SÜLZLE KLEIN

What SÜLZLE KLEIN does

Sülzle Klein GmbH is a German mechanical-engineering company headquartered in Niederfischbach that designs, manufactures, and services mechanical systems for sewage sludge treatment. Its product portfolio comprises four core lines: the registered Pro-Dry® low-temperature belt dryer (operating at 80-90°C, with water evaporation rates of 500-6,000 kg/h per line and residual moisture down to 8%), the solidXdrain gravity belt thickener (including mobile configurations at 5-25 m³/h per line), the solidXpress belt filter press for sludge dewatering, and the solidXfloc polymer preparation and dosing station for flocculation conditioning. The technology platform emphasizes energy and resource efficiency, modular scalability, ATEX-compliant construction, and the ability to utilize low-grade energy sources such as CHP waste heat and district-heating return lines.

The company sells predominantly to municipal wastewater treatment operators and public utilities, with secondary exposure to industrial process-water customers, distributing through direct enterprise sales augmented by channel partnerships with plant constructors and engineering firms (Zahnen Technik GmbH, IEA Derflinger GmbH, ARKO, SEEPEX). Revenue is generated through one-time equipment sales (single machines to turnkey plants), recurring service and maintenance contracts, spare-parts supply, and engineering services, all on quote-based, multi-year project pricing. Reference installations span more than 4,000 systems globally across Germany, Lithuania, New Zealand, the Czech Republic, and Southeast Europe, including large-scale projects such as the Christchurch earthquake-proof sludge drying plant (~45,000 t/yr) and the Kaunas two-strand drying plant (~30,000 t/yr).

Sülzle Klein GmbH is a wholly-owned subsidiary of the family-controlled SÜLZLE Gruppe (Rosenfeld, Germany), led by managing shareholders Heinrich Sülzle and Andreas Sülzle. The group has received Axia Best Managed Companies Awards in 2020, 2021, and 2022, and Sülzle Klein itself has been climate-neutral certified since October 2021 and recognized as an "Arbeitgeber der Zukunft" (Employer of the Future) in 2024. Operating with 11-50 employees, the firm operates as a specialized niche supplier within a broader environmental and energy-technology conglomerate, with no disclosed external funding and no public financial reporting.

Name

SÜLZLE KLEIN

Legal name

Sülzle Klein GmbH

Website

https://suelzle-klein.de

Company type

Private

Founded year

1905

Operating status

Operating

Headcount range

11–50 employees

Short description

Sülzle Klein GmbH is a German mechanical-engineering company that designs, manufactures, and services belt thickeners, polymer stations, belt filter presses, and the Pro-Dry® low-temperature belt dryer for municipal and industrial wastewater sludge treatment, with over 4,000 systems installed worldwide.

Ownership category

akta.pro rank

Product category

Industrial Sludge Treatment Equipment

akta.pro primary industry

Industrial Residuals & Septage Management (FOG, Grit/Screenings, Hauled Waste) (EUANAHAK)

Keywords

• Sludge treatment systems
• Belt dryer equipment
• Polymer preparation stations
• Wastewater treatment equipment
• Belt filter presses

Headquarters

HQ city

Niederfischbach

HQ country

Germany

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

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

Revenue model

1. Equipment Sales: Sale of standardized and customized mechanical systems for sludge treatment including belt thickeners, polymer stations, belt filter presses, and belt dryers. Equipment ranges from single machines to complete turnkey plant solutions.
2. Service and Maintenance: Comprehensive service offerings including maintenance, repair, overhauls, calibration, and remote monitoring for all SÜLZLE KLEIN machines and related equipment including eccentric screw pumps.
3. Spare Parts Supply: Supply of spare and wear parts according to SÜLZLE KLEIN specifications, using certified manufacturers and suppliers.
4. Engineering Services: Engineering support including digital plant planning, process engineering design, evaluation and optimization of existing drying plants, and engineering of new facilities.

