Raw sludge (raw sludge): Primary precipitated sludge without sludge treatment.
Secondary sedimentation of excess sludge or mixed sludge of both.
Primary sedimentation sludge (primary sludge): sediment discharged from the primary sedimentation tank.
The sediment discharged from the secondary sedimentation tank (or sedimentation zone) by the secondary sedimentation sludge (secondey sludge):.
Flocs containing various aerobic microbial populations are propagated in activated sludge (activated sludge): aeration tank.
Digested sludge (digested sludge): after aerobic or anaerobic digestion of sludge, the concentration of organic matter decreased to a certain extent, and tended to be stable.
The reflux sludge (returned sludge): is separated from the secondary precipitation (or sedimentation zone) and returned to the activated sludge in the aeration tank.
Excess sludge (excess activated sludge): activated sludge system discharges activated sludge from the secondary sedimentation tank (or sedimentation area).
Sludge gas (sludge gas): is the gas produced by the decomposition of sludge during anaerobic digestion, which is mainly composed of methane and carbon dioxide, and a small amount of hydrogen, nitrogen and hydrogen sulfide.
Commonly known as biogas.
