Water treatment for green hydrogen

H2 Hydrogen Technology Europe Expo 23. – 24. 10.  / OPEX Role of operating costs

Production of green hydrogen is growing rapidly

Green hydrogen is contributing to the goals of the Paris Climate Agreement. It is produced through the electrolysis of water. As the energy required for this comes exclusively from renewable energy sources, green hydrogen is considered climate neutral. Germany currently has an electrolysis capacity of 30 MW. This is expected to increase to over 200 GW by 2050. Green hydrogen is increasingly being used as an alternative fuel, for example in long-distance transport, and is to be used to decarbonise energy-intensive industries.

In addition, surplus energy generated by wind turbines during storms and overloading the grid, for example, can be converted into hydrogen. Long-term storage in cavern storage facilities is also conceivable (Source: Fraunhofer IAO – BLOG).


Modular and spacesaving water treatment systems

Ultrapure water is the key resource for the production of green hydrogen to ensure a damage-free electrolysis. We therefore develop modular, scalable water treatment systems to produce high-purity water. We focus on efficient water treatment to reduce your water consumption and thus operating costs (OPEX). We are also focusing on important areas of development, such as the treatment of seawater for electrolysis.

At our site in Freiberg, we produce compact water treatment systems for pilot projects, large-scale systems with sophisticated process technology and containerised systems for rapid installation and commissioning on site. We offer sustainable, long-lasting water treatment systems up to 100 m³/h.

We will be happy to advise you on the selection of the optimal system components.

High purity water extends the life of the electrolyser

"Foreign ions in the water such as iron reduce the cathode activity and thus reduce the performance of the electrolyser. At the same time, copper can increase membrane resistance."

Tugay Cerit, Product Manager

Our technology for the production of ultrapure water

1. Pre-treatment


2. Reverse osmosis

Reverse osmosis (RO)
Membrane degaser (MEG)
Electrodeionization (EDI)

3. Storage and distribution

Pure water tank
Booster system
Mixed bed demineraliser

4. Process water circuit

UV unit
Mixed bed demineraliser

High confidence in our efficient and reliable water treatment plants

Containerized water treatment system
customised special plant, electrolyser manufacturer, germany
more information

Reverse Osmosis System UO-D 900 FU CD / H2
customised special plant, electrolyser manufacturer, germany
more information

Reverse Osmosis Plant UO-D 100 CD SO
Compact Special Plant, electrolyser manufacturer, germany (Windpark in Sweden)
more information

Ultrapure Water Plant UP-S7 1500 FU/PP/SO
Water treatment system, Austria (Production of hydrogen as fuel for vehicles)

Ultrapure Water Plant UP-S7 1500 FU
Production of CO2-neutral fuel from hydrogen, Chile (German Automotive Manufacturer)

Reference project for a 20 MW AEL electrolyser:
Large water treatment system for use in containers

We have developed this high-quality plant for a pioneering 2 GW project for the production of ultrapure water, the most important raw material for the production of green hydrogen.


Plant engineering:

  • 2 x 40' high-cube containers incl. fixtures, C5 painted, C4 painted for stainless steel components, air conditioning

  • 5.8 m³ polypropylene storage tank

  • 2 x 100 % booster system with frequency converter

  • Sand filter, activated carbon filter

  • Dosing stations

  • 4500 l/h diluate, by CEDI, permeate-staged reverse osmosis, 2x100% high-pressure pump with frequency converter, low-pressure side made of polypropylene

  • 35 m³ DEMIN water storage tank (nitrogen-loaded)

  • Polisher through UV system for TOC reduction

  • Energy saving thanks to FU pump

  • HR membranes



For the production of green hydrogen



Electrolyser manufacturer Germany

Reference project:
Medium-sized water treatment plant for 2.9 MW PEM electrolyser

  • Double softener

  • Reverse osmosis system, 900 l/h permeate, high-pressure pump with frequency converter, high-rejection membrane, permeate recirculation

  • 400 l buffer tank made of polypropylene

  • Pressure booster system with frequency converter

  • Fine filter 0.5 µm as resin trap

  • Low-pressure polypropylene piping

  • Included: Mixed bed demineraliser with UP resin as polisher, UV system for TOC reduction, fine filter with V4A housing

Reference project::
Small water treatment plant for PEM electrolyser with 225 KW capacity

  • Entire unit on one frame (900 x 1000 x 1910 mm)

  • Low pressure side made of polypropylene

  • Double softening plant

  • Reverse osmosis system, 100 l/h, high-rejection membrane, permeate recirculation

  • 60 l buffer tank made of polypropylene

  • Pressure boosting system

  • Mixed bed desalination system (optionally with UP resin) as polisher

  • Fine filter 0.5 µm as resin trap

Semi-standardised and individual water treatment plants from 1 - 100 MW

For water treatment for the production of green hydrogen, we are developing more and more standards based on our experience from countless pilot projects:

We combine standard components that we stock or produce onsite in Freiburg am Neckar, enabling immediate availability of small systems up to approximately 30 m³/h, with systems up to 100 m³/h also on hand.

Our H₂ series covers the power classes from 1 to 100 MW.


The TOC content provides information about the water quality

TOC stands for Total Organic Carbon and indicates how much organic carbon is contained in a sample, thus allowing conclusions to be drawn about the water quality.

Reverse osmosis is the central principle in water treatment.

Reverse osmosis reverses the natural process whereby water is separated from and diffuses through a solution by a semi-permeable membrane.

Product overview

You will find our water treatment systems, including those for the production of ultrapure water, from page 40 onwards in our general product catalogue.

File format:
PDF / 4,9 MB

Energy efficiency

Our water treatment plants for breweries are also highly efficient thanks to our VSD pumps. Find out more in our brochure.

File format:
PDF / 160 KB

Ultrapure water for electrolysers

In this free 45-minute recording of our webinar on green hydrogen, product manager Birgit Fabritius presents the water treatment of feedwater for electrolysers and polishing for the PEM process water circuit. (The Webinar is in german.)

Made in Germany
We produce in Germany

We have many years of experience in plant construction, even for complex projects. Quality "Made in Germany", engineering spirit and adherence to delivery dates are our top priorities. Our employees test our high-quality machines and systems in our own test field to ensure Perfect functioning with factory acceptance and training on request.

Environmental management system
First EMAS-certified plant manufacturer in the water treatment sector

Herco Wassertechnik GmbH applies an environmental management system in accordance with Regulation (EC) No. 1221/2009 and EN ISO 14001:2015 (sections 4 to 10) for the continuous improvement of its environmental performance, regularly publishes an environmental statement, has the environmental management system and the environmental statement verified by an accredited, independent environmental verifier and is registered in the EMAS register (emas-register.de).

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