Between micropollutants, energy efficiency and operational reliability: wastewater treatment for modern treatment plants
Wastewater treatment plants are undergoing a fundamental transformation. New pollutants in wastewater, rising requirements for water quality and an expanding regulatory framework are significantly changing how plants are designed and operated. The revised Urban Waste Water Treatment Directive (UWWTD) further tightens existing regulations. Among other things, it requires additional treatment stages to remove micropollutants. Persistent substances such as pharmaceutical residues, hormones, PFAS and microplastics are therefore moving into sharper focus in wastewater treatment.
In addition, the energy consumption of wastewater treatment plants is coming under closer regulatory scrutiny. This is hardly surprising, as they are among the largest energy consumers in municipal infrastructure. Processes such as aeration and recirculation in particular drive energy demand during system operation. Under the revised UWWTD, energy neutrality in the wastewater sector will be mandatory by 2045.
Economic pressure is also increasing. Many wastewater treatment plants are already decades old and need to be modernised or expanded, often while remaining in operation. At the same time, investments must be planned in such a way that wastewater charges remain predictable for customers in the long term. Process reliability and dependable plant operation are essential, as they are the only way to safely comply with discharge limits and protect water bodies on a lasting basis.
The challenge lies in balancing all these requirements—higher treatment performance, stable processes, cost-effective operation, and compliance with new regulatory standards. Modern wastewater treatment therefore requires one thing above all else: the precisely coordinated interaction of all process stages within the wastewater treatment plant.
Requirements for modern wastewater treatment
- Removal of nitrogen and phosphorus
- Reduction of micropollutants
- Compliance with European wastewater directives
- Stable operation under fluctuating inflow volumes
- Energy-efficient plant management
Typical wastewater treatment process
- Mechanical treatment
- Biological treatment
- Chemical treatment
- Micropollutant removal
Our solutions for modern wastewater treatment
Wastewater treatment is a multi‑stage process in which different treatment methods must be precisely coordinated. We support you with comprehensive system expertise – from dimensioning and integration of the individual treatment steps through to the long‑term optimisation of existing plants.
This creates solutions that both meet new requirements and further develop existing infrastructure in a meaningful way.
Mechanical treatment
Reliably removing disruptive solids and stabilising inflow
Mechanical treatment forms the first stage of the wastewater treatment process. Here, coarse and fine solids such as hygiene products, plastics, wood and other foreign objects are removed from the wastewater before it enters the subsequent treatment stages. This is also crucial for protecting technical components. The more consistently disruptive solids are retained at this early stage, the more reliably and efficiently the biological and advanced treatment stages can operate later on.
We offer utility companies solutions for reliable solids retention and the safe transfer of raw sewage within the plant. Modern filterscreens (from Wilo FSM) enable effective removal of coarse and fine material, even under strongly fluctuating inflow conditions. At the same time, high‑performance sewage pumps ensure that large volumes of water are conveyed safely – even at hydraulic peak loads, for example after heavy rainfall events.
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In addition, we support an even feed to subsequent treatment stages. With a carefully matched combination of screens, pumping technology and pump systems, the inflow is reliably pre‑treated and the transfer of wastewater within the treatment plant is safely controlled. This creates robust pre-treatment processes that form the basis for high‑performance biological treatment and further advanced treatment stages.
Biological treatment
Precisely controlling biological processes and reducing energy consumption
In the biological treatment stage, dissolved organic matter as well as nitrogen and phosphorus compounds are broken down with the help of micro‑organisms. For these processes to run reliably, oxygen transfer, mixing and sludge recirculation must be carefully coordinated. Only when these factors work together optimally can stable biological processes and consistently compliant effluent values be ensured.
Aeration plays a central role. It supplies the oxygen needed for biological degradation. At the same time, however, it accounts for the largest share of a plant’s energy consumption. Activated sludge tanks must also be evenly mixed to prevent deposits and to provide micro‑organisms with an optimal supply of oxygen and nutrients. Recirculation of activated sludge between treatment zones is equally critical to ensure that nitrification and denitrification proceed as effectively as possible.
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We support wastewater treatment plants with solutions for precisely controlled biological process management. Energy‑optimised aeration systems provide demand‑driven oxygen supply, while high‑performance mixers ensure uniform tank mixing. In addition, efficient pump systems enable reliable recirculation of activated sludge and process water flows within the plant.
We also support consultants and operators right from the design phase. Using modern CFD simulation methods, flow conditions and oxygen transfer can be analysed in detail and tailored to the specific conditions of each plant. This creates an optimally coordinated interaction between aeration, mixing and recirculation.
Micropollutant removal
Advanced treatment stages for stricter water quality requirements
The revised Urban Waste Water Treatment Directive (UWWTD) places greater emphasis on the removal of micropollutants in wastewater treatment plants. For many plants, this will mean additional treatment stages to specifically remove trace substances from wastewater and reliably meet increasing water quality requirements.
Many anthropogenic substances can only be removed to a limited extent using conventional processes. These include pharmaceutical residues, hormones, pesticides and microplastics. Micropollutant removal therefore relies on a range of technologies and process combinations, such as adsorption using activated carbon, oxidative processes or membrane‑based filtration. It is crucial that these additional treatment stages are reliably integrated into existing plants and continuously supplied with wastewater from upstream process steps. At the same time, new processes must be operated safely and efficiently embedded into the existing infrastructure.
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We support wastewater treatment plants with solutions for safe wastewater transfer and controlled operation within this treatment stage. Efficient pump systems ensure a reliable feed to the various treatment steps. High‑performance mixers make sure that activated carbon or other reactive media are evenly distributed within the tanks so they can work to full effect. At the same time, coordinated recirculation solutions enable controlled return of process streams within the plant.
This allows new treatment processes to be reliably integrated into existing wastewater treatment plants and operated on a long‑term basis. The result is high‑performance plant concepts that meet future water quality requirements and further strengthen the protection of receiving waters.
Services and solutions for the entire lifecycle of your plant
Wilo supports you reliably in every project phase – from planning and design through to commissioning and maintenance. The goal is safe, efficient and predictable system operation.
Our offering at a glance:
- Support with planning and design (e.g., product selection, simulations, documentation)
- Commissioning and acceptance testing
- Maintenance, repair, and spare parts service
- Energy analyses
- Digital services for condition monitoring and predictive maintenance
- Trainings for operation and maintenance
With standardised and individually-tailored packages and digital tools, we create transparency around operating conditions, reduce unplanned downtime and ensure the long-term operation of water management infrastructure.
Optimise wastewater treatment processes holistically
Whether you are modernising existing infrastructure, adding new treatment stages or planning entirely new treatment systems – precisely coordinated process technology is key to reliable operation.
Talk to us about your project. Together, we will develop solutions for high‑performance, future‑proof wastewater treatment plants.
Contact our expertsSolutions across the water cycle
Our solutions cover the entire water cycle – from extraction and storage, through responsible use, to treatment and return to the natural environment. In this way, we safeguard water quality and availability for current and future generations.
