NOVELTY - Combined treatment of pig biogas using BCO-sequencing batch biofilm reactor (SBBR)-batch annealing furnace (BAF)-CW, comrpises (i) adding pig biogas into inflow regulation pool, and performing hydrolytic acidification and precipitation; (ii) performing denitrification reaction, removing organic matter, performing nitrification reaction, and performing denitrification reaction; (iii) performing anoxic-aerobic-precipitation process; (iv) perform gin reverse flushing; (v) subjecting the waste water to physical, biological and depth treatment of chemical; and (vi) precipitating.    USE - The method is useful in the combined treatment of pig biogas using BCO-SBBR-BAF-CW (claimed).    ADVANTAGE - The method has simple operation procedure, and occupies small working space; and is economical.    DETAILED DESCRIPTION - Combined treatment of pig biogas using BCO-sequencing batch biofilm reactor (SBBR)-batch annealing furnace (BAF)-CW, comrpises (i) adding pig biogas through a pipe network from an inflow regulation pool, and performing hydrolytic acidification and precipitation, and removing a portion of organic matter and suspended solids in the waste water; (ii) pumping the waste water by lifting to an denitrification zone of a BCO tank which is free from an aeration area, performing denitrification reaction of the waste water by using a carbon source, removing the organic matter by flowing into an nitrification zone, and simultaneously performing nitrification reaction, and supplying a substrate into the denitrification zone, and performing denitrification reaction in the denitrification area under low aeration effect; (iii) allowing the weir overflowing waste water into a SBBR tank, subjecting to anoxic-aerobic-precipitation process, and allowing the waste water to slow into the middle of the tank, so as to ensure the continuity of subsequent processing; (iv) removing ammonia nitrogen in the waste water by feeding into a BAF pool, and periodically carrying out reverse flushing, and allowing the reverse flushed waste water to flow into a regulating tank; (v) feeding the flowing BAF water into artificial wetlands, constructing artificial wetland into 3 levels, where the first level is a surface flow artificial wetland, and the second and third level is artificial wetland, and subjecting the waste water to physical, biological and depth treatment of chemical and other effects in the artificial wetland, and finally discharging; and (vi) allowing the waste water to flow from biological contact oxidation pool onto a biofilm of the SBBR tank, and carrying out precipitation in a precipitation phase, and drying the residual sludge discharged on a sludge drying bed, and transferring the supernatant into the regulating tank.