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

Ecology of Bulking Sludge - Filamentous & Non-Filamentous

6/8/2015

 
Often we do microscopic exams to identify filaments and other causes of bulking. In general, the reports give information on the top filaments or bulking agents and the conditions associated with their dominance in biomass. What is not often done is to take a step back and look at the ecology associated with the increased populations of filaments or high levels of viscous polymers that cause bulking.

What is interesting is that the causes of both filaments and viscous bulking are similar - it is just the mix of factors that determines if the system experiences which problem and to what extent.

The most common factors are:
  • Influent Composition - influents with high levels of soluble organic acids, sulfides, and other highly soluble organics often cause a oxygen depression near the influent and also favor organisms having the ability to quickly degrade soluble organics and metabolize sulfide. Other factors include oil and grease that in long MCRT systems can raise chances of Nocardia (thick greasy foam on aeration basins).
  • Dissolved Oxygen - persistent low dissolved oxygen (but no true designed anoxic zones) favors organisms with high surface area - filaments. This can occur with systems that have anoxic/aerobic zones for nutrient removal if flows increase changing the designed retention times which are predicated on the delicate balance required to prevent conditions favoring filaments. We often see the low DO filaments where we have prolonged zones with DO between 0.1 - 0.5 mg/L.
  • Macro Nutrients (N,P) - per 100 g biomass the cells contain 12 gram of nitrogen and 2.3 grams of phosphorus. This is where operators derive the 100:5:1 ratio for influent BOD:N:P. When you have long term significantly low N or P relative to carbon, the conditions favor organisms with more efficient nutrient uptake. Often we see filaments but a strategy of many non-filamentous bacteria under low phosphate stress is to excrete excess polysaccharides. Key here is a long run nutrient deficiency and the pressures for a change from good floc formation to either filamentous or viscous (non-filamentous) bulking.

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

    April 2023
    February 2023
    January 2023
    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