The invention is a composite 
bioreactor for treating high-concentration 
refractory wastewater, which consists of three parts: an immobilized 
biological reaction area, a comprehensive degradation area and a 
precipitation area.  There are 
engineering bacteria in the immobilized 
biological reaction area. There are water inlet, air inlet and mud 
discharge outlet at the bottom, and exhaust holes at the top. The air inlet is connected with the air inlet 
pipe and the 
aeration head.  There are multiple diversion holes, and the diversion holes are connected to the comprehensive degradation area; there are mixed 
bacteria in the comprehensive degradation area, the interior is filled with fillers, the bottom is equipped with 
aeration strips, and the middle part of the outer wall is equipped with multiple liquid diversion grooves.  The lower part of the flow tank has a ring-shaped bubble barrier, and the bottom is equipped with multiple 
sludge return channels. Both the liquid diversion channel and the 
sludge return channel are connected to the 
sedimentation area; the upper part of the 
sedimentation area is provided with a drainage port, and the bottom is provided with a 
sludge discharge port.  The invention effectively treats the waste water through the compound action of the 
engineering bacteria and the mixed bacteria.  The reactor of the invention has compact structure, can greatly reduce the 
dilution ratio of waste water, has small volume and low cost.