24 Annual report

Annual report as PDF

Foreword

Dr Uwe Sollfrank

Chairman of the Board of Directors & CEO

Dear shareholders, employees, clients and business partners,

HOLINGER is an independent service provider and a leading supplier of consulting, engineering and general planning services in Switzerland, Germany and Luxembourg. Across Europe, we are carefully evaluating opportunities for cooperation and expansion to strengthen our strategic position wherever compelling prospects arise.

At HOLINGER, we plan today what our clients will need tomorrow. While this may sound straightforward, it is a demanding tasks. It requires clear-sightedness, deep expertise and strong conviction. Our work focuses on wastewater, urban drainage, hydraulic engineering, watercourses, water supply, industry, environment, energy and infrastructure. These are our core competences. In these areas, we aim to lead – developing solutions and services that help shape the future for people and the natural environment.

Engineers without Borders

Clean drinking water through natural filtration

Despite ealier modernisation efforts the drinking water infrastructure in the village of Yrdyk in eastern Kyrgyzstan is in a sorry state. You can help change that with a donation to Engineers Without Borders.

 

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At a glance

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Locations

People

Inspiring work – Five employees interviewed.

Anna-Gesa MeierProject manager
Filip MarinkovicDraftsman apprentice (EFZ)
Christina MeyerCivil engineer
Andrea GigliottiBIM Specialist
Mario DolderConstruction and project manager

Balancing family, career and lectures

Born: 1983
Position: Project manager
Experience: 15 years, including 6 years at HOLINGER
Hobbies: Sewing, reading, walking/hiking with good music
Core HOLINGER value: Social and societal responsibility

Gaining experience and knowledge and learning for life

Do you think four years of training is a long time?

Honestly it flew by – probably because the work was so varied and interesting. I really can’t believe that my final exams are just around the corner.

Why did you choose to become a draftsman?

Because it’s a mix of everything. You get to work on all kinds of projects and you’re not stuck at a desk all the time – you get to visit construction sites. Plus, after the apprenticeship, there are plenty of cool options for further training.

Which parts of civil engineering do you find most interesting?

I’ve really got interested in structural engineering – especially formwork and reinforcement.

What’s your final project about?

A classmate and I planned a whole roadworks project from scratch. We created all the plans and wrote a full technical report.

What were some highlights of your apprenticeship?

The team outings; those were fun and a great way to bond. And I learned a ton during reinforcement inspections with my colleague Mirko. It helped me grow both professionally and personally.

What did you find difficult at first?

Initially, talking to all the different people on the project teams was a challenge. But over time, I learnt how to be clear and confident no matter who I am talking to.

What’s the most valuable thing you’ve learned?

Working successfully with so many different kinds of people allowed me to build a broad knowledge base while I was learning to be flexible and open to different personalities.

Was choosing HOLINGER for your apprenticeship the right call?

Absolutely! It has been extremely valuable. I was always supported by experienced and professional colleagues who were happy to help and guide me whenever I had questions or faced challenges.

 

 

You’re done this summer – what’s next?

I’m looking forward to some well-earned time off; ideally somewhere peaceful and sunny. After that, I will return the workplace with renewed energy, ready to take on some exciting new tasks and challenges.

 

Born: 2005
Position: Draftsman apprentice (EFZ), specialising in civil engineering
Experience: 4th year of apprenticeship
Hobbies: Crypto mining, trading, working out
Core HOLINGER value: Taking responsibility

A civil engineer for the future

What made you want to become a civil engineer?

I wanted a career where I could blend my interest in technology, mathematics and creativity; ideally something that would lead to tangible, meaningful results. Civil engineering has it all: it’s very varied, it’s hands-on, and it gives you the chance to help shape the buildings and infrastructure around you.

Was there a time when you considered another path?

Yes, because I didn’t know anyone in civil engineering who could give me insight into the job; especially what it’s like on site. But after two internships in engineering offices, just before finishing school, I got a chance to do an on-site stint. That is when I knew it’s the right for me.

Which of your personal interests do you see reflected in your work?

What I love is how the job blends technical thinking with creativity and practical problem-solving.

There’s also a strong element of strategic and economic thinking too. No two days are ever the same, which keeps it fresh. What I value most, though, is the collaboration—it’s that team spirit that really drives projects forward.

