The invention discloses a
sewage treatment system comprising a treatment
tower body, a muddy water outlet, a muddy water outlet, a muddy water inlet, a
clean water outlet and a
biogas outlet, wherein an anaerobic
fluidized bed reaction zone, a
sludge settling zone and a membrane separation zone are sequentially defined in the treatment
tower body from bottom to top; carrier particles attached with
anaerobic microorganisms are contained in the anaerobic
fluidized bed reaction zone which is provided with a vertical flow guide cylinder; a
solid-liquid separator is arranged at the upper end of the flow guide cylinder; the membrane separation zone is provided with a rotary membrane component; the
sewage inlet is formed in the lower part positioned on the side wall of the anaerobic
fluidized bed reaction zone; the muddy water outlet is formed in the upper part positioned on the side wall of the anaerobic fluidized
bed reaction zone; the muddy water inlet is formed in the lower part positioned on the side wall of the anaerobic fluidized
bed reaction zone and is communicated with the flow guide cylinder; the
clean water outlet is formed in a side wall positioned in the membrane separation zone; and the
biogas outlet is formed in the top part positioned in the membrane separation zone. The
system not only can realize purification of
sewage but also can generate a lot of high-caloric-value
biogas, and is compact in structure and low in running cost.