Treatments to eliminate nitrogen pollution
Biological treatment of wastewater

The elimination of nitrogen is increasingly required, particularly for discharges into sensitive areas, in order to limit :

• adverse and undesirable effects on the natural environment :

  • reduce oxygen demand (oxidation of 1 mg NH₄⁺ requires 4.57 mg O₂) and the toxicity of ammonia to certain fish,

  • avoid eutrophication of lakes and slow-flowing rivers, i.e. the development and overabundant growth of algae as a result of excessive nitrogen inputs;

• major drawbacks in the use of water for drinking water production, in the case of excessive ammonia and nitrate concentrations.

Today, aerobic biological processes are proving to be the most...