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Hitachi Infrastructure Systems (Asia) Pte. Ltd.


Adding supports with inclusively immobilized, highly concentrated microorganisms to the biological reaction tanks results in a nitrogen treatment process that shortens reaction time. In the inclusive immobilization method, microorganisms in the agar state are enclosed in the supports, and this method is effective for slow-multiplying microorganisms (example: nitrifying bacteria that change ammonia to nitric acid).


  1. The treatment time can be reduced to half that of existing treatment devices.
  2. The inclusive immobilizing supports achieve highly active treatment.
  3. This system can also be applied to waste water containing highly concentrated ammonia.

(in-house comparison)

System Overview

Image: System diagram

  Raw water Treated water
BOD (mg/L) 80-120 10-15
Nitrogen (mg/L) 30-40 6-10

Photograph: Comprehensive immobilizing nitrogen removal system
Comprehensive immobilizing nitrogen removal system


  • Industrial wastewater treatment