Versatile Pre-Digester Sludge Thickening Process for Tanilba Bay STP
The Tanilba Bay Wastewater Treatment Works has been upgraded to improve the performance of the plant to ensure desired environmental outcomes are met and is able to cater for the projected local population on growth to 2040.
Two HUBER S-DRUM thickeners were installed as part of the upgrade and can be used in a versatile configuration as required by operations with three different thickening modes as follows:
- Mode 1: Thicken waste activated sludge (WAS) from the bioreactors at 0.3% and thicken up to 5% to be sent to the aerobic digester. Sludge wasting is undertaken during the aeration phase as to ensure solids concentration on is constant for effective polymer dosing and thickening performance.
- Mode 2: Thickening of digested waste activated sludge (DWAS) from 1.5% up to 5% for storage in the sludge holding tanks meaning the timing for tankering of sludge off site is extended as the volume of sludge is reduced significantly.
- Mode 3: Recuperative mode where thickened sludge (1.2-4% %DS) is drawn from the process tank (either digester or sludge tank) and thickened to 5%.
HUBER’s S-DRUM is a mechanical sludge thickening technology that is used to thickened sludge prior to digestion or dewatering. It can be used on primary and secondary sludges to produce a thickened solids concertation of greater than 5%DS.
The use of an internal screw results a high degree of thickening and hence, volume reduction. Being a slow speed device, the unit is very energy efficient with low maintenance requirements. Washwater usage is intermittent and only a fraction of the water demand as compared to other mechanical thickener types.
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