Pricing tiers

Go-to-market motion3 records

Distribution channels2 records

Marketing channels7 records

Core offering

Sülzle Klein GmbH designs, manufactures, and installs mechanical sludge treatment equipment MADE IN GERMANY, covering thickening, polymer preparation, dewatering, and drying. The portfolio includes Pro-Dry® low-temperature belt dryers, solidXdrain belt thickeners, solidXpress belt filter presses, and solidXfloc polymer stations, delivered as standardized or custom system solutions for municipalities and industrial customers. Comprehensive maintenance, spare-parts supply, and engineering services round out the offering, supported by the company's own sludge laboratory for process optimization.

Product overview

SÜLZLE KLEIN offers a portfolio of mechanical solutions for sludge treatment (Eindickung, Polymerdosierung und Entwässerung) MADE IN GERMANY. The product range includes the Pro-Dry® belt dryer for low-temperature sludge drying, gravity belt thickeners (solidXdrain series), belt filter presses (solidXpress series), and polymer preparation stations (solidXfloc series). These systems are designed for municipalities and industrial applications, with offerings ranging from standardized solutions to custom system designs. The company also provides comprehensive service support including maintenance, spare parts supply, and engineering assistance.

Differentiator

Problem solved

Functional benefit

Brands

• Pro-Dry®: Belt dryer product line for sludge drying with water evaporation rates from 500-6,000 kg/h per line, operating at 80-90°C for low-temperature drying.
• solidXdrain
• solidXfloc
• solidXpress

Products and services

• Pro-Dry® Belt Dryer (Bandtrockner Pro-Dry®) Low-temperature belt dryer for sewage sludge drying with water evaporation rates of 500–6,000 kg/h per line, operating at 80–90°C to achieve residual moisture of 30–8%. Features modular design, ATEX-compliant construction, and the ability to utilize low-grade waste-heat energy sources such as CHP exhaust or hot water networks. Sold to municipal wastewater treatment plants and industrial customers.
• Belt Thickener (Bandeindicker, solidXdrain series) Gravity belt thickener for mechanical sludge thickening with throughput ranges of 5–25 m³/h per line. The solidXdrain series is also available in a mobile configuration for testing and interim plant operations. Designed for municipal and industrial sludge treatment applications.
• Belt Filter Press (Bandfilterpresse, solidXpress series) Energy-efficient belt filter press (solidXpress series) for mechanical sludge dewatering, installed in compact configurations within existing facilities. Suited for municipal and industrial wastewater treatment applications.
• Polymer Preparation Station (Polymerstation, solidXfloc series) Polymer preparation and dosing system (solidXfloc series, e.g., S1000 PL 2-2) for flocculation and conditioning of sludge prior to thickening or dewatering processes. Sold to municipal and industrial sludge treatment projects.
• Service, Maintenance, Spare Parts and Engineering Support Comprehensive after-sales service package covering maintenance, repair, overhauls, calibration, and remote monitoring of all SÜLZLE KLEIN machines and related equipment (including SEEPEX eccentric screw pumps). Spare and wear parts are supplied per SÜLZLE KLEIN specifications from certified manufacturers. Engineering support includes digital plant planning, process engineering design, evaluation and optimization of existing drying plants, and engineering of new facilities. Sold to owners and operators of installed SÜLZLE KLEIN equipment.

Quantifiable outcome

• 4,000+ systems installed worldwide
• +2 more outcomes

Named customers7 records

Segments2 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Six partnerships are on record, tiered core and minor.

• SEEPEXcoreTechnology or IntegrationSEEPEX is a premium partner for eccentric screw pump service. SÜLZLE KLEIN provides spare parts and service for SEEPEX pumps as part of their comprehensive support offerings for all Klein machines and related equipment including eccentric screw pumps.
• Zahnen Technik GmbHcoreStrategic or Co-development PartnerLong-standing plant construction partner awarded the sludge treatment contract for Kleve-Salmorth wastewater treatment plant lots 4 & 5. SÜLZLE KLEIN supplies core components including thickeners, dewatering, and drying equipment.
• IEA Derflinger GmbHcoreTechnology or IntegrationAustrian partner collaborating with SÜLZLE KLEIN on SP-HF 06 XLG screw presses for sludge dewatering. First-time supply of screw press technology for Kleve project.
• ARKOcoreStrategic or Co-development PartnerCzech partner for whom SÜLZLE KLEIN received engineering contract for the largest sewage sludge drying plant in the Czech Republic. Represents significant expansion into Czech market.
• AmodesminorStrategic or Co-development PartnerCollaboration on mobile dewatering systems. SÜLZLE KLEIN installed first Amodes mobile dewatering system on a trailer (2023) and second system (2024).
• SÜLZLE GruppecoreOthersParent company/group association. SÜLZLE KLEIN is part of SÜLZLE Gruppe based in Rosenfeld, Germany, which includes Sülzle Holding GmbH & Co. KG. The group specializes in sustainable environmental and energy technology including green steel.

