Abstract: The authors put forward a technical process to treat municipal wastewater using multi-stage two-phase anaerobic reactor, which not only increases the efficiency of mass transfer but also improves the biochemical activity of different kinds of microbe, and thereby greatly increases the efficiency of organic pollutants treatment through the design of anaerobic baffled reactor structure, flow velocity and multi-stage regulation of microbe. The experiment results show that when hydraulic residence time longer than 10 h is used, the removal rate of COD is above 90% and less affected by water temperature.

Key words: municipal wastewater treatment, anaerobic baffled reactor, multi-stage two-phase anaerobic process, mass transfer, separated-phase