Here is a small summary of ...

Here is a small summary of the different forms of nitrogen usually sought after in wastewater analyzes: 

- Nitrates: these are NO3 in solution. The pollution is calculated in mgNO3 / L. 
- Nitrogen nitrate : also represents nitrates but is expressed in milligram of nitrogen per liter (mgN / L) - Nitrogen nitrate = Nitrates / 4.43 --- (4.43 = Molecular weight of NO3 / mass of nitrogen). 
- Nitrites: these are NO2 in solution, very toxic for aquatic life. The pollution is calculated in mgNO2 / L. 
- Nitrous nitrogen:also represents nitrites but expressed in milligrams of nitrogen per liter (mgN / L) - Nitrous nitrogen = Nitrites / 3.28 --- (3.28 = NO2 molecular weight / mass of nitrogen). 
- Kjeldahl Nitrogen (NTK): It represents the sum of the organic nitrogen and the ammoniacal nitrogen contained in the water. It is expressed in milligram of nitrogen per liter (mgN / L). 
- Global Nitrogen (NGL): It is the sum, expressed in milligrams of nitrogen per liter, of Kjeldahl nitrogen, nitrates and nitrites - NGL = NTK + Nitrogen + Nitrogen Nitrogen. 

Hope it gives you clarification.

Regards,

Sushant Kumar