NOVELTY - Digested sludge, oxygen tank sludge and high-concentration organic wastewater are mixed in the ratio of 1:0.2-0.5:10-15, and 200 mg/L sulfate, 10 mg/L chromium(VI) ion and 56 mg/L iron(III) ion are added. The obtained mixture is placed in a digestion reactor, stirred uniformly, and digested. 1/2-2/3 Digestive liquid is discharged into sedimentation tank, maintained for 30 minutes, and precipitated sludge is discharged. The precipitated sludge and chromium(IV)-containing waste are mixed, maintained for 1 day, and waste is restored.    USE - Restoration of chromium(IV)-contaminated waste (claimed) e.g. soil.    ADVANTAGE - The chromium(IV)-contaminated waste is efficiently and quickly restored.    DETAILED DESCRIPTION - Digested sludge, oxygen tank sludge and high-concentration organic wastewater are mixed in the ratio of 1:0.2-0.5:10-15, and 200 mg/L sulfate, 10 mg/L chromium(VI) ion and 56 mg/L iron(III) ion are added. The obtained mixture is placed in a digestion reactor, stirred uniformly, and digested for 2-3 days. 1/2-2/3 Digestive liquid is discharged into a sedimentation tank, maintained for 30 minutes, and precipitated sludge is discharged. The precipitated sludge and high-concentration organic wastewater are mixed in the ratio of 1:10-15, and 300 mg/L sulfate, 20 mg/L chromium(VI) ion and 10 mg/L iron(III) ion are added. The obtained mixture is placed in a digestion reactor, stirred uniformly, and digested for 2-3 days. 1/2-2/3 Digestive liquid is discharged into a sedimentation tank, maintained for 30 minutes, and precipitated sludge is discharged. The above process is repeated 4-8 times by increasing the concentration of sulfate, chromium(VI) ion and iron(III) ion to 3000 mg/L, 200 mg/L and 100 mg/L, respectively. The obtained precipitated sludge and high-concentration organic wastewater are mixed in the ratio of 1:10-15, mixed solution is added to the digestion reactor, and digested for 2-3 days. 1/2-2/3 Digestive liquid is discharged into a sedimentation tank, maintained for 10-30 minutes, and precipitated sludge is discharged. The precipitated sludge and chromium(IV)-containing waste are mixed in the ratio of 1:10, maintained for 1 day, and waste is restored. The restored waste satisfies the emission standard HJ/T301-2007.