TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The water outlet of a sequencing batch type ASB reactor is arranged below an air chamber, utilizing interval sequencing batch type water-inlet method, draining water after sedimentation and depositing the digested solution, the two-stage aerobic SBBR fix film by combining filler, a primary SBBR utilizes activated sludge in city sewage processing factory to process cultivation and a second SBBR removes 3? of denitrifier, which is composed by strains of H9 (CCMCC-1010), H10 (CCMCC-1011), H13 (CCMCC-1006) according to the volume ratio of H9:H10:H13 is 1:1:0.5, and placing the flocculant (800-1000 mg/l) mixed by poly-ferric sulfate and ferric chloride heptahydrate according to weight ratio of 3:2 in the flocculation sedimentation, and stirring for 4-6 minutes and boiling. The method for processing ethanol waste water of sweet potato fuel comprises: (i) entering a reactor of mature granular sludge from the bottom of a sequencing batch type ASB reactor after adjusting pH of the ethanol waste water of sweet potato fuel to 6-6.8, digesting and producing methane at intermediate temperature of 32-38 degrees C, operating for 4 cycles everyday, hydraulic retention time (HRT) of 25-30 hours, where the volume load of the reactor is 28.86-34.5 kg of chemical oxygen demand (COD)/m3x d, the COD removal rate is 92-93%, the methane producing quantity is more than 0.55 m3/kg chemical oxygen demand, the granular sludge are black, the surface is smooth and shiny, good sedimentation properties, which is not influenced by suspended solids (SS) concentration changing in a range of 8370-11400 mg/l and the SS removal rate is more than 90.7; (ii) mixing supernatant and low pollution waste water at a ratio of 1:1 after boiling and depositing the digested solution in the step (1), adjusting the COD to 1240-1790 mg/l, pumping primary SBBR, which has fixed bio-film and processed cultivation, maintaining 1-2 mg/l of dissolved oxygen (DO) at 12-30 degrees C, aerating for 9-11 hours, where the COD removal rate is more than 75%, using activated sludge of city sewage factory as inoculum by the primary SBBR, where the concentration of inoculated sludge is 1g/l, flowing water is 500 mg/l COD in initial stage of cultivation, then increasing gradually the in-fluent concentration of water, and forming bio-film by microbial culture after 45 days; (iii) entering directly the outlet water of the primary SBBR in the step (ii) in a secondary SBBR reactor of 3? of denitrifier bio-film culture, which is composed by strains in a ratio of H9:H10:H13 is 1:1:0.5, maintaining DO for 2.5-3.5 mg/l at 12-30 degrees C, aerating for 3-5 hours, reducing outlet water ammonia nitrogen (NH3-N) less than 15 mg/l, and reducing COD less than 300 mg/l; and (iv) conveying the outlet water of the secondary SBBR in the step (iii) into a flocculation sedimentation tank, after decolorizing by 800-1000 mg/l of flocculant mixed by poly-ferric sulfate and ferric chloride heptahydrate according to weight ratio of 3:2, and removing the organic matter and phosphorus, where the outlet water can reach primary emission standard of integrated waste water discharge standard GB8978-1966.