What do you particularly enjoy about your work at HOLINGER?

At HOLINGER, I have the opportunity to help shape infrastructure that plays a crucial role in environmental protection and resource efficiency; especially in water and wastewater. I really enjoy the interdisciplinary collaboration here. It gives me a broader perspective and keeps the work varied and intellectually engaging.

What achievement are you particularly proud of recently?

In 2024, alongside my work at HOLINGER, I successfully completed a degree in business administration and management remotely. Balancing both wasn’t easy, but it was a very rewarding step.

What kinds of challenges do you face in your day-to-day work?

In Luxembourg, we work with people from many different nationalities and across multiple locations every day—which calls for a high level of flexibility.

New technologies, evolving regulations and individual client expectations make every project unique. When you’re working on big or overlapping projects, it’s really important to stay on top of everything and make sure all the moving parts fit together smoothly.

Do surprises still happen on site?

Certainly. For example, recently during the demolition of an old office building, even though everything had been carefully reviewed in advance, we discovered that the adjacent structure wasn’t connected as originally thought. So we had to rapidly reassess the structural situation and come up with a solution to stabilise the neighbouring wall.

How important is teamwork in your role?

Teamwork is vital, irrespective of the size or nature of the project. Complex projects demand close collaboration and clear communication. Through teamwork we can ensure efficient workflows, foster innovative solutions, and deliver economically successful outcomes. And by sharing responsibilities, leveraging individual strengths, and adhering to the four-eyes principle we can maintain high quality and reduce errors.

How does your work contribute to a better future?

Our projects, whether new builds or refurbishments, improve infrastructure that people rely on every day but take or granted.

Our projects help protect the environment: they preserve resources, underpin essential services, and address urgent challenges like climate change, environmental impact, and population growth.
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Born: 1979
Position: Project and construction management
Experience: 20 years civil engineering, 7 at HOLINGER
Hobbies: Travelling, sports
Core HOLINGER values: All of them

Using BIM as a versatile resource

What goes through your mind on a Monday morning?

As soon as I leave the house, I usually start gathering my thoughts, planning my strategies and centering so that I can begin the week with clear focus and a strong sense of direction.

What does your role at HOLINGER involve?

As a BIM specialist in Mendrisio, I model architectural and building technical details. Working closely with our teams and mentoring a junior colleague, I identify issues early on and help ensure successful project delivery.

Which of your personal passions come into play at work?

I love 3D modelling and creativity. BIM allows me to turn ideas into functional, intelligent models. Working closely with colleagues encourages innovation and that’s what keeps the job both dynamic and deeply satisfying.

How intensively is BIM used in Mendrisio?

I am using BIM almost 100% of the time. Occasionally, I still use 2D tools like AutoCAD or take part in coordination meetings with external partners, but otherwise I am working on BIM throughout the day.

How has BIM transformed the industry?

I’ve been involved with BIM for more than a decade and it’s clearly the future of planning. It enhances precision, prevents design conflicts, and significantly improves coordination between disciplines.

Compared to traditional methods, projects can be delivered faster, more reliably, and with fewer surprises.

What is the biggest challenge when working with BIM?

For BIM to work as a platform for collaboration and to have high quality models, everyone has to follow the same methodology and shared standards. There needs to be a structured approach to quickly identify and manage risks during both planning and execution.

How does it feel to be the BIM specialist in Mendrisio?

It is a lot of responsibility. I’m constantly balancing demands and deadlines. But having years of experience is useful and every new project, helps me to become more efficient and better at coordination and teamwork.

What personal qualities helped you specialise in BIM?

Being passsionate about both the technical and creative aspects of 3D modelling helped; but flexibility has also been vital because the BIM landscape is evolving rapidly.

What do you appreciate most about working at HOLINGER?

I really appreciate the positive and flexible work environment. It is good for a healthy work-life balance. I’m also fortunate to have skilled and supportive colleagues – they inspire me to keep improving and give my best every day.

Born: 1991
Position: BIM Specialist, Mendrisio office
Experience: 2 years at HOLINGER. Over ten years in BIM
Hobbies: New tech, writing historical fiction, and creating immersive role-playing games
Core HOLINGER value: Trust and mutual respect

From professional athlete to engineer

Born: 1990
Position: Construction and project manager
Experience: 5 years at HOLINGER
Hobbies: Sport, gardening
Core HOLINGER value: Personal responsibility

Projects

Explore the wide spectrum of our projects made possible by our interdisciplinary approach.

