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Updated: May 4, 2026

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Heterotrophic nitrification and aerobic denitrification of high-strength ammonium in anaerobically digested sludge by
Makoto Shoda1, Yoichi Ishikawa1
1Able Corporation, 7-9 Nishigoken-cho, Shinjuku-ku, Tokyo 216-0812, Japan.
Abstract:
Alcaligenes faecalis strain No. 4 which is capable of heterogeneous nitrification and aerobic denitrification, was used to remove high-strength ammonium (approximately 1 g NH4(+)-N/l) from digested sludge, the product of an anaerobic digestion reactor, in which methane was produced from excess municipal sewage sludge. Repeated batch operations were conducted at 20°C and 30°C for 550 h, using a jar fermentor. The removal ratios of high-strength ammonium reached 90-100% within 24 h, and the average ammonium removal rate was 2.9 kg-N/m(3)/day, more than 200 times higher than that in conventional nitrification-denitrification processes. During these operations, the cell density was maintained at 10(8)-10(9) cells of A. faecalis strain No. 4/ml. At 3% NaCl in the digested sludge, strain No. 4 exhibited an ammonium removal rate of 3 kg-N/m(3)/day.
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