ITEM | ROTARY PRESS | SCREW PRESS |
1. | Spare requirements | Spare requirements |
---|---|---|
Low footprint | Much larger footprint and installation is two stories high. This results in higher initial capital investment in building space. | |
2. | Maintenance cost | Maintenance cost |
Maintenance is less frequent, simple and easy. | Maintenance is frequent and troublesome. | |
Most maintenance can be performed by one person. | Maintenance cannot be performed by only one person. | |
Screens are long-lasting (over 10 years) | Screens need to be changed every 2-3 years. | |
3. | Wash water | Wash water |
No continuous wash water is required. | Continuous wash water is required | |
4. | Capture Rate | Capture Rate |
A high capture rate is intrinsic in the Rotary Press design and frequent adjustments are not required to maintain it high: 95% av. | Capture rate is low (less than 90%), and sometimes less than 65%. Capture rate evaluation needs to take into account both filtrate and wash water. | |
5. | Operation | Operation |
Adjustments to variations in sludge solids content and dewaterability are automated. | Manual adjustments are required. | |
6. | Partial operations | Partial operations |
For a multi-channel machine, one or more channel(s) may be removed for maintenance purposes, while the machine with the remaining channel(s) may still be operated. | Maintenance requires total machine shut-down, generating operations down time. | |
7. | Shut down procedure | Shut down procedure |
5-min system flush. | The whole machine needs to be flushed. |