Scale indicators5 records

Recent moves8 records

Expansion highlights6 records

Broad incumbents

• Alfa Laval: Alfa Laval supplies decanter centrifuges and separation equipment used in municipal and industrial sludge dewatering applications. It competes against SÜLZLE KLEIN's belt filter presses and thickening technologies in the broader sludge dewatering equipment market, particularly with larger municipal customers.
• ANDRITZ AG: ANDRITZ is a large Austrian industrial group whose Separation & Drying Technologies division supplies sludge dewatering, thickening, and thermal drying systems to municipal and industrial customers globally. As a broad incumbent with substantially deeper engineering and financial resources, it competes for the same large municipal sludge-drying tenders that SÜLZLE KLEIN pursues.
• Veolia Water Technologies: Veolia Water Technologies is a broad water-and-wastewater solutions provider offering full-plant design, build, and operation including sludge treatment. As an incumbent systems integrator, it competes against SÜLZLE KLEIN by bundling sludge thickening, dewatering, and drying into wider municipal EPC contracts.
• Hitachi Zosen INOVA: Hitachi Zosen INOVA is a Swiss-Japanese EPC and technology provider for energy-from-waste and sludge drying/biological waste treatment facilities, including belt drying systems. It overlaps with SÜLZLE KLEIN's Pro-Dry® thermal drying offering on larger municipal and regional biosolids projects.
• GEA Group: GEA is a global industrial group with a Separation & Flow Technologies division producing centrifuges, decanters, and drying systems used in municipal and industrial biosolids/sludge processing. Its mechanical and thermal sludge drying portfolio directly competes with SÜLZLE KLEIN's belt thickeners, presses, and Pro-Dry® drying systems for higher-capacity municipal tenders.

Direct peers

• Komline-Sanderson Engineering: Komline-Sanderson is a US-based manufacturer specializing in sludge and biosolids processing equipment, including gravity belt thickeners, belt filter presses, and drying systems for municipal and industrial wastewater treatment plants. It is a direct product-line peer to SÜLZLE KLEIN with overlapping core equipment in thickening, dewatering, and drying.
• HUBER SE: HUBER SE is a German manufacturer of machines, plants, and systems for water, wastewater, and sludge treatment, including thickening, dewatering, and drying equipment. It is the most direct geographic and product-line competitor to SÜLZLE KLEIN, serving many of the same municipal and industrial wastewater customers in the DACH region.
• SEEPEX GmbH: SEEPEX is a German manufacturer of eccentric screw pumps used in sludge and biosolids handling and a premium service partner of SÜLZLE KLEIN. Although not a direct competitor in drying/thickening, its pumps are integrated into sludge treatment trains that SÜLZLE KLEIN builds, making it a closely comparable process-equipment peer in the same market.
• Stord International: Stord International supplies thermal drying, pressing, and dewatering systems used in wastewater biosolids and industrial sludge processing. It competes with SÜLZLE KLEIN's Pro-Dry® belt dryers in higher-capacity municipal drying tenders across Europe and the Middle East.

Regional players

• Eggersmann Group (Fives / organics technology): Eggersmann Group is a German Mittelstand engineering company with divisions in recycling, organics treatment, and biogas including mechanical sludge dewatering and drying equipment. It is a regional peer with comparable custom-engineering capabilities serving municipal and industrial sludge-treatment customers, primarily in German-speaking markets.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks5 records

Key highlights7 records

Customer concentration

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Revenue estimate

Valuation estimate

Number of profiles

Profiles3 records

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 SÜLZLE KLEIN