Mastering shock loads safely: Dosing technology for the Winterberg wastewater treatment plants

The Challenge

The Winterberg Public Utilities operates two wastewater treatment plants that face high pollutant loads and peak flows during the winter due to heavy tourism. The change in usage patterns increased the urea content in the wastewater and shifted the C/N ratio from the usual 100:20 to a fluctuating ratio of approximately 80:40, which impaired denitrification due to a lack of carbon. In addition, cold wastewater from prolonged snowmelt led to poor sludge settling in the secondary clarifier. Both issues jeopardized treatment performance and operational reliability. A solution was needed that automatically compensates for both effects based on load.

The sera solution

sera supplied each of the two wastewater treatment plants with an insulated, heated hazardous materials container featuring two integrated dosing systems. For C/N balancing, a DAV2-type system doses acetic acid into the denitrification tank; two iSTEP S50 units handle both high demand peaks and continuous small volumes. For sludge settling, the containers integrated a CTD micro-dosing system for the preparation and dosing of polymeric flocculants. Polymer addition occurs automatically based on turbidity in the secondary clarifier. The containerized, turnkey concept enables weather-independent, monitored operation and rapid adaptation to highly fluctuating influent flows.

Customer Benefits

• Stabilization of denitrification through automatic C/N balancing with acetic acid
• Improved settling behavior in the secondary clarifier through demand-based polymer dosing
• Reliable operation despite seasonal peak loads and cold influents
• Uniform, maintenance-friendly solution for both wastewater treatment plants

Summary

The project demonstrates that highly fluctuating inflows from tourism can only be managed with automated, load-dependent dosing technology—and that containerized systems provide a robust operational foundation for this.