Sewer plants in Carbonne Shire, NSW, Australia have a problem with their waste activated sludge (WAS). This material is typically collected in sludge lagoons designed to collect the sludge as it settles out and release the excess water. As the sludge builds up over time, these lagoons need to be cleaned out. The local EPA wanted to do an permeability test on the clay liner from the centre of the lagoon. A centrifuge was considered but these lagoons typically collect leaves, cloth rags and other debris and because the sediment is so thick, water would need to be added to slurry the waste material to be pumped to the centrifuge, creating significant headaches for this method.
MetaFLO licensee, Polpure mobilized to the site of the lagoon and introduced a dry reagent polymer blend, MF006 to solidify the waste activated sludge very quickly and efficiently. Using an excavator to mix in the dry reagent 2500m3 was solidified in 4.5 days with a dosage rate of <.5% wt/wt. This stackable, dry material was removed with an excavator and taken to the tip 8 km away. The treated WAS will not leach fluid in transportation nor change the analytical properties of the material.
The Shire was very pleased with the process. Alternative methods would take up to 8 weeks to complete and add a significant amount of labour cost to the treatment process. Creating a dry product on site allowed the Shire to dispose of the material in very close proximity and avoid trucking liquids further distances for treatment. The dam was cleared and the core sample for the EPA was taken in one week. The process was simple to complete, did not have the headaches associated with centrifuge utilization, allowed the material to be disposed of in close proximity, allowed them to meet compliance requirements quickly and saved the Shire money.