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.