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

Zooglea - are organisms with high EPS production good or bad in wastewater treatment systems?

2/5/2018

 
Removing biological solids and insoluble compounds requires microbes to form floc or biofilms. Many desirable wastewater microbes prefer to exist in a biofilm matrix.  Extracellular Polymer Substances (EPS) are the glue in biofilm and floc. Consisting of polysaccharides, proteins, DNA, and humic substances, EPS can be either attached to the cell (capsular) or free in solution (non-capsular). In typical floc, EPS constitutes 50 - 90% of total organic matter.

The Zooglea family of microbes was one of the first wastewater organisms associated with floc formation. While not the only producer of floc forming EPS, the Zooglea family are very common in most wastewater plants and can be the cause of non-filamentous bulking, difficult to dewater biological solids, and difficult to settle floc.

Why biofilm and floc forms:
  • More consistent environmental conditions - protection from toxic compounds, pH swings, and predatory protozoa
  • Allows syntrophic organisms to function efficiently, or one microbes' waste is another microbe's food source
  • Helps to bring insoluble compounds close to microbes where extracellular enzymes can function
  • Promotes concentration of nutrients - nitrogen, phosphorus, and micronutrients
When EPS goes from good to bad
​
For keeping biological solids under control, you need EPS to be present in quantities that allow for binding biological solids. It is also better to have capsular EPS - attached to the cells - over free, unattached EPS. In free solution, the EPS acts much like agar or gelatin. Increasing viscosity, entrapping water, and creating the gelatinous matrix we associate with non-filamentous bulking. So what triggers the excess non-capsular EPS production?
  • Low nutrients - usually  nitrogen and phosphorous - when microbes face nutrient related stress, they attempt to concentrate/and capture vital nutrients in their EPS matrix. 
  • High levels of soluble organics - microbes use the EPS to accumulate soluble organics which can lead to excess EPS over extended periods of high organic loading
  • Insoluble compounds such as grease, oil, and long chain fatty acids - while usually associated with Nocardia form growth, grease can also result in non-capsular EPS production
  • Environmental stress - extreme temperatures, pH, and inhibitory influent organics can stress microbes which resort to producing more EPS for protection.



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