• Blog
  • Wastewater Testing
  • Bioaugmentation Applications
  • Useful Information
  • About Us
BIOLOGICAL WASTE TREATMENT EXPERT
Contact Us

Total nitrogen (TKN) is often more important than influent ammonia for nitrification purposes

4/24/2017

 
Picture
TKN distillation unit. Giangarlo Scientific.
While somewhat a challenge to run, total Kjeldahl nitrogen (TKN) has always been one of my favorite tests. I started my water treatment career examining petroleum refinery wastewater where operators complained that ammonia removal was not as expected after treatment in the first aeration basin. Inlet ammonia after the EQ tank was often 25 mg/L and after the first aeration basin was still in the 20 - 22 mg/L range. So what was happening? 

To understand what was happening, we need to look at the nitrogen cycle. Wastewater contains a blend of nitrogenous compounds including proteins, amines, amino acids, urea, nitrate, nitrite, and ammonia. Because of permitting, we normally just look at ammonia, nitrite, and nitrate. But at the influent to a wastewater system we should pay more attention total nitrogen.

Total Kjeldahl nitrogen (TKN) contains all organic, ammonia, and ammonium in the influent. Through a digestion step, organic nitrogen is converted into ammonium which is then extracted via distillation. With all organic nitrogen converted into ammonia, we can calculate total organic nitrogen (TON), ammonia and total Kjeldahl nitrogen. In biological treatment, the TON is eventually converted into biomass and ammonia/ammonium.

So in my  early refinery case, the influent TKN was actually 45 mg/L and through testing and performing a mass balance, we found that we were removing an average of 24 mg/L across the first aeration basin - we did this by evaluating TKN in & out, Ammonia in & out, and confirming results by looking at nitrite & nitrate outlet concentrations.

So if your ammonia removal efficiency appears low or even if ammonia increases across a basin, you should look to TKN along with ammonia numbers to better describe what happens inside the biological treatment unit.

Comments are closed.

    Author

    Erik Rumbaugh has been involved in biological waste treatment for over 20 years. He has worked with industrial and municipal wastewater  facilities to ensure optimal performance of their treatment systems. He is a founder of Aster Bio (www.asterbio.com) specializing in biological waste treatment.

    View my profile on LinkedIn

    RSS Feed

    Click to set custom HTML

    Archives

    December 2022
    November 2022
    October 2022
    September 2022
    August 2022
    June 2022
    May 2022
    March 2022
    February 2022
    January 2022
    November 2021
    October 2021
    September 2021
    August 2021
    June 2021
    April 2021
    March 2021
    February 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014

Proudly powered by Weebly
Photos used under Creative Commons from Picturepest, marcoverch, perzonseowebbyra, Picturepest, Picturepest, dsearls, dungodung, Massachusetts Office of Travel & Tourism, aqua.mech, vastateparksstaff, hile, Aaron Volkening, amishsteve, Neil DeMaster, mklwong88, KOMUnews, Picturepest, kaibara87