Hiroyuki KATO

Propionate oxidation highly effective in UASB method

Hideki HARADA, Akiyoshi OHASHI, Hiroyuki IMACHI

The Upflow Anaerobic Sludge Blanket(UASB) method is applied to industrial wastewater disposal, and because middle temperature UASB (about 35Ž) process is the processing performance, it is evaluated high. High temperature UASB (about 55Ž) process is developed now. However, the propionate accumulates in the process to react to environmental changes of the inhibitor and the overload, etc. sharply. It is one of the problems that this causes the failure of the process.
And so, Pelotomaculum thermopropionicum strain SI that was the propionate oxidation bacteria of the high temperature that was already separated and had paid attention in this research. Strain SI becomes possible the single processing of the propionate in the process because of the possession of the feature of doing the breath growth by using the propionate alone in the fumarate.

In this research, it aimed to attempt making of the propionic acid oxidation highly effective by adding the fumaric acid by using the feature of SI stock in processed high temperature UASB.
The long-term, continuous processing experiment was conducted with high temperature UASB reactor, and the influence of the fumaric acid on the propionic acid oxidation was investigated by the grasp of the processing characteristic and the batch experiment that used sludge.

As for the batch experiment, sludge and the medium were done to amount of note by the vial bottle. Afterwards, the one that the substrate was turned on was shaking cultured. The experiment was conducted in four factions of the substrate with different A)propionate, B)propionate and fumarate, C)propionate and hydrogen, D)propionate, fumarate and hydrogen.. As a result, the fumarate did not exert a clear influence on the propionate oxidation in all the factions.Therefore, it was suggested not to be able to promote the propionic acid oxidation only by adding the fumaric acid when the substrate was supplied to high temperature UASB reactor. And@it was confirmed that the achievement of@propionic acid oxidation highly effective was difficult only by adding the fumaric acid.