Wastewater
Energy
Urban Drainage
Environment & Sustainability
Hydraulic Engineering
Water Supply

Pipelines cleverly installed during ongoing operations

Heidelberg (Germany) – The Heidelberg wastewater treatment plant, designed for 360 000 population equivalents (PE), will soon be receiving a fourth treatment stage as the structural construction work that has been underway for over two years nears completion.

Some of the challenges included installing the filter floor slabs and connecting the inlet and outlet pipes. A truck-mounted Autocrane, was used to place 90 prefabricated filter slabs, each weighing 6.8 tons, into 18 filter chambers.

Then, the connection pipelines were installed as siphon pipelines underneath the existing inflow pipelines – while the system was still in operation. This required supporting the existing heavy cast iron pipes for the duration of the construction period. The technical system will be completed by the end of 2026, and the work on the road and outdoor facilities will follow in the second quarter of 2027.

Groundwater as an energy source

Brugg (AG) – IBB Energie has repurposed a decommissioned drinking water well in Brugg: the groundwater is now being used as the energy source for heat pumps that supply heating to nearby buildings.

HOLINGER supported IBB Energie in the planning of the 250 kW heating system. Our Energy team conducted a feasibility study on different heat supply options, prepared cost estimates, and handled the dimensioning of heat exchangers, heat pumps, thermal storage, and hot water production for the new energy centre.

Then our specialists developed detailed plans, piping and instrumentation diagrams, and precise 3D models for this complex project, and prepared all the submission documents.

This two-year 3D heating systems planning project is a significant milestone for HOLINGER.

Dynamic sewer network control for erzo

On behalf of erzo (The Waste Disposal Association of the Region of Zofingen), and in accordance with the GDP (General Drainage Plan), HOLINGER is constructing a stormwater overflow basin that will add 3 000 m³ of storage volume at the ‘Wiggermatten’ wastewater treatment plant.

To make the best use of both the existing and new storage capacity, HOLINGER conducted a feasibility study exploring various control strategies. Different approaches to dynamic sewer network control were compared using a SIMBA simulation model.

The study also assessed the added value of integrating weather forecasts into the treatment plant’s control system.

The preferred solution coordinates the emptying of nearly ten basins across the network using dynamic flow regulation, that takes into account the distribution of rainfall across the area. Thanks to the optimized operational strategy, the discharge of untreated overflow loads will be reduced by approximately 15%.

The new control system was approved by the cantonal authorities of Aargau and Lucerne and then successfully implemented by Chestonag AG in November 2024.

Extensive soil improvement measures

Buttisholz (LU) – The “Obergattwil” site between Buttisholz and Nottwil was formerly used for peat extraction and the disposal of excavation material. As a result, the terrain became uneven and waterlogged, severely restricting its agricultural potential.

In a pilot project planned by HOLINGER and supported by our soil science expertise, the Canton of Lucerne is aiming to establish new crop rotation areas to offset agricultural land lost to cantonal infrastructure developments. The project involves removing and temporarily storing the existing topsoil before replacing it with clean, uncontaminated soil from external construction sites.

A technically complex and labour-intensive drainage solution will address both groundwater and hillside runoff. Together with the new soil profile, this will sustainably improve the site’s condition and enable continued agricultural use. Due to its high dependency on weather conditions, project completion is not expected before autumn 2025.

New fish ladder and refurbished weir

Münchenstein (BL) – The Birs weir impounds water for the IWB’s “Neuewelt” small hydropower plant, generating renewable energy and feeding the historic St. Alban canal. Since its construction in 1880, the weir has settled unevenly due to subsoil weathering. To prevent groundwater underflow, an interlocked bored pile wall was installed, and existing voids were sealed using compaction grouting.

Because it is the last hydropower plant before the Birs flows into the Rhine, “Neuewelt” is vital for ecological connectivity. A newly constructed fish ladder, which includes some two-level sections, now enables fish, including salmon, to pass the weir freely in both directions. A horizontal rack protects the intake to both the power plant and the St. Alban canal, while a sediment bypass optimizes bedload transport. HOLINGER was responsible for design and site supervision throughout this comprehensive rehabilitation project.

