape of media may allow sludge accumulation inside the tube. The generation of bio mass not as in spirals. Hence requirement of media would be much more. |
| 11. |
6 hrs retention in aeration tank for sewage treatment adequate. |
May require at least 8- 12 hrs of retention in aeration tank. |
| 12. |
Spirals is the only PVC medium that fluidizes. |
No other PVC media such as pipe
cuttings or moulded product fluidizes.
Media settles at the bottom of the aeration tank. |
| 13. |
As spirals fluidizes along with sludge, no dead pockets in the reactor and no choking occurs in the media. |
Accumulation of sludge in the aeration tank floor over a period of time reduces treatment efficiency. This occurs as the PVC media is stacked and does not fluidize. |
