Retrofit of a sewage pond and biological treatment process

Many municipalities are facing the challenge of upgrading aging wastewater treatment infrastructure. Especially sewage ponds and lagoon systems often struggle to meet today’s stricter ammonium discharge limits.

In this project, a municipal wastewater treatment plant in Bavaria required a sewage pond upgrade after repeated ammonium limit exceedances. An aging rotating biological contactor from the 1990s was no longer able to provide reliable nitrification. Instead of building a new treatment plant or investing in a costly pumping station, the municipality opted for a smarter approach: upgrading the existing sewage pond system.

PPU Umwelttechnik implemented a ClearFox® FBBR fixed-bed container as part of a retrofit of the sewage pond and biological treatment process. The container was integrated as an additional biological stage, enabling stable nitrification and improved effluent quality — without major civil works or long shutdown periods.

This sewage pond retrofit demonstrates how modular containerized technology can significantly improve treatment performance while keeping the existing infrastructure in operation. The solution allows municipalities to upgrade sewage ponds, increase treatment capacity, and remain flexible for future regulatory requirements.

This project shows how to:
• Perform a cost-effective sewage pond upgrade
• Retrofit existing wastewater lagoons and treatment ponds
• Restore compliance with ammonium discharge limits
• Avoid expensive plant expansions or new construction
• Prepare sewage pond systems for future regulations

If you are looking for a practical solution for upgrading a sewage pond or planning a retrofit of an existing wastewater lagoon, this project provides a proven, efficient approach.

👉 Learn more or contact us:
ClearFox® – Modular solutions for sewage pond upgrades and future-ready wastewater treatment

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