NOVELTY - A cellulosic ethanol production wastewater recycling system comprises wastewater collection regulating module, wastewater fermentation module, and recycling module in which wastewater collection regulating module comprises water collecting tank (1) connected to cellulosic ethanol production system and regulating tank (2) connected to water collecting tank, wastewater fermentation module comprises 1st stage biogas fermentation cylinder (4), 2nd stage biogas fermentation cylinder (6), and biogas cabinet (5), and 1st stage biogas fermentation cylinder is connected to regulating tank.    USE - A cellulosic ethanol production wastewater recycling system (claimed).    ADVANTAGE - Cellulosic ethanol production wastewater recycling system improves cellulosic ethanol production wastewater recycling rate, reduces freshwater resource consumption, and has high CODSUBSCRIPTCr removal rate, organic matter removal rate, and biogas production and low energy consumption and operating cost.    DETAILED DESCRIPTION - A cellulosic ethanol production wastewater recycling system comprises wastewater collection regulating module, wastewater fermentation module, and recycling module in which wastewater collection regulating module comprises water collecting tank (1) connected to cellulosic ethanol production system and regulating tank (2) connected to water collecting tank, wastewater fermentation module comprises 1st stage biogas fermentation cylinder (4), 2nd stage biogas fermentation cylinder (6), and biogas cabinet (5), 1st stage biogas fermentation cylinder is connected to regulating tank, biogas cabinet is connected to 1st and 2nd biogas fermentation cylinders, and recycling module comprises biogas utilization module connected to biogas cabinet and biogas fermentation effluent utilization module connected to 2nd stage biogas fermentation cylinder. An INDEPENDENT CLAIM is included for recycling of cellulosic ethanol production wastewater which involves pooling cellulosic ethanol production wastewater in water collecting tank, sending to regulating tank, controlling 1st stage biogas fermentation cylinder effluent:production wastewater reflux ratio at 1:3-3.5 to adjust wastewater temperature to 55-60 degrees C and pH to 5-6, sending to 1st stage biogas fermentation cylinder, performing thermophilic anaerobic fermentation with volume load of 15-20 kgCODSUBSCRIPTCr/m3.d to convert 80-85% of organic matter into biogas, reduce chemical oxygen demand (COD)SUBSCRIPTCr content to 8000-12000 mg/L, and obtain effluent with temperature of 40-50 degrees C and pH of 6.5-7.5, returning part of effluent using reflux mechanism (3) to regulating tank, sending remaining effluent to 2nd stage biogas fermentation cylinder, performing mesophilic anaerobic fermentation at 35-40 degrees C with pH of 6.5-7.5 to reduce organic matter content to 2-5% and CODSUBSCRIPTCr content to 800-2000 mg/L, sending biogas produced in 1st and 2nd stage fermentation cylinder, sending biogas in biogas cabinet to biogas utilization module, performing power generation or combustion, returning 2/3 of 2nd stage biogas fermentation cylinder effluent to cellulosic ethanol production with cellulosic ethanol production wastewater reuse rate of 66.7%, sequentially sending remaining 1/3 of 2nd stage biogas fermentation cylinder effluent to aerobic tank (7), secondary sedimentation tank (8), membrane bioreactor (MBR) reaction tank (10), and reverse osmosis (RO) membrane (11), processing to irrigation standard, and using as irrigation water.    DESCRIPTION OF DRAWING(S) - The drawing shows a process flowchart of cellulosic ethanol production wastewater recycling system. (Drawing includes non-English language text).    Water collecting tank (1)    Regulating tank (2)    Reflux mechanism (3)    1st stage fermentation cylinder (4)    Biogas cabinet (5)    2nd stage fermentation cylinder (6)    Aerobic tank (7)    Secondary sedimentation tank (8)    MBR reaction tank (10)    RO membrane (11)