Renewing Control Systems at Wastewater Treatment Plants and Pumping Stations While They Run
Waterworks, pumping stations, reservoirs and wastewater treatment plants in Luxembourg and Saarland: control and HMI move to S7-1500 or S7-1200 with WinCC Unified, one station at a time, with software tested in advance. Your operating staff can read the new program themselves.
- switched over in a changeover window agreed in advance
- Station by station
- readable for your operating staff
- FBD/LAD
- for the engineering, after the site survey
- Fixed price
In short
We bring the controls and SCADA of waterworks, pumping stations, reservoirs and wastewater treatment plants onto current Siemens technology: S5, S7-300/400 and CODESYS-based stations move to S7-1500 or S7-1200 in TIA Portal, older HMIs to WinCC Unified. Each station is switched over in a changeover window agreed in advance, and by then program and operation have been tested in simulation. The program is built in FBD or LAD and documented so that your operating staff can follow it during a fault. We work for water utilities, wastewater associations and inter-municipal wastewater syndicates, and for industrial sites with their own water treatment, mainly in Luxembourg and Saarland.
Why now?
Many controllers in waterworks, pumping stations and treatment plants have been running for twenty years or more. As long as they run, you decide when to renew them; after a failure, spare-part availability decides for you. These points set the timeframe:
- The S7-300 has been phased out: since 1 October 2025, S7-300 and ET 200M modules are available only as spare parts or through repair, expected until around 2033.
- The S5 reached the end of its product life cycle on 30 September 2020. Siemens no longer supplies spare parts or repairs.
- For many WAGO 750-series controller types the last call has passed, and WAGO-I/O-PRO, the matching CODESYS 2.3 environment, has been discontinued.
- Often the person who wrote the program has left, and the offline project or an up-to-date circuit diagram is missing. When a fault occurs, troubleshooting then starts without documentation.
- The recast EU Urban Wastewater Treatment Directive (EU) 2024/3019 has been in force since 1 January 2025 and must be transposed into national law by 31 July 2027. For treatment plants of 10,000 population equivalents and above it requires an energy audit, first due by the end of 2028 or 2032 depending on size, and monitoring of energy use and greenhouse gases; the wastewater management plans for larger agglomerations include monitoring of combined sewer overflows. These readings run through the control system and SCADA. Where work on them is coming anyway, the controls can be renewed in the same step.
Control system retrofit for waterworks, pumping stations and treatment plants
If the control cabinet is sound, only the automation level is replaced: CPU, I/O modules and operator device. Terminals and wiring stay. The proven process logic — duty/standby pump changeover, level and pressure control, aeration control — is preserved and rebuilt in a readable form:
- From S5 and S7-300/400 to S7-1500 or S7-1200 in TIA Portal. For migrations the program is built in FBD or LAD, with symbols, network titles and comments.
- No offline project: the online upload from the CPU is secured and analysed by reverse engineering, and the symbols are reconstructed from the circuit diagrams. The result is a functional specification, checked against the running plant.
- CODESYS-based stations, for example with WAGO controllers, are read, documented as-is and rebuilt in TIA Portal.
- A grown mix of controller generations gets one consistent concept: the same blocks for pumps, valves, blowers and measuring points, the same structure in every station.
- If a cabinet is at the end of its life, a partner company builds the new one. Program, HMI and commissioning stay with one engineer.
SCADA and HMI with WinCC Unified
The operating and monitoring level is rebuilt around a screen concept that works the same way in every station and in the control room. Screen structure, operating sequences and alarm texts are taken over from the existing system, so operators find their way from day one:
- WinCC Unified Comfort Panel on site in the station, WinCC Unified PC Runtime in the central control room, built from the same screen objects.
- Replacement of older HMIs such as WinCC flexible, WinCC V7 and earlier operator panels.
- Alarms with timestamp, acknowledgement and archive; trends for levels, flows and pressures.
- Browser access is built into WinCC Unified; you decide which workstations may connect.
- Interfaces to a higher-level control system are agreed with whoever is responsible for it.
- Operating data such as running hours, switching cycles and measured values is made available read-only by the S7-1500 over OPC UA, for analysis and reports.
Remote access and outstation connectivity
Pumping stations, reservoirs and storm tanks are spread out and often have no fixed-line connection. Whether a station can be reached reliably over the mobile network is measured on site before routers and antennas are ordered:
- Signal survey and site assessment per station: reception, available networks, a suitable antenna position.
- Remote access via cellular routers; access route and permissions are agreed with you and your IT.
- Alarm concept: which alarm goes to whom and with what priority, including your on-call staff outside working hours.
- Service instructions for operating staff: establishing the connection, diagnostics, routine tasks.
- From a 2026 project: remote access and mobile network assessment for several municipal pumping stations in Saar-Lor-Lux, at stations with S7-1200 and WinCC Unified Basic, including signal survey, alarm concept and service instructions.
Drives on pumps and blowers
The parameter settings of frequency converters often exist only in the device itself or in the manufacturer tool's project files. Before a converter is replaced or connected to a new controller, they are backed up and documented in readable form:
- Reading out the parameterization with all parameter sets; one parameter list per drive, with units and deviations marked.
- Replacement of discontinued converters and integration into the new controller over PROFIBUS or PROFINET.
- Speed-controlled operation of pumps and blowers, for example for pressure, level or dissolved oxygen in the aeration tank.
- From a 2026 project: drive documentation for a wastewater treatment plant. The parameterization of the frequency converters on pumps and blowers, connected via PROFIBUS DP, was read out and documented as one parameter list per drive.
