Which factors or parameters must I change to stop the methanogenic activity in my UASB reactor?
The objective is to have a UASB reactor with only acid-producing bacteria.
My UASB reactor is pilot scale and is working with municipal wastewater, the current temperature is 25 C and it is producing methane.
I would like to stop it producing methane but keeping the acid producing bacteria.
Should I try to lower the pH to 5.0? (Current pH=6.7)
Should I try to lower the temp? (Current temp=25C)
Should I try to acidify the influent wastewater?
Suggestions?
Thanks in advance
2-bromoethanesulfonic acid (BESA) with a concentration of 50 µM could be added into anaerobic sludge of the UASB. Herein, methanogens within sludge will be eliminated by BESA to prevent VFAs oxidation during the hydrolysis-acidification step. This method is one sure way to shut down the activities of methanogens in an AD system. However, i will advise that, you first conduct this experiment in batch mood to also appreciate the method scientifically before applying to your pilot scale system. To compartmentalize the UASB is quite a challenge although some reports had indicated this task as almost impossible. For instance, increasing the upflow velocity may reduce the contact time for methanogen to oxidize available VFAs but at the same time, this may cause washout of the hydrolyzable or acidogenic bacteria. On the other hand, increase or reduction in temperature may affect methanogens for a while but with time, they may acclimatize with the new environment and begin to produce methane upon contact with VFAs. Therefore the addition of BESA is highly suggested.
Thank you very much, Antwi.
I will read more about BESA and I will perform laboratory scale experiment as you suggested.
Regards,
Raul
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