The invention discloses a three-stage
sewage treatment system of a
constructed wetland. The
system comprises a mud scraping vehicle, a water inlet, a mudapron, a mud outlet, a mud scraping board, an
active filter screen, a
sedimentation tank, an anaerobic
pool, a
turbine exhaust fan, air holes, an
aeration tank, a ventilating hole, a control valve, a first gravel packing layer, a mud-free coarse sand
coating layer, a second gravel packing layer, a filter gravel packing layer,
water seepage holes, a water outlet
pipe, a sealing cover and a sliding rail. The three-stage
sewage treatment system has the beneficial effects that the mud scraping vehicle and the scraping board effectively remove
sludge and other
solid impurities so as to prevent the
sludge and the other
solid impurities from blocking a running track, and prevent the
system from collapsing; the
active filter screen effectively adsorbs fine particles in the
sewage, and thoroughly performs
solid-liquid separation; the air holesguarantee the low-
oxygen environment of the anaerobic
pool, and enables the
oxygen inside the anaerobic
pool to be conveniently and quickly extracted, thus increasing the working efficiency; the control valve facilitates the control of the speed and flow volume of
water flow, and effectively prevents the hand from slipping during rotation; the filter gravel packing layer enables the treated sewageto be unblocked.