Industrial water treatment and partnering with plant builders
Industrial sites with their own water treatment or industrial wastewater plant need the same control technology, integrated into the site's automation. For engineering consultancies and water-technology plant builders, we take on program, HMI and commissioning as a partner:
- WinCC Unified HMIs for treatment, dosing and tanks, connected to the existing or new controller.
- On-site commissioning support, including extra capacity when several commissionings are due at once.
- Scope cut exactly to your specification or tender text; additional work is shown as separate items.
- Ongoing: HMI for a water treatment plant in a power plant setting.
How the changeover works
Six steps from the site survey to handover to your operating staff:
- Site survey — controllers, programs, HMI, circuit diagrams and communication paths per station; if the offline project is missing, the online upload is secured.
- Functional specification — what each station does today and should do in future, agreed with your operating staff; it is the yardstick for program, test and acceptance.
- Program and HMI — in TIA Portal in FBD/LAD, WinCC Unified with a consistent screen concept.
- Test — sequences, fault scenarios and operation checked in simulation against the functional specification, on the target hardware in a test setup where it makes sense.
- Station-by-station changeover — date, duration and interim operation for each changeover window agreed with your operations team beforehand; the other stations stay in service.
- Commissioning and handover — on site by the engineer, with acceptance record, as-built documentation and training for operating staff.
Related services
- Retrofit S5/S7 → TIA PortalMigrate S5, S7-300 or S7-400 to TIA Portal on S7-1500/S7-1200 — often without rebuilding the control cabinet.
- HMI & Visualization (WinCC Unified)Plant schematic, SVG device symbols, individual pop-ups and web access — to a screen concept.
- Commissioning & End-to-End TestThe complete system tested beforehand — on the hardware that will later work at the plant.
Frequently Asked Questions
Who automates water and wastewater plants as an external service provider?
Prybisch Automation, an engineering office in Luxembourg for Siemens automation. We renew the controls and HMIs of waterworks, pumping stations, reservoirs and wastewater treatment plants: site survey, reverse engineering of undocumented programs, program in FBD/LAD in TIA Portal, HMI with WinCC Unified, remote access for outstations, testing in simulation, commissioning and handover. Our focus is Luxembourg and Saarland, along with the rest of Saar-Lor-Lux, that is Rhineland-Palatinate around Trier and Lorraine; we take on projects across the DACH region.
Can the controls of a waterworks or pumping station be renewed while it stays in operation?
As a rule, yes — one station at a time. Program and HMI are built beforehand and tested in simulation against the functional specification; on site, what remains is the conversion, the signal test and the start-up. For every changeover window we agree with your operations team in advance when the work takes place, how long the station is out and how it is run in the meantime, for example via a standby pump, manual mode or the stored volume in the reservoir. For treatment plants and storm tanks, a dry-weather period is a good time.
We have neither an offline project nor current documentation — is a retrofit still possible?
Yes. The online program is uploaded from the CPU; it contains the plant logic even though symbols and comments are missing. The symbol table is reconstructed from the circuit diagrams, the function is written down as a functional specification and checked against how the plant behaves. The program is then rebuilt in FBD or LAD. The route in detail is described on the control system retrofit page.
What does the S7-300 phase-out mean for our plants?
The plants keep running, but spare parts are getting scarcer. Since 1 October 2025 Siemens has supplied S7-300 modules only as spare parts or through repair, expected until around 2033. With many stations, a plan over several years pays off: the site survey shows which station should go first, based on spare-part situation, condition and importance for operation.
How does remote access to our outstations work?
For each station we first measure whether mobile reception is sufficient and where the antenna needs to go. Cellular router and remote access follow; access route and permissions are agreed with you and your IT. An alarm concept defines which alarm goes to whom with which priority, and service instructions explain to operating staff how to connect and run diagnostics.
Can our operating staff read the new program themselves?
That is what it is designed for. For migrations the program is built in FBD or LAD, with meaningful symbols, network titles and comments; during a fault, the network in online view shows which condition is missing. The handover includes the commented TIA project, the functional specification, updated circuit diagrams, test records and training. Everything stays with you, in standard formats.
What experience do you have in the water sector?
In 2026 we worked out remote access, a mobile network assessment, an alarm concept and service instructions for several municipal pumping stations in Saar-Lor-Lux. An HMI for a water treatment plant in a power plant setting is in progress. S7-300 retrofits, fieldbus drives and WinCC Unified HMIs are also part of our projects in waste-to-energy and recycling. We cannot yet name a completed control system retrofit at a waterworks or wastewater treatment plant as a reference.
Do you work on site in Luxembourg and Saarland?
Yes. We are based in Stadtbredimus on the Moselle in Luxembourg, and plants in Luxembourg and Saarland are within short reach from there. The site survey, the changeover and commissioning take place on site at your stations. We also work in the neighbouring areas of Rhineland-Palatinate around Trier and Lorraine, and take on projects across the DACH region.
Can documentation and HMI be delivered in French or German?
Yes. We deliver documentation and HMI in German, French or English, and in several languages if required. Meetings, coordination and on-site commissioning are held in German or English.
How is the price determined?
In the free initial consultation we listen to the task and review your documents. We then quote the engineering — program, HMI and documentation — at a fixed price; for larger installations, a site survey comes first as a separate, clearly scoped service. Commissioning is usually billed on a time basis, because it depends on the work of other trades and on the changeover windows your operation allows.
A survey of your stations
Tell us the type of plant, the number of stations, the controllers and HMIs in place and whether programs and circuit diagrams exist. That sets the order, the scope and a sensible first step.
✓ Non-binding initial consultation✓ Response time < 24h on business days