NOVELTY - Treating acid mine waste water with sulfate, by transferring supernatant which is fermented by acid from acid mine waste water and sludge in sewage factory into sulfate biological reducing reactor, reducing sulfate bivalent ion by SRB, refluxing by part yielding water of reactor, transferring yielded water into biological oxidation reactor, oxidizing hydrogen sulfide, passing water through slow sand filter, filtering and discharging biological treated water, dissolving elemental sulfur of sand filter material, separating sulfur by device, drying and recovering sulfur.    USE - The biological technology is useful for treating acid mine waste water with sulfate (claimed).    ADVANTAGE - The method enables to treat acid mine waste water with sulfate, recover elemental sulfur, and makes the sludge of sewage treatment factory be reused and recycled.    DETAILED DESCRIPTION - A biological technology for treating acid mine waste water with sulfate, where the technology is a carbon source technology for treating acid mine waste water with sulfate and recovering elemental sulfur by taking the sludge acid fermentation of sewage factory as sulfate reducing bacteria, involves initially transferring the supernatant which is fermented by acid from acid mine waste water and sludge in sewage factory into sulfate biological reducing reactor, reducing the sulfate bivalent ion to be hydrogen sulfide or sulfur bivalent ion by sulfate reducing bacteria (SRB), refluxing by part yielding water of reactor, then transferring the processing yielding water of reactor into hydrogen sulfide or sulfur bivalent ion biological oxidation reactor, oxidizing hydrogen sulfide or sulfur bivalent ion biologic to be elemental sulfur by colorless sulfur bacteria (CSB), then passing the yielding water with elemental sulfur through the slow sand filter, filtering, striking off and trapping the elemental sulfur and discharging the biological treatment yielding water, then dissolving elemental sulfur of sand filter material by extraction device, separating extracting agent, sand, filter material and bio-membrane by solid-liquid separation device, separating out elemental sulfur from solution which is distilled and extracted by the distillation device, finally drying by drying device, recovering elemental sulfur, mainly involves (I) reducing the sulfate bivalent ion to be hydrogen sulfide or sulfur bivalent ion by SRB, (i) finishing the sulfate biological reducing technology in anaerobic biological reactor, (ii) the dominating strain of reactor is SRB, the sulfate biologic is reduced to be hydrogen sulfide or sulfur bivalent ion by SRB, (iii) using the sludge acid fermentation of sewage factory as carbon source, controlling the addition of sludge acid fermenting liquid in waste water according to the ratio of COD/sulfate (COD/SO4) bivalent ion in mixed liquid, the controlling range of COD/SO4 bivalent ion is 0.9-1.5, (iv) the load of sulfate is 1.0-0.7 kg sulfate bivalent ion/m3.d, temperature is 20-35 degrees C, pH value of yielding water is 3.5-6.5, ascending velocity of anaerobic expansion grain sludge bed reactor (EGSB) is 3.0-6.0 m/hour, reflux ratio is 80:1-200:1, hydraulic power stay time (HRT) is 0.2-0.85 d, reflux ratio of upflow anaerobic filter (AF) is 20:1-60:1, HRT is 0.25-1.25 d, HRT of anaerobic baffling board reactor ABR is 0.2-1.0 d, HRT of anaerobic fluid-bed reactor AFBR is 0.02-0.3 d; (II) (a) oxidizing the hydrogen sulfide or sulfur bivalent ion biologic to be elemental sulfur by CSB carrying out the hydrogen sulfide or sulfur bivalent ion biological oxidation technology in the aerobic bio-membrane reactor, (b) the dominating strain of reactor (3) is CSB, the sulfate biologic is reduced to be hydrogen sulfide or sulfur bivalent ion by CSB, (c) the yielding value is 6.5-8.0, the temperature is 15-25 degrees C, controlling the load of sulfide and concentration of dissolved oxygen (DO), making the hydrogen sulfide or sulfur bivalent ion biological oxidation products be elemental sulfur, the concentration of dissolved oxygen DO increases along with the increase of load of sulfide, (d) assuring the load of sulfide and concentration of dissolved oxygen in CSB aerobic biologic reactor of fillers with different types by experiment; (III) (i) using slow sand filter to trapping elemental sulfur filtering, using slow sand filter to filtrate yielding water of CSB biological oxidation hydrogen sulfide, trapping the element sulfur in water and released bio-membrane on surface of filter bed, reaching to solid-liquid separation, the filtering speed of slow sand filter is 0.1-0.3m/hour, particle diameter of sand filter layer is 0.5-1.2 mm, thickness is 25 cm, the particle diameters of sand grain of supporting layer are 5.0-10.0 mm, 2.5-5.0 mm and 1.2-2.5 mm from up to the end, height of every layer is 3 cm, trapping the elemental sulfur and released bio-membrane into the sand layer with 5-6 cm on surface layer of slow sand filter, and (ii) striking off, striking off sand layer with sulfur with 5-6cm thickness on surface layer of sand filter material; (IV) recovering elemental sulfur (a') extracting, taking carbon disulfide disulphide (CS2) as extracting agent, making the strake sand filter material contact with the extracting agent CS2 solution by extraction device, dissolving elemental sulfur grain by CS2 adequately, (b') separating, using solid-liquid separation device, separating extracting agent CS2 which dissolves the elemental sulfur from sand filter material and bio-membrane by gravity sediment separation, centrifugal separation or filter separation operation, (c') distilling, the temperature is 48-55 degrees C, using distillation device to distil and separate out elemental sulfur, using extracting agent CS2 repeatedly, (d') drying, the temperature is 165-175 degrees C, using drying device to dry the separated elemental sulfur for 1-2 hours, recovering the elemental sulfur.