A truly first-rate reservoir

Birsfelden (BL) – The newly constructed “Rütihard” reservoir boasts a total drinking water storage capacity of 3 400 m³. Thanks to the hygienic design of the two chambers, this water can be delivered to the local population without the need for further treatment.

HOLINGER acted as general planner, responsible from initial design through to commissioning. To ensure exceptional longevity, the piping system was constructed using corrosion-resistant stainless steel. The concrete structures were built using Zemdrain® formwork technology, which eliminates the need for formwork oil while delivering a smooth surface with hygienic properties.

Before construction could begin, two of the three existing chambers had to be removed to make room for the new facility. These works were carried out while maintaining the operation of the third chamber. Upon completion, the entire reservoir was covered with soil. Thanks to careful landscaping, in accordance with strict ecological guidelines, and meticulous attention to the façade architecture, we were able to ensure that the facility is fully integrated into the natural surroundings.

Technologies

High societal benefits thanks to comprehensive expertise – selected insights into our specialist areas.

Wastewater
Energy
Urban Drainage
Environment & Sustainability
Hydraulic Engineering
Water Supply

Competence across all project phases

With locations across Switzerland, Germany and Luxembourg, our specialists in municipal and industrial wastewater treatment have unrivalled customer proximity. In 2024 alone, we worked on approximately 681 projects in the waste water sector including major significant infrastructure initiatives such as the Heidelberg WWTP project.

Professional construction, operation and maintenance of wastewater treatment plants (WWTPs) is essential for safeguarding water quality.

WWTP Oberes Wiggertal

The S-Select® process was implemented to enhance the biological treatment performance of the WWTP

Climate change and population growth are placing increasing demands on treatment infrastructure. In the EU and Switzerland, stricter legislation is currently being drafted for the elimination of nitrogen and micropollutants. Looking ahead to 2025, additional challenges such as minimising greenhouse gas emissions and integrated management of water within the WWTP network will continue to shape the sector. Drawing on extensive experience and innovative solutions, HOLINGER’s wastewater team develops sustainable concepts for efficient, future-ready and environmentally sound wastewater treatment.

Own contribution by department

Two-path GAC Filter System

New two-path GAC filter system very efficiently eliminates micropollutants at a Swiss pharmaceutical site

Sustainable energy with district heating

Our Energy division delivers advanced, green engineering services for the extraction, conversion, transmission, storage and delivery of fuels, electricity and thermal energy.

In 2024, we further strengthened our team and now have enough experts to cover all our market regions. We also grew our client base and successfully implemented a range of exciting, interdisciplinary projects.

Watt d'Or

HOLINGER wins the Watt d’Or Energy Award with IWB
More

With both general and specialist planning capabilities, we develop sustainable and innovative energy solutions for energy suppliers, municipalities, cities and area utilities. And last year, we added specialist planning services for district heating networks to our service portfolio.

In their quest for more resilient energy infrastructure, client will now be able enjoy the added value of comprehensive planning services for energy centres and their associated distribution networks from a single source.

Own contribution by department

Biomass

Study on usable energy potential from digestible biomass, Switzerland
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In harmony with the water cycle

Urban drainage plays a key role in the water cycle and is closely interlinked with all areas of expertise across the HOLINGER Group. Our employees actively promote this interdisciplinary collaboration, which our customers appreciate and reward with challenging and exciting projects.

The continued development of blue-green infrastructure in urban environments remains a dynamic challenge. Alongside the careful selection of materials and vegetation, precise hydrological and hydraulic modelling is required to design effective systems. 

Chamberonne

Completion of the “PREE Chamberonne” Regional drainage project concept for the Chamberonne – catchment area: 39 km², watercourse length: 58 km

Increasingly, urban surroundings or peripheral areas are being taken into consideration in the process of urban drainage planning which offers new options for the protection of infrastructure against intense rainfall.

In 2025, with unwavering commitment to water protection, HOLINGER’s Urban Drainage team will implement targeted measures to remove microplastics from the water cycle, optimise wastewater network management to safeguard receiving waters, and promote the rainwater infiltration. In this way, we are strengthening the natural water cycle and reducing the likelihood that heavy rains will flush untreated wastewater into lakes and rivers.

