Stereau

What Stereau does

Stereau is a French water treatment engineering and construction firm, wholly-owned subsidiary of the Saur Group, headquartered in Issy-les-Moulineaux with a Swiss entity (Stereau Suisse SA). The company designs and builds drinking water production plants, wastewater treatment facilities, and sludge valorization infrastructure for public-sector clients — primarily French municipalities, intercommunal authorities, public water utilities (Eau de Paris, Vendée Eau, SDAEP), and Swiss wastewater operators. Notable projects include the €47.5 million Douda plant extension in Djibouti, the modernization of the Orly 2 drinking water plant serving 800,000 Parisians, and the Wattrelos–Leers wastewater facility for the Métropole Européenne de Lille.

Stereau's competitive position rests on seven patented proprietary processes: CarboPlus® and Carboflux® (micropollutant removal via activated carbon in fluidized beds), Calcycle® (calcium hardness decarbonation), Aqua-RM® (membrane bioreactor for water reuse), Lanodor® (biological deodorization), Ammonair® (aeration optimization), and Aéroflux® (dissolved air flotation for algae-laden waters). The company applies full-cycle BIM methodology from design through operations, integrated with GMAO/CMMS, and won the 2022 BIM d'Argent award for Orly 2. Beyond core EPC, the portfolio extends to sludge methanization, biomethane grid injection, and treated wastewater reuse (REUT).

The business model is project-based revenue from competitive public procurement tenders, with multi-year construction contract durations. Revenue derives from one-time design-build contracts plus recurring equipment supply and professional services (commissioning, operational support, maintenance). The go-to-market is exclusively enterprise field sales targeting public decision-makers through industry events, technical white papers, and direct tendering. The company has no public pricing disclosure and operates without an indirect or reseller channel. As of early 2026, Stereau is actively expanding its technology stack via partnerships with BKT – Tomorrow Water (Proteus™ biofiltration) and Enosis (biological methanation), and has launched France's first professional BIM-for-water-treatment degree program with Ensiate and Cnam Paris.

Name

Stereau

Legal name

Société Stereau

Website

https://stereau.com

Company type

Private

Operating status

Operating

Headcount range

101–250 employees

Short description

Stereau is a French engineering and construction subsidiary of the Saur Group that designs and builds drinking water and wastewater treatment plants, using seven patented proprietary processes, primarily for public authorities in France, Switzerland, and select international markets.

Ownership category

akta.pro rank

Product category

Water Treatment Engineering Services

NAICS

Sewage Treatment Facilities (221320)

SIC

Water, Sewer, Pipeline, Comm & Power Line Construction (1623), Pumps & Pumping Equipment (3561)

akta.pro primary industry

Water Treatment Plant Construction (Drinking Water) (IMAFAGAA)

akta.pro secondary industries

Water Reuse & Reclamation Infrastructure Construction (Recycled Water Systems) (IMAFAGAH), Sludge/Biosolids Handling & Treatment Facilities Construction (IMAFAGAJ)

Keywords

• Water treatment engineering
• Drinking water production
• Wastewater treatment construction
• Sludge valorization solutions
• Water infrastructure projects

Headquarters

HQ city

Maurepas

HQ country

France

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Supply Chain, Technology or R&D, Infrastructure, Marketing or Sales

Revenue model

1. Engineering and construction contracts: Stereau generates revenue primarily through design-build and turnkey engineering contracts for water treatment plants, awarded via public procurement tenders by municipalities, intercommunal authorities, and public water utilities. Revenue is project-based, with multi-year contract durations tied to construction phases.
2. Equipment and services: Supply of proprietary equipment (CarboPlus®, Calcycle®, Aqua-RM®, Lanodor®, Ammonair®, Aéroflux®) and associated technical services including commissioning, operational support, and maintenance. Provides recurring service revenue after initial construction completion.

Go-to-market motion1 record

Distribution channels4 records

Marketing channels5 records

Core offering

Stereau designs and builds drinking water production and wastewater treatment plants, delivering end-to-end engineering, project management, construction, and consulting services for public water utilities and local authorities. The company integrates a portfolio of patented proprietary treatment processes (CarboPlus®, Carboflux®, Calcycle®, Aqua-RM®, Aéroflux®, Lanodor®, Ammonair®) and BIM-based digital methodology into each project, while also supplying related equipment and long-term operational services.

Product overview

Stereau is a water treatment engineering and construction company (subsidiary of Saur group) offering comprehensive services across drinking water production, wastewater treatment, and sludge valorization. The company's product portfolio centers on proprietary patented treatment technologies including CarboPlus® (micropollutant removal via activated carbon), Carboflux® (pesticide elimination), Calcycle® (water decarbonation), Aqua-RM® (membrane bioreactor), Aéroflux® (clarification/flotation), Lanodor® (biodesodorization), and Ammonair® (aeration optimization). These technologies are complemented by BIM digital methodology for plant design and maintenance. The company provides integrated services from engineering and project management to construction and commissioning.

Differentiator

Problem solved

Functional benefit

Brands

• Mission Water: A movement by the Saur group focused on protecting and recovering water as a precious resource.

