HUBER Screw Press Q-PRESS® with intelligent conveyor and distribution system for the Parsberg sewage treatment plant
The town of Parsberg lies in the heart of the Bavarian Jura between Nuremberg and Regensburg. It is particularly popular with tourists as a local recreation area and thanks to its perfect connection to the Five Rivers Cycle Route.
The Parsberg sewage treatment plant is located in the valley alongside the Schwarze Laber river. It has a mechanical, biological and chemical treatment stage and is designed for up to 13,300 PE.
A two-storey building was specifically constructed on the hilly terrain for local sludge dewatering, which was a conscious decision by the town of Parsberg.
New building to optimize sludge dewatering
The decision to construct a new sludge dewatering and storage facility near the existing sludge storage tank was made because the load on the sewage treatment plant had steadily increased by 10 to 15%, and the dewatering carried out by a contractor was costly. Sludge dewatering had been carried out on a quarterly basis until then. This resulted in large quantities of stored sewage sludge and filtrate building up in excess every four months. The large quantity that accumulated in a very short time could not be fully returned to the system and had to be disposed of at additional cost.
New technology, new buildings
At the end of 2022, the presentation of the new sludge dewatering building to the city council marked the start of construction at the Parsberg sewage treatment plant. In addition to the sludge dewatering plant building, it was also decided to build an integrated mixed sludge storage tank with a gas hood and a sludge storage hall. In addition to the HUBER Screw Press Q-PRESS®, the following equipment was also requested for sludge dewatering: the entire pump and measurement technology, polymer preparation including polymer mixing, switchgear and control technology with control system connection.
Initial tests and positive results for the HUBER Screw Press Q-PRESS®
The performance of the HUBER Screw Press Q-PRESS® Q440.2 was already tested on site in 2017 using our mobile demonstration unit in order to investigate the dewatering potential of the sewage sludge.
The positive characteristics of the HUBER screw press were confirmed there:
Dewatering performance > 26% DR
Throughput of up to 4 m³/h
Possibility of 24/7 operation
Very good separation efficiency of > 98%
Construction and commissioning
Construction of the sewage sludge dewatering building began in autumn 2023. The building was designed to optimally accommodate the equipment. The mechanical and electrical peripherals for the HUBER components were supplied by SCHARR TEC at Hunderdorf (Lower Bavaria), the general contractor for the overall project, for which the HUBER Screw Press Q-PRESS® with intelligent conveyor system, including process technology, was supplied.
The HUBER Screw Press Q-PRESS® Q440.2 was then commissioned in January 2025. The screw press control system regulates the machine to the preset optimum operating point, with the aim of achieving a high degree of dewatering and minimal filtrate load. Additionally, the receiving tank is equipped with an automatic sludge level reduction system. This system uses a double-secured level detection mechanism for automatic feeding of the machine.
Performance data and optimizations
The following sludge dewatering performance data was achieved:
Dewatering performance of 25% to 28% DR
25% reduction in polymer consumption with 25% outlet DR compared to 28% outlet DR (desired outlet DR: 25%)
Throughput of up to 15 m³/h
Very good separation efficiency of > 98%
Screw shaft speed of 0.3 rpm
Electrical drive power of the machine of 0.4 kW
Additional positive side effects:
The operator can optimize system operation independently.
Automated sludge transport and container change
The dewatered sludge is then automatically transported from the upper floor to the basement via a shaft connected to the Q-PRESS®, and is then further conveyed into a container by a HUBER Ro8 TC distribution conveyor. The two degrees of freedom of the Ro8 TC – rotation and translation motion – ensure the container is filled to its optimum volume. The 20 m³ container is filled evenly due to the automatic swivel mechanism created by the rotational movement and the additional position adjustment of the screw conveyor’s chute with integrated fill level detection. The alternating filling of two containers is fully automated at the Parsberg sewage treatment plant, thus eliminating the need for employees to be present at any specific time. There is also no requirement for staff to be present when the dewatered sludge is transported away, which takes place every 6–7 days. By independently activating the ‘container change’ switch, the distribution screw automatically moves into a parking position, allowing the container to be changed independently without collision.
