The Wasserburg am Inn sewage treatment plant is one of Hiller’s longest-standing customers. As early as 1992, a Hiller thickening machine was used to start the long-term cooperation. In addition to thickening, the dewatering of the sewage sludge was started in 2002 with the help of a Hiller DP54-422 decanter.


Early research project with the Hiller lysate device

The continuous further development and optimisation of the thickening and dewatering performance has always been important to the Wasserburg am Inn sewage treatment plant. Thus, in the early 2000s, it was decided to install a Hiller lysate device on the existing thickening machine as a research and development project.

The desired advantages of the lysate device were:

- Reduced viscosity and better pumping properties

- Increased degradation of the organic part (i.e. extended well time in the digestion tank)

- Increase in gas yield

- Improved drainage behaviour


Over the years, the lysate device has been able to consistently convince the customer, and so it was again requested in 2017 when the now outdated thickening decanter was put out to tender again.

Hiller was awarded the contract and was commissioned to install a Hiller decanter with lysing device, type DP484.


Renewing the dewatering system

The customer was still satisfied with the Hiller DP54-422 installed in 2002 thanks to its reliable performance and good dewatering results. However, Hiller was able to prove in an on-site test that with the latest decanter technology an even better dewatering result with a simultaneous reduction in the use of flocculants was possible and that the new acquisition would therefore pay for itself within a few years. Compared to the existing machine, for example, an up to 2.5 % higher DS could be achieved. Based on this test, the sewage treatment plant again published a tender for the renewal of the dewatering decanter with award to the most economical offer. Hiller was able to prevail here and was awarded the contract for a Hiller DP574 decanter of the latest series in 2020.


Engineering service

In addition to the decanter itself, a comprehensive engineering service was also awarded. Parts of this included a new steel structure, an associated switchgear and a conveyor system. The conveyor system is a special feature here due to its size and process of sludge distribution. It is about 20 metres long and gives the sludge another opportunity to dry thanks to four discharge outlets. Hiller planned and implemented the complete plant construction for the sewage treatment plant according to the customer’s wishes.


„We have always been very satisfied with the performane of Hiller decanters and Hiller’s fast and always reliable after-sales service. The two newly installed thickening and dewatering decanters are running to our complete satisfaction and also the complete trial and project handling has always been highly professional and pleasant,” says the head of the wastewater treatment plant, Mr. Grasberger.


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