EFFECT OF DRY PERIODS IN A MIST-FOAM BIOREACTOR DESIGNED FOR GASEOUS SUBSTRATE

The ''Mist-Foam'' concept for gaseous substrates involves mixing a gas eous substrate and a liquid nutrient solution using a nozzle to genera te a mist which passes trough a synthetic foam. In this type of reacto r, control of the active biomass growth is very important in order to permit an optimum activity in the filter-bed without clogging. A previ ous paper has presented a ''pressure drop controller'', creating succe ssive dry periods in a ''Mist-Foam'' reactor. This system was tested w ith spent liquor from citric acid fermentation as a model nutrient sol ution and air as gas. The results obtained showed that the pressure dr op was successfully controlled even when filter-bed clogging was expec ted. This paper then presents the effects of dry periods on the degrad ation of a gaseous substrate using a ''Mist-Foam'' reactor.