Alum sludge from a potable water treatment plant is thickened then gravitates periodically to a Geotube® dewatering container positioned on a purpose built drying bed. Solids concentration were taken from ~2% to 40-50% within a matter of 60-90 days.

Alum sludge is ideally suited for dewatering within the Geotube® dewatering containers as are PAC and ferric sludges. The filtrate from the Geotube® container is of very good quality and can be collected and pumped or gravitied back up the process or disposed of to waste.