Abstract
Multi-Stage Reversing flow Bioreactor (MRB) is multi-stage sludge blankets type bioreactor for municipal wastewater treatment utilizing the symbiotic relationship between microaerofilic and anaerobic bacteria. The most interesting characteristic of MRB is the formation of the self granulated sludge consist of anaerobic bacteria including Sulfate Reducing Bacteria and Beggiatoa. The hypothetical mechanism of the granule formation and the results of one year operation is summarized.
(1) Once Sulfate Reducing Bacteria (SRB) are accumulated in the reactor, Beggiatoa utilize sulfide whitch is produceed by SRB, then wrup up the anaerobic bacteria frock, make the self granulated sludge.
(2) The effluent quality rose 30 mg - BOD /l in winter becouse of the slagging of the self granulated sludge though less than 20 mg/l in summer without the slagging.
(3) Sludge producing ratio was 0.22 (produced SS/removed BOD) and 0.43 produced SS/removed SS.
