Introducing advanced technologies such as ozonation, activated carbon or hybrid systems enhances water quality but requires higher energy consumption, more sophisticated monitoring and reinforced maintenance regimes. Because these systems sit at the end of the existing treatment chain, they often require hydraulic modifications and new pumping stages. Plants that are already operating close to capacity must reconsider their process layout, automation level and long-term operational capabilities. This shift inevitably increases technical and digital skill requirements for operating teams.

Managing such projects successfully also depends on governance. When municipalities, engineering partners and authorities work together, early coordination helps prevent costly redesigns and schedule delays. A clear distribution of responsibilities and a shared understanding of risks create the foundation for reliable long-term performance. These lessons are consistently confirmed across complex projects where multiple stakeholders are involved.

Sulzer’s approach focuses on early involvement. By working with operators from the first planning steps, the company assesses which parts of the existing infrastructure can be reused, how the new process can be integrated and whether gravity flow is feasible or pumping is required. Space constraints, particularly in older sites, heavily influence the final design. From these parameters, Sulzer develops treatment concepts that combine process performance with practical feasibility while making full use of existing assets.

When selecting between ozonation, activated carbon or mixed solutions, the decision depends on a combination of process-specific and site-specific factors. For instance, the presence of bromides may limit the suitability of ozonization due to bromate formation. Expected removal performance, carbon consumption and replacement intervals also play crucial roles, alongside broader operational considerations such as energy demand, flexibility and long-term maintenance intensity. The size of the plant and local conditions, including available land and the potential to reuse structures, determine which option is most appropriate.

Pilot trials have become an indispensable step in this journey. They provide real data on how micropollutants behave under actual operating conditions, and they allow combined strategies, for example, linking phosphorus removal with micropollutant treatment to be tested on a small scale. Pilot results form the basis for accurate sizing, detailed engineering and realistic operating cost estimates. Experience from projects in Germany and Sweden shows that pilot phases significantly improve planning security and long-term reliability of full-scale installations.

Sulzer’s involvement extends beyond design and commissioning. Operators are familiarized with new technologies early on, often through pilot projects, and benefit from continuous knowledge transfer during installation and start-up. Once operational, the plants continue to receive technical support, optimization services and maintenance assistance. With decades of experience and a broad technology portfolio, Sulzer helps operators address performance challenges, refine operational strategies and build expertise in new process technologies.

Digital tools now play a central role in optimizing these installations. Continuous monitoring, such as correlating pressure loss with the level of sand or granular activated carbon in filters, reduces maintenance time and costs while making performance more predictable. By assisting operators with sensor selection and configuration, Sulzer enables proactive adjustments before performance deviations become critical. Continuous 24/7 digital monitoring reduces the need for manual sampling and supports more stable, data-driven operations.

For wastewater treatment teams, the fourth stage introduces new responsibilities. Monitoring becomes more demanding, activated carbon systems require specialized handling and digital tools must be integrated into daily workflows. This evolution encourages closer cooperation between plant operation, maintenance and laboratory teams, and requires targeted upskilling.

For municipalities beginning this journey, one piece of advice stands out: dedicate sufficient time to preliminary planning. Pilot testing, realistic assessments of long-term operating costs and transparent communication among all stakeholders are essential to developing robust, future-proof wastewater treatment solutions.