Capillary Suction Time (CST) has been used since the 1970s as a quick and reliable method of characterising sludge filterability and conditionability. It is sludge filterability that, predominantly, governs the output of nearly all various types of dewatering equipment, including: drying beds, belt press, vacuum filters, filter presses and centrifuges. The capillary suction pressure generated by standard filter paper is used to ‘suck’ water from the sludge. The rate at which water permeates through the filter paper varies depending on the condition of the sludge and the filterability of the cake formed on the filter paper. CST is obtained from two electrodes placed at a standard interval from the funnel. The time taken for the water front to pass between these two electrodes constitutes the CST. The force generated by capillary suction is much greater than the hydrostatic head within the funnel, so the test is independent of the amount of sludge, as long as there is sufficient to generate the CST.
Each Type 304 CST comes with:
- CST Meter
- Perspex Block Assembly
- Stainless-Steel Funnels
- Filter Papers (200 with 304M and 20 with 304B)
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