Performance range

ENR® – Electrodialytical Nitrate Removal


The ENR® Process – Electrodialytical Nitrate Removal

The electrodialysis process enables specific, partial desalination and has been employed for many years for the desalination of sea- and brackish water. On this basis, in co-operation with the Vienna University of Agricultural Sciences, WABAG has developed the ENR®-process for the denitrification of groundwater.

The most important advantages of the process are:

  • Nitrate selectivity
  • A low general level of desalination
  • Reduction of hardness
  • Limited space requirement
  • Simple operation and quick start-up.

A large-scale ENR® plant with a capacity of 3,450 m3/d was started-up in Austria during 1997. The nitrate concentration in this case has been reduced from 150 mg/l to < 50 mg/l.

The process

During electrodialysis, salts are separated via ion exchanger membranes by means of an electrical field. Raw water passes through a stack of alternately placed anionic and cationic permeable membranes. The membrane stack is fixed between electrodes, which generate a direct current field. Due to the alternating selectivity of the membranes, cells are formed, some containing diluted water with a low level of salinity, and others filled with concentrated water, which is rich in inorganic salts. Thus, low-nitrate drinking water is produced together with a small amount of concentrate with a correspondingly high nitrate content.

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