Device and method for treating sewage by utilizing spare ditches and fields

The invention provides a device and method for treating sewage by utilizing spare ditches and fields. The device comprises a ditch-type sewage treatment integral device and an enhanced wet land, wherein the ditch type sewage treatment integral device comprises a baffled anoxic/anaerobic reaction region, a circulating aeration region, a precipitate separation region, a clear water region, a solar and wind energy power generation system and a sludge concentration system; the baffled anoxic/anaerobic reaction region comprises an facultative section, an anoxic section and an anaerobic section which are separated by a water retaining wall and a baffle wall; the circulating aeration region is located in the middle of the ditch-type sewage treatment integral device, and comprises an isolating wall, an inverted umbrella surface aerator, a blast aeration system, suspension packing, an overflow wall and an intercepting grid; the precipitate separation region is located on the downstream of the circulating aeration region, and is connected with the overflow wall of the circulating aeration region; the sludge concentration system comprises a sludge concentration tank, a sludge pump and a sludge discharge pipe; the enhanced wet land has a trapezoidal pool-shaped structure, and sequentially comprises an anti-seepage layer, a gravel blanket layer, a filter layer and a soil layer from bottom to top.