The utility model discloses a multi-stage
sewage treatment tank which comprises a main tank, a first-stage
enclosure and a second-stage
enclosure, an inner tank cavity and a plurality of sub tank cavities are separated, a
sewage one-way circulation structure is arranged among the sub tank cavities, the first-end sub tank cavity is connected with a
sewage inlet
pipe, the
tail-end sub tank cavity is connected with the inner tank cavity through a standby pumping pipeline, and the inner tank cavity is connected with a
purified water outlet
pipe. The sub-tank cavity at least comprises a primary
sedimentation tank, an
aerobic reaction tank and the like, and the inner tank cavity is provided with a deep treatment tank. The secondary
sedimentation tank is provided with a
sludge hopper, the aerobic and anoxic reaction tanks are provided with stirring devices, and the aerobic tank is provided with an
aeration device. The main body
pool can be rectangular or annular, and the inner
pool cavity is consistent with the main body
pool in shape and is reduced in equal proportion. The
sewage treatment tank is small in occupied area, compact in structure, convenient to maintain, capable of achieving sewage staged treatment and efficiently removing
organic matter,
suspended solids and
nitrogen and
phosphorus nutrient substances, capable of meeting the high requirement standard, convenient to configure an
automatic control system and accurately controlling the treatment process, suitable for different
sewage treatment requirements, especially suitable for urban
sewage treatment, and wide in application prospect.