HILLER technology for thickening and disintegration of excess sludge with HILLER thickening centrifuge at the Munich Grosslappen WWTP
At the WWTP the surplus sludge was thickened statically. Prior to the project realised with Hiller, the thickened sludge could be pumped to the digestion towers with a maximum of 5 – 6 % DS. A higher degree of thickening could not be handled by the installed pumps.
The objective was to increase the degree of thickening to 8 % DS in order to relieve the hydraulic load on the digestion capacities. In 2019, Hiller was therefore commissioned to carry out a large-scale trial with a mobile thickening centrifuge.
The trail was to provide reliable performance data that can be used for a system comparison of the results obtained with static thickening versus possible results with mechanical sludge thickening using a thickening centrifuge with a lysate disintegration device.
Results:
– Excess sludge can be thickened very stably up to 10 % DS with lysate technology
– Operating with active disintegration equipment, the viscosity of the thickened sludge reduced by approx. 1/3
– The existing pumping system was able to pump a sludge thickened to 8 % DS over 300 m without any problems. (Pressure reduction of 33 % compared to operation without a disintegration)
– A stable degree of separation in the centrate > 98.5 %
– Results are reproducible regardless individual sludge specifications
The effects achieved from the extended residence time in the digestion tower, an increased digestion gas yield with an improved degree of stabilization and increased organic degradation were the basis for the decision-makers to put a corresponding investment out to public tender in October 2020.
Hiller GmbH was awarded the contract for the construction of a complete thickening plant for 100 m3/h. The new thickening line was commissioned in April 2022 and confirmed the results from the trial operation right from the start.
