|
ITEM
|
ROTARY
PRESS
|
BELT
FILTER PRESS
|
| 1.
Labour costs |
The
Rotary Press requires little attention. |
To
properly operate the BFP, it requires constant adjustment and attention. |
| |
|
|
| 2.
Airborne contamination |
Totally
enclosed process. |
Open
process with frequent spills and sprays. |
| |
Sludge
will not run on the floor. |
Large
air handling system is required to eliminate airborne contamination, corrosion
and airborne pathogens. |
| |
|
|
3.
Spare
requirements |
Less |
More
- Higher initial investment in building space. |
| |
|
|
| 4.
Maintenance costs |
Maintenance
is less frequent, simple and easy. |
Many
parts (bearings, belts, doctor blades, shafts, etc) require frequent maintenance
and adjustment, and can cause shut down of the machine. |
| Most
maintenance can be performed by one person. |
| |
Equipment
is very simple and reliable. |
The
complex equipment can easily become unreliable. |
| |
|
|
| 5.
Wash water |
No
continuous wash water is required. |
The
requirement for wash water is substantial 40 to 110 USGPM at 80 to 130 PSI
(60,000 - 160,000 USG/day). |
| |
25
USGPM/Channel for 5 minutes per day for a system flush. |
Equipment
to pretreat this water may be required. |
| |
(500
USG/day for a 4-channel unit). |
This
wash water supply consumes power at a rate of 5-14 HP and needs to be considered
in the overall analysis. |
| |
|
This
wash water poses an additional load on the plant since it is sent to the
head works. |
| |
|
|
| 6.
Capture Rate |
A
high capture rate is intrinsic in the Rotary Press design and frequent adjustment
is not required to maintain it high: 95% av. |
The
capture rate may not be very good (less than 90%), and sometimes less than
65%. |
| |
|
It
depends how close the BFP is being operated to the optimum conditions. |
| |
|
Analysis
of the capture rate needs to take into account both filtrate and wash water. |
| |
|
The
solids from the filtrate and the solids from the wash water pose additional
substantial loads on the plant. |
| |
|
|
| 7.
Cake dryness |
High |
Lower |
| |
|
|
| 8.
Operation |
Simple
and adjustments to the cake dryness are very easy. |
Not
so easy especially for inexperienced operators. |
| |
Normally
a PLC is included for easy control. |
The
BFP requires continuous adjustment. |
| |
The
control loops will allow for some variation of sludge. |
|
| |
|
|
| 9.
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. |
The
whole machine is in operation or it is shut down. |
| |
|
|
| 10.
Shut-down procedure |
5-min
system flush.Frequent shut-down and start-ups are possible. |
Thirty
(30) minutes to one (1) hour plus time to wash down the belts and structural
components of as required for a hygienic environment. |
| |
|
|
11.
Total
maintenance
and operation
costs |
LOW
|
HIGH
|
