Abstract
Several conditions for the extraction of vitamin B_<12> from activated sludge and for the adsorption of the vitamin on active carbon were investigated. The results obtained from the experiments indicate that the satisfactory extraction of vitamin B_<12> from activated sludge is attained by heating at 90-100℃ for 30-60 minutes with 5 parts of water to the dried raw material, and that the addition of 0.2-0.5% (weight/volume) of active carbon to the extract makes an adsorption of 70-90% of the vitamin possible.
