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

How can adding peroxide upstream increase my influent BOD5? Why BOD5 vs BOD20 is key to understanding the phenomenon.

4/5/2017

 
Picture
HACH BODTrak II - from HACH.com
Wastewater contains a blend of many organic and inorganics compounds. In operating a treatment facility, we look at the oxygen demand from the pollutants. Wastewater oxygen demand can be estimated by tests such as BOD5, BOD20, COD, and TOC. The oldest tests are the microbial based BOD5 and BOD20. In these tests, a diluted sample of the influent is allowed to react with a microbial seed @ 20 Deg C for either 5 or 20 days. During this time, the microbes consume oxygen while digesting organics in the influent. Compounds that are not readily biodegradable or soluble are not fully consumed in the 5 day test. While the 20 day test will pick up more of the long run oxygen demand from insoluble compounds such as cellulose, long chain fatty acids, and grease. Always remember, COD > BOD20 > BOD5.

Now back to the case of hydrogen peroxide being used in a process upstream from the plant. While peroxide can be used to decrease BOD/COD by directly oxidizing the organics, in lower doses it can also increase the proportion of soluble vs insoluble organics. The peroxide reacts indiscriminately with the organics in solution. As a result, some of the recalcitrant and insoluble compounds become more bioavailable (or soluble). If there is not enough peroxide to actually fully oxidize the organics - you end up with higher levels of soluble organics that will show up in a BOD5 test. To see if this phenomenon is occurring in your system, you can check the waste stream with and without peroxide addition. You an also look at COD, filtered COD, and BOD20 - if these are relatively unchanged, it means BOD5 was impacted by increased organic bioavailability.

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

    May 2025
    April 2025
    March 2025
    February 2025
    January 2025
    December 2024
    November 2024
    October 2024
    April 2024
    March 2024
    February 2024
    December 2023
    September 2023
    August 2023
    July 2023
    June 2023
    May 2023
    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 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, Bernd Thaller