As aeration equipment, roots blower has such advantages: air pressure (0.1kgf/cm2~2.0kgf/cm2), high air output (0.8~450m3/min), longer service time (more than 5 years) and lower noise (with suction silencer and export muffler). Roots blower is generally used together with a nanotube in a bottom aeration system; this aeration system has 3~4 levels: root blower, main air pipe, side tube, soft air tube, nanotube coil, it can quickly improve the DO level of bottom water, and is an energy-saving way of aeration.