Own contribution by department

Bern Sponge City

Development of guideline for good rainwater management in public spaces

Stewarding resources- from planning to realisation

Our Environmental and Sustainability specialists take a hands-on, solutions-oriented approach and support a wide range of tasks – both in direct client mandates and as advisors in interdisciplinary projects. Our services span the entire project lifecycle, from initial studies to permit applications and realisation.

During the planning phase, we identify environmental protection measures, prepare environmental impact assessments, assess potential for groundwater and geothermal energy use, and assess contaminated sites.

Swiss Krono

Preparation of an environmental impact report and investigations of contaminated sites, Menznau (LU)

During construction, our soil protection specialists ensure the careful stewardship of soil resources, the proper handling of hazardous materials and compliance with environmental regulations. In this way, we help to make project execution sustainable.

We also offer carbon accounting for wastewater treatment plants and provide the basis for targeted emission reduction measures. With their broad expertise and interdisciplinary perspective, our specialists actively contribute to sustainable, future-proof infrastructure.

Following around 1 600 assignments in 2024, we are entering 2025 with continued momentum and a strong order book.

Own contribution by department

EBL Contaminated Sites

Support for legal assessment of contaminated sites belonging to electricity provider, Liestal (BL)
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An integral approach and sustainable measures

While watercourses pose various perils, they are also valuable habitats. That is why HOLINGER’s Hydraulic Engineers work hard every day to ensure flood protection as part of an integrated planning approach that seeks to enhance the ecological value of rivers and their surroundings and to create attractive recreational areas.

During the past year it was again evident that innovative and robust measures are needed to address climate change and the rise of extreme weather events.

Revitalisation of the Birs

Nature and recreation area Schänzli, Muttenz (BL)

However, we need to look beyond the risk of damage to watercourses: the impact of heavy precipitation and the resulting surface runoff must be minimized holistically through interdisciplinary project teams that take the big picture into consideration.

Sustainability plays a central role in our projects – not only through planning for resilience, but also in the implementation, where we attach particular importance to resource-saving building materials and the promotion of the circular economy.

Own contribution by department

Revitalisation project

Revitalisation of the Herblingerbach, Schaffhausen (SH)
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Sustainable strategies and pragmatic operational solutions

Changing climate conditions, increasingly scarce water resources and a persistent shortage of skilled professionals are just some of the challenges facing our industry. That is why we at HOLINGER, believe in the vital importance of supporting our clients with well thought-out solutions and long-term strategies from concept to implementation. Once again, in 2024, our Water Supply Division helped numerous water utilities modernise and adapt to evolving needs. For example, we developed effective operational solutions to address quagga mussels in both new and existing lake water treatment plants.

Lake Water Plant Riet

Construction project lake water plant Riet, Lake Constance region (SG) More

Looking ahead, as we continue to apply our expertise and experience, we will deliver sustainable added value in all our projects. We will leverage interdisciplinary teams and digital solutions to optimise resources while creating an engaging, forward-looking work environment for our employees. And we will pursue our goal of delivering the best possible solutions for all our clients with unwavering commitment.

Own contribution by department

Asset Maintenance Concept Birmensdorf

Development of a risk-based asset maintenance concept, Birmensdorf (ZH)

Subsidiaries

Dynamic markets in Switzerland and neighbouring countries – a sample of our subsidiaries.

IATIngenieurberatung
HOLINGERLuxembourg
MAULER SA
ENVILAB AG

Growth and vision

In 2024, HOLINGER Ingenieure GmbH opened two new offices reinforcing our market position. While successfully executing a number of major projects, we initiated a company-wide reorganisation process and moved steadily forwards with the integration of iat Ingenieurberatung GmbH.

During the financial year, our work in the Water, Environment and Energy sectors resulted in strong gains in revenue, client satisfaction and market presence. By delivering innovative, sustainable engineering solutions, we completed complex projects and forged valuable new partnerships.

Thanks to our new branches in Karlsruhe and Neu-Ulm, we are now closer to clients and better positioned to meet the growing demand for visionary infrastructure planning and engineering across our market region.

Thanks to targeted organisational restructuring, we have been able to streamline internal processes, unlock synergies, and establish resilient structures for continued success.

