Tunnel sewage treatment system and method

The invention discloses a tunnel sewage treatment system. Comprising a horizontal flow type desilting basin used for carrying out preliminary sand removal on tunnel construction sewage, an efficient sedimentation basin used for carrying out further sand removal on a water body subjected to preliminary sand removal, quartz sand used for carrying out deep filtration on the water body subjected to further sand removal, an activated carbon filter and a recycling water tank used for collecting the water body subjected to deep filtration, the sludge concentration tank is used for performing concentration treatment on mud and sand generated by the horizontal flow type grit chamber and the efficient sedimentation tank; and the plate-and-frame filter press is used for performing compaction and solid-liquid separation on the mud and sand subjected to concentration treatment. According to the tunnel sewage treatment system, through layer-by-layer progressive arrangement of the horizontal flow type grit chamber, the effi