Operation And Regulation Of A New Fluidized-pellet-bed Bioreactor

Owing to the construction of sewage treatment plants, more and more wastewateris collected and treated. But the disadvantage of centralized sewage treatment systemhas appeared, for example, it has a large floor area, a large investment for the sewagepipe network and is helpless for the wastewater which can not be collected. So moreattention has been payed to the decentralized sewage treatment system and more studyhas been done. And the fluidized pellet bed （FPB） is a good example.This fluidized pellet bed （FPB） have some improvements:1. A larger outer columntwice as big as the inner column is set for the activity regeneration of granule sludge.2.A waste sludge column is fixed to the system wich has a little influence to thesuspended blanket of high volumetric concentration.3. The agitator is helix agitatorinstead of the paddle agitator, which has a good mixer performance for the suspendedblanket.4. The structure has been well optimized, which is compact and small floor area.This process is phy-chemistry and bio-chemistry combination process which combinesthe traditional fluidized pellet bed with the activated sludge system. It is a short process,that can reach the biological degradation and solid/liquid separation at the same time.By the experiment the best operation condition has been made:[PAC]=60～80mg/L,[PAM]=4～6mg/L, ω=6r/min,Qmax=5m³/h. The mixed liquor suspended solids（MLSS） of the outer column is2400～3300mg/L. And the sludge volume index （SVI）=50～70. The dissolved oxygen （DO） is reach the saturation point. There is a declinetendency of the DO along the height of inner column. And there exists a largemicroorganism. The experimental results show that the reactor have a good performance onremoving SS, chroma, COD, NH₃-N, TN, TP, that the average removal efficiency is90%,97%,90%,87%,44.9%and87%respectively. And all the items can reach the Bstandard （GB18918-2002）.