However, our flagship projects in 2024 presented us with the challenges of complex permitting processes and technical requirements as well as numerous stakeholders requiring intensive coordination efforts. Nonetheless, our longstanding expertise made all the difference. Our highly qualified team was able to both plan and deliver cutting-edge wastewater treatment plants.

Thanks to the integration of iat Ingenieurberatung GmbH in Stuttgart, we can now also meet the rising demand for operational consulting services.

Image: © Lutz Hannemann

Addressing Berlin’s growth with double the treatment capacity

Stahnsdorf (DE) – HOLINGER is leading the “H2SA” joint venture, which has been awarded the contract by Berliner Wasserbetriebe for the construction of the new Stahnsdorf wastewater treatment plant.

This forward-looking facility will include twelve SBR reactors, advanced trace substance removal, and an innovative energy concept. Designed to treat 100 000 m³ of wastewater per day – twice the current volume – the plant will significantly strengthen the region’s infrastructure. This major infrastructure project which will be realised over the next ten years, is a significant milestone for HOLINGER.

Two wastewater treatment plants become one

Vaihingen an der Enz (Germany) – The Strudelbach wastewater treatment plant is being expanded to accommodate a second municipal treatment facility.

After upgrading the secondary clarification stage, the City of Vaihingen commissioned HOLINGER Ingenieure GmbH to plan and supervise the construction of new preliminary treatment systems, aeration tanks, and a blower station. The project is currently under construction and is scheduled for completion in 2027.

Relying on innovative membrane technology

Leonberg (Germany) – After more than 40 years of continuous operation, the aeration basin at the “Mittleres Glemstal” wastewater treatment plant requires refurbishment.

Following a comprehensive assessment of different options by HOLINGER Ingenieure GmbH, the City of Leonberg and HOLINGER jointly decided to replace the basin with a membrane bioreactor (MBR). This state-of-the-art technology combines the advantages of conventional activated sludge treatment with membrane filtration.

Comprehensive support for WWTPs

2024 was a dynamic year for iat-Ingenieurberatung, with numerous challenging projects — from implementing fourth treatment stages and expanding wastewater treatment facilities to providing holistic operational support, maintenance and refurbishment services.

This year, we completed the design and permitting phases for several major projects. These included the expansion of the Bösingen wastewater treatment plant, which will serve a future capacity of 9 300 population equivalents; the extension and integration of a fourth treatment stage at the Sulmtal joint wastewater treatment plant for 40 000 PE; and the fourth treatment stage for the Wiesloch Association wastewater treatment plant, which will handle a capacity of 110 000 PE.

Providing technical and legal operational support remains a core focus of our business. In 2024, we were pleased to further expand this service area through new assignments and long-term support contracts. Demand in this area continues to grow, prompting us to strategically strengthen our team and portfolio.

Our services increasingly address the legal and regulatory requirements associated with wastewater treatment plant operation. This includes conducting risk assessments, preparing explosion protection documentation, advising on CE conformity, and developing service and operating manuals. We also manage indirect discharge registers and provide ongoing consulting in these areas.

Looking ahead, we remain committed to expanding our expertise and driving innovative, sustainable solutions in water management.

The flying silo

Eglosheim, Ludwigsburg (DE) – As part of the construction of the fourth treatment stage and the expansion of the activated sludge tanks, the Eglosheim wastewater treatment plant was equipped with a new silo for powdered activated carbon (PAC). The PAC plays a key role in the plant’s advanced treatment process and is used for the elimination of trace substances. The delivery of the silo was nothing short of spectacular: as the access roads to the sewage treatment plant were unsuitable for a wide heavy goods vehicle, the silo, which is over eleven metres high, had to be lifted onto the site from the adjacent main road using a hydraulic crane. We coordinated this operation with the road traffic authorities, closing the B 27 in the direction of Ludwigsburg for a short time. Once the mechanical installations were completed, the silo was lowered into place on the PAC dosing building.

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Modernisation during ongoing operation

Waiblingen (DE) – The Waiblingen wastewater treatment plant is being equipped with a new mechanical stage and a central influent lift station to replace the old intermediate lift station.

A particular challenge was that the new systems had to be accessible from two different levels. In addition, the plant had to continue to operate in the greatly reduced available space. The inlet lift screw pumps were delivered and installed in early 2025, and both systems are scheduled to be commissioned in the second quarter of 2025.

