Water treatment in container for Power-to-Gas facility

EUROWATER has designed and manufactured the water treatment solution for the world's first commercial plant that increases biogas production through electrolysis and biological methanisation.

The energy and fibre network group Andel and the global biogas producer Nature Energy are behind the Power-to-gas plant in Glansager on Als in Denmark. 

Here, excess electricity from wind turbines is utilised to increase biogas production while reducing CO2 emissions. This is achieved by converting CO2 into biogas through the addition of hydrogen. Hydrogen production is based on alkaline electrolysis (AWE) using ultrapure water as feedstock.

The water treatment consists of softening followed by membrane filtration and membrane degassing. The solution also includes a pumping station and CIP unit.

Treatment steps in the solution

The 3 x 3 MW alkaline electrolyser relies on a stable supply of 1,600 litres of ultrapure water per hour with a conductivity below 5 μS/cm.

The raw water is city water that has already undergone aeration and sand filtration. To achieve the desired water quality it undergoes additional purification to eliminate metal ions, organic substances and CO2. The water treatment therefore consists of the following treatment steps:

  • Softening as a pre-treatment for the reverse osmosis system to avoid fouling and limescale deposits in the membranes
  • Membrane filtration with a double-pass reverse osmosis system, where ions and organic substances are removed from the water, resulting in demineralised water. This system incorporates Grundfos energy-optimised e-pump, which significantly reduces energy consumption compared to traditional pumps. 
  • Membrane degassing ensures efficient CO2 removal as the reverse osmosis system does not remove dissolved gases 

The solution consists entirely of standard EUROWATER units that are commenly used in power plants. The quality of boiler water in power plants closely aligns with the water quality specifications needed for electrolysers.

The water treatment solution is installed in a 20' container. The solution comes with all internal piping and wiring, pre-assembled at the factory.

Mobile solution

The water treatment is installed in a 20' container as an alternative to constructing a dedicated building for the solution. A containerized solution provides a flexible and mobile solution where fixed maintenance costs can be minimised.

The solution is assembled, factory-tested and delivered with all internal piping and electrical connections. This significantly reduces installation time as the solution is ready to use upon delivery.


About the Power-to-Gas plant

The energy and fibre network group Andel and the world's largest producer of biogas Nature Energy are behind the first commercial plant where surplus electricity from wind turbines increases biogas production and reduces CO2 emissions.

Using electrolysis, ultrapure water is split into hydrogen and oxygen. The hydrogen is added to the biomass, where it combines with captured CO2. This creates methane gas that has the same quality as the natural gas extracted from underground. The process also excels by producing 60% more methane from the same amount of biomass.

Technical data

  • Water source: city water without chlorine
  • Flow: 1.6 m³/h
  • Conductivity: < 5 μS/cm

Units in plant: 

  • Softening unit type SM82-F
  • Double-pass reverse osmosis unit type DPRO B2-8/6 with Grundfos CRNE pump
  • Membrane degasser type MDU for CO2 removal
  • Pumping station
  • CIP unit

See more references

Let us elevate your
water treatment solution 

If you want to learn more about our solutions and technologies, your local team of specialists are ready to assist you.

Find your local office