Authors: Kazuichi Isaka Yasuhiro Date Tatsuo Sumino Satoshi Tsuneda
Publish Date: 2007/07/25
Volume: 76, Issue: 6, Pages: 1457-1465
Abstract
Anaerobic ammoniumoxidizing anammox bacteria were immobilized in polyethylene glycol gel carriers A small amount of seed sludge 024 w/v was entrapped in the carriers and continuous feeding tests were performed Nitrogen removal activity increased gradually reaching 37 kg N/m3 reactor per day on day 67 The average of nitrogen conversion rate was calculated as 34 kg N/m3 reactor per day Microscopic examination clearly showed that small red clusters formed in the gel carrier Moreover fluorescence in situ hybridization analysis revealed that these clusters consisted of anammox bacteria From realtime polymerase chain reaction analysis the growth of anammox bacteria in the gel carriers was clearly shown by increased concentration of 16S rRNA gene of planctomycete from 43 × 108 to 42 × 109 copies/ml between days 41 and 55 To determine the effects of inoculation on the startup of the reactor the amount of seed sludge in the gel carrier was varied and it was found that the startup period could be reduced to as little as 25 days when a sludge concentration of 14 w/v was used This is the first report of successful immobilization and cultivation of anammox bacteria in a gel carrier
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