Products and services

• Drinking Water Treatment Engineering (Eau potable)

Quantifiable outcome

• Up to 80% reduction in micropollutants (drug residues, pesticides, biocides) in treated wastewater (CarboPlus®)
• +5 more outcomes

Named customers13 records

Segments3 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature8 records

Partnerships

Eight partnerships are on record, tiered core and minor.

• BKT – Tomorrow WatercoreTechnology or Integration · 25 November 2025Stereau and BKT – Tomorrow Water formed a partnership to deploy the Proteus™ biofiltration process in France and Switzerland. This technology partnership expands Stereau's portfolio of proprietary and licensed water treatment processes, targeting municipal wastewater treatment plants seeking advanced biofiltration solutions.
• EnosiscoreStrategic or Co-development Partner · 24 November 2025Stereau and Enosis partnered to integrate biological methanation into next-generation wastewater treatment plants. This strategic collaboration aims to enhance energy recovery and biomethane production from sewage sludge, supporting circular economy objectives of municipal wastewater operators.
• Ensiate (École nationale supérieure d'ingénieurs en sciences de l'eau et de l'assainissement)minorStrategic or Co-development Partner · 12 June 2024Stereau and Ensiate partnered with Cnam Paris to launch France's first professional Licence in BIM Modeling for Water Treatment (rentrée 2026). The alternating (work-study) program combines water sector expertise with BIM digital skills, addressing the industry's talent pipeline needs.
• Cnam Paris (Conservatoire national des arts et métiers)minorStrategic or Co-development Partner · 12 June 2024Partnership with Ensiate and Stereau to co-develop and deliver the first professional Licence in BIM Modeling for Water Treatment, starting September 2026. Cnam Paris provides academic accreditation and educational infrastructure.
• Vinci ConstructioncoreImplementation/ SI/ Consulting Partner · 27 February 2024Stereau and Vinci Construction formed a consortium for the extension of the Douda wastewater treatment plant in Djibouti City (capacity increased to 80,000 PE). Egis serves as project manager under ONEAD direction. The €47.5 million project is co-financed by AFD and the European Union.
• EgisminorImplementation/ SI/ Consulting Partner · 27 February 2024Egis acts as project management consultant for the Douda wastewater treatment plant extension in Djibouti, overseeing the Stereau–Vinci Construction consortium's work.
• ONEAD (Office National de l'Eau et de l'Assainissement de Djibouti)coreOthers · 27 February 2024National Water and Sanitation Office of Djibouti is the public authority commissioning the Douda wastewater treatment plant extension. One of Stereau's most significant international public infrastructure mandates.
• Cise RéunionminorImplementation/ SI/ Consulting PartnerCise Réunion partners with Stereau to operate the Leveneur drinking water plant on Reunion Island during the industrial commissioning year. Supports transition from construction to operations.

Scale indicators5 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• Egis: Major French engineering group active in water, environment, and infrastructure; serves as project manager on international mandates (e.g., Douda in Djibouti) alongside Stereau. Comparable in delivering water and wastewater engineering services to public clients in France and internationally.
• Naldeo: French engineering group specialized in water, energy, and environmental infrastructure, providing design, project management, and consulting for water treatment and distribution — a similar mid-sized French engineering-services peer competing for the same municipal tenders.
• Veolia Water Technologies: The water technology and EPC subsidiary of Veolia, offering design-build of drinking water and wastewater treatment plants, proprietary treatment processes, and digital plant operations — directly comparable to Stereau's EPC + proprietary-tech model across municipal and industrial clients.
• Degrémont: Suez's historical water treatment plant construction subsidiary, executing large municipal and industrial water/wastewater EPC projects globally with proprietary processes — closely aligned with Stereau's combination of design-build capabilities and patented technologies like CarboPlus®.
• Artelia: French multi-disciplinary engineering firm with strong water, environment, and urban infrastructure practices, delivering design and supervision of water treatment plants for public authorities — a like-for-like French engineering peer targeting the same municipal client base.
• WABAG: India-headquartered global pure-play water EPC company delivering municipal and industrial water and wastewater treatment plants with proprietary process know-how. Comparable in scale, EPC business model, and proprietary technology portfolio targeting public and industrial clients worldwide.

Broad incumbents

• Saur Group: Stereau's parent company and a major French water services operator offering end-to-end water management (concessions, delegated management, works). Comparable as a broader incumbent in the same French public-water-services market, though Stereau is its specialized EPC arm.
• VINCI Construction: Major global general contractor with significant civil engineering and environmental infrastructure capabilities, including water treatment plant construction. Already co-bid with Stereau on Douda; serves as a larger incumbent that may internalize certain EPC scopes that Stereau targets.

Emerging players

• IDE Technologies: Israel-based water technology company specializing in desalination, water treatment, and industrial water solutions with proprietary thermal and membrane processes. Comparable as a mid-sized EPC-and-tech player targeting municipal and industrial water infrastructure with patented offerings.
• H2O Innovation: North-American water treatment specialist focused on membrane systems, water reuse, and turnkey treatment plants for municipal and industrial clients. Comparable as a mid-sized water EPC player with proprietary technology emphasis, though geographically focused on the Americas.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/stereau-sas

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Subsidiaries1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Stereau