Effect of a Methane Inhibitor, Sodium 2-Bromoethanesulfonate (BES) on Hydrogen
Production in Primary and Secondary Sludge Batch Reactors.
A.H. Pham
Mentor: B.H. Olson
The production of hydrogen was studied in the presence and absence of methane
inhibitor, sodium 2-bromoethanesulfonate (BES), over 54 hours in unamended sludges.
Batch cultures were flushed with nitrogen containing 50ml of sludge (wt/wt) and a final
concentration of 0.1M BES to determine if methanogens were completely inhibited in
treated batch reactors. Methanogen concentrations were measured using qPCR primer
and probe sets for the orders Methanobacteriales (MBT), Methanosarcinales (MSL),
Methanomicrobiales (MMB), and Methanococcales (MCC). Hydrogen producing
bacteria were measured using qPCR primer and probe sets for the hydA gene based on
Clostridium sp., the hyfG gene associated with hydrogenase IV system, as well as the 16S
rDNA of Clostridium, Archaea, and total bacteria. The results showed that both methane
inhibited and uninhibited cultures approximately equal the amounts of total bacteria and
archaea present. Methanogens were present in all samples over the 54-hour test period
and the types of organisms fluctuated over time. Hydrogen production was approximately
3–5 fold less than when glucose was added to the same sludge mixtures, and CO2
production was less in the unamended cultures over the first 12 hours of the study, after
which no statistical difference in production was noted. Without methane inhibition, no
hydrogen was produced. These experiments show that, if hydrogen were to be produced
in anaerobic digestion, an additional reactor would be required with a short residence
time; heat shocked or treated sludge to inhibit methanogens would also be required.
Augmentation of human waste digestion with agricultural or other wastes containing
carbohydrates that break down into glucose or sucrose would also increase hydrogen
production.