| 1. |
Continuous operation |
Cyclical batch-type operation |
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Constant low pressure sludge feed. (10 à 50 kPa). |
Variable high pressure sludge feed. (Up to 1500 kPa) |
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Constant cake production. |
Batch type. |
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Stable cake dryness. |
Cake dryness may vary a great deal from one batch to the next. Important quantities of badly dewatered cake are produced when the operating cycle is interrupted. |
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| 2. |
Simple, reliable, very few ancillary equipment, screens with long life. |
Complex systems, many ancillary equipment. Filter cloth requires frequent replacement. |
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| 3. |
The wash cycle consists of an internal flush cycle lasting approximately 5 minutes per day. |
The wash cycle may last for two (2) hours and may generate dangerous airborne contamination. |
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| 4. |
Totally enclosed process. |
The exposed process may require an important odor treatment system. |
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Manpower is not exposed to the sludge and/or cake. |
From time-to-time, the process may generate high pressure sprays from hoses, plates, diaphragms, etc.Manpower is exposed to sludge/cake/filtrate. |
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| 5. |
Little manpower is required. |
Manual discharge of complete cake is usually the norm. |
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Automation is very simple. |
Automation is next to impossible. |
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Simple start-up and shut down procedure. |
Complex operational cycle. |
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| 6. |
Low maintenance and operation cost. |
High maintenance and operation cost.Sludge feed pump wear can be very costly. |
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| 7. |
Low overall capital cost. |
Large overall capital cost. |
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| 8. |
Small space. |
Large space (as much as 4 times). |
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| 9. |
Low overall energy consumption.20 kW-hr/dry ton (includes pumping). |
High overall energy consumption. |
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| 10. |
Low installed HP. |
High installed HP with the ancillary equipment. |
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| 11. |
Low noise |
Noise operation during several parts of the operating cycle. |
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| 12. |
For the 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 is shut down. |