Abstract
Investigation on the seasonal variation of vitamin B_<12> content in activated sludge was made three times a month for a year with the samples in the sewage treatment plant of Kyoto. The results that periodic variation is recognized in the vitamin content. That is to say, the highest vitamin content of over 10 μg/g on dry basis is observed in the samples of September to November, the lowest of 5-6 μg/g in June, and small peaks also in May and February. The results obtained with the samples of Kyoto are nearly in agreement with those in the sewage treatment plants of Nagoya, previously reported. (Vitamins 8,443,1955)
