Tower earthworm ecological filter tank system

Disclosed is a tower earthworm bio-filter system, which is composed of a hydrolysis acidification tank and a multi-stage tower earthworm bio-filter. The hydrolysis acidification tank is a buried tank, the tower earthworm bio-filter employs modes of a modular structure, a gradient tower layer design and multistage units in series connection, and tower layers employ mode combination of a stair type or a rotary type. Inner water distributors are additionally arranged inside an earthworm bed for uniformly distributing water. The drop-aeration technique and the water spray technique are employed to increase the concentration of dissolved oxygen in sewage. The tower earthworm bio-filter system can effectively increase impact load to the sewage, and the surface hydraulic load can reach up to 1m3/ (m2,d). Capability of denitrification and dephosphorization of the system can be largely increased, total nitrogen removal efficiency of the system can be higher than 80% as tested, the total phosphorous removal efficiency can be more than 90%, and discharged water can meet the qualifications of GB8978-1996 national sewage discharge standard. The system is low in project and operation costs and less in accommodation area, can realize automatically controlling of operation, and is adaptable to domestic sewage treatment of relatively concentrated discharge at towns and villages and scenic spots.