what is tkn nitrogen
Total Kjeldahl Nitrogen (TKN) is the U.S. EPA-approved parameter used to measure organic nitrogen and ammonia. The TKN content of influent municipal wastewater is typically between 35 and 60 mg/L. Organic nitrogen compounds in wastewater undergo microbial conversion to NH3 and ammonium ion NH+ 4. Ammonium ion is the first inorganic nitrogen species produced during biological wastewater treatment.