The wastewater treatment plant of the Ager-West Wastewater Association treats the wastewater of thirteen municipalities in the Vöcklabruck district in Upper Austria and is designed for 90,000 population equivalents. In recent years, the association has continuously modernized its infrastructure and focused on efficiency and sustainability. Another planned step in this development was the renewal of mechanical sludge dewatering. With the installation of the new HILLER high-performance centrifuge, a significant contribution was made to improving efficiency and optimizing process performance.

Sludge treatment plays a central role in the overall wastewater treatment process: after the mechanical, biological, and advanced treatment stages, the treated wastewater is discharged into the Ager River. Reliable sludge treatment, supported by modern decanter centrifuges, is essential for stable and efficient plant operation. Each year, around 30,000 to 32,000 m³ of digested sludge with a dry solids content of 2.5 to 3% is generated at the plant.

Test phase with mobile Hiller test unit: practical experience under real conditions

In March 2023, the wastewater association initially conducted trials using a mobile Hiller test unit to evaluate the technology under real operating conditions and create a reliable decision-making basis. The results of the test phase were convincing: the existing chamber filter press, which had been in operation for over 30 years and required significant maintenance costs and high personnel effort, was to be replaced by modern decanter technology. “What made the difference was the convincing trial operation and the competent consultation from Hiller, which inspired us to adopt the technology,” explains Peter Neudorfer, Managing Director of the Ager-West Wastewater Association.

Decision for modern centrifuge technology from Hiller: focus on efficiency and sustainability

In October 2024, a public tender was issued by the civil engineering office HIPI ZT GmbH. After evaluation of all bids, the contract was awarded to Hiller as general contractor based on economic and technical criteria. The scope of supply included a high-performance decanter of type DecaPress 574, complete plant peripheral equipment, as well as a system for post-liming the dewatered sludge using quicklime. The total project value amounted to approximately EUR 860,000.

Construction and commissioning: seamless transition thanks to mobile interim dewatering

Construction work began in June 2025, marking the start of project implementation. To ensure uninterrupted dewatering operation throughout the construction and installation phase, Hiller provided a mobile interim dewatering system. This allowed continuous and reliable plant operation at all times. The new decanter centrifuge was commissioned in September 2025. After successful performance testing and fulfillment of all guaranteed process parameters, final acceptance of the plant took place in October 2025.

Modern decanter centrifuge: efficient, economical, and space-saving

With eight employees on site, the Ager-West Wastewater Association now benefits from a modern, compact, and cost-efficient sludge dewatering solution. At the same time, operating effort is reduced and the conditions for long-term reliable plant operation are improved. The project highlights the importance of modern separation technology and demonstrates how powerful and reliable decanter centrifuges can be in municipal wastewater treatment applications.

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