Two-stage biological sewage treatment process and apparatus for making the same

摘要

In the present invention there is disclosed two-stage biological sewage treatment process using fluidized activated sludge. The process is characterized in that sewage is supplied into an equalizing tank and during filling a reactor, sewage is subsequently pumped by a crude water pump into a reactor for additional treatment. During filling from the minimum to the maximum level, the reactor is aerated, whereby the equalizing tank is aerated during the emptying phase of the reactor from the maximum to the minimum level. Claimed is also a two-stage biological sewage treatment plant using fluidized activated sludge wherein the plant comprises an equalizing tank /1/ with sewage inlet /3/ and an excessive sludge pump /12/, a maximum and minimum level float switch /26/, a purified water pump /13/, an aeration device /11/, a float change-over switch /7/ maintaining a hold mode in the tank /1/ for blocking the purified water pump /13/, wherein in the reactor /2/ there is situated at the level between the maximum and minimum levels a float change-over switch /4/ of the purified water pump /13/.