Ismail Alaoui You are right ...

Published March 15, 2018 16:48 by Bruno Peeters, managing director at Model Engineering

Ismail Alaoui

You are right that Total Nitrogen TN (NGL) is always higher than Total Kjeldahl Nitrogen TKN (NTK) in the effluent of a biological WWTP. However this is NOT because there is always residual organic nitrogen but because there is always some residual oxidized nitrogen N-NOx (nitrite + nitrate nitrogen). As explained by others TKN = organic nitrogen + ammonia nitrogen and TN = TKN + N-NOx. Hence N-NOx > 0 implies TN > TKN.

Regards,

Bruno