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

 Non-Filamentous (Viscous) Bulking

7/28/2014

 
PictureIndia Ink Showing Excessive EPS in Floc
Non-filamentous bulking is often overlooked as a wastewater treatment problem. Operators facing viscous bulking often complain of "gelatinous" floc, that billows over the clarifier weir and is difficult to dewater on the secondary press.

We see viscous bulking when the bacteria begin to produce excessive quantities of extracelluar polysaccharides (EPS). In normal good floc, it is the EPS that acts as the glue to hold bacteria cells and adsorbed (outside cell wall) particles. When cells begin to overproduce the EPS, the previous glue begins to hold excessive amounts of water and is very vulnerable to sheer. The resulting sludge does not compact well and can easily be carried over secondary weirs. The return sludge (RAS) concentration is lower as we are returning more water relative to biological solids which further compounds the problem.

You can see viscous bulking under normal light microscopy as "fingers" and gelatinous appearance. The appearance can be enhanced for better observation by adding India Ink to the slide. The India Ink will not penetrate the EPS and will appear as clear zones around the floc.


Causes of Viscous Bulking


  • Lack of a vital macronutrient (Nitrogen or Phosphorus)
  • Micronutrients (Fe, Mg, etc) being deficient
  • Excess influent organic acids usually from anaerobic activity
  • High fat, oil & grease loadings
  • Temperature stress

Control Options
  • Check nutrients and add as necessary
  • Increase wasting to rid system of existing viscous floc
  • In severe cases, we often couple wasting with seeing cultures (bioaugmentation). In this case we use cultures with excellent floc forming characteristics and often seed with strains capable of producing cationic EPS versus the more common anionic EPS.

Mohamed Al Ansary
11/11/2014 05:51:15 am

Could you please send more information about non filamentous bulking

Jack Crosby link
2/22/2017 12:33:17 pm

One solution is thought to be lowering the food to mass ratio. However, operators also need to be aware that low f/m may also promote long-chained filaments.

Erik Rumbaugh
2/23/2017 08:13:42 am

Thank you for making the F/M control comment. I forget about lowering F/M since my only option to do that is hold water back in EQ tanks. In my systems having the most non-filamentous bulking problems we see the excess EPS form after influent campaigns with high levels of resistant compounds, elevated TDS, or excess oil & grease

Jeff
1/11/2019 11:45:37 am

Hello. Every winter we experience high EPS in my aerobic digesters. We can’t figure out why and it affects our dewatering drastically. I’m positive that nutrients aren’t a problem. Do you think it’s possible that the cold temperatures of winter are causing this?

Erik Rumbaugh
1/11/2019 12:45:16 pm

Many of the high EPS organisms function well at lower temperatures and make more EPS as temperatures drop below 20 Deg C. In digesters, nutrients or high soluble BOD (organic acids) should not be the trigger for EPS formation.

Lucas
10/22/2020 05:40:15 pm

Hello!
In normal condition, what we should see when aplying the india ink stain? The ink covers everything and we are not able to see anything?

Erik Rumbaugh
10/23/2020 05:42:34 am

You may want to use less India Ink if everything is blacked out. I use just enough to see clear zones in the floc and at floc edges related to excess EPS. If you have no excess EPS, you will have a completely dark slide - but even in well running systems, you usually see differences in India Ink saturation with floc.


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