Written by Marius Schaub
Water and wastewater technology is part of critical infrastructure. The sector faces pressure from two sides: on one hand, municipal and industrial operators must ensure high availability, meet regulatory limits, and support environmental targets. On the other hand, rising energy costs, limited investment budgets, a shortage of skilled workers, and new climate risks directly affect day-to-day operations. For many plant managers, shift supervisors, and engineering teams, this means: the current operation must keep running while modernization, automation, and preparation for new stress scenarios happen in parallel.
A large share of existing treatment plants and pumping stations date back to the 1970s and 1980s and have only been modernized in parts since then. In many networks, valves are still operated manually, pumps run at constant full speed without variable control, and individual process units are insufficiently automated. This not only increases energy consumption but also ties up scarce personnel resources – for on-site checks, troubleshooting, and recurring switching tasks.
Compounding this is the shortage of skilled workers. In many municipalities and utilities, it is difficult to recruit enough qualified staff for operations, maintenance, and on-call duty. In practice, this results in situations where small teams must look after a growing number of decentralized pump stations, stormwater retention basins, and plant components. Every additional fault call and every unnecessary on-site visit hits twice: as a cost factor and as a burden on already stretched shift schedules.
Given tight budgets, a complete rebuild or comprehensive overhaul of entire treatment plants is rarely realistic. A more practical approach is to identify the biggest levers and proceed in stages. This includes particularly energy-intensive drive trains, manually operated valves, and equipment without demand-based control. Targeted retrofits – such as introducing variable-speed drives, automating individual pump groups, or upgrading critical measurement points – can unlock savings without requiring a full rebuild.
Another building block is the replacement of old motors with more efficient drives. High-efficiency synchronous reluctance or permanent magnet motors can significantly reduce losses compared to older standard motors. Combined with appropriate control technology, this creates a foundation for lasting energy optimization.
A central area lies in how pumps and blowers are operated. Rather than running a single large pump at constant full load, a network of several smaller units can be used to share the load. Intelligent control strategies ensure that only as much flow capacity is provided as actually needed. At the same time, starts and stops are distributed evenly across the pump inventory, reducing wear. Operators benefit from lower energy costs, reduced mechanical stress, and greater redundancy in the system.
Where foreign objects cause problems, a closer look at the combination of mechanics and control systems pays off. Automated cleaning cycles, in which pumps briefly run in reverse at defined intervals, can dislodge deposits before blockages form. In many cases, this significantly reduces manual interventions.
In the long term, prevention at the source also pays off: public awareness campaigns, guidance to connected households, and adjustments to drainage regulations can help reduce the share of problematic foreign objects in the system. Technical and organizational measures go hand in hand here.
On the electrical side, solutions that prevent harmonics at the source or reduce them significantly are gaining relevance. Modern drive systems can shape currents so that they place less load on the grid while simultaneously minimizing reactive power. Compared to purely downstream grid filters, additional energy consumption is reduced and plant stability increases.
For operators, the critical factor is to integrate this topic early in planning and procurement processes. The more comprehensively grid power quality, on-site generation, and new consumers are considered together, the lower the risk of unexpected interactions during later operation.
In the day-to-day reality of water and wastewater operations, a range of technical and organizational challenges converge and directly affect operational safety, costs, and workload.
One thing is clear: wastewater treatment plants are among the largest electricity consumers in the municipal sector. Aeration, pumps, mixers, and blowers run for many hours each day and directly shape the energy balance. Against this backdrop, efficiency measures are not only a contribution to climate protection but also a central lever for reducing operating costs.
At the same time, new opportunities for on-site electricity and heat generation are emerging: sewage gas can be used in combined heat and power (CHP) units for electricity and heat production, rooftop or open-area photovoltaic systems supplement the energy supply, and heat recovery from process streams or buildings can partly replace external energy sources. Mono-incineration of sewage sludge with downstream energy recovery is also gaining relevance in Germany. The vision of treatment plants with very low – or even positive – energy balances is moving within reach.
With each additional energy source and each new electrical consumer, however, the demands on grid power quality within the facility increase. On-site generation units, variable-speed drives, and new treatment stages can generate harmonics and reactive power. If these effects are not addressed, motor malfunctions, measurement disturbances, or even grid disconnections by the network operator can result. For operators, it is therefore important not to treat energy efficiency and grid stability as separate issues, but as two sides of the same coin.
Another lever lies in the digitalization of drive technology and auxiliary equipment. When pumps, blowers, and other components are connected via secure communication links, operating data can be analyzed in real time, faults can be detected early, and many adjustments can be carried out without on-site presence.
Complementing this, fallback functions are growing in importance: configurations in which drives switch to a defined emergency mode during communication failures and maintain, for example, a constant pressure or fill level. Such concepts increase plant resilience without requiring additional systems to be built.
With an eye on heavy rainfall events and flooding risks, a robust expansion of stormwater overflow basins, retention volumes, and pumping stations is essential. At the same time, operators must ensure that the technology used is flexible enough to cover very different operating states – from dry weather operation to rare but intense rainfall events. Intelligent control of pumps, valves, and weirs helps to use available storage volumes optimally and defuse critical situations.
Where water is transported across regions – for example in interconnected supply systems spanning several municipalities – additional requirements arise for pressure management, redundancy, and communication. Technical solutions that can securely network and automate multiple pump stations help operate such systems economically while maintaining operational safety.
For plant managers in water and wastewater technology, the question is less about individual trend technologies than about a workable sequence: which measures deliver noticeable results in the short term, where are the greatest risks, and how can limited budgets be sensibly planned over several years? From a technical standpoint, several key priorities stand out:
Those who address these areas in a structured and timely way not only create greater safety in day-to-day operations but also improve the starting position for future investment decisions – regardless of whether the focus is on expanding individual treatment stages, integrating new energy sources, or interconnecting entire supply regions.
