Development of a membrane-aerated biofilm reactor applicable to livestock wastewater

The discharge of livestock wastewater that contains high concentration of nitrogen causeseutrophication,其他blooms and groundwater pollution. We developed a membran -aerated biofilm reactor （MABR）simultaneous nitrification and denitrificaiton (SND) in a single reactor.1.Analysis ofdissolved oxygen profile in biofilmsDO profile in biofilms of several thicknesses wasinvestigated using an oxygen microelectrode. From this experiment，a large anaerobic zone was observed at the bottom of the thick biofilm. This result clearlyindicated the possibility that quite different microenvironment is created in a same biofilm，allowing for SND.2.Feasibility of SND using the MABRFeasibility of SND on the MABR for treatment ofdomestic wastewater was conducted for 150 days. After 50 day，removal efficiencies of organic carbon and nitrogen were more than 90%which indicates that SND can be accomplished using the MABR.3.Application of the MABR to livestockwastewaterThe removal characteristics from livestock wastewater were investigated for 1 year.Average removal efficiencies of organic carbon and nitrogen were 96% and 83% at removal rates of5.76 g-C/(m^2 day) and 4.48 g-N/（m^2 day）respectively. The combination of The in situ detection of specific bacteria and determination of TheDO microprofiles made it possible to prove the mechanism of SND and the microbial ecology in thebiofilm . furthermore,nitrogen removal not via nitrate but nitrite was mainly achieved in the MABR system. the MABR takesadvantage of the easy control of oxygen mass transfer这是很有用的when removing nitrogen from low carbon/nitrogen-ratio wastewater such aslivestock。

The discharge of livestock wastewater that contains high concentration of nitrogen causes eutrophication, algal blooms and groundwater pollution. We developed a membrane-aerated biofilm reactor (MABR) capable of simultaneous nitrification and denitrificaiton (SND) in a single reactor.1.Analysis of dissolved oxygen (DO) profile in biofilmsDO profile in biofilms of several thicknesses was investigated using an oxygen microelectrode. From this experiment, a large anaerobic zone was observed at the bottom of the thick biofilm. This result clearly indicated the possibility that quite different microenvironment is created in a same biofilm, allowing for SND.2.Feasibility of SND using the MABRFeasibility of SND on the MABR for treatment of domestic wastewater was conducted for 150 days. After 50 day, removal efficiencies of organic carbon and nitrogen were more than 90%, which indicates that SND can be accomplished using the MABR.3.Application of the MABR to livestock wastewaterThe removal characteristics from livestock wastewater were investigated for 1 year. Average removal efficiencies of organic carbon and nitrogen were 96% and 83% at removal rates of 5.76 g-C/(m^2・day) and 4.48 g-N/(m^2・day), respectively. The combination of the in situ detection of specific bacteria and determination of the DO microprofiles made it possible to prove the mechanism of SND and the microbial ecology in the biofilm. Furthermore, nitrogen removal not via nitrate but nitrite was mainly achieved in the MABR system. The MABR takes advantage of the easy control of oxygen mass transfer, and thus it is useful when removing nitrogen from low carbon/nitrogen-ratio wastewater such as livestock.