Regionally anchored, internationally connected

Despite the 2024 downturn in the construction industry in Luxembourg and other European countries, which also affected infrastructure projects, HOLINGER Luxembourg had a successful year. We implemented several complex undertakings, including work for the City of Luxembourg on the continued expansion of the Mamer wastewater treatment plant and the construction of a new vehicle hall with sewer flushing waste processing.

Looking ahead to 2025, we expect a moderate recovery in the construction sector as there is an increase in planned projects, particularly in the fields of water supply and renewable energy,

At the same time, significant future challenges are envisaged in the areas of energy efficiency, resource conservation, stricter environmental regulations (e.g. EU Urban Wastewater Directive), infrastructure security (NIS2) and further digitalisation.

To meet these demands, we are continuing to invest in our organisation, in the standardisation of processes and in digital tools. These support the efficient and sustainable implementation of our wide range of projects.

New vehicle depot with sustainable waste water treatment

City of Luxembourg – Sustainability and resource efficiency are key priorities for the City of Luxembourg that we addressed during the construction of a new vehicle and storage facility with an integrated grit treatment system for sewer flushing material.

A photovoltaic system with a peak output of 104 kWp was installed on the building’s roof. The flushing grit treatment system operates entirely with rainwater and bank filtrate from the Alzette River. This infiltrated surface water is used for cleaning and then recycled via a dedicated filtration system. Construction works have been completed, and the installation of the mechanical and electrical equipment is now in its final phase.

New SBR biology for the Mamer WWTP

Mamer (Luxembourg) – In spring ’24, the new biological treatment stage with four SBR reactors was commissioned. The system quickly achieved excellent treatment performance, consistently meeting all effluent quality standards. Following a successful trial under real operating conditions, the old continuous-flow biology and secondary clarifiers were gradually decommissioned and dismantled.

In their place, a modern sludge treatment facility is being built, comprising sludge digestion, dewatering, and biogas utilisation. The new circular digesters are being constructed using an innovative anchor-free climbing formwork system, eliminating the need for post-sealing of anchor points. Commissioning of the new sludge treatment line is scheduled for early 2026.

Sustainability, precision, progress

In the heartland of exceptional watchmaking, we stand for outstanding engineering! At Mauler, we design and implement sustainable and innovative infrastructure projects. Working in both urban and rural areas, we contribute to road, rail and hydraulic engineering projects as well as the design of public spaces.

With remarkable growth of 50% over four years, our focus in 2024 was on expanding our team and on ensuring the necessary resources for project development.

Now with 45 employees and a confirmed order backlog of over two years, we are entering the new year with confidence and clear goals: we will strengthen partnerships, maintain client trust, and safeguard our competitiveness as we continue to grow our position as a regional market leader. In this way we are contributing to the development of the HOLINGER Group.

The quality of life and the professional growth of our employees are of vital importance. In 2025, a trip to Athens will offer the opportunity to strengthen team spirit as we immerse ourselves in Greek culture.

Major upgrade for the A5 between Yverdon and Concise

Yverdon–Concise (VD) – After eight years of construction, the ASTRA UplaNs project for the renewal of the A5 motorway has been successfully completed, significantly enhancing the region’s transport infrastructure. HOLINGER was responsible for the project planning and execution of the section between the Grandson and Yverdon-Sud junctions.

The extensive works, carried out by Walo Bertschinger and Weibel, involved the refurbishment of slip roads and engineering structures – including Switzerland’s longest viaduct, which spans 3.8 kilometres. Alongside the renewal of the carriageways and drainage system, the project also encompassed the repair and installation of noise barriers, as well as the replacement of the operational and safety equipment.

More space for the young people of Fleurier

Fleurier (NE) – The commune of Val-de-Travers is building an extension to the “Collège de Longereuse”, designed by the architect Andrea Pelati. HOLINGER was responsible for the design and execution of the wooden and concrete load-bearing structures of the building, as well as a staircase and ramp, the outdoor facilities and the adaptation of the pipe network.

Due to the low load-bearing capacity of the ground, special foundations were required to ensure optimum load transfer. The innovative timber-concrete composite construction combines the rigidity of concrete with the lightness of timber, making it ideal for large spans. It also gives the building a distinctive aesthetic quality.

Cutting edge analytics

Our motto is ‘a passion for analysis’ and that passion has never waned even after two decades.

In 2024, Envilab AG, which specialises in environmental analysis and consulting, celebrated its 20th anniversary with noticeable growth: Last year, we carried out 5 050 organic and 10 800 inorganic analyses. The year was further defined by exciting projects, including Per- and Polyfluoroalkyl substance (PFAS) and trace substance analyses, feasibility studies for ozonation processes, and construction material assays.

With a high order volume, Envilab is entering 2025 with great motivation. New analytical methods are being developed, such as ion chromatography ammonium assays and an extended PFAS range. A key milestone in our quality assurance will be the upcoming re-accreditation audit in early summer, which will enable the certification of our new methods.

Envilab is committed to the continuous expansion of its client base with the inclusion of additional wastewater associations from across Europe.

Facts and figures

The consolidated financial statements of the HOLINGER Group are prepared in accordance with Swiss GAAP FER.

The rounded figures are an extract from the complete consolidated financial statements 2024 of the HOLINGER Group. The consolidated financial statements were prepared pursuant to Swiss GAAP FER and audited by OBT AG, Zurich, on 19th May 2025 without reservations or qualifications.

The Annual General Meeting of HOLINGER AG will take place on 23 June 2025.

The Board of Directors proposes the distribution of a dividend of TCHF 398.

Key figures
2023 2024 Change to previous year
Head count 679 712 +33
31.12.2023 [CHF million] 31.12.2024 [CHF million]
Sales volume 81,6 88,0 +7,9 %
Own services 75,9 81,3 +7,2 %
EBITDA 4,9 5,2 +5,9 %
Incoming orders 85,6 85,5 -0,1 %
Order backlog 87,6 91,8 +4,8 %
Investments 3,2 1,2 -60,7 %
Key figures employees
2024 Change to previous year
Number of employees 712 +4,9 %
Women 259 +3,2 %
ETH/FH (Fed. Inst. of Technology / Technical College) 453 +2,7 %
Technical school 42 -26,3 %
Site manager, designer, draughtsman 118 +11,3 %
Commercial and IT employees 78 +39,3 %
Apprentices 21 +10,5 %
Staff turnover [%] 10 +28,2 %
Average absence due to illness or accident per employee [h] 73 +55.3 %
Income statement
2023 2024
[TCHF] [TCHF]
Net proceeds 81 565 88 040
Income from own services 75 895 81 327
Personnel costs 61 274 64 787
Other operating expenses 9 699 11 240
Balance
Assets 2023 2024
[TCHF] [TCHF]
Current assets 43 522 42 263
Non-currant assets 13 278 11 182
Total assets 56 800 53 445
Liabilities 2023 2024
[TCHF] [TCHF]
Current financial liabilities 33 262 30 695
Non-current financial liabilities 6 934 6 117
Debt capital 40 196 36 812
Share capital 398 398
Equity capital 16 604 16 633
Total liabilities 56 800 53 445
Sustainability

Sustainability Report 2023

Every two years, we provide information on the status of sustainability in our company. This report is based on data from 2023. We report on how our company is developing in terms of sustainability based on aspects that are important to us in the economic, environmental and social areas.

 

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Outlook

HOLINGER holds a strong position in attractive markets across Switzerland, Luxembourg, Germany and Europe as a trusted provider of comprehensive consulting, engineering and general planning services. The expertise, quality and broad-based knowledge of our approximately 700 employees clearly set us apart from the competition. In recent years, HOLINGER has demonstrated its ability to deliver resilient and consistent growth, even in challenging market conditions – adapting its service and product portfolio with agility to meet evolving demands. Looking ahead, we must continue to generate sufficient added value to ensure that we can achieve sustainable profitability even as costs rise.The impacts of demographic change in our cities and urban areas, the causes and consequences of climate change, and future climate-related water challenges represent growth markets in which HOLINGER is already active and where we intend to engage further.

The impacts of demographic change in our cities and urban areas, the causes and consequences of climate change, and future climate-related water challenges represent growth markets in which HOLINGER is already active and where we intend to engage further.

 

 

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Basel WWTP: MV stage, sludge treatment

Expansion stage 2 shortly before commissioning
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